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WATER POLLUTION ASSESSMENT

WATER POLLUTION ASSESSMENT. Environmental Standards and Discharge Consents. Environmental Regulation. Regulation of impacts on the environment is now a crucial area of public policy. Over $500 billion p.a. is spent globally on compliance.

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WATER POLLUTION ASSESSMENT

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  1. WATER POLLUTION ASSESSMENT Environmental Standards and Discharge Consents.

  2. Environmental Regulation • Regulation of impacts on the environment is now a crucial area of public policy. • Over $500 billion p.a. is spent globally on compliance. • Environmental impact without any regulation would cost many times that sum.

  3. Setting Standards. • Scientific Understanding • The starting point for setting environmental standards. • Essential to determine dose-effect relationships. • Uncertainties and limitations in the data must be recognised. • the science must provide a firm basis for policy decisions • Precautionary Principle • Mechanism* • identify problem, policy, set standard, monitor *see 21st Report of Royal Commission on Environmental Pollution “Setting environmental standards”

  4. Environmental Standards • Forms of Environmental Standard. • Biological. Limits of physiological change.e.g. lead in blood. • Biomarkers of exposure, not effect. • Inform after exposure has occurred, hence do not prevent the effect. • Exposure from a number of routes, hence no indication of course of action.

  5. Environmental Standards • Forms of Environmental Standard. • Exposure. Acceptable doses at the point of entry to an organism. • Tolerable Daily Intakes (TDIs) • International Programme on Chemical Safety (IPCS) • UNEP, ILO, WHO • Often standards not set (due to lack of information). • Acceptable Daily Intakes (ADIs) • Mainly internationally based health standards. • Food and Agriculture Organisation/WHO • e.g. pesticides, medicines and max residue levels (MRLs)

  6. Environmental Standards • Forms of Environmental Standard. • Environmental Quality. • Acceptable concentration of substance in the environment (air, soil, water) • Water Quality Objectives (WQO), Water Quality Standards (WQS) • benefit the natural environment. • Freshwater fish, Shellfish • benefit human health • bathing waters • quality of water abstracted for use as drinking water

  7. Environmental Standards • Forms of Environmental Standard. • Emission load of pollutant discharged to the environment • car exhaust • but BATNEEC probably better (e.g. legislate for catalytic converters) • Effluent Discharges • main basis for controlling organic pollution and toxic substances in Europe • UK also uses WQO

  8. Environmental Standards and Objectives Therefore, two different approaches to tackle water pollution: 1. The Water Quality Objective (WQO) approach • defines the minimum quality requirements of water to limit the cumulative impact of emissions. • Achieves a certain quality level of the water not harmful for the environment and human health (even after discharges of polluted water). • E.g. early EU water directives (1970-1980) such as: • the Surface Water (Abstraction) Directive (1975), • the Bathing Water Quality Directive (1976), • the Freshwater Fish Directive (1978), • the Shellfish Water Directive (1979)

  9. Environmental Standards and Objectives • 2. The Emission Limits Value (ELV) approach • maximum quantities of pollutants allowed to be discharged from a particular source into the aquatic environment. • Specifies the efficiency of wastewater treatment • Specifies what quantities of pollutants may be released • Subsequent EU directives (1990s) • the Urban Waste Water Treatment Directive (1991) • the Nitrates Directive (1991) • the IPPC Directive (Integrated Pollution Prevention and Control, 1996)

  10. Future - Environmental Standards and Objectives 3. Future approach • Water Framework Directive (2000/86/EEC) • aims • expanding the scope of water protection to all waters, surface waters and groundwater • achieving "good status" for all waters by a set deadline (2015) • water management based on River Basins • “combined approach" of emission limit values and quality standards • getting the prices right • getting the citizen involved more closely • streamlining legislation

  11. Reviewing Standards. • Key Changes in the Policy process. • Numerical standards. • Maturity of toxicology and ecotoxicology • Advances in measurement science. • Improved understanding of the behaviour of substances in the environment. • Pan European Policies

  12. Discharge Consents • basis for setting discharge consents. • water quality objectives (WQO) • river ecosystem classification scheme (RE1 - 5) • Statutory Water Quality Objectives (SWQO) (currently under consideration in UK for use in planning) • Statutory Emission Standards • UWWT Directive 1991 • Dangerous Substances Directive 1976

  13. Discharge Consents Aim - provide adequate monitoring of compliance with standard • Numerical standards should always incorporate protocols for sampling and measurement. • Laboratories should be accredited to appropriate proficiency testing schemes. • Numerical standards should consider the extent of statistical variation (look-up tables) • Self regulation - EA has passed sampling responsibility to water undertaker

