§ Mr. Allan RobertsTo ask the Secretary of State for the Environment whether he will revise his Department's estimate of the potential efficiency of conventional inland sewage treatment works in eliminating faecal bacteria from the aqueous phase of sewage.
§ Mr. HowardConventional inland sewage treatment works are designed primarily to reduce the biochemical oxygen demand and the suspended solids content of sewage. At the same time, treatment also substantially reduces the faecal bacteria count in the sewage effluent which is discharged. The efficiency with which bacteria are removed varies from works to works and, for this reason, the Department has made no overall estimate.
§ Mr. Allan RobertsTo ask the Secretary of State for the Environment what would be the effect on bacterial levels in the river Ribble of uprating the Clifton Marsh sewage treatment works to include full conventional treatment and disinfection using environmentally benign methods.
§ Mr. HowardThe North West water authority is currently evaluating the effects of uprating Clifton marsh sewage treatment works, including the effects on bacterial levels in the river Ribble.