Objective
To use an anaerobic digestion process to simultaneously purify brewery effluent and produce biogas to be used for hot water generation. Biogas yield should reach 400 litres/Kg COD, with a methane content of 68%.
The biomethanation system has been implanted according to the project description at the brewery "Le Pecheur" at Schiltigheim, near Strasbourg, France.
The methane digester was seeded with 15 kg anaerobic sludge from a wastewater treatment plant and loaded with wastewater at a concentration of 18 g COD per litre. The start-up lasted 6 months during which the space loading rate was progressively increased from 1 to 10 kg COD per m3 digester working volume per day.
Under the final stationary conditions, the biogas production amounts to 600-800 m3 per day with a methane content of 65-68 %. The wastewater treatment efficiency is at all times higher than 90 % whether expressed in COD, BOD or suspended solids. The mean hydraulic retention time must remain higher than 4 days. The biogas produced is burned in the furnace of a boiler of 400 kW capacity. The produced hot water is utilized in the beer-canning plant. Twenty per cent of the produced energy needs to be recycled as hot water toheat the methane digester which requires furthermore 70 kWh as electricity per day. The net energy production amounted to 4140 kWh per day (as heat) or 90 toe per year.
When the polluting taxes are included as fringe benefits, a simple payback period of as low as 2. 6 years may be expected for similar commercial plants.
The anaerobic digestion process is based on the application of mobile and recyclable microbial cells. Thus, effluents of a brewery, at the nominal daily rate of 56 m3 with a COD of 50 g per litre at the temperature of 15 deg. C will be treated in a digester of 260 m3 total volume and 210 m3 working volume in mesophilic conditions.
The methane digester itself includes two zones: a lower zone of 210 m3, in which effluents are mixed with the active sludge with the help of a mechanical mixing device, and an upper zone of 50 m3 used for biogas storage. A solid liquid decanter of 55 m3 is located besides the methane digester. The biogas produced will be used for hot water generation.
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
78373 PLAISIR
France