§ Mr. FlynnTo ask the Secretary of State for the Environment how many sewage treatment plants in England and Wales use the root-zone method to reduce river eutrophication.
§ Mr. Heathcoat-AmoryThe root-zone method of sewage treatment is claimed to be a cost-effective treatment of sewage for small communities. In the United Kingdom it is not primarly used to control the discharge of nutrients and is not noticeably better in this respect than conventional sewage treatment.
I understand that there are currently some 35 trial or test sites in England and Wales at which the process is being evaluated.
§ Mr. FlynnTo ask the Secretary of State for the Environment what guidance is available for the National Rivers Authority and sewage undertakers on(a) controlling the level of phosphates entering rivers and lakes and (b) the maximum acceptable concentration of phosphates in rivers and lakes to prevent deleterious effects on waters of high wildlife interest.
§ Mr. Heathcoat-AmoryThe National Rivers Authority is responsible for the quality of rivers and lakes and for controlling discharges into these waters, and makes it own decisions on these matters. There are no national guidelines for rivers and lakes.