Process Design Report (Revision 02)

Project: “Mainstreaming Climate Change Adaptation through Water Resource Management in Leather Industrial Zone Development” (GEF ID 5666; SAP ID 150052)

“Common Effluent Treatment Plant for Sialkot Tannery Zone”

March, 2018

Process Design Report

(Revision 02)

APPENDIX 1 - ANNEX 1

Project:

“Mainstreaming Climate Change Adaptation through Water Resource Management in Leather Industrial Zone Development”

(GEF ID 5666; SAP ID 150052)

Common Effluent Treatment Plant

For

Sialkot Tannery Zone

Process Design Report (Revision 02)

March, 2018

A project of:

United Nations Industrial Development Organization (UNIDO)

http://www.unido.org/


Common Effluent Treatment Plant for Sialkot Tannery Zone

I

CONTENTS

LIST OF ANNEXURES .........................................................................................................................II

LIST OF TABLES ............................................................................................................................... III

LIST OF FIGURES ............................................................................................................................. IV

ACRONYMS ..................................................................................................................................... V

SALIENT FEATURES ........................................................................................................................ VII

1.1 GENERAL .............................................................................................................................. 1

1.2 TREATMENT CONCEPT ......................................................................................................... 2

1.3 THIS REPORT ........................................................................................................................ 2

CHAPTER 2: REVIEW OF AVAILABLE DATA ...................................................................................... 3

2.1 STZ PRODUCTION DATA ....................................................................................................... 3

CHAPTER – 3: INFLUENT AND EFFLUENT ........................................................................................ 6

3.1 WASTEWATER QUANTITY AND CHARACTERISTICS ............................................................. 6

3.2 REVISED WASTEWATER DESIGN DATA ................................................................................ 9

3.3 EFFLUENT REQUIREMENTS ................................................................................................ 12

CHAPTER 4: ALTERNATIVES ANALYSIS .......................................................................................... 13

4.1 SEGREGATION OF WASTEWATER CONVEYANCE SYSTEM ................................................. 13

4.2 OPTIMUM MODULAR APPROACH ..................................................................................... 13

4.3 TREATMENT TECHNOLOGY ................................................................................................ 14

4.3.1 Treatment System Objectives ........................................................................................ 14

4.3.2 General Selection Criteria for Wastewater Treatment System ..................................... 14

4.3.3 Treatment System Requirements for CETP .................................................................... 15

4.3.4 Evaluation of Alternate Preliminary Treatment Processes ............................................ 16

4.3.5 Evaluation of Alternate Primary Treatment Processes .................................................. 18

4.3.6 Evaluation of Alternate Biological Treatment Processes ............................................... 19

4.3.7 Comparative Analysis of Alternate Treatment Processes .............................................. 22

4.3.8 Comparative Analysis of Alternate Treatment Technologies in Combinations ............. 24

4.3.9 Evaluation of Alternate for Aeration System and Sludge Dewatering........................... 27

4.4 KEY TREATMENT SYSTEM COMPONENTS AND FACILITIES ................................................ 27

CHAPTER 5: DESIGN OF WATER LINE ............................................................................................ 29

5.1 BAR RACK FOR ULTIMATE FLOW ....................................................................................... 30

5.2 FINE SCREENS ..................................................................................................................... 31

5.3 VORTEX TYPE GRIT CHAMBER............................................................................................ 32

5.4 OIL & GREASE SEPARATOR ................................................................................................. 33



II

5.5 EQUALIZATION TANK # 1 WITH SULPHIDE CATALYTIC OXIDATION – BEAM HOUSE

EFFLUENT ...................................................................................................................................... 33

5.6 EQUALIZATION TANK # 2 – TANNING & POST TANNING EFFLUENT ................................. 35

5.7 COAGULATION AND FLOCCULATION ................................................................................. 35

5.8 PRIMARY SEDIMENTATION TANK ...................................................................................... 36

5.9 AERATION TANK ................................................................................................................. 38

5.10 SECONDARY SEDIMENTATION TANK ................................................................................. 42

5.11 ADVANCED CHEMICAL OXIDATION ................................................................................... 43

CHAPTER 06: TERTIARY TREATMENT ............................................................................................ 45

6.1 RAPID SAND FILTERS .......................................................................................................... 46

6.2 LOW PRESSURE MEMBRANE TREATMENT ........................................................................ 47

6.3 LOW PRESSURE VACUUM EVAPORATION ......................................................................... 49

CHAPTER 7: DESIGN OF SLUDGE LINE ........................................................................................... 50

7.1 COMBINED SLUDGE THICKENERS ...................................................................................... 50

7.2 SLUDGE DEWATERING ....................................................................................................... 51

7.3 SLUDGE DISPOSAL .............................................................................................................. 52

CHAPTER 08: PRELIMINARY PROJECT COST .................................................................................. 53

8.1 CAPITAL COST ..................................................................................................................... 53

8.2 OPERATION AND MAINTENANCE COST ............................................................................. 53

8.3 COST ESTIMATE FOR TERTIARY TREATMENT ..................................................................... 54

CHAPTER 09: HUMAN RESOURCE REQUIREMENTS FOR OPERATION AND MAINTENANCE ........ 55

9.1 PLANT OPERATING HOURS ................................................................................................ 55

9.2 SHIFT TAKE OVER PROTOCOL ............................................................................................ 55

9.3 STAFF TRAINING ................................................................................................................. 56

LIST OF ANNEXURES

Annexure I: “Basic Information and Guidelines for Segregation of Streams in Sialkot Tannery

Zone” ........................................................................................................................................ 58

Annexure II: UNIDO Documents .............................................................................................. 70

Annexure III: Drawings ............................................................................................................. 74

Annexure IV: Punjab Environmental Quality Standards for Municipal and Liquid Industrial

Effluents ................................................................................................................................... 78

Annexure V: Schedule of Plant ................................................................................................ 82

Annexure VI: Motor List ........................................................................................................... 98



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LIST OF TABLES

Table 1: Number and Type of Tanneries to be established in STZ ............................................ 3

Table 2: Area Allocated for Amenities ....................................................................................... 5

Table 3: Planned Production Capacity for STZ ........................................................................... 5

Table 4: Calculated Wastewater Quantity, Pollution Load and concentration based on

maximum production capacities and emission factors ............................................................. 7

Table 5: Average Concentrations of Tannery Wastewater computed using Emission Factors . 8

Table 6: Concentrations of tannery wastewater, domestic sewer and combined effluent ...... 8

Table 7: Adopted Design Values for CETP .................................................................................. 9

Table 8: Average Values of Pollution Load Discharged (Conventional Process) - UNIDO ....... 10

Table 9: Concentration Estimation based on Loads per Ton of Production – Phase I ............ 11

Table 10: New Estimated and Adopted Raw Effluent Design Data – Phase I .......................... 11

Table 11: Summary of Key Parameters; Punjab Environmental Quality Standards (PEQS) -

2016 ......................................................................................................................................... 12

Table 12: Treated Effluent Requirements ............................................................................... 14

Table 13: Screening of Preliminary Treatment Technologies: Screen ..................................... 16

Table 14: Screening of Preliminary Treatment Technologies: Grit Chamber .......................... 17

Table 15: Screening of the Primary Treatment Technologies ................................................. 18

Table 16: Screening on the Basis of Desired BOD Removal Efficiency .................................... 23

Table 17: Screening on the Basis of Ability to Treat High Strength Wastes and Resistance to

Shock Loads .............................................................................................................................. 24

Table 18: Comparative Analysis of Various Treatment Technologies ..................................... 24

Table 19: Comparative Analysis of Aeration System ............................................................... 27

Table 20: Comparative Analysis of Sludge Dewatering ........................................................... 27

Table 21: Summary of Wastewater Design Data for Phase I of STZ ........................................ 29

Table 22: Design Criteria and Unit Dimensions for Bar Rack ................................................... 30

Table 23: Screen Chamber Design Details ............................................................................... 32

Table 24: Design Criteria and Design of Vortex Grit Chamber ................................................ 32

Table 25: Design of Equalization Tank for Beam House Effluent ............................................ 34

Table 26: Design of Equalization Tank for Tanning & Post Tanning Effluent .......................... 35

Table 27: Design of Coagulation Flocculation Unit .................................................................. 35

Table 28: Primary Sedimentation Tank Design ........................................................................ 37

Table 29: Biological Process Parameters adopted for Aeration Tank Design ......................... 38

Table 30: Design Parameters Adopted for Aeration Tank Design ........................................... 39

Table 31: Design Check Parameters ........................................................................................ 39



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Table 32: Design of Aeration Tanks ......................................................................................... 40

Table 33: Pre-selector Design .................................................................................................. 40

Table 34: Design of Aeration System ....................................................................................... 41

Table 35: Design Criteria of Secondary Sedimentation Tank .................................................. 42

Table 36: Design of Secondary Sedimentation Tank ............................................................... 42

Table 37: Chemical Oxidation Tank with Neutralization Tank ................................................. 43

Table 38: Capacities of Tertiary Units ...................................................................................... 45

Table 39: Influent Data and Design Criteria for Rapid Sand Filters ......................................... 46

Table 40: Design of Rapid Sand Filters ..................................................................................... 47

Table 41: Required Quality of Reclaimed Water ..................................................................... 47

Table 42: Energy Consumption, Product Recovery, and Removal Efficiencies of Different

Residual Particulate Matter Removal Operations ................................................................... 48

Table 43: Primary Sludge Thickener (Picket Fence Type) ........................................................ 50

Table 44: Sludge Conditioning Tank and Filter Press ............................................................... 51

Table 45: Landfill Area Requirement for CETP Sludge Disposal .............................................. 52

Table 46: Capital Cost for Single Module of CETP (4,000 m3/day) .......................................... 53

Table 47: Annual Operation and Maintenance Cost ............................................................... 53

Table 48: Unit O&M Cost for Wastewater Treatment............................................................. 54

Table 49: Staffing Requirement & Recommendation .............................................................. 55

LIST OF FIGURES

Figure 1: Layout of Sialkot Tannery Zone .................................................................................. 4

Figure 2: Available Biological Methods for Wastewater Treatment ....................................... 19

Figure 3: Available Combinations of Biological and Physico-chemical Methods for

Wastewater Treatment............................................................................................................ 25

Figure 4: Available Combinations of Biological and Physico-chemical Methods for

Wastewater Treatment; black cross, eliminated option due to non-compliance with effluent

standards; grey cross: eliminated due to too high space requirements. ................................ 26

Figure 5: Simplified Scheme of Treatment Options ................................................................. 26



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ACRONYMS

STZ Sialkot Tannery Zone

STAGL Sialkot Tannery Association (Guarantee) Limited Company

EIA Environmental Impact Assessment

ACO advanced chemical oxidation

BLC-CTPKT British Leather Centre – Clean Technology Program for Korangi Tanneries

CMAS Complete Activated Sludge

UNIDO United Nations Industrial Development Organization

CETP Common Effluent Treatment Plant

HRT Hydraulic Residence Times

PEQS Punjab Environmental Quality Standard

CSA Climate and Social Assessment

TSS Total Suspended Solids

COD Chemical Oxygen Demand

BOD Biochemical Oxygen Demand

Cr Chromium

S2- Sulphide

NH3-N Ammonium Nitrogen

TKN Total Kjeldahl Nitrogen

TN Total Nitrogen

Cl Chloride

SO4 Sulphate

pH Potential of Hydrogen

SS Suspended Solids

UASB Up flow Anaerobic Sludge Bed

RBC Rotating Biological Contactors

RO Reverse Osmoses

MBR Membrane Bioreactor

CEPT Chemically Enhanced Primary Treatment

O&M Operation & Maintenance

RCC Reinforced Cement Concrete

PST Primary Settling Tanks

PE Polyvinyl Ethylene

MLSS Mixed Liquor Suspended Solids




VI

VSS Volatile Suspended Solids

SRT Solids Retention Time

RSF Rapid Sand Filter

F:M Food over Micro Organism Ratio

TDS Total Dissolved Solids



VII

SALIENT FEATURES

Project Name Establishment of Combined Effluent Treatment Plant (CETP) for Sialkot Tannery Zone, Pakistan

Client UNIDO

Location Sialkot Tannery Zone, Airport Road, Sialkot

Type of Wastewater Tannery Wastewater

Quantity of Wastewater Initial Phase: 4,000 m3/day.

Quality of Wastewater BOD5@20oC = 1,600 ppm, COD = 4,400 ppm, TSS = 2,500ppm

Applicable Standards Punjab Environmental Quality Standards - 2016, ‘Inland Water Discharge Limits’

Treatment Technology Activated Sludge Treatment System with Chemically Enhanced Primary Treatment (CEPT)

Key Components Water Line

Prescreen Chamber

Screen Chamber

Detritor Grit Chamber

Equalization Tank with Catalytic Sulphide Oxidation

Coagulation and Flocculation Tank

Primary Sedimentation Tank

Aeration Tank (Activated Sludge Process)

Secondary Sedimentation Tank

Advanced Chemical Oxidation

Final NeutralizationSludge Line

Sludge Thickening

Sludge Conditioning Tank

Sludge Dewatering (Belt-Press Type Sludge Filter)

Area Required Initial Phase requirement is 3.0 acres

Estimated Tentative Capital Cost

PKR 300 Million for initial phase

Tentative Annual Operation and Maintenance Cost

PKR 141.2 Million/year for initial phase + PKR 16.96 Million Annual Depreciation.

Energy Requirement 598 KW for initial phase

1

CHAPTER – 1: INTRODUCTION

1.1 GENERAL

The town of Sialkot is located about 130 km from Lahore, in the province of Punjab. Currently, there are 250 tanneries located in 10 different clusters, scattered all around Sialkot city and suburbs. These scattered tanneries are unable to meet the international standards which are becoming more and more stringent with the passage of time. Meeting the international standards needs proper infrastructure which is not possible to be extended to each tannery in scattered locations all around the city. The foremost and critical requirement for international trade and exporting leather goods is the environmental and social compliance.

Relocation of the tanneries to a more spacious location with appropriate infrastructure for efficient and cost effective treatment of solid and liquid wastes has thus become a prerequisite for survival and growth of this vital export-oriented sector of the country’s economy and for protecting the region’s agriculture and health.

Based on these factors, it is planned to shift the tanneries at a dedicated tannery zone away from the main city. The proposed Sialkot Tannery Zone (STZ) is a project initiated and managed by Sialkot Tannery Association (Guarantee) Limited Company (STAGL). The STAGL has been established as a special initiative of the Sialkot Tannery Association and, Government of Punjab. Sialkot Tannery Association (Guarantee) Limited is registered under section 32 of the Companies Ordinance 1984 (XLVII of 1984) to develop focused industrial growth in Sialkot by developing international standard Tannery Zone in the region. The company is limited by guarantee having share capital.

STZ with an area of 392 Acres will provide a central place for various scattered tannery clusters of Sialkot and the surrounding areas. It shall mitigate the environmental pollution in the city. It will be an international standard industrial zone equipped with all facilities & infrastructure like roads, sewerage, water supply, drainage, effluent treatment plants and others. (Ref: EIA of STZ, 2011)

STAGL is supported by UNIDO, which is working on a GEF funded project entitled: ‘Mainstreaming Climate change Adaptation through Water Resource Management in Leather Industrial Zone Development’, has intended to implement a project of Combined Effluent Treatment Plant (CETP) for the STZ.

