SUSTAINABLE WATER AND WASTE MANAGEMENT IN URBAN AREAS

Sewerage system and centralised aerobic wastewater treatment plants (W TP) should not be considered as the only possible solution for sanitat ion. Systems with source control can avoid many problems of the end-of -pipe technology by respecting different qualities of wastewater and b y treating them appropriately for reuse. Different qualities of waste and wastewater in human settlements and appropriate treatment technolo gies can be: 1. low diluted faeces with/without urine and bio waste (c omposter or anaerobic digester), 2. grey water/aerobic biofilm plant, 3. storm water (usage and infiltration) and 4. non-biodegradable waste (reuse as raw material). In order to perform resource management, the material originating from agriculture should be returned to the soil as fertiliser. Of similar importance is the organic material. This hel ps maintaining or building up humus and-creates a sink for carbon when the C-content in the soil is increased. Energy will be saved, too: en ergy-intensive aerobic treatment with nitrification is obsolete as wel l as the production of the respective amount of replaced artificial fe rtiliser. A pilot project for a new settlement for about 300 inhabitan ts in Lubeck, Germany, shall demonstrate the feasibility of a new inte grated system with vacuum toilets and pipes for the collection of blac k water. This will be mixed with shredded bio waste and fed to a semic entralised biogas plant that produces liquid fertiliser without dewate ring. Grey water will be treated in decentralised biofilm systems. Sto rm water is collected, retained and infiltrated in a trench system. Th is way the expensive centralised sewerage system can be avoided for th is settlement. (C) 1997 IAWQ. Published by Elsevier Science Ltd.