Objectif The project aims at constructing a biomethanation plant for the treatment of wastewaters containing organic compounds originating from a chemical industry. The wastewater will be depolluted at 90%. The biogas will be recovered as a gaseous fuel. The innovative aspect of the project is the adaptation and application of a technology, known for other wastewater treatments, to a new type of wastewater. The expected energy saving by substituting the produced biogas to fuel is equivalent to 1420 TOE per year. The expected simple payback is calculated at 4 years.At this day the biomethanation plant treats the 12 000 kg COD produced each day. The loaded volumic charge can reach 14,5 kg of COD/m3 of Flocor/day, and the pollution abatement is often superior to 95% with an hydraulic retention time of 6 days.The energy balance is also greatly improved with front and anaerobic processing as we can see here after.FOR EACH TON OF COD REMOVED KWh TOEMaintenance of the plant at 37 deg. C Steam (ton) = - 0,02 - 0,096 - 0,007Electricity consumptionElectricity kWh = - 110 - 0,11 - 0,024Methan producedCH4 Nm3 PCI = + 350 + 1,354 + 0,300Electricity saved on aerobictreatmentElectricity (kWh) = + 558 + 0,558 + 0,124Energy saving on each ton of COD removed = 1,706 0,393Including the saving price of nutrients and other products to treat the sludges, theannual cost saving is about 2,5 MFF nnd the return on investment time is about 3 years. Other SGN biomethanation plants are under erection to treat the same kind of chemical effluents.The biomethanation system proposed uses the downflow stationary film technique namely the immobilisation of the active microbial biomass on a fixed macro-carrier and downflow liquid flow within the methane digester. Innovative for the contractor is the use of the FLOCOR R, a PVC macro-carrier in the form of ondulated rings (230 m2/m3 specific surface). The methane digester has a cylindrical form and a capacity of 2150 m3.The influent is introduced in the top part of the methane digester and the effluent and excess solid material removed from the bottom part. Some mixing of the macro-carriers is provided by periodical gas recirculation.The methane digester mixed liquor is maintained at 37 deg.C. The expected gas production rate is about 5.5 Nm3 biogas per m3 digester volume and per day.Upstream of the biomethanation system, the chemical plant discharges about 350 m3/d wastewater with a chemical oxygen demand (COD) of about 47 g/l. This amounts to 16 t COD daily. The wastewateris then heated at 37 deg.C in a heat exchanger of 260 th/h capacity before being led to the methane digester.Downstream of the biomethanation system, the biogas is recovered and burned in the furnace of an existing boiler. The digested liquid effluent will be further treated in the existing aerobic wastewater treatment plant. Programme(s) ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985 Thème(s) 1.3 - PRODUCTION AND USE OF BIOGAS Appel à propositions Data not available Régime de financement DEM - Demonstration contracts Coordinateur SOCIETE GENERALE TECHNIQUES NOUVELLES (SGN) Contribution de l’UE Aucune donnée Adresse RUE DES HERONS 1 78182 SAINT-QUENTIN, YVELINES France Voir sur la carte Coût total Aucune donnée