A result of these joint efforts was the Technical Report depicting Conceptual Design of the Common Effluent Treatment Plant, prepared by UNIDO in 2015. On the basis of this report, to fulfill the requirements of the project, UNIDO seeks the services of consultants for detailed designing and supervision of the implementation of CETP for STZ.



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1.2 TREATMENT CONCEPT

The concept of the CETP is to have the pre-treated wastewater collected from all the units located within STZ to a common facility for treatment to comply with PEQSs.

1.3 THIS REPORT

In this report a process design for the CETP is presented, based on consideration of both wastewater characteristics, opportunities for cost reduction and design criteria.

In Chapter 2 summary of available data is presented, after which the wastewater data is presented in Chapter 3. In Chapter 4 a brief of various alternatives is discussed. A design, which always should be the logical result from the combination of wastewater characteristics and the design criteria, which themselves are by and large defined by the effluent requirements, follows in Chapter 5 and 6. In chapter 7, tertiary treatment is discussed and chapter 8 and 9 deals with cost estimates and human resource requirements for CETP.

This version of the report is for review and comments on the local and international level. As soon as the process design of CETP concludes, CETP hydraulic profile will be developed on the basis of the definitive process design and accordingly, will be documented as a Chapter in the final report.


CHAPTER 2: REVIEW OF AVAILABLE DATA

The Sialkot Tannery Zone is just initiated and still relocation of tanneries in the zone is yet to get pace. Therefore, data required for CETP design in terms of quality and quantity is to be extracted from Secondary Sources. Basically the planning documents of the proposed zone, Environmental Impact Assessment (EIA - March 2011) of the Sialkot Tannery Zone Project and Climate and Social Assessment Study (CSA – February 2015) are the main documents for development of CETP design data. At the same time, information provided by the Management of Sialkot Tannery Association (February 2017) regarding Size and production of Sialkot Tanneries is used to verify and update the production statistics.

Secondly, the Technical Report prepared by UNIDO (May 2015) addressing the conceptual design of CETP STZ was also used to arrive at a safe conclusion.

Layout of the proposed Sialkot Tannery Zone is shown in Figure-1. A brief of the data is presented in the following sections of the report.

2.1 STZ PRODUCTION DATA

Total area of proposed STZ is 160.175 hectares. As per the latest data of STZ, a total of 554 industrial are planned to be located in the zone. The details are as follows:

Table 1: Number and Type of Tanneries to be established in STZ (Ref: February 16, 2017, STZ Meeting)

# Process No. of

Tanneries

1 Raw to Wet blue or Finish 60

2 Wet blue to Finish 244

3 Wet blue to Crust 150

4 Finish goods factories (leather garments & gloves manufacturers) 100

Total No. of Units 554

The area covered by these Units will be 112 Hectare. Out of 112 Hectares, area reserved for processing units is 83 Hectares. Another 48 Hectares are reserved for various purposes as per following details.




Figure 1: Layout of Sialkot Tannery Zone



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Table 2: Area Allocated for Amenities

# Land use Area (Hectare)

1 Waste Management Facility 13.18

2 Roads 30.44

3 Parks 4.92

Total 48.54

As per surveys carried out in 2000 and accordingly, production planned for STZ in 2014, following production figures were finalized;

Table 3: Planned Production Capacity for STZ

# Process Surveyed in Year 2000 (Kg/day)

Planned for STZ in 2014

(Kg/day)

No. of Units

1 Raw to Finish 88,108 153,626

2 Raw to Wet Blue 7,240 12,624

3 Raw to Crust 20,520 35,779

Subtotal 115,868 202,029 60

4 Wet Blue to Crust 50,079 87,317 150

5 Wet Blue to Finish 48,020 83,727 244

Subtotal 98,099 171,044 394

6 Finish Goods Factories (Leather garments & gloves manufacturers)

100

Total 213,967 373,073 554

The surveyed carried out in Year 2000 among 189 tanneries located in Sialkot showed that about 4.5 tons of Hides/Skins are being processed per hectare of land. The same ratio has been used to finalize the design production of STZ for 83 Hectares allocated to processing tanneries.

The Zone is planned for processing of about 1,400,000 sft per day, although current production in Sialkot is about 700,000 sft/day.

It is estimated in the Master Plan that about 13,500 work-force will be available in the STZ.

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CHAPTER – 3: INFLUENT AND EFFLUENT

3.1 WASTEWATER QUANTITY AND CHARACTERISTICS

Production data, as discussed in chapter 02 is used in estimation of quantity and quality of the effluent to be discharged from STZ. Unit Pollution Loads as provided in following International Documents are used for computations purpose. Data thus generated is compared with other similar cluster data (Korangi tannery cluster) to arrive at a safe conclusion;

1. UNIDO Publication ‘The Scope for Decreasing Pollution Load in Leatherprocessing’ Prepared by j. Ludvik – August 2000,

2. International Environment Commission (IUE-1995), and3. British Leather Centre – Clean Technology Manual – Part B; Tannery Effluent

Treatment and Available Technologies. BLC-CTPKT, 2002.

It shall be noted that all aforesaid references presents unit pollution loads more or less in the same ranges.



7

Table 4: Calculated Wastewater Quantity, Pollution Load and concentration based on maximum production capacities and emission factors

Process

Maximum Production

Capacity (Kg/day)

Wastewater (m3/day)

Pollution Load - Range (Kg/day)

TSS COD BOD Cr S2-

NH3-N TKN Cl SO4 Range Average

Raw to Finish 153,626 5,223 - 8,603 6,913 12,751- 22,890 22,276- 35,488 7,681 - 13,212 461 - 1,075 615 - 1,383 615 - 922 1,782 - 2,750 21,047 31,032 7,989 - 16,899

Raw to Wet Blue 12,624 328 - 505 417 972 - 1,717 1,528 - 2,348 530 - 871 25 - 63 50 - 114 47 - 69 134 - 201 1,666 - 2,424 530 - 1,073

Raw to Crust 35,779 1,181 - 1,896 1,538 2,970 - 5,260 5,188 - 8,086 1,789 - 3,005 107 - 250 143 - 322 143 - 215 415 - 640 4,902 - 7,227 1,861 - 3,936

Subtotal 202,029

Wet blue to Crust 87,317 611 - 1,135 873 87 - 175 873 - 1,048 262 - 437 9 - 35 - 9 - 17 17 - 44 262 - 524 349 - 786

Wet blue to Finish 83,727 670 - 1,340 1,005 84 - 335 837 - 1,005 251 - 419 8 - 33 - 8 - 17 17 - 42 251 - 502 335 - 754

Subtotal 171,044

Total 373,073 8,013 - 13,479 10,746 16,864- 30,376 30,702- 47,974 10,514 -17,944 611 - 1,457 808 - 1,818 821 - 1,240 2,365 - 3,677 28,128- 41,710 11,063- 23,447

Concentrations Range (mg/l) 1,569 - 2,827 2,857 - 4,464 978 - 1,670 57 - 136 75 - 169 76 - 115 220 - 342 2,617 - 3,881 1,030 - 2,182



8

On the basis of these computations, average quantity of wastewater (10,746 m3/day) is multiplied by minimum and maximum pollution loads. An average of both is also depicted in the Table-5.

Table 5: Average Concentrations of Tannery Wastewater computed using Emission Factors

Parameter Tannery Wastewater Concentration

Unit Range Average

Q m3/day 8,013 - 13,479 10,746

pH - 7 - 8 8

Temp °C 30 30

TSS mg/L 1,569 - 2,827 2,198

COD mg/L 2,857 - 4,464 3,661

BOD5@20°C mg/L 978 -1,670 1,324

Cr mg/L 57 - 136 96

S2- mg/L 75 - 169 122

NH3-N mg/L 76 - 342 209

TKN mg/L 220 - 342 281

Cl- mg/L 2,617 - 3,881 3,249

SO4 mg/L 1,030 - 2,182 1,606

Remaining wastewater from commercial and institutional establishments is estimated on the basis of standard value of 75 litres/capita/day. Calculating the quantity for 13,500 work-force it will be about 1,012.5 m3/day. Domestic characteristics are taken as high strength sewer characteristics (Ref: Metcalf and Eddy). Combining the Industrial and domestic wastewater the outcome is presented in the Table-6.

Table 6: Concentrations of tannery wastewater, domestic sewer and combined effluent

Parameter Unit Tannery Wastewater Domestic Sewer Combined Effluent

Q m3/day 10,746 1,012.5 12,000*

pH - 8 7 7 - 8

Temp °C 30 30 30

TSS mg/L 2,198 400 2,043

COD mg/L 3,661 800 3,414

BOD5@20°C mg/L 1,324 350 1,240

Cr mg/L 96 0 88



9

Parameter Unit Tannery Wastewater Domestic Sewer Combined Effluent

S2- mg/L 122 1 112

NH3-N mg/L 209 45 195

TKN mg/L 281 70 263

Cl mg/L 3,249 90 2,977

SO4 mg/L 1,606 50 1,472

Rounded off to 12,000

These values are further compared with the similar cluster’s data obtained from Korangi Tannery Cluster, presented hereunder. Adopted design values are rounded off figures with nominal safety margin to remain in line with the similar data. However, SO4 values are taken lower than the Korangi value due to the fact that in Korangi, brackish ground water (due to proximity of ocean) is being used in processes, containing high SO4 concentrations, which is not the case in Sialkot.

Table 7: Adopted Design Values for CETP

Parameter Unit STZ Effluent CETP - Korangi Adopted Design

Values

Production Tons/day 458 373

Q m3/day 12,000 13,500 12,000

pH 7 - 8 7-8 8

Temp °C 30 30 30

TSS mg/L 2,043 2,000 2,100

COD mg/L 3,414 3,570 3,600

BOD5@20°C mg/L 1,240 1,390 1,400

Cr mg/L 88 6.2 100

S2- mg/L 112 N/T 200

NH3-N mg/L 195 N/T 200

TKN mg/L 263 300 300

Cl mg/L 2,977 N/T 3,000

SO4 mg/L 1,472 2,210 1,500

3.2 REVISED WASTEWATER DESIGN DATA

In accordance with the aforementioned data, a detailed process design report was prepared in March 2017 and submitted to the UNIDO and STAGL for review and comments. After review of the report, UNIDO experts emphasise on the need of



10

fresh production data from the STAGL. Subsequently, on October 19, 2017, STAGL held a meeting to review the availability of fresh production data. After a thorough discussion with the stake holders, technical consultants and UNIDO expert, STAGL recommended the following revised data to be adopted as design parameters for the first phase of CETP design:

1. The CETP will be established on modular approach and the first module will befor the treatment of 4,000 m3/day of tannery effluents.

2. Effluents from industries will be in two separate channels – “Chrome free” frombeam-house operations 1,500 m3/day and 2,500 m3/day from tanning & posttanning operations.

3. It was also decided that CETP will have separate sulphide oxidation for Beam-house effluents. For tanning liquors STAGL will arrange Chrome Recovery Unitseither within individual tanneries or on cluster level.

4. It was also deliberated that the CETP design will be replicable for rest of the twoor three modules.

In the light of above discussion and conclusion on the wastewater quantity following estimations are made for the pollution concentration for Phase I of the project.

Table 8: Average Values of Pollution Load Discharged (Conventional Process) - UNIDO

Parameter Unit Beam House Tanning & Post

Tanning

Wastewater m3/ton 17.0 23.0

BOD, total kg/ton 53.0 15.5

COD, total kg/ton 144.5 43.5

TSS kg/ton 99.0 17.0

TN kg/ton 12.5 2.3

Sulphide kg/ton 6.5 -

Chloride kg/ton 112.0 57.5

Chromium kg/ton - 5.0

SO4 kg/ton 21.0 60.0

Beam house operations: soaking, liming, deliming & bating Tanning & post tanning operations: tanning, post tanning & finishing



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Table 9: Concentration Estimation based on Loads per Ton of Production – Phase I


Tanning

Wastewater* m3/day 1,500 2,500

BOD, total mg/L 3,118 674

COD, total mg/L 8,500 1,891

TSS mg/L 5,824 739

TN mg/L 735 98

Sulphide mg/L 382 -

Chloride mg/L 6,588 2,500

Chromium mg/L - 217

SO4 mg/L 1,235 2,609

* MoM_19Oct2017_NEC_STAGL_UNIDO

Table 10: New Estimated and Adopted Raw Effluent Design Data – Phase I

Parameter Unit Combined Raw

Effluent Adopted Design

Values

Wastewater m3/day 4,000 4,000

BOD, total mg/L 1,590 1,600

COD, total mg/L 4,370 4,400

TSS mg/L 2,646 2,500

TN mg/L 337 335

Sulphide mg/L 143 143

Chloride mg/L 4,033 4,000

Chromium mg/L 136 140

SO4 mg/L 2,094 2,100

The new design values are representative of the untreated combined raw effluent from tanneries’ operations. While, in accordance with the discussion above, the beam house effluent will be transported separately and primarily treated for sulphide removal. Similarly chrome tanning effluent will first go through chrome recovery unit. The two primarily treated streams will then be combined and treated for BOD, COD and TSS removal as conventionally.



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3.3 EFFLUENT REQUIREMENTS

The Punjab Environmental Quality Standards (PEQS)-2016, pertaining to the wastewater under study in this report, are summarised in Table-11.

Table 11: Summary of Key Parameters; Punjab Environmental Quality Standards (PEQS) -2016

Parameter Unit Value

COD mg/L 150

BOD5@20°C mg/L 80

TSS mg/L 150

NH3 mg/L 40

Sulphide mg/L 1

It shall be noted that the treated wastewater through most efficient biological treatment process will treat the wastewater in conformance to all PEQS except TDS and its constituent Chlorides and Sulphates. These details will be presented in Chapter 4 and 5 of this report.

However, to further treat the water to bring down the TDS limits, high cost technologies would be required, such as Membrane Filtration, etc. This aspect has been discussed in detail in Chapter 6 of this report.

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CHAPTER 4: ALTERNATIVES ANALYSIS

Alternative analysis has been done for the following three important decisions:

1 Segregation of wastewater conveyance system 2 Optimum modular approach 3 Selection of appropriate technology

4.1 SEGREGATION OF WASTEWATER CONVEYANCE SYSTEM

A separate report has been prepared to discuss and finalize the various alternatives pertaining to segregation of conveyance system in STZ. The report has been submitted to UNIDO and STAGL and duly finalized after a detailed deliberation in the Month of July 2017. For ready reference the said report is attached as Annexure-I with this document.

4.2 OPTIMUM MODULAR APPROACH

It is obvious that starting with the operational functioning of the estate, the wastewater flows and pollution loads would keep on increasing with time, as the individual production units come into operation one by one, and it would take certain period of time, till all the individual industrial units in the estate are operating at their full capacities and, consequently, the ultimate wastewater flows and pollution loads are being generated by estate. This period to the full development may be in years. Keeping this aspect in view, commonly the CETPs are not constructed at their ultimate design capacity at the start and are rather executed in phases, commensurate with the actual growth of the flows and pollution loads from the estates, as established by actual time-to-time monitoring. This course is adopted primarily to avoid the waste of facilities and equipment, owing to their prolonged disuse and useless maintenance expenses, during the periods of their disuse, both leading to the wastage of the financial resources. In such cases, the capacity of the CETP, to be executed at the start, may range from 25 – 50% of the ultimate capacity, depending upon the assessment of the growth patterns during initial stages of the development.

