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Volume 175: debated on Monday 25 June 1990

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To ask the Secretary of State for the Environment if he will list the research which he has commissioned into denitrification technology; what reports he has received; and if he will place copies in the Library.

[holding answer 21 June 1990]: The Department has been involved with research into denitrification processes as follows:(1) 1972–74, research by the Metropolitan Water Board, Middle Lee Main Drainage Department and the Water Pollution Research Laboratory into the denitrification of sewage effluent by the modified activated sludge process (part funding);(2) 1973–75, research by the Water Research Centre into denitrification by ion-exchange and biological processes;(3) 1977–79, field studies by the Anglian Water Authority of ion-exchange denitrification using fixed bed and experimental continuous loop plants (part funding);(4) 1980–82, field trials by the Anglian Water Authority of fluidised bed biological denitrification plant (part funding);(5) 1987, review by Consultants in Environmental Science Limited of the effects of nitrate removal on water quality in distribution; and collection of information on the operation of denitrification plants in Europe and the United States of America;(6) 1988–89, studies by the Cranfield Institute of Science and Technology of the combined use of ion-exchange and biological denitrification processes (part funding);(7) 1988–89, project by the Cranfield Institute of Science and Technology to develop a computer model of the ion-exchange process for optimum operation;(8) 1990, studies by the Water Research Centre to improve the biological denitrification process.Reports in various forms on all the projects were received, but not all are readily available.I am arranging for copies of reports on projects (5) and (7) to be placed in the Library of the House.