Cel The aim of the project is to demonstrate the innovative satisfactory utilization of sludge beds to treat anaerobically low-strength urban waste waters at psychrophilic temperatures. The expected yearly energy-saving is 165 toe. The expected simple payback period is about 5 years.L%The aim of this project was to build a demonstration plant designed for anaerobic treatment of domestic waste waters in a seaside town with a large summer population.The plant, built in Biscarrosse (France) was designed to receive, at peak load, a pollution flow from 10,000 inhabitants. Results obtained during summer 1989 can be summarized as below :- for a pollution flow corresponding to 5,000 inhabitants, (BOD5 : 250 kg/d, COD : 420 kg/d, flow : 550 m3/d), depollution rates were 56% on BOD5, 52% on COD and 67 % on SS (suspended solids);- for a pollution flow corresponding to 10.000 inhabitants, depollution rates were respectively 47 % on BOD5, 43 % on COD and 60% on SS.These results were obtained in live hydraulic conditions of a town sewage plant,which means with high peaks in the hourly flow (maximum hourly flow/average hourly flow = 2.2). On the basis of the experience gained at full scale, an optimization of the equipments design must allow to reach higher depuration yields in case of replication.For what concerns the energy savings, under the assumption of a plant running at full-capacity 180 d/y and at half-capacity 185 d/y (when the effluent temperature is below 15 deg.C) the same depuration yields lead to a primary energy saving of 56 toe/y.From the economical stand-point, taking into account that production of sludge and operating costs are very low, the additional cost of a plant including an anaerobic stage and a finishing aerobic stage (this combination allows to meet the required levels of depuration) compared to the cost of a conventional aerobic plant, can be paid off in less than 2 years.The anaerobic waste water treatment plant consists of a cylindrical concrete fermentor (diameter: 18.5 m; height: 4 m) with a PVC cover and a diameter of 10 m decanter which prevents wash-out of sludge from the system.Waste water will be distributed at the bottom of the digester by a network of 24 pipes and circulate from bottom through a sludge bed to top where it overflows to the decanter.The digester will be covered by a plastic sheet. The top part of the basin will hence serve as intermediary gas holder.The waste water treatment plant will treat daily at the innovative temperature of 15-22 C 1500 m3 of waste water (10,000 population equivalents) at a daily load of 1250 kg COD equivalent to 500 kg BOD. The running parameters will be: mean hydraulic residence time of 13 h, space loading rate of 1 kg COD per m3 of digester per day, food to microorganism ratio of 0.2-0.3 kg COD per kg volatile suspended solids per day, expected yield of 85-90 % on BOD.165 toe will be saved yearly, a calculation made by comparison with the energy demand of an analogous aerobic process. The simple payback period is about 5 years, as calculated taking into account the price of the energy saved and the saving of the reduced maintenance compared to the aerobic analogous process.Monitoring will include physical parameters (flow rates, and temperatures), chemical parameters (pH, BOD, COD, volatile fatty acids, suspended matter, nitrogen and gas composition) and microbiological parameters. Program(-y) ENG-ENDEMO C - Programme (EEC) of demonstration projects and industrial pilot projects (EEC) in the energy field, 1985-1989 Temat(-y) 1.6 - TREATMENT OF WASTE Zaproszenie do składania wniosków Data not available System finansowania DEM - Demonstration contracts Koordynator Bertin & Cie Wkład UE Brak danych Adres 59 rue Pierre Curie Zone Industrielle des Gatines 78373 Plaisir Francja Zobacz na mapie Koszt całkowity Brak danych
