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)