Integració de legislació ambiental d'aigües i de gestió de les estacions depuradores d’aigües residuals

Corominas Ll, Acuña V, Ginebreda A, Poch M

Low cost method for determining occurrence and duration of combined sewer overflows

A. Montserrat, O. Gutierrez, M. Poch, Ll. Corominas

7th International Conference on Sewer Processes and Networks

(28-30 Sep 2013)

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Table of contents

• INTRODUCTION• THE METHOD• CASE-STUDY• RESULTS• CONCLUSIONS

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

• Combined sewer overflows (CSO) are a threat for the environment

PROBLEM STATEMENT

EPA

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

CSO legal frameworkUWWTD (1991) – Dot not precise control measures

WFD (2000) – Requires good quality for waters

Updating of UWWTD transpositions to account for CSOs (e.g. Real Decreto 1290/2012)

MONITORING

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Reviewed CSO monitoring methods

Visual inspections Conductivity meter Water quality sensor

Level sensor Flowmeter

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

CSO Occurrence

CSO Duration

CSO Volume Strengths Constraints Indicative

Cost* References

- Easy to implement

- High personnel requirement

Not available · EP A, 1999

- Accurate data

- High cost - Technical knowledge required

20,000 · Gruber et al., 2005 · Caradot et al. (2011)

- Best CSO characterization - Accurate data

- High cost - Technical knowledge required

6,000 - 17,000

· Field et al., 1995 · FWR, 1998

· Blanksby, 2002 · Leonhardt et al., 2012

500 - 1,000- Accurate data - Easy to implement

METHOD

- Moderate cost - Low autonomy - High maintenance

- Moderate cost - Rough estimation of volume

· ADASA Sistemas (personal

communication, 2012)

· Dirckx et al., 2011 · Kleidorfer et al., 2011 · Sonnenberg et al. (2011) · Leonhardt et al., 2012

1,200

Water quality sensor

- Accurate data - Easy to implement

Visual inspection

Sensors

Conductivity meter

Flowmeter

Level sensor

MAIN DRAWBACK: TOO EXPENSIVE TO MONITOR THE ENTIRE CSO NETWORK

Reviewed CSO monitoring methods

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Principle: temperature differences between the sewer gas phase and the CSO

THE METHOD

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Materials & installation setup

Tº sensorWaterproof casing45€ per unit

Optic data readerWaterproof casing240€

3-minutes frequency logging interval -> 120 days storing data

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Materials & installation setup

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Case-study

Barcelona

La Garriga village(16.000 inhabitants)

Besòs river basin

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

La Garriga CSS370Ha drainage area7.3 km long pipesØ 300-800mm13 weirs studied:

- 6 transverse w.- 7 side-flow w.

Flow direction

Case-study

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

La Garriga CSS370Ha drainage area7.3 km long pipesØ 300-800mm13 weirs studied:

- 6 transverse w.- 7 side-flow w.

TOTAL MATERIAL INVESTMENT

924€

Flow direction

Case-study

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Method validation for one single weir

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Method validation for one single weir

1h CSO

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

3 categories of temperature response were defined

Types of temperature responses

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

WeirCSO

1 CSO

2CSO

3 CSO

4 CSO

5CSO

6CSO

7CSO

8CSO

9CSO

10CSO

11CSO

12CSO

13TOTAL

(%)

Clear response 30 27 36 32 35 31 43 29 12 34 18 20 5 48,0

Null response 27 5 13 15 18 15 14 17 11 18 13 37 23 30,0

Not clear response 0 7 8 10 4 11 0 11 34 5 26 0 29 20,0

No Data 0 18 0 0 0 0 0 0 0 0 0 0 0 2,0

EP mean80

93EP (%) 100 82 86 82 100 4981 100 81 40 91 54

For 1 year period, 57 rainfall episodes, 13 weirs:723 responses

Method effectiveness assessment for the entire CSO network

EP = (Category 1 responses + Category 2 responses) / (Category 1,2,3 responses) * 100

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

WeirCSO

1 CSO

2CSO

3 CSO

4 CSO

5CSO

6CSO

7CSO

8CSO

9CSO

10CSO

11CSO

12CSO

13TOTAL

(%)

Clear response 30 27 36 32 35 31 43 29 12 34 18 20 5 48,0

Null response 27 5 13 15 18 15 14 17 11 18 13 37 23 30,0

Not clear response 0 7 8 10 4 11 0 11 34 5 26 0 29 20,0

No Data 0 18 0 0 0 0 0 0 0 0 0 0 0 2,0

EP mean80

93EP (%) 100 82 86 82 100 4981 100 81 40 91 54

For 1 year period, 57 rainfall episodes, 13 weirs:723 responses

Method effectiveness assessment for the entire CSO network

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Low effectiveness closely related to the characteristics of the weir

Stuck water in the structureHigh turbulence in the sewer pipe

Sensor in contact with the water in dry conditions

Method effectiveness assessment for the entire CSO network

CSO9EP: 40%

CSO11EP: 54%

CSO13EP: 49%

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Characterization of the La Garriga CSS

Weir CSO 1 CSO 2 CSO 3 CSO 5 CSO 6 CSO 7 CSO 8 CSO 10 CSO 12

Total Nº CSOs 43 45 64 72 56 103 47 70 43Total CSO duration (min) 898 660 1214 2137 1261 1788 993 1410 870Mean CSO duration (min) 21 15 19 30 23 17 21 20 20Nº of times in Position 1 1 1 5 3 1 15 4 11 0

Nº of times in Position 2 0 2 2 3 4 10 5 8 1

Nº of times in Position 3 3 8 4 4 2 7 3 3 0

Looking for the critical weirs

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INTRODUCTION THE METHOD CASE-STUDY RESULTS CONCLUSIONS

Conclusions

• A low-cost method to quantify occurrence and duration of CSOs was developed

• The method was validated, and high effectiveness obtained in most cases

• The effectiveness was affected by some physical characteristics of the weir

• Highly valuable data was obtained with a minimal investment of 924€

• The method offers potential applications

Science of the Total Environment 463–464 (2013) 904 – 912

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Acknowledgements

ENDERUS (CTM2009-13018)

Juan de la Cierva (jci-2009-05604)

EcoMaWat (MC-CIG Career Integration Grants, ref 293535)

FPI (BES-2010-039247)