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Manish Singh, Atanu Basu

15 June 2012

3D TRASAR Technologies for Reliable Waste Water Recycle and Reuse

Outline

Introduction

3D TRASAR Technology for Sugar Background

Technology overview

Data

Summary

3D TRASAR Technology for Membrane Background

Technology overview

Case Study

Summary

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Introduction

There is increasing stress on water resource, and increasingly stringent regulatory norms on water consumption and discharge

Recovery of the effluent streams is a rather daunting task as the quality can have dynamic variations

3D TRASAR Technologies have been developed to automatically handle such dynamic variations and ensure efficient system operation.

These technologies have demonstrated significant water savings, energy savings and asset protection.

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3D TRASAR Technology for Sugar

Sugar Industry Trends and Needs

Trends

• An increasing trend in sugar industry is the production of cogeneration power in addition to producing sugar

• Such cogen plants have boilers and condenser cooling water systems

• Increase in the quantity and quality requirements of water

Needs

• To reduce the water and energy footprint

• Protection of assets (boiler, cooling tower)

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Sugar Cane Milling Process

More than 70% of sugarcane by weight is water !

Lot of water is generated in the form of process condensate when sugar juice is concentrated in evaporator from 12 – 16% solids to 60% solids

This condensate has potential for reuse as boiler water or cooling water make up

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• Very low in dissolved solids• Low in Organics• Has Ammonia

Characteristics

• There are huge dynamic variations in the quality of condensate

Variability

• Difficult to treat in a wastewater plant (high hydraulic load with low organic load)

• When sent to the drain high discharge costs• Frequent variations in quality makes it difficult for

reuse in a boiler / cooling water application

Challenges

Sugar Process Condensate

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Reuse challenges

Formation of organic acids

Decrease in boiler water

pH

Increased caustic dose;

corrosion

Shutdown

Increased organics load

Increased microbial fouling

Increased biocide dose;

corrosion

Tower collapse

Contaminated process condensate, if reaches boiler or cooling tower, can cause serious problems

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Current technologies in market

• Not online• Labor intensive

-naphthol test

• Low sensitivity• Low selectivity

Conductivity

• Very expensive• Time lag in response

Total Organic Carbon (TOC)

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3D TRASAR Technology for Sugar

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Fluorometry based automation that monitors “sugar shots” online, controls the condensate discharge, helps sugar mills maximize the condensate recovery while maintaining the reliable and efficient operation of the boiler and cooling systems.

Process Condensate Return Line To Boiler / Cooling Tower

Blo

wd

ow

nDetect the sugar contamination level with on-line sugar fluorometerDetermine by comparing the sugar reading with the setpointDeliver a signal to trigger alarm and turn on the blowdown valve

during sugar shot

Lower than setpoint

Higher than

setpoint

possibly contaminated with sucrose, organics and inorganics

Sampling Line

3D TRASAR Sugar Fluorometer

Specific to fluorophores present inherently in sugar cane juice

Developed after analyzing data from fluorescence spectroscopy done on sugar juice and condensate samples from various cane sugar mills

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3D TRASAR Technology for Sugar

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Data from Field Application

Sensitivity3D TRASAR® for Sugar is much more sensitive than conductivity

Early detection3D TRASAR® for Sugar detected the entrainment event about 30 min prior to its detection by conventional method being used at site

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Summary & Key Benefits 3D TRASAR Technology for Sugar is a fluorescence-based monitoring technology that is

able to detect the condensate quality variations with high sensitivity and selectivity, and provides early detection

Reliable reuse of vapor condensate as boiler make-up, cooling tower make-up, or other sections of plant (assurance that only good quality condensate goes to boiler / cooling tower)

Water savings (reduced wastewater discharge; reduced raw water consumption) and energy savings; improved environmental sustainability

Meet discharge norms set by environmental regulatory authorities (savings on punitive charges)

Protection of assets (boiler, cooling tower) from potential corrosion, scaling, microbiological fouling

Efficient power co-generation (lesser fresh water, lesser chemicals, cleaner cooling water for cogen plant)

24×7 Remote monitoring and troubleshooting via Nalco 360TM

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3D TRASAR Technology for Membrane

Obstacles to optimal RO performance

Lack of analysis and interpretation of operating data, leading to inappropriate, insufficient or no corrective action being taken

Limited or missing monitoring of operational variables

Insufficient resources to make the proper changes

Operation and/or water source has changed since the original installation

Mechanical limitations of equipment

Bad design

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RO Best Practices

Normalize data

Take action based on normalized trends Detect fouling

Detect scaling

Schedule cleanings

Absolute Chlorine removal to protect the membranes

Optimize Recovery (yield) without compromise

Monitor feed water changes

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Automation

Chemicals & Consumables

Service

Equipment

3D TRASAR Technology for Membrane

3D TRASAR Technology for Membrane Objective

Drive performance towards Best Practices1. Immediate feedback on problems

2. Cleaning at the right time

3. Reduce risk for chlorine exposure

4. Safely operate at optimal (maximum) recovery

5. Improve chemical control

Leading to improved efficiency and reduced costs 1. Water savings

2. Waste water savings

3. Chemical savings

4. Consumables savings

5. Energy savings

• Reduced downtime• Reduced labor cost• Reduced off spec product• Increased capacity• “Green” operation

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1. Immediate Feedback of problems

The main reasons for short membrane life are: Scaling/Fouling

Deferred Cleaning

Halogen attack (chlorine damage)

3DT Technology for Membranes can detect all of these problems and notify with alarm.