Implementation of STZ is just initiated and relocation of industrial units is yet to gain pace. Industrial estates in Pakistan may take 10 to 15 years to reach the optimum occupancy. It would be advisable to construct the CETP in modules as per increase in occupancy level.

Alternative 1 could be the construction of complete plant having capacity of 16,000 m3/day. Though in cost terms, it will be cheaper due to use of ‘common walls’ approach in construction of various units. Similarly, mechanical equipment, electrical and instrumentation will also become cheaper. On the other hand, almost 70 - 80 % of the tanks and equipment will remain unused for many years resulting in complete damage of assets within three to four years.



14

As Alternative 2, it would be better to start with 25 % of capacity for at least next 4 to 5 years and then add another 25 % and so gradually reach 100 % capacity in next 15 years. This will not only save the finances but also allow the possibility of adjusting and modifying the design in the forthcoming modules.

However, the STAGL management has decided to construct first module of CETP having a capacity of 4,000 m3/day and subsequent modules will be planned after reviewing the actual occupancy and growth rate of industries in STZ

4.3 TREATMENT TECHNOLOGY

4.3.1 Treatment System Objectives

As already established in Chapter 3, the CETP shall be intended to bring the values of wastewater BOD, COD, SS and oil & grease within the limits set by National Environmental Quality Standards for Inland Waters, as promulgated under Pakistan Environmental Protection Act, 1997. However, removal of chromium present in the wastewater shall be carried out within the industries.

Table-12 presents the design influent concentrations for BOD, COD and SS, applicable PEQS values, design effluent concentrations and respective required treatment efficiencies.

Table 12: Treated Effluent Requirements

Parameter

PEQS Value (mg/L) Design

Concentrations (mg/L)

Required Treatment Efficiency

(%) Into Inland

Waters Into Sewage Treatment

Into Sea Influent Effluent

BOD5 @20°C 80 250 80 1,600 80 95

COD 150 400 400 4,400 150 96.6

TSS 200 400 200 2,500 200 92

COD removal, by any biological treatment, would not exceed about 1.6 to 1.8 times the amount of BOD removed. The design effluent concentration for COD is established on the assumption that the ratio of biodegradable/bioeliminable COD to BOD shall be of the order of 1.6. Residual COD exceeding the limits will be treated by additional treatment unit.

4.3.2 General Selection Criteria for Wastewater Treatment System

The wastewater treatment facilities shall be selected after taking due consideration of the pertinent technical, operational and economic factors, limitations and constraints. The key factors, which govern the choice of the treatment system, are as follows:



15

Nature and Strength of Wastewater: The applicable physical, chemical andbiological treatment processes are primarily governed by the nature of pollutantsto be removed and their strengths in the wastewater. The treatment systemselected shall ensure the required pollutant removal efficiencies.

Physical Constraints: Physical constraints, principally being the area available andthe topography of the plant site with reference to the system hydraulicrequirement, govern the selection of treatment technology.

Cost: The system selected should be the least cost alternative, keeping in viewboth capital as well as operational costs, within the range of technically feasibleoptions.

Operational Skills: Skills required for the routine operation and maintenance ofthe treatment system should be available locally, with only a minimum oftraining. The proposed system shall have relative ease of operation andmaintenance.

Mechanical Equipment: The selected system shall be such that minimummechanical equipment needs to be provided. Unnecessary mechanicalequipment shall be avoided. The system shall be designed such that maximum ofthe mechanical equipment is from local manufacture.

Nuisance: The degree of color, odor and noise shall be below the nuisancethreshold, especially, with reference to the proximity of the treatment system tothe build-up areas.

4.3.3 Treatment System Requirements for CETP

The principal pollutants to be removed are BOD, COD and SS. It implies that a combination of physical and biological treatment processes shall be required. The ratio of COD-to-BOD is such that the removal of BOD, by biological treatment, would not bring the COD within the PEQS limits and advanced/tertiary treatment will be needed.

In the case of Sialkot Tannery Zone, tannery wastewater treatment may call for a sequence of anaerobic /chemically enhanced Primary Treatment - aerobic treatment, which is known to be rather effective in the removal of high organic pollutants.

Therefore, biological treatment technology with various combinations will be further evaluated for wastewater treatment.

Evaluation of alternate biological treatment processes unit for selection of themost appropriate one for CETP is made in Section 4.3.4.



16

Sludge, produced by removal of suspended solids by physical or biologicalprocesses, shall need to be treated, for rendering it suitable for transportationfor disposal or reuse, as the case may be. The suitable sludge treatment for CETPis laid down in Section 4.3.5.

4.3.4 Evaluation of Alternate Preliminary Treatment Processes

Mainly preliminary treatment process system consists of following:

Screening

Grit removal

Following Table-13 and 14 provides a detail comparative analysis of preliminary treatment for Sialkot Tannery Zone CETP in consideration with local conditions:

Table 13: Screening of Preliminary Treatment Technologies: Screen

Selection of Screens Large Solids

Small Solids

Remarks Justification

Bar Screens (Coarse) High Low

Easy operation andmaintenance.

High skill labor notrequired.

Efficient in removinglarge solids.

Mechanically Cleaned Fine Bar Screens High High



Efficient in removingsmall solids.

Rotary Screens High High

Complex operation andmaintenance.

High skill labor required.

Very efficient inremoving small solids.

Disc Screen High High

Complex operation andmaintenance.


Very efficient inremoving small solids.



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Table 14: Screening of Preliminary Treatment Technologies: Grit Chamber

Selection of Grit Removal Unit

% Removal of 0.3 mm

Particle

% Removal of 0.2 mm

Particle Remarks Justification

Horizontal Grit Chamber without Mechanical Aid

90 90



Simple construction

Large footprint

Head loss is excessive

Channels withouteffective flow control willremove excessiveamounts of organicmaterial

Detritor (Mechanical)

95 90


Do not require flowcontrol because allbearings and wearablemoving mechanical partsare above the water line.

Minimal head loss

Large footprint thanvortex type.

Removal system removeslarge quantities oforganic material

In shallow installationsthe rake arm of scrapingmechanism can createagitation of settled grit

Vortex Grit Chamber (Mechanical)

95 95

Remove a highpercentage of fine grit

Small footprint

Minimal head loss

Energy efficient andrequire less power ascompared to detritor.

Feasible for small flows

Modifications in thesystem are difficult at alater stage



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4.3.5 Evaluation of Alternate Primary Treatment Processes

A brief description of primary treatment technologies is as follows:

Plain Sedimentation: Sedimentation tanks are large circular basin with retentiontime of not less than 1.5 hours to hold water under quiescent conditions. Noagitation helps to remove settleable solids under their own weight or gravity. Inplain settling no chemical aid is provided. Requires slow loading rates, produceless sludge and consumes less energy. However due to low loading rate, largesurface area is required.

Chemically Enhanced Sedimentation: In this process, chemicals namelycoagulants are first added which help solids particles to come closer and makeflocs. Flocculants are also used sometime to strengthen the flocs bond. In thisway the weight of the flocs is increased and the gravity settling time is reduced.

Chemical aid reduces the loading requirement and higher surface loading rates can be achieved. However the sludge quantity is increased substantially because of the formation of chemical sludge.

Dissolved Air Flotation: in this process, air is dissolved in wastewater under acertain pressure. This pressurized liquid-water is then released at atmosphericpressure level in the flotation tank. The released air forms tiny bubbles whichadhere to the suspended matter causing the suspended matter to float to thesurface of the water where it may then be removed by a skimming device.

The loading rates are much higher than the gravity settling types but high amount of air is required, hence increasing energy requirement of the system. The sludge quantity is also increased because of the chemical sludge. Increased number of equipment, hence maintenance requirement is more. Skilled labour is required to operate the system.

Table 15: Screening of the Primary Treatment Technologies

Primary Treatment Technologies

*TSSRemoval (%)

Energy Required

Foot Print Upkeep Remarks

Plain Sedimentation 50 – 70 Low High Low

Chemically Enhanced Sedimentation

80 – 90 Low Medium Low to

medium

Dissolved Air Flotation 80 – 95

Medium to high

Low High

* Treatment of Tannery Wastewater: Naturgerechte Technologien, Bau-und Wirtschaftsberatung (TBW) GmbH, Frankfurt (Germany), April 2002



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4.3.6 Evaluation of Alternate Biological Treatment Processes

4.3.6.1 Screening Process for Treatment Technology Selection

At the first step all available and applicable treatment technologies are brought under review. Generally following biological treatment technologies are available for industrial wastewater treatment:

Figure 2: Available Biological Methods for Wastewater Treatment

Above mentioned technologies are listed in simplified form as below:

■ Aerobic

Oxidation Ponds

Trickling Filters

Expanded Bed

Aerobic Anaerobic

Suspended Growth

Completely Mixed

Sludge Blanket

Lagoons

Attached Growth

Trickling Filter

RBC

Fluidized Bed

Suspended Growth

Activated Sludge Lagoon

Aerated

Oxidation Pond

Facultative Lagoons

Biological Methods of Wastewater Treatment

Attached Growth

Packed Bed

Fluidized BedConventional

Extended

High Rate

Contact Stabilization

Sequencing Batch Reactor



20

Aerated Lagoons

Activated Sludge

Rotating Biological Contactors

Membrane Bioreactors

■ Anaerobic

Anaerobic Ponds

Up flow Anaerobic Sludge Bed (UASB)

A brief description of these processes is as follows:

Oxidation Pond System: Oxidation ponds are large shallow basins, in which rawwastewater is treated entirely by natural processes, involving both algae andbacteria. They are the most important method of wastewater treatment in hotclimates. However, since the rate of unaided oxidation is slow, large areas arerequired for their construction. Their specific advantages are simple operationand reduced sludge management problem.

Tricking Filter Process: In this process, the settled wastewater is allowed to trickledown over a circular deep bed of coarse aggregates filter or plastic media filter.The microbial film, developed on the surface of filter media over time, treats thewastewater. A part of this film, washed away by the hydraulic action of tricklingwastewater, is separated in secondary clarifier, in form of humus sludge,disposed of after sludge treatment, or returned for digestion into the UASBreactor, if applicable.

Aerated Lagoons: Aerated lagoons are completely mixed basins, with detentionperiods ranging from 2 to 6 days, in which wastewater is generally treated onflow through basis (without solids recycling), with forced aeration. The aerobicsuspended biological flocs, responsible for the waste conversion, closelyresemble to that of activated sludge process. Area requirements are in betweenthose of the oxidation ponds and activated sludge process.

Activated Sludge Process: Activated sludge process is the biological treatment, inwhich aerobic microorganisms present in wastewater, use the colloidal anddissolved organic matter of the wastewater, for their multiplication and growth,with the help of oxygen thus converting them into readily settleable biomass.Generally, the required oxygen supplies are maintained by forced supply of air tothe wastewater in the aeration tank. The aerated effluent is then allowed to passthrough a secondary settling tank to separate the biomass or the “activatedsludge”. A part of the "activated sludge" is recycled to the aeration tank tomaintain optimum microorganism concentrations. The remaining secondarysludge is removed from the system periodically; dewatered and dried; anddisposed off.



21

Rotating Biological Contactors (RBC): Rotating Biological Contactors (RBCs) aremechanical secondary treatment systems, which are robust and capable ofwithstanding surges in organic load. An RBC unit comprises a series of closelyspaced "circular disks" normally made from a plastic material. The disks arepartially submerged in the sewage and are slowly rotated through it.

The rotating disks support the growth of bacteria and micro-organisms present in the sewage, which breakdown and stabilize organic pollutants. To be successful, micro-organisms need both oxygen to live and food to grow. Oxygen is obtained from the atmosphere as the disks rotate. As the micro-organisms grow, they build up on the media until they are sloughed off due to shear forces provided by the rotating discs in the sewage.

Membrane Bioreactor (MBR): The term membrane bioreactor (MBR) defines acombination of an activated sludge process and membrane separation. The MBRprocess can be employed in activated sludge processes, using the membranes asliquid-solid separation instead of the usual settling. Suspended solids can beremoved completely and bacteria-free treated water produced. The sludgeconcentration and hydraulic loading rates are considerably higher than inconventional treatment.

Pre-treated, screened influent enters the membrane bioreactor, where biodegradation takes place. The mixed liquor from the bioreactor is withdrawn and pumped along submerged or semi-cross flow filtration membrane modules.

Upflow Anaerobic Sludge Bed (UASB): UASB technology, normally referred to asUASB reactor, is a form of anaerobic digester that is used in the treatment ofwastewater. The UASB reactor is a methanogenic (methane-producing) digesterthat evolved from the anaerobic clarigester (digester + clarifier).

UASB uses an anaerobic process whilst forming a blanket of sludge in the lower parts of the tank. Wastewater flows upwards through the blanket and is processed by the anaerobic microorganisms. The upward flow combined with the settling action of gravity suspends the blanket. The blanket begins to reach maturity at around 3 months after start-up.

Biogas with a high concentration of methane is produced as a by-product, and this may be captured and used as an energy source, to generate electricity for export and to cover its own running power.

Anaerobic Ponds: Anaerobic ponds are normally used to treat high strengthconcentrated industrial waste and no oxygen is present in the pond. All thebiological activity is anaerobic decomposition. These ponds are 8 to 12 feet deepand are anaerobic throughout. Scum forms on the top of the most anaerobicponds. This scum stops air from mixing with the wastewater. The gases that areproduced by the anaerobic bacterial action cause odor problems.

javascript:pop2('../','bookuse/00016.popuphyp.html')

http://www.stowa-selectedtechnologies.nl/Sheets/Sheets/Submerged.Fixed.Beds.html#submerged

javascript:pop2('../','bookuse/00123.popuphyp.html')

http://en.wikipedia.org/wiki/Anaerobic_digester

http://en.wikipedia.org/wiki/Wastewater

http://en.wikipedia.org/wiki/Methanogenic

http://en.wikipedia.org/wiki/Anaerobic_clarigester

http://en.wikipedia.org/wiki/Anaerobic_digestion

http://en.wikipedia.org/w/index.php?title=Anaerobic_microorganisms&action=edit

http://en.wikipedia.org/wiki/Gravity

http://en.wikipedia.org/wiki/Biogas

http://en.wikipedia.org/wiki/Methane

http://en.wikipedia.org/wiki/Electricity



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4.3.7 Comparative Analysis of Alternate Treatment Processes

All of these technologies are screened for applicability in the specific Sialkot Tannery Zone conditions. Following is a comparative analysis of above treatment systems, with respect to their suitability for CETP of STZ:

■ Step 2: Screening on the basis of desired BOD removal efficiency (%)

Anaerobic Ponds: Maximum BOD removal efficiency percentage of AnaerobicPonds as reported in the literature is 70%. In STZ conditions, neither removal oforganic pollutants could be achieved, at the desired level, through thistechnology nor is the required area available. Therefore this technology couldnot qualify for further screening.

Rotating Biological Contactors: For RBCs also, maximum BOD removal efficiencyas reported in literature is 85%, therefore the technology could not be applicablein STZ conditions.

