CONSTRUCTED REED BEDS - A COST-EFFECTIVE WAY TO POLISH WASTE-WATER EFFLUENTS FOR SMALL COMMUNITIES

This paper outlines the increasing need for effluent polishing in the United Kingdom. It puts that need in the context of the more than 700 sewage treatment works serving populations of less than 2000 in Severn Trent Water's area of the English Midlands. Constructed reed beds have their place in a design selection matrix. At the end of 1991, they were in use at 12 sites and more than 60 are programmed for completion in 1992. The design and construction of reed beds used for effluent polishing is described. Detailed results are given for five of the works commissioned between 1987 and late 1991. All produce high quality effluents in terms of BOD5 and total suspended solids. A cost comparison between reed beds and modular sandfilters, based on recent contract prices, is shown. Estimates of maintenance, labor costs, and asset life are included.