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1. Immediate Feedback of Problems

3DTTfM Monitoring

AlarmNotifications!

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2. Cleaning at the right time

Membrane elements MUST be cleaned when one of the following parameters is noticed 15% loss in normalized permeate flow

15% increase in normalized differential pressure

15% increase in salt passage

Failure to follow these rules will result in reduced membrane life

Remember, operation of a membrane system at higher pressure will use more energy!

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2. Cleaning at the right time

Cleaning should have been done here

Ineffective cleanings

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3. Reduce risk for chlorine exposure

Protect against permanent membrane damage from an unforeseen (sudden) increase of chlorine in the feed water

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4. Safely operate at Optimal recovery

Key feature of the technology

Most RO systems are designed for only 75% recovery Because it is conservative

Because these systems are likely not maintained properly

They would rather waste the water than have to replace the membranes

With this technology, we can operate more efficiently and closer to the limits

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Low recoverywasted feed water and excessive water to waste

High recoveryadditional cleaning or destroyed membranes due to scale

5. Improved Chemical control

Dose rate could safely be decreased from 4 ppm to right around 1 ppm

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Good control at 3.5 ppm antiscalant, even with a system that is ON only intermittently.

Implementation

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Concentrate

Permeate

Feed Water

F FuS uSP

P

P

P

TFL

FL

FL

PP

Multiple data streams come into a central unit

3D TRASAR for Membrane Equipment

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A Case Study

System

RO Train (2 stages)

Permeate demand:100 gpm (22.7 m3/h)

Feedwater flow: 160 gpm(36.3 m3/h)

60% recovery

Goals

Obtain stable water production

Decrease water consumption

Decrease total cost of operation

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Halogen controlBefore

Prior to using this technology, halogen control was erratic

A predetermined amount of SBS (sodium bisulfite) is added to the RO feedwater to control free chlorine.

Only spot checks were possible due to limited personnel resources

Occasional ORP surges were likely, but there was no way to know

ORP(Oxidation Reduction Potential) is used to detect the existence of residual chlorine in feedwater to the RO. Even

very low levels of chlorine (< 0.1 mg/L) can harm RO membranes.

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0

100

200

300

400

500

600

700

3/21 3/22 3/23 3/24 3/25 3/26 3/27 3/28 3/29 3/30

Fee

d O

RP

(m

V)

Sulfite pump replaced

0 1 2 3 4 5 6 7 8 9

Time (day)

Occasional ORP surges

Halogen controlAfter

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Better “eyes” on the system, 24/7

Close 24/7 monitoring by Nalco 360TM

Detected occasional ORP surges

Replaced sulfite pump

Protected $10,600 worth of customer assets (membranes)

Water Recovery control

Low recovery levels at ~60% to obtain stable water production.

Low recovery was due to high conductivity in feedwater and high scaling potential at the high pH employed by the system (to prevent excess CO2 leaking through the permeate).

There was a desire to increase recovery, but the existing monitoring system was insufficient to track and detect potential system failures.

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Before After

water recovery rates were increased methodically to 73%

Result – Economic benefit with mitigated risk

Close 24/7 monitoring by Nalco 360TM allowed more aggressive water recovery without hampering system operation

Water recovery was raised to 73%

Cost savings were estimated at $67,000/year

Additional observations: ORP Alerting – SBS chemical pump failure that would have been almost

undetectable without the trended data and alarms of the 3D TRASAR Technology for Membrane systems.

RO Operation – Due to unbalanced changes between the flows and pressures in the system, we were able to identify that the RO system’s concentrate valve had started to fail. We were able to prevent any RO catastrophic damage, stop unnecessary water loss, and most importantly, avoid unplanned RO shut down to fix the valve.

Bad Sensors – Alert notifications for instrumentation issues.

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Summary and tangible benefits Water and waste water savings

- If actual recovery is lesser than design

Increased time between membrane replacement- If membrane life is extended from 2 years to 4 years

Decreased cleaning frequency- If membranes are cleaned once a quarter rather than once a month

Minimize cost / consequence of poor water quality on final product- Ability to be proactive; address water quality issues before they impact

process performance or product quality

Operate on different / lower quality feed water- Lower cost of water when switching from well to surface water- Ability to maintain production when placed under local water use restrictions

Minimize downtime / full availability- Lost production associated with unplanned downtime due to membrane

fouling or membrane replacement

Maximize capital utilization- Get as much water, of “just right” quality, from your existing RO system; avoid

the cost of adding a new RO system

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