Oxidation Pond System: For Oxidation Pond also, maximum BOD removalefficiency as reported in literature is 90%, therefore the technology could only beapplicable as pretreatment unit in STZ conditions. Moreover, these ponds needvery large areas, for their construction. In STZ conditions, the area requirement isof the order of 50 -60 acres. The pond area required, to achieve the desiredtreatment efficiency, in case of CETP, is far in excess of the available area. Thisoption therefore cannot be considered at all.

Aerated Lagoons System: For Aerated Lagoons also, maximum BOD removalefficiency as reported in literature is 90%, therefore the technology could only beapplicable as pretreatment unit in STZ conditions. Moreover, Aerated Lagoons, incomparison with the activated sludge and trickling filter process, need morearea. Estimated area requirement for the STZ case is about 30 - 45 acres which is2 - 3 times of those required for activated sludge (conventional) or trickling filterprocess. In any case, the area required for CETP, to achieve the desiredtreatment efficiency, is more than that available.

Upflow Anaerobic Sludge Bed (UASB): For UASB also, maximum BOD removalefficiency as reported in literature is 80 - 90%, therefore the technology can onlybe applicable as pretreatment unit in STZ conditions. Anaerobic treatmentprocesses in comparison to aerobic treatment processes, except for oxidationponds systems, are highly energy efficient, particularly in hot climates.

In aerobic biological systems, such as, activated sludge and aerated lagoons processes, energy is required for artificial aeration of wastewater. In case of activated sludge process, energy is also consumed in sludge recycling process. For trickling filters, hydraulic energy is needed to rotate the rotary distributor by pressurized feeding of the influent and recirculation wastewater to it. Introduction of an anaerobic treatment reduces the overall operational cost of the biological treatment, because lesser amount of organic matter is to be



23

degraded by the subsequent aerobic process. Various alternate types of anaerobic wastewater treatment processes are available. Most of these processes have come up recently as a result of the extensive research, which is still going on. UASB Reactor is the most common one.

Table 16: Screening on the Basis of Desired BOD Removal Efficiency

# Treatment Technologies Maximum BOD

Removal Efficiency Reported

Remarks

1 Oxidation Ponds 90

2 Trickling Filters (Two Stage + recycling) 95

3 Aerated Lagoons 90

4 Activated Sludge 95

5 Anaerobic Ponds 70

6 Membrane bioreactors 98

7 Rotating Biological Contractors 85

8 Up flow Anaerobic Sludge Bed (UASB) 80

■ Step 2: Screening on the basis of ability to treat high strength wastes andresistance to shock loads

Trickling Filter Process: The principal advantages claimed for attached growthprocesses, like trickling filters, over the activated sludge process include lessenergy requirement and better sludge thickening properties; whereas thedisadvantages often cited are poorer effluent quality and greater sensitivity tolower temperatures. In most cases, the reaction rates for soluble industrialwastewaters are relatively low and hence filters are not economically attractivefor high treatment efficiencies. Reported BOD removal efficiencies for industrialwastewaters range from as low as 10% to most of them lying below 60%.Another problem associated with trickling filters is breeding of filter flies(psychoda), which is a nuisance for plant area as well as the surroundingcommunities.

Activated Sludge Process: This process is in fact the most commonly employedtreatment process worldwide for the removal of BOD from the domestic as wellas from a variety of individual and combined industrial wastewaters, because ofits operational flexibility and its capability to furnish higher removal efficienciesin varying conditions with suitable level of process control, besides othercomparative advantages.



24

Membrane bioreactors: A latest type of Activated Sludge Process withcombination of membrane technology also qualifies the required parameters forselection for STZ CETP.

Table 17: Screening on the Basis of Ability to Treat High Strength Wastes and Resistance to Shock Loads

# Treatment Technologies Sensitivity Remarks

1 Trickling Filters (Two Stage + recycling) High

2 Activated Sludge Process Moderate

3 Membrane bioreactors Moderate

Results of aforesaid discussion are presented in the Table-18.

Table 18: Comparative Analysis of Various Treatment Technologies

# Treatment Technologies

Maximum BOD Removal

Efficiency Reported

Tentative Area Requirement

(acres)

Sensitivity to Shock Loads

1 Anaerobic Ponds 70

2 Rotating Biological Contractors 85

3 Oxidation Ponds 90

4 Aerated Lagoons 90

5 Up flow Anaerobic Sludge Bed (UASB) 80

6 Trickling Filters (Two Stage + recycling) 95 25 - 35 High

7 Activated Sludge 95 15 - 20 Moderate

8 Membrane Bioreactors 98 10 - 15 Moderate

4.3.8 Comparative Analysis of Alternate Treatment Technologies in Combinations

Treatment may also be performed in combined treatment steps. Regarding the treatment in combined systems, the following systems may be observed.

After preliminary treatment (reception, screening, sand trap), the following treatment alternatives are possible:

for primary or first-step treatment, there may be

− anaerobic lagoon− chemically enhanced primary treatment (CEPT) or



25

− upflow anaerobic sludge blanket (UASB) system− alternatively, there may be no first-step treatment

These treatment steps may be seen as a total treatment, followed by advanced chemical oxidation (ACO) or a second treatment step before ACO may be included. This second treatment step may consist of:

− oxidation pond− aerated lagoon− activated sludge system− membrane bioreactor

The various options are schematically represented in Figure-3.

Figure 3: Available Combinations of Biological and Physico-chemical Methods for Wastewater Treatment

With regards to the estimated efficiencies of the first treatment step, it may be noted that a second treatment step is absolutely necessary in order to comply with the effluent standards. For this reason, the option “no treatment” should be left out of the options for the second step. In view of the limited space available, the hydraulic residence times (HRT) that are normally applied in the various systems may prove helpful in deciding for the best combinations for further study. It may be noted that with a HRT of more than 5 to 7 days, the system under study may be considered too large for application in the CEPT. In Figure-4, the indicative HRTs of the various systems are presented. They will lead to exclusion of a number of systems from the scheme.

A C O preliminary treatment

anaerobic lagoon

C E P T

U A S B

(none) oxidation pond

aerated lagoon

M B R

(none)

activated sludge



26

Figure 4: Available Combinations of Biological and Physico-chemical Methods for Wastewater Treatment; black cross, eliminated option due to non-compliance with

effluent standards; grey cross: eliminated due to too high space requirements.

The elimination of a number of options leads to a more simple scheme for treatment options, which is shown in Figure-5.

Figure 5: Simplified Scheme of Treatment Options

MBR is very expensive technology in Pakistan’s local context. It will be 2.5 times higher than Activated Sludge System in terms of Capital Cost and about 1.5 times higher in terms of O&M Cost.

Considering the high Sulphate concentration in tannery wastewater which are more than 2,100 mg/L in this case and corresponding COD:Sulphate ratio which is about 2.1, it will be high risk to opt for the UASB technology. As the desired concentration for UASB is less than 1,000 mg/L and COD:Sulphate ratio is 3:1, therefore, it is expected that emissions of Hydrogen Sulphide will be generated which are fatal for the human life.

■ Selected Biological Treatment Process

On the basis of afore-stated comparative analysis of anaerobic and aerobic treatment processes, the Activated Sludge Process is the only suitable secondary processes for the CETP and is selected for detailed design. The primary treatment will comprise of physico-chemical treatment, like coagulation/flocculation followed by sedimentation.

G A Cpreliminary

treatment

anaerobic

lagoon

C E P T

U A S B

(none)oxidation

pond

aerated

lagoon

M B R

(none)

activated

sludge

HRT 4 d

HRT 1.5 h

HRT 8 h

HRT 7 d

HRT 1 d

HRT 0.5 d

HRT 20 d

G A Cpreliminary

treatmentC E P T

U A S B

(none)

M B R

activated

sludge

A C O

A C O



27

4.3.9 Evaluation of Alternate for Aeration System and Sludge Dewatering

Following Table-19 and 20 provides a detail comparative analysis of Aeration System and Sludge Dewatering for Sialkot Tannery Zone CETP in consideration with local conditions:

Table 19: Comparative Analysis of Aeration System

Selection of Aeration System Efficiency Labor Skill Maintenance Remarks

Surface Aerators 1.5 lb O2 per kWh Moderate Moderate

Fine Bubble Diffusers with Blower 4.9 lb O2 per kWh High Very High

Jet Aeration System with Blower 3.9 lb O2 per kWh High Moderate

Table 20: Comparative Analysis of Sludge Dewatering

Selection of Sludge Dewatering

Efficiency Labor Skill Maintenance Area

Requirement Environmental

Nuisance Remarks

Sludge Drying Beds Low Low Low Very High Very High

Sludge Filter Press (Belt Type)

High Moderate Moderate Low Low

4.4 KEY TREATMENT SYSTEM COMPONENTS AND FACILITIES

In light of the above discussion, following are the key components of treatment system and facilities proposed for CETP.

■ Water Line

o Beam House Effluent

Prescreen Chamber

Screen Chamber

Grit Chamber

Equalization Tank with Catalytic Sulphide Oxidation

o Tanning & Post Tanning Effluent

Prescreen Chamber

Screen Chamber

Grit Chamber

Equalization Tank




o Combined Effluent

Coagulation and Flocculation Tank


Aeration Tank - Activated Sludge Process

Secondary Sedimentation Tank

Advanced Chemical Oxidation

Final Neutralization

■ Sludge Line

Sludge Thickeners

Sludge Conditioning Tank

Sludge Dewatering (Belt-Press Type Sludge Filter)

Details of each aforesaid unit are discussed in Chapter 5 and Chapter 6 of this report.


CHAPTER 5: DESIGN OF WATER LINE

In the following sections detailed design of CETP will be presented. Table-21 depicts the Wastewater data used for designing of the CETP.

Table 21: Summary of Wastewater Design Data for Phase I of STZ


Tanning

Wastewater flow m3/day 1,500 2,500

Peak Factor - 2.50 2.50

Peak Rate m3/hr. 156.25 260.4

TSS mg/L 5,824 739

COD mg/L 8,500 1,891

BOD5@20°C mg/L 3,118 674

Cr mg/L 0 217

S2- mg/L 382 0

TN mg/L 735 98

Cl mg/L 6,588 2,500

SO4 mg/L 1,235 2,609

The targeted effluent characteristics shall be in conformance to PEQSs of Pakistan:

Water line of the proposed CETP will be consisting of the following components:

Pre-screen Chamber #1 for Beam House Effluent

Screens #1 for Beam House Effluents

Grit Chamber #1 for Beam House Effluents

Pre-screen Chamber # 2 for Tanning and Post Tanning Effluent

Screens # 2 for Tanning and Post Tanning Effluents

Grit Chamber # 2 for Tanning and Post Tanning Effluents

Equalization Tank # 1 with Catalytic Sulphide Oxidation for Beam House Effluent

Equalization Tank # 2 for Tanning and Post Tanning Effluent

Wastewater Pumping Station

Coagulation Flocculation Tank


Aeration Tank – Extended Activated Sludge System

Secondary Sedimentation Tank – Extended Activated Sludge System

Tertiary Treatment Unit




Description of each aforesaid component with its design and basis of design is presented in this chapter. However, details regarding hydraulic profile are presented in the Chapter 7 of this report.

5.1 BAR RACK FOR ULTIMATE FLOW

It is recommended that the Pre-Screen Chamber shall be provided for the ultimate

flow of 6,000 m3/day for beam house and 10,000 m3/day for tanning and post

tanning effluents, so that future Phases could start directly from here.

The chambers are provided to act as a receiving structure for the wastewater from

the industrial estate. It will receive wastewater for screening through RCC sewers.

The design criteria and the unit dimensions are provided in the Table-22.

Table 22: Design Criteria and Unit Dimensions for Bar Rack


Tanning

Wastewater flow

Maximum m3/day 4,500 – 6,000 7,500 – 10,000

Peak Factor - 2.50 2.50

Peak Flow m3/hr. 470 – 625 781 – 1,040

Design of Pre-Screen Chamber

Retention time seconds 15 10

Length m 1.5 1.5

Width m 2.0 2.0

Water Depth m 0.9 0.96

Mechanical Bar Rack

Numbers Nos. 2 + 1 Standby 2 + 1 Standby

Capacity, each m3/hr. 235 – 313 390 – 520

Clear spacing b/w bars mm 20 20

Screen angle degree 60 60

Screen channel width m 0.60 1.00

Approach velocity m/sec 0.650 0.650

Depth of flow m 0.25 – 0.33 0.25 – 0.33

In case of complete accidental shutdown of CETP, the chamber will also act as the bypass structure so that all the effluent can be bypassed directly to the ultimate




disposal point. For this purpose the chambers will be equipped with a penstock, each, at the inlet point.

After Bar Screen, all the subsequent units are designed for Phase I of the CETP having average capacity 4,000 m3/day.

5.2 FINE SCREENS

From the coarse screen chamber, the wastewater will flow into the fine screen channel which will be provided with mechanically & manually cleaned screens. The wastewater has to be screened in order to remove the large floating constituents present in it. At the top of the screening channels, RCC platforms, of adequate space, shall be provided for manual cleaning of the screens, operation of the sluice gates and other purposes. The screenings shall be disposed to the landfill site along with dewatered sludge. For safe operation, 1 + 1 screens for each wastewater stream shall be provided, each capable of handling the full flow.

Two numbers of screening channels for each stream of wastewater in parallel will be constructed. The channels shall be of rectangular geometry in plan. One of the channels will be equipped with mechanically operated coarse screens. While the other will be equipped with manually cleaned screens as standby operations. Two (2) sluice gates at inlet and outlet of each screen channel are also provided to take any channel out of operation for maintenance purpose. Under normal operating conditions, the wastewater will flow through all channels.

Following are the key components of the Screen Channel:

Two Screening Compartments (RCC), in parallel, with 1 Penstock (CI) each, at itsinlet and outlet to the common Influent & Effluent Chamber, in order to bringany of the compartments out of operation

One mechanically cleaned Screen in one of the two channels. One manually cleaned screen to act as standby. Two Operating Platforms constructed 1 each in the 2 Screening Compartments,

at level of top of screens, in order to receive screenings, for their subsequenttransfer to the ground level

Common Effluent Chamber (RCC) One effluent pipes (RCC), to the Grit Chamber. Access Walkways Monkey Ladders (SS)

Table-23 presents the design criteria for mechanically cleaned screen chambers adopted for the Project:




Table 23: Screen Chamber Design Details


Tanning

Wastewater flow

Average m3/day 1,500 2,500

Peak factor 2.50 2.50

Peak flow m3/hr. 156.25 260

Mechanically Cleaned Screen

Type reciprocating rake bar screen

Numbers Nos. 1 + 1 Standby 1 + 1 Standby

Screen bar width mm 15 15

Screen bar depth mm 75 75

Clear spacing b/w bars mm 06 06

Screen angle with horizontal degree 60 60

Screen channel width m 0.60 1.00

Approach velocity m/sec 0.65 0.65

Depth of flow m 0.30 0.30

5.3 VORTEX TYPE GRIT CHAMBER

The screened wastewater will pass through grit chamber prior to entering the respective equalization tanks. Grit removal is essential for safe operations of pumps and to avoid overloading of the aeration tanks with inert inorganic material.

The grit chamber is designed on a loading rate of 0.02 – 0.04 m3/m2/sec for effective grit removal. The design criteria and unit dimensions are given in Table-24.

