A Point Source of a Different Color: Identifying a Gap in United States Regulatory Policy for “Green” CSO Treatment Using Constructed Wetlands
Abstract
:1. Introduction
2. Methods
3. Results and Discussion
3.1. Current U.S. Regulatory Framework
3.1.1. “Grey” vs. “Green” Wastewater Treatment Policy
Parameter | Secondary Treatment Standards (“grey”) | Equivalent to Secondary Treatment Standards (“green”) | ||
---|---|---|---|---|
30-day average | 7-day average | 30-day average | 7-day average | |
BOD5 | 30 mg/L (or 25 mg/L CBOD5) | 45 mg/L (or 40 mg/L CBOD5) | not to exceed 45 mg/L (or not to exceed 25 mg/L CBOD5) | not to exceed 65 mg/L (or not to exceed 60 mg/L CBOD5) |
TSS | 30 mg/L | 45 mg/L | not to exceed 45 mg/L | not to exceed 65 mg/L |
BOD5 and TSS removal (concentration) | not less than 85% | - | not less than 85% | - |
pH | within the limits of 6.0–9.0 | within the limits of 6.0–9.0 |
3.1.2. CSO Control Policy
- (1)
- Proper operation and regular maintenance programs for the sewer system and the CSOs;
- (2)
- Maximum use of the collection system for storage;
- (3)
- Review and modification of pretreatment requirements to assure CSO impacts are minimized;
- (4)
- Maximization of flow to the publicly owned treatment works for treatment;
- (5)
- Prohibition of CSOs during dry weather;
- (6)
- Control of solid and floatable materials in CSOs;
- (7)
- Pollution prevention;
- (8)
- Public notification to ensure that the public receives adequate notification of CSO occurrences and CSO impacts; and
- (9)
- Monitoring to effectively characterize CSO impacts and the efficacy of CSO controls.
3.1.3. Green Infrastructure Policy
3.2. CSO Treatment Wetlands in the United States
3.2.1. History and Specifications
CSO Community | Construction Completed | Treatment System Area (Acres) | Maximum Capacity (MG) | Peak Design Flow (MGD) | Grit and Floatables Removal | Treatment Wetland Components | Receiving Water |
---|---|---|---|---|---|---|---|
Elkhart, IN | 1999 | 0.5 | NA | NA | Bar screen and sedimentation basin | Free-water surface (shallow and deep zones) wetland, vertical down-flow wetland | Elkhart River |
Akron, IN | 2001 | 6 | 0.5 | NA | Swirl concentrator | Two free-water surface wetlands (“serpentine earthen channels”) | Town Lake |
Washington, IN | 2012 | 27 | 25 | 307.7 | Nutrient baffle and forebay pond | Free-water surface wetland, UV disinfection system | Hawkins Creek |
Syracuse, NY | 2013 | 2 | 0.7 | 28.4 | Swirl concentrator | Floating wetland islands, vertical down-flow wetland, free-water surface wetland | Harbor Brook |
3.2.2. Regulatory Standards and Practices
CSO Community | NPDES/SPDES Permit | Compliance Monitoring (effluent, unless otherwise specified) | Effluent Limits | Basis for Effluent Limitations |
---|---|---|---|---|
Elkhart, IN | None | None | None | None |
Akron, IN | General NPDES | Flow i (MGD) | Report (Daily Maximum and Monthly Average) | Water Quality-Based, Indiana Administrative Code limits for lake dischargers (327 IAC 2-1-6) [48] |
CBOD5 (mg/L) | Monthly Average: 10, Weekly Average: 15 | |||
TSS (mg/L) | Monthly Average: 12, Weekly Average: 18 | |||
Ammonia-nitrogen (mg/L)—Summer | Monthly Average: 1.1, Weekly Average: 1.6 | |||
Ammonia-nitrogen (mg/L)—Winter | Monthly Average: 1.6, Weekly Average: 2.4 | |||
Phosphorous (mg/L) | Monthly Average: 1.0 | |||
pH (standard units) | Daily Minimum: 6, Daily Maximum: 9 | |||
Dissolved Oxygen (mg/L) | Daily Minimum 6 | |||
Escherichia coli (E. coli) (colonies/100 mL) | Monthly Average: 125, Daily Maximum: 235 | |||
Washington, IN | General NPDES | Effluent Flow (MGD), CBOD5 (mg/L), TSS (mg/L), Ammonia-nitrogen (mg/L), pH (s.u.), Dissolved Oxygen (mg/L) | Report | Technology-Based, primary treatment and disinfection [52,54] |
Escherichia coli (E. coli) (colonies/100 mL) | Monthly Average: 125, Daily Maximum: 235 | |||
Syracuse, NY | Draft General SPDES | Event Flow i (MG), BOD5i (mg/L), TSS i (mg/L), Settleable Solids i (mL/L), Oil & Grease (mg/L), Floatable Material (visual obs.), Screenings (Monthly Total—influent only), Ammonia i (mg/L), TKN (mg/L), Total Phosphorous i (mg/L), Dissolved Oxygen (mg/L) | Report | Draft for pilot purposes; Technology-Based, primary treatment and disinfection [51,56] |
Fecal Coliform i (colonies/100 mL) | Overflow Event: 200 | |||
Total Residual Chlorine (mg/L) | Overflow Event: 0.2 |
3.3. European CSO Treatment Wetland Policy
3.4. Sustainability Criteria for CSO Treatment Wetlands
3.4.1. Construction and Avoided Infrastructure Costs
3.4.2. Long-Term Operations and Maintenance
3.4.3. Ecosystem Services
3.5. Critical Analysis and Recommendations
- There is a precedent for different technology/performance-based standards between “grey” and “green” wastewater treatment systems;
- Federal CSO control policy favors technology-based treatment alternatives; and
- Federal guidelines support the integration of sustainable GI alternatives into LTCP’s and NPDES permits.
- (1)
- Benefits of “grey” and “green” CSO treatment systems are assessed using sustainability analyses that include construction and avoided infrastructure costs, long-term operations and maintenance, ecosystem services;
- (2)
- Effluent limits and compliance monitoring requirements take into account fundamental technical differences between “grey” and “green” CSO treatment systems; and
- (3)
- Design recommendations facilitate meeting LTCP goals by versatile application of different treatment wetland technologies (e.g., vertical down-flow, free-water surface).
4. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References and Notes
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Levy, Z.F.; Smardon, R.C.; Bays, J.S.; Meyer, D. A Point Source of a Different Color: Identifying a Gap in United States Regulatory Policy for “Green” CSO Treatment Using Constructed Wetlands. Sustainability 2014, 6, 2392-2412. https://doi.org/10.3390/su6052392
Levy ZF, Smardon RC, Bays JS, Meyer D. A Point Source of a Different Color: Identifying a Gap in United States Regulatory Policy for “Green” CSO Treatment Using Constructed Wetlands. Sustainability. 2014; 6(5):2392-2412. https://doi.org/10.3390/su6052392
Chicago/Turabian StyleLevy, Zeno F., Richard C. Smardon, James S. Bays, and Daniel Meyer. 2014. "A Point Source of a Different Color: Identifying a Gap in United States Regulatory Policy for “Green” CSO Treatment Using Constructed Wetlands" Sustainability 6, no. 5: 2392-2412. https://doi.org/10.3390/su6052392
APA StyleLevy, Z. F., Smardon, R. C., Bays, J. S., & Meyer, D. (2014). A Point Source of a Different Color: Identifying a Gap in United States Regulatory Policy for “Green” CSO Treatment Using Constructed Wetlands. Sustainability, 6(5), 2392-2412. https://doi.org/10.3390/su6052392