Research and analysis

Wastewater treatment in England: data for 2020

Published 21 December 2022

Applies to England

Summary

Urban wastewater includes water from domestic and industrial premises and urban pollution from surface water run-off. Without treatment, urban wastewater has significant adverse impacts on our water environment. This is because it:

• contains nutrients which, when in excess, can speed up the growth of certain plants, disrupting natural processes and harming wildlife
• can be contaminated with harmful chemicals and bacteria which present risks to human health and the wider ecology of our water bodies

The Urban Waste Water Treatment (England and Wales) Regulations 1994 aim to protect the environment from the adverse effects of untreated urban wastewater. The main requirements of the regulations are:

• the establishment of systems to collect wastewater from urban ‘agglomerations’ (towns and cities)
• the secondary treatment of collected wastewater
• the identification of sensitive areas (for example, areas susceptible to eutrophication)
• more stringent treatment of wastewater discharged to sensitive areas

The regulations implement the European Union Urban Waste Water Treatment Directive (91/271/EEC). This publication fulfils the requirement under section 12A(1) of the regulations to regularly publish a situation report on the treatment of urban wastewater and disposal of sludge in England.

An assessment of compliance with these regulations under section 12A(2) can be found in the full datasets on data.gov.uk.

2020 Situation Report for England

Treatment of urban wastewater

In 2020, 99.8% of England’s generated load from wastewater treatment works was compliant with the Urban Waste Water Treatment Regulations.

There were 1,442 agglomerations generating more than 2,000 population equivalent (PE) of wastewater:

• 1,430 agglomerations, generating 59,948,276 PE of wastewater, complied with the requirements of the regulations
• 12 agglomerations, generating 98,190 PE of wastewater, did not comply with the requirements of the regulations

For the 1,442 agglomerations generating more than 2,000 PE of wastewater, there were 1,443 urban wastewater treatment plants with a total design capacity of 78,002,354 PE:

• 914 plants were equipped with technology for primary and secondary treatment
• 529 plants were equipped with technology for more stringent treatment than secondary treatment
• 99.61% of the collected wastewater load was compliant with secondary treatment requirements
• 99.59% of the collected wastewater load was compliant with more stringent treatment requirements

100% of wastewater load was connected to a collecting system or to individual and appropriate systems.

0.65% of wastewater load (388,084 PE) was treated by means of individual or other appropriate systems (non-centralised sanitation systems).

Disposal of sludge

In 2020, water companies produced 807,882 tonnes of sludge. 94% of sludge was reused for soil and agriculture, 3% was incinerated, and 3% was reused through a variety of ‘other’ uses. This includes:

• land reclamation and restoration
• composting
• forestry
• industrial crops
• coppice and vermiculture
• cement manufacture and retail

Wastewater reuse

Approximately 0.06% of wastewater was reused.

Glossary

Population equivalent

The unit of measure used in the Urban Waste Water Treatment Directive for assessing the polluting potential of wastewater discharges. 1 population equivalent (PE) means the organic biodegradable load having a 5-day biochemical oxygen demand (BOD5) of 60g of oxygen per day. This means the oxygen used, largely by bacterial organisms, in breaking down the organic matter in wastewater.

Agglomerations

An agglomeration is an area where the population and/or economic activities are sufficiently concentrated for their wastewater to be collected and conducted to a wastewater treatment plant or to a final discharge point.

Eutrophication

Eutrophication means the enrichment of water by nutrients, especially compounds of nitrogen and/or phosphorus, causing an accelerated growth of algae and higher forms of plant life to produce an undesirable disturbance to the balance of organisms present in the water and to the quality of the water concerned.