Table 24: Design Criteria and Design of Vortex Grit Chamber

Parameters Unit Beam House Tanning & Post

Tanning

Sewage Flows

average flow m3/d 1,500 2,500

peak factor 2.50 2.50

peak flow m3/hr. 156.25 260

Design Criteria

Type Vortex Vortex




Parameters Unit Beam House Tanning & Post

Tanning

maximum overflow rate m3/m2/sec 0.025 0.040

HRT seconds 60 60

Design

Numbers nos. 1 + 1 Standby 1 + 1 Standby

Diameter m 1.50 1.50

It should be noted that for each module one number vortex grit chamber is proposed as duty. For ultimate capacity two numbers are proposed as standby. One of the standby will be constructed during Phase I and other will be constructed in Phase III of the CETP.

Each vortex grit chamber is equipped with:

Motion unit Central shaft with paddles Air lift for extraction of grit Coaxial gearmotor

5.4 OIL & GREASE SEPARATOR

After degritting, the effluent shall pass through the oil separator. It is a packaged device to remove oil from water. The separated oil is collected inside the separator unit while the wastewater is directed to the effluent line. The flow capacity of oil separator for beam-house effluent is 43 Lt/sec, and for tanning & post tanning effluents is 72.2 Lt/sec.

5.5 EQUALIZATION TANK # 1 WITH SULPHIDE CATALYTIC OXIDATION – BEAM HOUSE EFFLUENT

Bea house wastewater, after passing through respective grit chambers will enter into the designated Equalization Tanks. These tanks will equalize the characteristics and flow for onward treatment processes. This is necessary because of the expected large fluctuations in the quantity of the wastewater. It is expected that a substantial number of the industrial units will be working in one shift only. Therefore, for a 24 hours smooth biological treatment process, continuous supply of wastewater is essential. The equalization tanks will also act as a reserve buffer for storage and onward unhindered supply of wastewater to the biological reactors.

Other main function of this equalization tank is to provide sulphide elimination by catalytic oxidation. Table-25 presents design of the equalization tank # 1.




Table 25: Design of Equalization Tank for Beam House Effluent

Parameter Unit Phase I

Influent Data

Inflow m3/d 1,500

Sulphide mg/L 362

Design Criteria

Residence Time Hrs. 24

Oxygen requirement kg O2/ kg S 2.0

Dose of catalyst gm-MnSO4/m3 20

Sulphide in effluent mg/L 1

Design

Total Volume required m3 1,500

Number of Tanks nos. 01

Length x Width m 23.80 x 21.00

Depth m 3.0

Minimum Free Board m 0.5

Aeration

Theoretical Oxygen requirement kg-O2/day 1,144

Standard oxygen requirement kg-O2/day 2,400

Air requirement Nm3/hr. 1,500

Mixing device Self- Aspirating Submersible Jet Aerator

Number Nos. 02

Capacity, each m3/hr. 750

Pressure Head atm. 0.350

Wastewater Pumping

Type Dry Mount, Non Clog, Open Impeller

Number Nos. 1 + 1 Standby

Discharge m3/hr. 75.0

Chemical Dosing

MnSO4 Dosing Tank No. 1

Dosing Pumps No. 1 + 1 Standby

It is expected that influent will contain a concentration of 365 mg/L of Sulphide which will be controlled through catalytic Oxidation of Sulphide in presence of Manganese Salt. Equalization tanks will be equipped with Jet Aerators for Mixing and Catalytic Oxidation of Sulphide. Dosing tanks along with pumps will be associated with the Equalization Tank.




5.6 EQUALIZATION TANK # 2 – TANNING & POST TANNING EFFLUENT

Tanning & post tanning wastewater, after passing through respective grit chambers will enter into the designated Equalization Tanks. These tanks will equalize the characteristics and flow for onward treatment processes. This is necessary because of the expected large fluctuations in the quantity of the wastewater. It is expected that a substantial number of the industrial units will be working in one shift only. Therefore, for a 24 hours smooth biological treatment process, continuous supply of wastewater is essential. The equalization tanks will also act as a reserve buffer for storage and onward unhindered supply of wastewater to the biological reactors.

Table-26 presents design of the equalization tank # 2.

Table 26: Design of Equalization Tank for Tanning & Post Tanning Effluent

Parameter Unit Phase I

Inflow m3/d 2,500

Residence Time Hrs. 24

Design

Total Volume required m3 2,500

Number of Tanks nos. 01


Depth m 3.0

Minimum Free Board m 0.5

Mixing

Mixing device Submersible Mixers

Number Nos. 05

Wastewater Pumping

Type Dry Mount, Non Clog, Open Impeller

Number nos. 1 + 1 Standby

Discharge m3/hr. 125

5.7 COAGULATION AND FLOCCULATION

The wastewater from the equalization tanks # 1 and equalization tanks # 2 shall be pumped to Coagulation Flocculation Unit of the CETP. Alum will be used as Coagulant and Poly electrolyte Flocculants will be used for proper flocs formation. Details are as under:

Table 27: Design of Coagulation Flocculation Unit




Description Unit Value

DESIGN DATA

Average Wastewater Flow m3/day 4,000

Peak Pumping Rate, combined m3/hr. 200

pH of incoming wastewater - 8.00

Temp of incoming wastewater °C 30.0

Type of Coagulant - Alum

Flash Mixing Tank

Type of Mixing Device - Turbine & Propeller

Mixers

Contact Time minutes 1.0

Volume of Tank m3 3.30


Liquid depth m 1.25

Flocculation Tank

Type of Mixing Device - PADDLE MIXER

Residence Time for Paddle Mixing min 20

Volume of Tank, Required m3 66.67

Numbers of Tanks nos. 1.0

Liquid Depth m 3.00

Length / Width of tank, each m 5.40

Volume of Tank, provided m3 68.7

5.8 PRIMARY SEDIMENTATION TANK

The flocculated wastewater shall enter Primary Sedimentation Tank under gravity. Quiescent conditions will ensure the settling of > 80% of suspended solids in the Tank. Details are as follows:

Chemically enhanced primary wastewater treatment, the second step in the wastewater treatment process beyond the preliminary treatment of headwork’s, involves the physical separation of suspended solids from incoming sewage flow using Primary Settling Tanks (PST). In PST, suspended solids are allowed to settle via gravity under quiescent condition.

Settled sludge is collected and removed through an opening provided in the sludge hopper at bottom whereas clarified wastewater is collected through overflow weirs. It is perceived that the system will give 85% TSS, 30% BOD & 40% COD removal efficiencies.




Table-28 presents influent characteristics and design criteria used for design of new PSTs along with design summary for existing units.

Table 28: Primary Sedimentation Tank Design


INFLUENT CHARACTERISTICS

Average Flow m3/day 4,000

Peak Pumping Rate m3/hr. 200

Biochemical Oxygen Demand, Total mg/L 1,473

Chemical Oxygen Demand, Total mg/L 4,051

Total Suspended Solids mg/L 2,537

EFFLUENT CHARACTERISTICS

Biochemical Oxygen Demand, Total mg/L 1,031

Chemical Oxygen Demand, Total mg/L 2,430

Total Suspended Solids mg/L 380

DESIGN CRITERIA

Surface Settling Rate-Average Flow m3/m2/day 30

Surface Settling Rate-Peak Flow m3/m2/hr. 1.29

Output Sludge Concentration kg/m3 35

type of coagulant chemical Alum Sulphate

dose of coagulant chemical mg/L 200

Dose of PE Flocculent g/m3 3

DESIGN OF SEDIMENTATION TANK

Number of Tanks nos. 1.0

Geometry of the Tank Circular

Internal Tank Diameter m 14.10

Surface Area, Provided m2 156

Side Liquid Depth m 3.00

Bottom Slope m 12.0

Hydraulic Retention Time

Average hrs 2.6

Peak hrs 2.2

SLUDGE PRODUCTION





Total Sludge production by weight kg/day 9,264

SS sludge kg/day 8,624

Alum sludge kg/day 600

PE sludge kg/day 12

Volume of sludge m3/day 264

Numbers of primary sludge pumps nos. 1 + 1 Standby

Capacity of Pump, each m3/hr. 35.0

5.9 AERATION TANK

In aeration tanks, microorganisms under aerobic condition convert the dissolve and colloidal organic matter in wastewater to mineralized products. One Aeration Tank will be provided which shall receive screened, equalized, grit-free and 70% suspended solids removed wastewater from the primary sedimentation tank under gravity.

The current worldwide practice is to base the design of activated sludge process on Solids Retention Time (SRT) and Mixed Liquor Suspended Solids (MLSS). Same is adopted for the project. Values of solids retention times (SRT) and mixed liquor suspended solids (MLSS) concentrations, for CMAS process, as suggested in literature and as adopted for the project are given in the Table-29.

Secondary sludge produced in terms of volatile suspended solids (VSS) is computed by accounting for the following component contributions:

Heterotrophic biomass Biomass cells debris Influent non-biodegradable volatile suspended solids (nbVSS)

Secondary sludge produced in terms of suspended solids (SS) is computed by accounting for the following component contributions:

Heterotrophic biomass Biomass cells debris Influent non-biodegradable volatile suspended solids (nbVSS) Influent Inert suspended solids

Following are the values of different biological parameters adopted for the process design:

Table 29: Biological Process Parameters adopted for Aeration Tank Design




Biological Process Parameters Unit Value

Design Wastewater Temperature – Minimum (Winter) – TMIN °C 20

Biomass Yield Coefficient – Y VSS/bCOD 0.30

Biomass Decay Coefficient @ 20 °C (1/d) – KD-20 1/d 0.12

Biomass VSS/SS Ratio – FVS 0.85

Biomass Cell Debris Fraction – FD VSS/VSS 0.15

Biomass Max Specific Growth Rate @ 20°C – GM-20 1/d 1.05

Half-Velocity Constant – KS mg-bCOD/L 20

Table-30 presents other design parameters, their typical ranges and the values adopted for the aeration tank design.

Table 30: Design Parameters Adopted for Aeration Tank Design

Parameter Unit Design Values

Wastewater flow

Daily Design Flow m3/d 4,000

Principle Design Parameters

bCOD/BOD5 Ratio – FU 1.70

VSS/TSS Ratio in Influent to Aeration Tank 0.80

nbVSS/VSS Ratio in Influent to Aeration Tank 0.28

Solids Retention Time – TC d 20

MLSS (mg/l) – XL-SS mg/L 4,000

Following are the key secondary design parameters which are computed for the proposed design and checked against the literature-reported values:

Table 31: Design Check Parameters

Parameter Unit Value

F:M Ratio 1/d 0.25

BOD Loading kg-BOD/m3-d 0.7

Hydraulic Retention Time – TD h 40

MLVSS mg/L 1,951




On the basis of above presented design parameters and wastewater characteristics with a safety factor (+10%), design of the Aeration Tanks is presented in the Table-32.

Table 32: Design of Aeration Tanks

Parameter Unit Design Values

Design Flow

Daily Design Flow – Q m3/d 4,000

Peak Design Flow – QP m3/h 200

Aeration Tank Dimensions

Number of tanks nos. 02

Volume of tanks m3 10,400

Liquid Depth m 6.00

Length x Width m x m 36.0 x 24.0

Surface area of tank, each m2 864

Free Board @ no-flow Conditions m 0.75

Total Sludge Production – PX-TSS kg/d 2,072

Total Sludge Production – PX-VSS kg/d 1,011

Recirculation Ratio - 0.60

Volume of Sludge Recycled m3/day 2,400

Sludge Wasting Rate m3/day 165

Number of sludge recirculation pumps nos. 2 + 2 Standby

Capacity of sludge recirculation pumps m3/hr. 60

A pre-selector will be provided for return sludge before mixing in the aeration tank, details are presented in the Table-33.

Table 33: Pre-selector Design

Influent Parameter Unit Value

Peak pumping rate, Qpeak m3/min 3.33

Peak Sludge Recycling Flow m3/min 2.0

Total inflow to Pre-selector m3/min 5.33

Design criteria

Retention Time min 30

Design

Number of selectors nos. 02




Influent Parameter Unit Value

Side liquid depth m 4.00

Width of selector, each m 4.00

Length of selector, each m 5.00

Volume, total m3 160

■ Design Basis for Aeration System

Aeration is an integral part of activated sludge system. Various types of equipment are available to supply air required by the system viz. mechanical surface aerator, aspirating aerators and diffused aerators. Diffused aeration system is adopted for supply of air due to its higher oxygen transfer efficiency.

The design of aeration system is presented in Table-34. While designing the aeration system biomass growth and other factors are considered at maximum design temperature.

Table 34: Design of Aeration System

Aeration Requirement Unit Value

Theoretical daily O2 requirement kg-O2/day 6,000

Operating O2 Concentration in Reactor mg/L 2.00

Saturation of O2 for tap water at 20°C mg/L 9.08

Altitude Correction Factor – FA 0.975

Salinity Correction Factor – b 0.85

Field Sat. O2 Conc. – Cs mg/L 9.02

O2 Transfer Correction Factor for Waste – a 0.6

O2 Req. @ Stand. Cond. – No [ N/aDF ] kg-O2/day 11,986

Standard daily O2 requirement kg-O2/hr. 250

Total Air Flow m3/hr. 14,218

Blowers Details

Number of Blowers 2 + 1 Standby

Blower Capacity, each (@ 70% eff.) Nm3/min 170

Blower Pressure atm. 0.45

Mode of Aeration Jet Aeration

Numbers of Recirculation pumps Nos. 02

Capacity of Recirculation pumps m3/hr. 650 - 860




5.10 SECONDARY SEDIMENTATION TANK

The effluent from aeration tanks will flow to the sedimentation tank, where mixed liquor is allowed to settle under dormant condition. Settled sludge is removed from bottom whereas clarified wastewater is recovered from weirs. Settled sludge will be returned to the aeration tank through opening at bottom of the tank. Table-35 presents influent characteristics and design criteria used for design of sedimentation tank.

Table 35: Design Criteria of Secondary Sedimentation Tank

Process Parameters Unit Range Value

Wastewater flow

Average Wastewater Flow m3/day 4,000

Peak hourly flow m3/hr. 200

MLSS in Aeration Tank mg/L 4,000

Recirculation ratio - 0.6

Design Criteria

Overflow Rate – Peak Flow m3/m2-hr <1.0 0.50

Solid Loading – Peak kg-SS/m2-hr 2 – 3 3.0

Diameter of Inlet Drum % >20 15

Surface area for sedimentation tank was calculated for each loading rate. Solid loading rate governed the area requirement. The design of sedimentation tank is presented in Table-36.

Table 36: Design of Secondary Sedimentation Tank

Design Unit Value

Number of units - 02

Diameter of tank m 16.5

Surface Area (Provided) m2 214


Bed Slope 1:12

Free Board (minimum) m 0.50




5.11 ADVANCED CHEMICAL OXIDATION

The wastewater discharged from SST will still have COD greater than the PEQS values. Therefore, a chemical Oxidation unit will be required to bring the COD to the required limits. The details are presented in the Table-37.

