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Disease-producing microrganisms.


Polychlorinated biphenyls: a group of industrial chemicals found in the environment.


Population Equivalent, the amount of oxygen-demanding materials discharged by one person each day.

Per capita consumption (PCC)

The measure of average use per person in an appointed water company’s area. Companies are required to report estimates for both metered and non-metered consumers.


The ability of a medium to pass a fluid under pressure.


A group of aromatic organic compounds which may adversely affect biological sewage-treatment processes or sludge digestion, or cause taste problems in drinking water.

Physical and chemical treatment

Processes generally used in wastewater treatment facilities. Physical processes are for instance filtration. Chemical treatment can be coagulation, chlorination, or ozon treatment.


The ability to dissolve lead.


A contaminant at a concentration high enough to endanger the life of organisms.

Polluter pays principle (PPP)

The Polluter Pays Principle is the principle that the polluting party should pay for the damage they have caused to the natural environment.

Polluting load

The quantity of polluting matter entering a treatment plant or in the effluent discharged into a receiving water during a given period.


Persistent Organic Pollutants, complex compounds that are very persistent and difficultly biologically degradable.

Population equivalent (PE)

The amount of oxygen-demanding materials discharged by one person each day.

Potable water

Water of a quality suitable for drinking.


Periodic Review 2004; the Ofwat periodic review of price limits completed in 2004 to set prices for 2005-2010.


Periodic Review 2009; the Ofwat periodic review of price limits to be completed in 2009 to set prices for 2010-2015.


Processes used to reduce or eliminate wastewater pollutants from before they are discharged.

Primary wastewater treatment

The first stage of the wastewater-treatment process where mechanical methods, such as filters and scrapers, are used to remove pollutants. Solid material in sewage also settles out in this process.

Private sewer

A sewer which is not a public sewer as defined in Section 20 of the Public Health Act 1936.

Process water

Water that serves in any level of the manufacturing process of certain products.

Product water

Water that has passed through a water treatment plant and is ready to be delivered to consumers.

Public sewer

A sewer vested in a water authority by virtue of the provisions of Section 20 of the Public Health Act 1936, as amended by Section 40 and Paragraph 33 of the 8th schedule to the Water Act 1973.

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