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.

• Environmental impact without any regulation would

cost many times that sum.

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”

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.

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)

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

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

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)

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)

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

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

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

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

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

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

• Apply to “Controlled Waters”– virtually all freshwaters, groundwaters, tidal and coastal

waters

1. 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)

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

Discharge Consents

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

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

UWWTD Monitoring for BOD

Is BOD removal> 70% ?

Is Final Effluent< 50 mg/l ?

PASSYES

NO

PASSYES

NOLook-uptableFAIL/Pass

YES

Is Final Effluent< 25 mg/l ?

NO

Upper-TierFAIL

UWWTD Monitoring for COD

Is COD removal> 75% ?

Is Final Effluent< 250 mg/l ?

PASSYES

NO

PASSYES

NOLook-uptableFAIL/Pass

YES

Is Final Effluent< 125 mg/l ?

NO

Upper-TierFAIL

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.

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)

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.

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)

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