Experience with separating wastewater treatment systems - the ecological housing estate Luebeck Flintenbreite

摘要

The idea of a separating wastewater treatment system is basing on the closing of the water andrnthe nutrient cycle nearly separated from each other and the usage of the nutrients from thernoutput of housing areas. The basic flows of the system are blackwater (the wastewater fromrnthe toilets), graywater (the remaining waste water of the househoulds, from the kitchen andrnthe bathroom) and stormwater. Each flow will be collected and treated separately.rnThe advantages of this system are:rn1. the reuse of the nutrients of the blackwater as liquid fertilizer, the closing of the nutrientrncycle and the production of energy in the biogas plantrn2. a graywater treatment with a low energy demand, return of the cleaned graywater in thernlocal water cyclern3. an on-site stormwater treatment and infiltration for maintaining of the local water cycle.rnThe construction of the "ecological housing estate Luebeck-Flintenbreite" started in 1999.rnThe new housing area will consist of 12 twin houses, 45 terraced houses and 56 flats forrnalltogether 350 people. The wastewater of the houses is separated into three different flows:rnblackwater (collection with vacuum toilets), graywater (treatment in reed bed filters) andrnstormwater (infiltration to the ground). The blackwater is treated in a small scale biogas plantrnand will be converted into biogas and into liquide fertilizer for the use in agriculture. It willrnalso be produced biogas, wich is used in a combined heat and power unit (CHP) for thernheating of the households and of the hot water.rnOtterWasser GmbH and the Technical University of Hamburg-Harburg have started arnresearch programm for the scientific accompaniment of the start up and the first period of thernoperation of the wastewater treatment systems. This includes the investigations of thernefficency of all components as well as mass and energy balances.rnFirst results are:rn3. The water consumption is much lower than in conventional systems (70 l/(cap*d)rninstead of 129 l/(cap*d) as an overall average value for germany)rn4. Due to the separation a significant distribution of the nutrients accurs: 90 % of thernnitrogen, 60 % of the phosphor , 74 % of the potassium are collected in the lowvolumedrnblackwaterrn5. Operational costs for the separating sanitation systems are 20 % less than for thernconventional wastewater system.