  14. Discharge Consents • History • mid 19C Typhoid, TB, Cholera • epidemics , mortality 46/1000 • Royal Commission on Sewage Disposal • nine reports 1901 -1915 • recommended a discharge standard • 20 mg/l BOD, 30 mg/l SS

  15. Discharge Consents Recent legislation • Water Industry Act (1991) • water undertakers can charge, and set consents to sewer • Water Resources Act (1991) • EA authorised to set discharge consents to watercourses • Urban Wastewater Treatment Directive (1991) i.e UWWTD • pan-european standards

  16. Discharge Consents • Apply to “Controlled Waters” • virtually all freshwaters, groundwaters, tidal and coastal waters • Descriptive consents • Discharges that are small, have a low potential to impact the environment (c. 50,000 in UK) 2. Numeric Consents • Discharges having most potential to affect the quality of the receiving water (i.e. large flows, Industrial, STW) • may apply to an individual substance or group of substances (c. 30,000 in UK) • based on Royal Commission Standards, and EU Directives (UWWT Directive)

  17. Discharge Consents Water Companies • Water plc’s set their own consents for sewer discharges • For Commercial and Industrial discharges • Ensures the performance of Municipal WWT Plant (compliance) • Review of existing consents • appeals • Granting of new consents

  18. UWWT Directive (1991) • Size of plant • < 2000 pe are exempt • > 2000 pe before 2006 to comply • Sensitive waters • EA and English Nature interpret the definition of “sensitive waters” • Habitats Directive(1992) • Special Protection Areas (SPAs) • Birds Directive (1979) • Special Areas of Conservation SAC

  19. UWWT Directive (1991) Samples • 24h composite • for 95%ile comparison • for Upper tier • usually 2 X 95%ile limit • waived for exceptional weather conditions • Parameters • BOD5, COD, Suspended Solids (optional) • N & P

  20. Is Final Effluent < 25 mg/l ? YES PASS NO YES PASS NO Look-up table FAIL/Pass YES NO Upper-Tier FAIL UWWTD Monitoring for BOD Is BOD removal > 70% ? Is Final Effluent < 50 mg/l ?

  21. Is Final Effluent < 125 mg/l ? YES PASS NO YES PASS NO Look-up table FAIL/Pass YES NO Upper-Tier FAIL UWWTD Monitoring for COD Is COD removal > 75% ? Is Final Effluent < 250 mg/l ?

  22. UWWTD Monitoring for Phosphorous • STWs discharging to Sensitive waters (inland) must also demonstrate Phosphorous removal. The measurement criteria is different: • Based on annual “average concentration” • average for year (1st January to 31st December) < 2 mgP/l, or minimum 80% removal (<100,000 pe) < 1 mgP/l, or minimum 80% removal (>100,000 pe) e.g. A STW <50,000 pop. has 12 samples taken, meaning that the ‘total’ for the year must not exceed 12 x 2 = 24, (2mg/l average) or must have achieved 80% removal.

  23. UWWTD Monitoring for Nitrogen • STWs discharging to Sensitive waters (inland) must also demonstrate Nitrogen removal. • Sum Individual sample results. • Divide by the number of samples taken to give an average. • average for year (1st January to 31st December) < 15 mgN/l, or minimum 70 - 80% removal (<100,000 pe) < 10 mgN/l, or minimum 70 - 80% removal (>100,000 pe)

  24. UWWTD Monitoring • Key Points • UWWTD uses the same Look-up Table as Water Resources Act. 12 samples taken - maximum number of parameter failures permitted = 2 24 samples taken - maximum number of parameter failures permitted = 3 • UWWTD samples are based on a fixed 12 month programme running from 1st January - 31st December. (Spot Water Resources Act compliance is based on a rolling 12 month programme) • All works are sampled (24 h composite) on pre-determined dates agreed with the Environment Agency.

  25. Coastal Sites • Bathing Water Directive • typically enterovirus critical • Modelling dispersion & dilution • Standard 0 PFU/10litres • typically need 5 log removal • treatment & dispersion/dilution (typ. 4 log) • UV disinfection (typ. 1 - 2 log)

  26. Future Improvements • WQOs Continually Reviewed • LEAPs • Asset management Plans (AMP4,2005) • Undertaker / EA / DEFRA • capital investment for “best ecological effect” • Upgrading works • Relaxation of Consent (typ. 6 months) • interim measures • better primary settlement • supplementary oxygen

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