Table 37: Chemical Oxidation Tank with Neutralization Tank

Description Units Value

Influent Parameters

Daily Wastewater Flow m3/day 4,000

Peak Pumping Rate m3/hr. 200

Influent Chemical Oxygen Demand mg/L 570

Effluent COD mg/L 150

Chemical Oxidant

Name of Chemical Fenton’s Reagent

Typical Dosing Rate

Fe gm/gm COD rem. 30

H2O2 gm H2O2/gm Fe 15

Reaction Time H2O2 minutes 45

Removal Efficiency % 74%

Design of Chemical Oxidation

Fe Dosing

Chemical Consumption of Fe kg/hr. 2.78

Mixing time minutes 1.0

Flash Mixing Tank



Length x width m x m 1.65 x 1.65

Volume m3 3.33

Velocity Gradient sec-1 500 - 1500

Design of Tank for H2O2 Dosing

Volume of reactor, Required m3 150



Length x width m x m 7.0 x 7.0

Chemical Consumption

H2O2 Consumption kg/hr. 41.7

H2O2 (50% Solution) Liters/hr. 69.5





Design of Neutralization Tank

Design Criteria

Retention Time minutes 10

Design of Tank @ Peak Flow



length m 4.40

Width m 2.65

Volume, provided m3 33.8


CHAPTER 06: TERTIARY TREATMENT

The treated wastewater will be in conformance to all PEQS except TDS and its constituent Chlorides and Sulphates. To further treat the water to bring down the TDS limits is possible through Membrane Filtration. It would be advisable to install Rapid Sand Filters before the Low Pressure Membrane Treatment. At the same time, the concentrate (Reject) which will contain very high ppm of TDS will also be required to pass through some evaporation process to extract salt from it. Therefore, bringing the TDS below 3,500 ppm treated wastewater could be discharge into the inland water.

This scheme will have very high capital and operational cost. It is advisable to design tertiary treatment after at least one year of CETP smooth and stable operations. At that time various options shall be studied for reused of treated wastewater such as;

1. Further treatment with domestic sewer of Sialkot City,2. Recycle in the soaking process,3. Reuse in irrigation or greening of STZ through cultivation of salt tolerant species of

plants,4. Use in the composting of Solid waste, etc.

After having one year’s data based precise information on treated water quality will enable designer to choose any option from the aforesaid alternatives or select proper membranes for RO treatment. In the following section, a conceptual design and cost estimate has been presented to support the decision making process.

The proposed membrane treatment will comprise the following:

Rapid Sand Filtration/Activated Carbon Filtration Low pressure RO Unit Vacuum evaporation

Table 38: Capacities of Tertiary Units

Description Feed water (m3/hr) Recovery

(%) Product (m3/hr)

Total Product (m3/hr)

Capacity of single train (consisting pretreatment followed by RO membrane)

Pretreatment 167 100 167 Total feed to RO

RO System 167 60 100 100

Total 100

Concentrate that will be taken to Vacuum Evaporation 67

Details of Sand Filters are presented hereunder:




6.1 RAPID SAND FILTERS

Wastewater from Neutralization Tank will flow into Rapid Sand Filters for further polishing. The design criterion of filter is presented in Table-39.

Table 39: Influent Data and Design Criteria for Rapid Sand Filters

Parameters Units Range Value

Influent Characteristics

Daily Wastewater Flow m3day 4,000

Peak Flow m3/hr. 200

Influent Suspended Solids mg/L 200

Influent BOD Concentration mg/L 80

Influent COD Concentration mg/L 150

Temperature °C 20

Design Criteria

Filtration Rate

Average flow condition m3/m2.hr 5 – 10 7

Peak flow condition m3/m2.hr ≤ 10 8

Backwash Rate m3/m2.hr 45 – 75 45

Water Depth above media mm > 1000 1,000

Viscosity m2/s 9.42E-07

SS Removal Capacity kg/m2 2.5 – 4.5 4.0

Filter Media

Clean Silica Sand

Uniformity Coefficient 1.40

Shape Factor 0.75

Porosity 0.40

Size (2mm for Single Bed) mm 0.80

Depth of Bed mm 1,000

Anthracite


Shape Factor 0.60

Porosity 0.56

Size mm 0.80




Parameters Units Range Value

Depth of Bed mm 750

Gravel (Provided As Support Medium)


Shape Factor 0.73

Porosity 0.50

Size mm 25

Depth of Bed mm 150

Design of gravity filter is presented in Table-40;

Table 40: Design of Rapid Sand Filters

Parameters Unit Value

Filter service time hrs 2.7

Surface area, required m2 25

Number of filters - 1 + 1 Standby

Tank diameter m 5.70

Surface area, provided m2 25.5

Total depth m 3.90

Backwash time min 30

Treated water tank would serve as source water for filter backwash. The backwash pump shall be connected to the electrically operated valves installed at inlet and outlet of filter to facilitate automatic backwash.

6.2 LOW PRESSURE MEMBRANE TREATMENT

The wastewater from the RSFs will be pumped to the RO unit for further treatment. The required quality of treated water to used in agriculture or can be discharged to irrigation canal is shown in the Table-41.

Table 41: Required Quality of Reclaimed Water


Ammonia mg/L --

Arsenic mg/L 0.10

Bicarbonate (HCO3) mg/L --





BOD5 mg/L 30

COD mg/L --

Cadmium mg/L 0.01

Chromium mg/L 0.1

Chloride mg/L --

Calcium mg/L --

Lead (Pb) mg/L 5.0

Magnesium mg/L --

Nitrate mg/L --

Nickel mg/L 0.2

Sulphate mg/L --

TSS mg/L 30

TDS mg/L < 500

Total Hardness mg/L --

Turbidity NTU --

Zinc mg/L 2.0

Coliform -- 23/100ml

Chlorine (Residual) mg/L < 1

pH -- 6-9

Temperature C --

Selection of appropriate membrane will be done as per the criteria shown in the Table-42.

Table 42: Energy Consumption, Product Recovery, and Removal Efficiencies of Different Residual Particulate Matter Removal Operations

Factors Reverse osmosis

Membrane Driving Force Hydrostatic pressure difference

Typical pore size (µm) Dense (<2nm)

Typical operating range 0.0001 to 0.001

Selected for influent TDS range > 2000 mg/L

Typical constituents removed Very small molecules, color, hardness, sulfates, nitrate, sodium and other ions

Operating pressure 16 bars

Energy consumption 3 – 10 kWh/m3

Product recovery 70 – 85 %




Simulation of selected RO membrane is done with the help of ROSA a purpose built Software.

6.3 LOW PRESSURE VACUUM EVAPORATION

The concentrate having very high ppm of TDS will be taken to the evaporator for extraction of salt. Vacuum evaporator will be selected for 50 m3/hr flow and 17,000 ppm TDS.


CHAPTER 7: DESIGN OF SLUDGE LINE

This chapter presents the Design of the Sludge Line of CETP for Phase I for total capacity of 4,000 m3/day. Sludge line shall consist of following units:

Combined Sludge Thickener

Inline Sludge Conditioning

Sludge Belt Press

Description of each component with its design and basis of design is presented in the following sections.

7.1 COMBINED SLUDGE THICKENERS

There will be two main sources of sludge generation in the CETP; the Primary and the secondary sedimentation tanks. Both the sludge will be taken to Combined Sludge thickened. From the thickener the sludge will be conditioned inline and finally to Filter press for dewatering. Details of thickening unit are presented hereunder:

Table 43: Primary Sludge Thickener (Picket Fence Type)


Primary Sludge

Load kg-SS/d 9,236

Volume m3/day 264

Percent Solids % 3.5

Secondary Sludge

Load kg-SS/d 2,072

Volume m3/day 207


Total Sludge

Load kg-SS/d 11,309

Volume m3/day 471


Design Criteria

Overflow rate m3/m2-d 10

Solid loading rate kg-SS/m2-d 64

Design of Tank


Surface area, required m2 176.7





Geometry of the tank CIRCULAR

Internal tank diameter 15.00

Surface area, provided m2 176.7

Side liquid depth m 3.00

Bottom slope 1 : 10

Volume of tank m3 596

Retention time hrs. 30.4

Output Sludge Characteristics

Output sludge concentration 5.5

Solid capture efficiency % 85

Output sludge amount kg-SS/day 10,178

Output sludge volume m3/day 186

7.2 SLUDGE DEWATERING

The thickened sludge from combined sludge thickener will be conditioned with Polyelectrolyte inline through inline mixer or orifice plate, before final dewatering. The details are provided in the Table-44.

Table 44: Sludge Conditioning Tank and Filter Press


Thickened Sludge Volume m3/day 186

Total sludge dewatering time hrs. 10

Sludge Filter Press

Number of filter press nos. 1 + 1 Standby

Capacity of filter press m3/hr. 20

Operating hours hrs. 9.35

Filter Press Feed Pumps

Number of pumps nos. 1 + 1 Standby

Capacity of pumps m3/hr. 20

Operating duration hr. 9.35

Dewatered Sludge Characteristics

Output sludge concentration % 15 – 20

Solid Capture efficiency % 90

Output Sludge Amount kg-SS/day 9,206

Output Sludge Volume m3/day 46 – 60





Polyelectrolyte Dosing

Chemical dose kg PE/ton SS 5.0

Tentative dose kg PE/d 50.89

Tentative dose (@ 5%) Liters PE/d 110

7.3 SLUDGE DISPOSAL

The dewatered sludge from filter press will be disposed of into designated landfill. The landfill site is proposed and shown alongside the CETP site. The type of landfill proposed is “Area/Mount type” as the ground water table during rainy seasons is up to 1.52m (5 ft.) as provided by STAGL.

The required area for the landfill for disposal of CETP sludge is anticipated to be 27,000m2 (6.67 acres), mainly because of the restriction of mount height of not more than 3 meters.

Table 45: Landfill Area Requirement for CETP Sludge Disposal


Dewatered Sludge Volume m3/day 46 – 60

Dewatered Sludge Amount kg-SS/day 9,206

Total sludge dewatering time hrs. 10

Area of Landfill

Landfill Life years 5.0

Total volume of sludge to be disposed in 5 years m3 108,000

Depth of Mount m 3.0

Compaction % 25

Volume after compaction m3 81,000

Area required m2 27,000

Area required Acre 6.67


CHAPTER 08: PRELIMINARY PROJECT COST

8.1 CAPITAL COST

Table-46 presents estimated and tentative capital cost for single module of CETP, having capacity of 4,000 m3/day.

Table 46: Capital Cost for Single Module of CETP (4,000 m3/day)

# Description Amount

(Million Rs.)

1 Civil Works Including Building, Roads and Yard Piping 200.00

2 Mechanical Works including Machinery, Equipment with Allied Piping 80.00

3 Electrical Works Including External Illumination 15.00

4 Contingency 5.00

TOTAL 300

The prices presented above are tentative and preliminary in nature. Precisecosting will be furnished in ‘Engineers Estimate’ along with the tenderdocuments.

It should be noted that the above mentioned capital cost estimates for civilworks are based on structural design taking into account a normal bearingcapacity of 1.85 kg/cm2 at 1.5 meter depth

Estimates are based on the market rates prevailing in the month of December2017. USD conversion rate is taken at Rs. 110 / USD.

8.2 OPERATION AND MAINTENANCE COST

Table-47 presents annual operational and maintenance cost of CETP.

Table 47: Annual Operation and Maintenance Cost


(Million Rs.)

A Operations and maintenance items

1 Human Resource 10.00

2 Chemical 42.00

3 Energy 80.00

4 Sludge Disposal 7.00

5 Maintenance 1.20





(Million Rs.)

6 Laboratory Cost 1.00

Sub - Total - A 141.2

B Depreciation cost (using straight line depreciation)

1 Civil (based on 25 years span) 8.00

2 Mechanical (based on 10 years span) 8.00

3 Electrical (based on 25 years span for cables and 10 years span for equipment)

0.96

Sub - Total - B 16.96

Grand Total (A+B) 158.16

Rounding Off, Say 158

Table 48: Unit O&M Cost for Wastewater Treatment

# Description Rs./Unit

1 O&M cost Rs./m3 of wastewater 118

2 O&M cost Rs./gallon of wastewater 0.53

The prices presented above are tentative and shall be considered as reference only.

Only depreciation cost is added, other financial costs (capital cost refund, bankcharges, currency devaluation margin, etc.) are not included.

8.3 COST ESTIMATE FOR TERTIARY TREATMENT

The initial estimates show that the capital cost of Tertiary Treatment system will beabout PKR 100 – 115 million. And annual operating cost will be around PKR 90/m3 ofwastewater. This is in addition to the aforesaid costs of secondary treatment.


CHAPTER 09: HUMAN RESOURCE REQUIREMENTS FOR OPERATION AND MAINTENANCE

This component of operation and maintenance mechanism presents the chain of command, number of personnel required to run the plant and specific recommendations for staffing including specific man-hours, job responsibilities according to qualification, experience necessary for proper operation of each unit operation and process.

9.1 PLANT OPERATING HOURS

The plant, under normal course of operation, shall run for 24 hours a day, in following three shifts:

Shift-1 (Morning) 0800 to 1600 (08:00 AM to 04:00 PM)

Shift-2 (Evening) 1600 to 2400 (04:00 PM to 12:00 PM)

Shift-3 (Night) 2400 to 0800 (12:00 PM to 08:00 AM)

9.2 SHIFT TAKE OVER PROTOCOL

Following are some protocols that shall be followed while shift take over:

The predecessor shall hand-over all log books of operation and maintenance datato the successor.

The predecessor shall inform the successor of any accidents that has occurredduring the preceding shift.

The predecessor shall inform the successor of any mechanical and electricalequipment and instrument malfunctioning that has occurred during precedingshift.

The predecessor shall inform the successor of the status of chemical supplies, ifneeding refill, required by the wastewater treatment processes.

Table 49: Staffing Requirement & Recommendation

# Category Staff (No.)

Management and Office Staff

1 Plant Manager (Environmental Engineer) 1

2 Administration & Purchase Officer 1

3 Accountant 1

4 Office Attendants 1

5 Janitors for Plant Building 1




# Category Staff (No.)

Laboratory Staff

7 Chemist 1

8 Assistant Chemist 1

7 Laboratory Attendant 1

Operation Staff

9 Senior Operators 2

10 Operators’ Helpers 3

11 Laborer and Coolies 2

Maintenance Staff

12 Mechanic 1

13 Mechanic Helper 1

14 Electrician 1

15 Electrician Helper 1

16 Equipment Cleaners 1

17 Janitors 2

Miscellaneous

18 Tractor-Trolley Drivers 1

19 Gardener 1

20 Security Guards 2

Total 26

9.3 STAFF TRAINING

Plant staff shall be trained on all the relevant issues relating to plant operation & maintenance and data documentation. Frequency of these trainings can be established according to the need. Consultants, trainers and people from different agencies working on these issues can provide in-house trainings to the relevant staff. Staff should be provided training in the following key areas:

Wastewater Treatment Processes Wastewater Treatment Processes Operating Principles & Controls Wastewater Treatment Processes Trouble Shooting Sludge Collection & Handling Wastewater Treatment Plant Startup & Shutdown Procedures Mechanical & Electrical Equipment and Instrumentation Handling & Maintenance Operational and Maintenance Data Log Books Preparation and Upholding Occupational Health & Safety Operating Data Reporting and Analysis Technical Records & Report Composing / Documentation Computer Proficiency Development / Enhancement


ANNEXURES




Annexure I: “Basic Information and Guidelines for Segregation of Streams in Sialkot Tannery Zone”

Project: “Mainstreaming Climate Change Adaptation through Water Resource Management in Leather Industrial Zone Development” (GEF ID 5666; SAP ID 150052)

“Common Effluent Treatment Plant for Sialkot Tannery Zone”

July 26, 2017

Basic Information and Guidelines for Segregation of Streams in Sialkot Tannery Zone


Project:

“Mainstreaming Climate Change Adaptation through Water Resource Management in Leather Industrial Zone Development”

(GEF ID 5666; SAP ID 150052)

Common Effluent Treatment Plant

For

Sialkot Tannery Zone

Basic Information and Guidelines for Segregation of Streams in Sialkot Tannery Zone

July 26, 2017

A project of:

United Nations Industrial Development Organization (UNIDO)





CONTENTS

1.1 GENERAL INTRODUCTION

1.2 REQUIREMENT OF SEGREGATION

1.3 AVAILABLE OPTIONS FOR SEGREGATION

LIST OF TABLES:

Table 1: Anticipated Chromium content in the CETP Sludge

Table 2: Decision Support Framework

LIST OF FIGURES:

Figure 1: Stream Segregation within Tanneries

Figure 2: Illustration for Option 2


Figure 4: Egg-Shaped Sewer to maintain self cleansing velocity in large variations in flow




1.1 GENERAL INTRODUCTION

The town of Sialkot is located about 130 km from Lahore, in the province of Punjab. Currently, there are 250 tanneries located in 10 different clusters, scattered all around Sialkot city and suburbs. These scattered tanneries are unable to meet the international standards which are becoming more and more stringent with the passage of time. Meeting the international standards needs proper infrastructure which is not possible to be extended to each tannery in scattered locations all around the city. The foremost and critical requirement for international trade and exporting leather goods is the environmental and social compliance.

