| Abstract: | The Ruhr River is the major source of water supply for the North Rhine-Westphalian industrial district. To ensure drinking water supply from the river a system of reservoirs has been constructed for low flow augmentation. Five additional river impoundments have been built for the abatement of nonpoint pollution. The Ruhr River Association was established in 1913. Its first task was the reduction of coarse pollution by mechanical treatment plants. Activated sludge plants were introduced as early as 1926. Developments continued and presently tertiary treatment is performed by polishing lagoons on one-third of the Ruhrverband plants and a programme of storage and subsequent biological treatment of stormwater is underway. One important future task is nutrient removal from municipal wastewater by chemical precipitation and biological processes. Phosphorous concentrations in river water have to be diminished to fight eutrophication while nitrogen must be reduced because of drinking water considerations. Heavy metals have to be further controlled and organically attached halogens have to be diminished. |
