§ Dr. CunninghamTo ask the Secretary of State for the Environment if he will list by water authority area the number of sewage outfalls to the sea; and, of those, how many include primary treatment works.
§ Mr. Ridley[holding answer 14 March 1989]: This information is not held centrally.
Applications for new or varied consent conditions for all sewage outfalls to sea are considered by Her Majesty's inspectorate of pollution.
Quantitative conditions are set in all cases and these have regard to the impact of the discharge in the receiving waters. Her Majesty's inspectorate of pollution also requires all new outfalls to include provision for the removal and disposal of screenings and non-biodegradable materials such as plastics. My hon. and learned Friend the Minister for Water and Planning has placed copies of the inspectorate's guidelines for the construction of new sea outfalls in the Library.
We do not set specific treatment standards for discharges to the sea; but authorities, in preparing proposals to improve sewage disposal arrangements in coastal areas will want to consider alternative options including inland treatment and sometimes disinfection. However, as the Royal Commission on environmental pollution made clear in its 10th report, the use of long sea outfalls, which rely upon the action of sea and sunlight to break down bacteria, is often the most environmentally satisfactory system of disposal.