Relocation of the tanneries to a more spacious location with appropriate infrastructure for efficient and cost effective treatment of solid and liquid wastes has thus become a prerequisite for survival and growth of this vital export-oriented sector of the country’s economy and for protecting the region’s agriculture and health.

Based on these factors, it is planned to shift the tanneries at a dedicated tannery zone away from the main city. The proposed Sialkot Tannery Zone (STZ) is a project initiated and managed by Sialkot Tannery Association (Guarantee) Limited Company (STAGL). The STAGL has been established as a special initiative of the Sialkot Tannery Association and, Government of Punjab. Sialkot Tannery Association (Guarantee) Limited is registered under section 32 of the Companies Ordinance 1984 (XLVII of 1984) to develop focused industrial growth in Sialkot by developing international standard Tannery Zone in the region. The company is limited by guarantee having share capital.

STZ with an area of 392 Acres will provide a central place for various scattered tannery clusters of Sialkot and the surrounding areas. It shall mitigate the environmental pollution in the city. It will be an international standard industrial zone equipped with all facilities & infrastructure like roads, sewerage, water supply, drainage, effluent treatment plants and others. (Ref: EIA of STZ, 2011)

STAGL is supported by UNIDO, which is working on a GEF funded project entitled: ‘Mainstreaming Climate change Adaptation through Water Resource Management in Leather Industrial Zone Development’, has intended to implement a project of Combined Effluent Treatment Plant (CETP) for the STZ.

A result of these joint efforts was the Technical Report depicting Conceptual Design of the Common Effluent Treatment Plant, prepared by UNIDO in 2015. On the basis of this report, to fulfill the requirements of the project, UNIDO seeks the services of consultants for detailed designing and supervision of the implementation of CETP for STZ. Services of NEC Consultants (Pvt.) Ltd are taken by the UNIDO as per a predetermined TOR and subsequent contract.

As per the TORs, NEC is supposed to provide the following:




‘Provide basic information and guidelines for STZ management for segregation of the streams in the tannery/STZ in order to reduce volume of sludge contaminated with chromium. ‘

Accordingly, this report is focused on the essentiality for segregation of tannery wastewater streams and available options:

1.2 REQUIREMENT OF SEGREGATION

It should be noted that characteristics of wastewater discharged from different process (Soaking to Finishing) streams of leather processing are different. They have different pH and chemical compositions. Segregation of these streams is essential because of following three main reasons;

1 Discharge of liming effluent, containing substantial quantities of Sulphide, when

mixed with tanning effluent having pH of 4 -5, results in release of H2S gas which

is fatal to human life. As reported by International literature, it is the most

significant cause for the fatal accidents in tanneries.

2 Discharge of tanning and post tanning effluent contains significant quantity of

Chromium Sulphate. This Cr2SO4 settles in the primary settling tank of any

WWTP/CETP, whenever, it gets higher pH (more than 8). Primary Sludge thus

produced contains significant quantity of Chromium content in it. Disposal of

chrome containing sludge becomes problematic due to following two reasons:

a. Environmental laws: At present, available environmental laws in Pakistan do

not directly address sludge and solid waste discharges. However, it is

anticipated that gradually with the due passage of time such laws will also be

developed and enforced. It should also be noted that International laws and

certifications such as LWG also consider chrome containing sludge as

Hazardous waste. Therefore, it is very important for any new tanning zone or

even individual tannery to consider this aspect very seriously.

b. Health and safety issues. Although the major quantity of Chrome is in the

form of trivalent Chromium, but different environmental conditions such as

high temperature can change it into Hexavalent Chromium which is

reportedly carcinogenic.

Sludge having nominal content of chrome can be safely disposed in any landfill site or alternatively can be fed to composting unit for conversion as fertilizer.




3 Chromium Sulphate is an expensive resource which shall not be wasted into the

drains and logically shall be recovered and reused.

In specific case of Sialkot Tannery Zone, based on the data provided in February 2017, following are the expected quantities of Chromium in the wastewater:

Table 1: Anticipated Chromium content in the CETP Sludge

# Parameter Unit Quantity

1 Wastewater quantity m3/day 3,000

2 TSS mg/l 2,100

3 Chrome concentration mg/l 100

4 Expected Sludge from the Primary Settling Tank Kg/Day 4,725

6 Chrome content in the Primary Sludge Kg/Day 280 - 300

7 Chrome % in Primary Sludge % 6 - 6.4

8 Full Scale CETP 12,000

9 Chrome content in primary Sludge in Full Scale Tons/Day 1.1 – 1.2

Even if the primary sludge is mixed with the secondary sludge and other sludges like alum etc, even then it will be more than 3 % of the total sludge. This high content of chromium will definitely hinder the final disposal or utilization of sludge.

Aforesaid three points, made it absolutely necessary to make such arrangement that following targets can be achieved:

1 100 % fool proof system to avoid mixing of tanning and post tanning effluent

with liming discharge. It will eliminate the risk of H2S production and subsequent

accidents.

2 Recovery of Chromium from wastewater and ultimately from sludge.

1.3 AVAILABLE OPTIONS FOR SEGREGATION

It shall be mandatory in each tannery to have a segregated system of streams as per following scheme:

1 Separate line for Liming discharges

2 Separate line for tanning and post tanning discharges

Subsequently, following options are available for further treatment and conveyance of wastewater:




Option 1:

This option will have the following essential components; (Figure 1, illustratesthe scheme)

Recovery of chrome through Installation of Chrome Recovery Plants in each

wet-blue processing tannery,

Catalytic Oxidation of Liming Discharge within each Tannery,

Mixing of Post CRRP effluent and Post Liming Oxidation effluent with all other

wastewater streams in a common channel equipped with screen. Final

discharge into a common channel towards CETP for complete treatment.

Figure 1: Stream Segregation within Tanneries

Ref: Introduction of Treatment of Tannery Effluents – UNIDO – 2011

Option 2:

Following essential components will be the part of this option.

Separate line from tann-yard of each tannery to common CRRP at CETP site

Separate line from beam house to the CETP site for common Catalytic

Oxidation.

Post CRRP and Post liming oxidation effluents mixed in the CETP treatment

scheme





Option 3:

Recovery of chrome through Installation of Chrome Recovery Plants in each

wet-blue processing tannery. Conveyance of this chrome free effluent mixed

with other finishing effluent to CETP Site.

Separate line from beam house to the CETP site for common Catalytic

Oxidation.





All above options are workable and will necessarily achieve the desired targets. Selection of any one option from the aforesaid three options shall be based on the enforcement authority of industrial by-laws entrusted to STAGL management. To support the decision, a framework summarizing the important factors is presented in Table 2:

Table 2: Decision Support Framework

# Description Option 1 Option 2 Option 3

1 Segregated Streams within Tannery Yes Yes Yes

2 Segregated Streams at Cluster Level No Yes Yes

3 Common Chrome Recovery Plant at Zone Level No Yes No

4 Chrome Recovery Plant within Tannery Yes No Yes

5 Catalytic Oxidation of Liming effluent within Tannery Yes No No

6 Chrome free Sludge Yes Yes Yes

7 H2S Elimination Yes Yes Yes

8 Disposal of nominal chrome sludge in landfill Yes Yes Yes

9 Use of nominal chrome sludge as fertilizer after composting

Yes Yes Yes

10 Cost of CRRP to be borne by: Tannery STZ Tannery

11 Cost of Liming effluent Oxidation to be borne by: Tannery STZ STZ




# Description Option 1 Option 2 Option 3

12 Cost of conveyance system Minimum Higher

than other options

Nominally higher than

option 1

13 Vigilance Requirement from STZ Very High Minimum Moderate

14 International Certification (LWG) fulfillment Yes Yes Yes

15 Acceptable to UNIDO Yes Yes Yes

16 Local Laws compliance Yes Yes Yes

If STAGL can locate all the wet blue processing tanneries in one sector nearest to the CETP, than option 3 would be the best option. Installation of CRRPs in each tannery with a separate line for tanning and post tanning effluents to the CETP site and a separate line for beam-house discharge to the CETP Site may be the best choice.

All the other tanneries which are not involved in the wet-blue processing can use a single conveyance system upto the CETP site.

If relocation of Wet-blue processing tanneries is not possible, than the option 1 would become the best option.

If STAGL foresees weak implementation authority to oversee the individual tanneries, than option 2 is the best fool proof option.

In addition to above mentioned recommendations regarding segregation of Streams, it should also be noted that as per International BEST PRACTICES, a properly designed closed conveyance system having sufficient self cleansing velocity shall be designed and installed. An ideal profile of the conveyance system is the so called egg-shaped sewer:



69

Figure 4: Egg-Shaped Sewer to maintain self cleansing velocity in large variations in flow



70

Annexure II: UNIDO Documents

■ “The Scope for Decreasing Pollution Load in Leather Processing, August 9, 2000



71

■ Emission Factors for the Calculation of the Wastewater Quantity and Quality of the LeatherManufacturing Process



72



73

■ Pollution levels per ton from other types of hides processed (British Leather CompanyDocument)

■ Distribution of effluent pollution according to the different stages of conventional leatherprocessing in kg/t rawhides (salted weight) (British Leather Company Document)



74

Annexure III: Drawings



75

Process Flow Diagram




Layout Plan



77

Master Layout Plan



78

Annexure IV: Punjab Environmental Quality Standards for Municipal and Liquid Industrial

Effluents



79



80



81



82

Annexure V: Schedule of Plant

Wastewater Pump for Beam House Effluent (WP01)

Equipment Wastewater Pumps (WP01)

Location Equalization Tank Beam House

Numbers 02 (01 operating + 01 standby)

Pump

Medium Tannery Wastewater

Pump Type Heavy-duty (horizontal, direct-coupled /vertical, pedestal mounted dry- pit), single-suction, centrifugal, CW rotation, Centrifugal

Capacity 75 m3/h

Head 08 m

Free Pass 80 – 100 mm

Efficiency Guaranteed Duty Point (GDP) is between 80% and 120% of the flow rate at the Best Efficiency Point (BEP).

Pump Casing Cast Iron and shall comply with BS EN 1563 / EN-GJS-700-2

Casing Wear Ring Cast S.G. Iron and shall comply with BS EN 1563 / EN-GJS-450-10

Impeller Cast S.G. Iron and shall comply with BS EN 1563 / EN-GJS-700-2

Make KSB, Flygt, Bedford Pumps, Torishima, Flowserve, Goulds, Sulzer Pumps or approved equal

Motor

Make SIEMENS, ABB or approved equal

Phase/Voltage 3/400 V

Frequency 50 Hz

Efficiency Motor efficiency shall comply with the requirements of IEC 60034 - 30 high efficiency Class IE2.

IP 55

Insulation Class F

Wastewater Pump for Tanning and Post Tanning Effluent (WP02)

Equipment Wastewater Pumps (WP02)

Location Equalization Tank Tanning and Post Tanning


Pump


Pump Type Heavy-duty (horizontal, direct-coupled /vertical, pedestal mounted dry- pit), single-suction, centrifugal, CW rotation,



83

Centrifugal

Capacity 125 m3/h

Head 08 m

Free Pass 80 – 100 mm

Efficiency Guaranteed Duty Point (GDP) is between 80% and 120% of the flow rate at the Best Efficiency Point (BEP).

Pump Casing Cast Iron and shall comply with BS EN 1563 / EN-GJS-700-2

Casing Wear Ring Cast S.G. Iron and shall comply with BS EN 1563 / EN-GJS-450-10

Impeller Cast S.G. Iron and shall comply with BS EN 1563 / EN-GJS-700-2

Make KSB, Flygt, Bedford Pumps, Torishima, Flowserve, Goulds, Sulzer Pumps or approved equal

Motor

Make SIEMENS, ABB or approved equal


Frequency 50 Hz

Efficiency Motor efficiency shall comply with the requirements of IEC 60034 - 30 high efficiency Class IE2.

IP 55

Insulation Class F

Coarse Screens (01)

Equipment Mechanical Coarse Screens (CS) Beam House

Location Coarse Screen Chamber Numbers 03 (02 operating + 01 standby) Medium Tannery Wastewater

Clear spacing b/w bars 20 mm

Height of Screen 1500 mm (Will be Finalized)

Screen angle with horizontal

600

Screen Chamber width 600 mm

Approach velocity 0.65 m/sec

Water depth 300 mm

Material Stainless Steel 316

Make Sun Engineers, Ovivo, ESTRAUGA, COSME or approved equivalent.



84

Coarse Screens (02)

Equipment Mechanical Coarse Screens (CS) Tan House

Location Coarse Screen Chamber Numbers 03 (02 operating + 01 standby) Medium Tannery Wastewater


Height of Screen 1500 mm (Will be Finalized) Screen angle with horizontal

600



Water depth 300 mm



Fine Screens (01)

Equipment Mechanically Cleaned Mechanically Operated rake type Fine Screens (FS 01) Beam House

Location Fine Screen Chamber Numbers 02 (01 operating + 01 standby) Medium Tannery Wastewater

Screen bar depth 75 mm


Screen Chamber width 600 mm Screen angle with horizontal

600


Water depth 300 mm



Fine Screens (02)

Equipment Mechanically Cleaned Mechanically Operated rake type Fine Screens (FS 02) Tan House

Location Fine Screen Chamber Numbers 02 (01 operating + 01 standby) Medium Tannery Wastewater

Screen bar depth 75 mm





85

Screen angle with horizontal

600


Water depth 300 mm



Vortex Grit Chamber

Equipment Vortex grit chamber with grit conveyor, pumps and classifier

Location Grit chamber


Max overflow rate 0.025 and 0.040 m3/m2/sec for Beam House and Tanning & Post Tanning respectively.

HRT 60 seconds

Mechanism Automatic Grit Removal Mechanism

Oil and Grease Separator (01)

Equipment Oil and Grease Separator Beam House

Location Oil and Grease Chamber


Max overflow rate 45 liters/sec

Mechanism Automatic Oil and Grease Removal

Oil and Grease Separator (02)

Equipment Oil and Grease Separator Tan House

Location Oil and Grease Chamber


Max overflow rate 75 liters/sec

Mechanism Automatic Oil and Grease Removal

Jet Aerator (JA01)

Equipment Jet Aerator (JA01)

Location Equalization Tank Beam House

Numbers 02

Type Submersible Ejector Shaft

Air Discharge (each) 18 Nm3/min

Pumping Head 4.0 m

Make Flygt or approved equivalent.



86

Submersible Mixer

Equipment Submersible Mixer

Location Equalization Tank Tanning and Post Tanning Effluent

Tank

Length 33.15 m

Width 25.5 m

Depth 3.0 m

Medium Tanning and Post Tanning Effluent

Density 1,000 kg/m³

Mixer

Numbers 05

Material (Shaft & Propeller) SS 316

Material (Flange, Nuts & Bolts)

SS 316

Make Flygt, SERECO or approved equal

Geared Motor

Make SEW, Flender or approved equal


Frequency 50 Hz

IP 68

Insulation Class F

Mixer Coagulation Tank (MCT)

Equipment Mixer Coagulation Tank (MCT)

Location Coagulation Tank

Type Turbine Propeller Mixers

Numbers of Tank 01

Length 1650 mm

Width 1650 mm

Water Depth 1250 mm


Density 1000 Kg/m³

Agitator

Numbers of Agitator 01

Agitator type Top Entry, Turbine 6 Blades with 45˚ with Agitator Shaft

Make INVENT, Flygt, SHARP MIXER, SERECO, ABS, KSB, LIGHTNIN or approved equal

Material (Shaft & Propeller) SS 316L


SS 316L



87

Geared Motor



Frequency 50 Hz

Velocity gradient 1500/sec

IP 65

Insulation Class F

Accessories Oil level glass etc.

External Finish Epoxy coating on gear box

Miscellaneous

Foundation plate SS 316 plate

Mixer Flocculation Tank (MFT)

Equipment Mixer Flocculation Tank (MFT)

Location Flocculation Tank

Type Paddle Mixers

Numbers of Tank 01

Length 5600 mm

Width 5600 mm

Water Depth 3250 mm


Density 1,000 Kg/m³

Agitator


Agitator type Top Entry, Paddle Type




SS 316L

Geared Motor



Frequency 50 Hz

Speed of rotation (output) 10-15 rpm

IP 65

Insulation Class F



Miscellaneous




88

Mixer Pre-selector Tank (MPT)

Equipment Mixer Pre-selector Tank (MPT)

Location Pre-selector Tank

Type Turbine Propeller Mixers

Numbers of Tank 02

Length 5000 mm

Width 4000 mm

Water Depth 4000 mm


Density 1000 Kg/m³

Agitator






SS 316L

Geared Motor



Frequency 50 Hz

Speed of rotation (output) 50 rpm

IP 65

Insulation Class F



Miscellaneous


Mixer Chemical Oxidation Tank (MCOT)

Equipment Mixer Chemical Oxidation Tank (MCOT)

Location Chemical Oxidation Tank

Type Turbine 6 Flat Blades, Vain Disk

Numbers of Tank 01

Length 7000 mm

Width 7000 mm

Water Depth 3100 mm


Density 1000 Kg/m³



89

Agitator






SS 316L

Geared Motor



Frequency 50 Hz

Velocity gradient 100/sec

IP 65

Insulation Class F



Miscellaneous


Sludge Scraper for Primary Sedimentation Tank (PSCR)

Equipment Sludge Scraper for Primary Sedimentation Tank (PSCR)

Location Primary Sedimentation Tank

Numbers 01

Type Peripheral Driven Rotating Half-Bridge Type Scraper


Tank diameter 13100 mm

Side Liquid Depth 3.0 m

Bed Slope 1:12

Free Board (Minimum) 0.50 m

Make (Motor) Flender, SEW or approved equal

Central Support Unit

Type Ball type turntable

Main Components Stainless Steel

Make Ovivo, Hambaker Adams, Varis Engineering, ESTRAUGA, Landustrie, COSME, or approved equivalent.

Scum Removal Tray

Main Components Stainless steel




90

Sludge Scraper for Secondary Sedimentation Tank (SSCR)

Equipment Sludge Scraper for Secondary Sedimentation Tank (SSCR)

Location Secondary Sedimentation Tank

Numbers 02

Type Peripheral Driven Rotating Half-Bridge Type Scraper




Bed Slope 1:12







Scum Removal Tray

Main Components Stainless steel


Sludge Scraper for Picket Fence Sludge Thickener (PFST)

Equipment Sludge Scraper for Picket Fence Sludge Thickener (PFST)

Location Sludge Thickener

Numbers 01

Type Peripheral Driven Rotating Full-Bridge Type Picket Fence Sludge Scraper




Bed Slope 1:8









91

Aeration System for Aeration Tank Jet Aerators (JA03) Recirculation Pumps (RP01) Air Blower (BL01)

Aeration Tank Dimension

Length 36000 mm

Width 24000 mm

Water Depth 6000 mm

Depth 6750 mm

Equipment Recirculation Pumps

Numbers 02

Pump Type Horizontal, Centrifugal, Dry Mounted

Make KSB, Goulds, Sulzer or approved equal

Efficiency >75%

Pumping Capacity 870 m3/h (approx.)

Head 6.0 m


Frequency 50 Hz

Equipment Air Blower


Type Positive Displacement Air Blowers

Make Dresser Roots, Kaeser, Robuschi or approved equal

Material Cast Iron

Aeration Capacity 170 Nm3/min

Differential Pressure 0.7 bar

Phase/Voltage 3/380

Frequency 50 Hz

Calculated Lifetime 100,000 hrs

Equipment Jet Aerator

Numbers 2

Type Jet Aerators with Nozzles

Make Arbiogaz, Mixing Systems, or approved equal

Material Body: Stainless Steel

Bubble Type Fine bubble

Differential Pressure 0.7 bar

Transfer Efficiency >25 %



92

Primary Sludge Pumps

Equipment Primary Sludge Pumps (PSP)

Location Primary Sedimentation Tank


Each Pump

Medium Tannery Wastewater Sludge

Type Horizontal, Dry Mounted, Screw Centrifugal Impeller

Capacity 35 m3/h

Head 10 m

Sludge Type 3% Solid contents

Pump casing Cast iron (EN-JL 1040, GG25, ASTM A 48 Class 40B)

Rotor 1.4301 / 304 SS, Chrome-plated tool steel

Protection Over Pressure and Dry Run Switch

Make Hidrostal, Vaughan Triton Pumps or approved equal

Each Motor

Make SIEMENS, ABB, Flender or approved equal


Frequency 50 Hz

IP 65

Insulation Class F

Secondary Sludge Pumps

Equipment Secondary Sludge Pumps (SSP)

Location Secondary Sedimentation Tanks


Each Pump



Capacity 60 m3/h

Head 10 m






Each Motor



Frequency 50 Hz

IP 65

Insulation Class F



93

Thickened Sludge Pumps

Equipment Thickened Sludge Pumps (TSP)

Location Primary Sludge Thickeners


Pump



Capacity 20 m3/h

Head 10 m






Each Motor



Frequency 50 Hz

IP 65

Insulation Class F

Sludge Belt Filter Press

Equipment Sludge Belt Filter Press (SFP 01)

Numbers 02 (01 Operating + 01 Standby)

Type Belt Press


Make European / North American Brand or approved equal

Loading Sludge Rate 20.0 m3/hr

Input Sludge Concentration 5%

Output Sludge Concentration

15 – 20 %

Essential Component 1. Washing Water Pump2. Air Compressor

K-Polymer Dosing Pumps

Equipment K-Polymer Dosing Pumps (DP)

Location K-Polymer, Chemical Dosing Tanks

Numbers 03 (2 operation + 1 standby)

Pump

Medium K-Polymer

Pump Type Diaphragm with controller



94

Make European / North American Brand or approved equal Capacity 100-150 lit/hHead Minimum Head Required Motor Make European / North American Brand or approved equal Phase/Voltage 1/200 V Frequency 50 Hz IP 65 Insulation Class F

A-Polymer Dosing Pumps

Equipment A-Polymer Dosing Pumps (ADP)Location A-Polymer, Chemical Dosing TanksNumbers 02 (1 operation + 1 standby) Pump Medium A-PolymerPump Type Diaphragm with controller Make European / North American Brand or approved equal Capacity 5-15 lit/hHead Minimum Head Required Motor Make European / North American Brand or approved equal Phase/Voltage 1/200 V Frequency 50 Hz IP 65 Insulation Class F

Alum Dosing Pumps

Equipment Alum Dosing Pumps (ADP) Location Alum, Chemical Dosing Tanks Numbers 02 (1 operation + 1 standby)

Pump Medium Alum Pump Type Diaphragm with controller Make European / North American Brand or approved equal Capacity 25-100 lit/hHead Minimum Head Required Motor Make European / North American Brand or approved equal Phase/Voltage 1/200 V Frequency 50 Hz IP 65 Insulation Class F



95

Hydrogen Peroxide Dosing Pumps

Equipment Hydrogen Peroxide Dosing Pumps (HDP)

Location Hydrogen Peroxide, Chemical Dosing Tanks


Pump

Medium Hydrogen Peroxide (50% Solution)



Capacity 50-120 lit/h

Head Minimum Head Required

Motor



Frequency 50 Hz

IP 65

Insulation Class F

Ferric Chloride Dosing Pumps

Equipment Ferric Chloride Dosing Pumps (FDP)

Location Ferric Chloride, Chemical Dosing Tanks


Pump

Medium Ferric Chloride (40% Solution)





Motor



Frequency 50 Hz

IP 65

Insulation Class F

Manganese Sulphate Dosing Pumps

Equipment Manganese Sulphate Dosing Pumps (MDP)

Location Manganese Sulphate, Chemical Dosing Tanks


Pump

Medium Manganese Sulphate





96

Capacity 5-50 lit/h


Motor



Frequency 50 Hz

IP 65

Insulation Class F

Sodium Hydroxide Pumps

Equipment Sodium Hydroxide Dosing Pumps (DP)

Location Sodium Hydroxide, Chemical Dosing Tanks


Pump

Medium Sodium Hydroxide





Motor



Frequency 50 Hz

IP 65

Insulation Class F

HCl Dosing Pumps

Equipment HCl Dosing Pumps (DP)

Location HCl, Chemical Dosing Tanks


Pump

Medium HCl





Motor



Frequency 50 Hz

IP 65

Insulation Class F



97

Dissolved Oxygen Meter

Equipment Dissolved Oxygen Meter

Location Aeration Tank, Equalization Tank Beam House

Numbers 03

DO Meter

Specific Requirement

The aim of dissolved oxygen measurement is to keep the waste treatment process functioning properly and to hold the dissolved oxygen level within an acceptable range and avoid conditions detrimental to the process. The equipment shall be controlled by the PLC system.

Meter shall be of the floating ball type. Measurement range 0-10 mg O2/l.

Accuracy of ±0.1 on oxygen content. Accuracy on zero ± 0.1 ppm.



pH Meter

Equipment pH Meter

Location Equalization Tanks, Mixing Tank, Flocculation Tank, Aeration Tank, Chemical Oxidation Tank, Neutralization Tank

Numbers 08

pH Meter

Specific Requirement Online pH measurement, range pH 2-12. Accuracy of meter ± pH 0.1.





98

Annexure VI: Motor List

Equipment Working Standby Power (kW)

Total kW

Working Hours

Daily kW/h

Wastewater Pumps Beam House (Capacity 75 m3/hr & Head 8 m)

1 1 3.7 3.7 20 74.0

Wastewater Pumps Tan House (Capacity 125 m3/hr & Head 8m)

1 1 4.0 4 20 80.0

Coarse Screen Beam House (Clear spacing 20 mm)

2 1 0.75 1.5 24 36.0

Coarse Screen Tan House (Clear spacing 20 mm)

2 1 0.75 1.5 24 36.0

Fine Screen Beam House (Clear spacing 06 mm)

1 1 0.75 0.75 24 18.0

Fine Screen Tan House (Clear spacing 06 mm)

1 1 0.75 0.75 24 18.0

Vortex Grit Chamber (Beam House) Sand Classifier + Sand Trap

1 1 1.65 1.65 24 39.6

Vortex Grit Chamber (Tan House) Sand Classifier + Sand Trap

1 1 1.65 1.65 24 39.6

Oil and Grease Separator Beam House (Capacity 45 liters/sec)

1 1 0.18 0.18 24 4.3

Oil and Grease Separator Tan House (Capacity 75 liters/sec)

1 1 0.37 0.37 24 8.9

Jet Aerator (Submersible Ejector Shaft for Beam House 18 Nm3/min each)

2 0 37 74 24 1,776.0

Submersible Mixer (Volume of tank 2,536 m3)

5 0 2.5 12.5 24 300.0

Mixer for Coagulation Tank (Volume of tank 3.40 m3)

1 0 0.18 0.18 24 4.32

Mixer for Flocculation Tank (Volume of tank 101.9 m3)

1 0 1.5 1.5 24 36

Mixer for Pre-Selector Tank (Volume of tank 80 m3)

2 0 3 6 24 144

Mixer for Chemical Oxidation Tank (Volume of tank 152 m3)

1 0 1.5 1.5 24 36

Sludge Scraper for PST (Diameter of tank 13.1 m)

1 0 0.25 0.25 24 6

Sludge Scraper for SST (Diameter of each tank 16.5 m)

2 0 0.25 0.5 24 12



99

Equipment Working Standby Power (kW)

Total kW

Working Hours

Daily kW/h

Sludge Scraper for Picket Fence Sludge Thickener (Diameter of tank 15.0 m)

1 0 0.37 0.37 24 9

Recirculation Pumps for Aeration Tank (Capacity 870 m3/h and Head 6.0 m)

2 0 30 60 22 1,320

Blower for Aeration Tank (Capacity 170 Nm3/min and Differential Pressure 0.7 bar)

2 1 245 490 20 9,800

Primary Sludge Pumps (Capacity 35 m3/h)

1 1 4 4 24 96

Secondary Sludge Pumps (Capacity 60 m3/h)

2 2 9.3 18.6 22 409

Thickened Sludge Pumps (Capacity 20 m3/h)

1 1 3 3 10 30

Sludge Belt Filter Press (Capacity 20 m3/h)

1 1 2.2 2.2 10 22

K-Polymer Dosing Pumps 2 1 0.026 0.052 10 1

A-Polymer Dosing Pumps 1 1 0.026 0.026 20 1

Alum Dosing Pumps 1 1 0.026 0.026 20 1

Hydrogen Peroxide Dosing Pumps

1 1 0.026 0.026 20 1

Ferric Chloride Dosing Pumps 1 1 0.026 0.026 20 1

Manganese Sulphate Dosing Pumps

1 1 0.026 0.026 20 1

Sodium Hydroxide Pumps 1 1 0.026 0.026 20 1

HCl Dosing Pumps 1 1 0.026 0.026 20 1

kW/day 14,359

kW/hour 598

Process Design Report (Revision 02)

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Transcript of Process Design Report (Revision 02)