IMPROVEMENTS TO FACILITIES AND PROCESSES FOR BIOLOGICAL CLEANING AND PREPARATION OF FUEL GASES BY ANAEROBIC FERMENTATION IN TWO PHASES

摘要

1. An installation for the preparation of combustible gases by anaerobic two-phase fermentation, notably of an industrial effluent whose pollutant load is made up essentially of dissolved organic matter, of a type comprising : - a single reactor (1) ; - two distinct zones (2, 3) provided inside this single reactor, i.e., a dead lower zone (3) for acidogenic fermentation, made up of a sludge bed on which the acidogenic microorganisms are grafted, and an upper zone (2) stirred by methanogenic fermentation, the volume of the upper methanogenic zone being about 4 to 10 times greater than the volume of the lower acidogenic zone ; - a baffle (4) for separating these two zones (2, 3), attached to the inner wall of the single reactor (1) and inclined in relation to the latter ; - stirring means (9), notably provided in said upper methanogenic zone (2) ; - pipes (8) crossing the upper methanogenic zone (2) and connected to a tank (7) for conveying the sludge, with the liquid effluent to be directly purified in the lower acidogenic zone (3) ; - pipes (11, 19) for discharging produced gases and sludge ; an accumulation zone for produced gases, stacked upon the methanogenic zone, and - a sludge accumulation zone at the bottom of the acidogenic zone, which installation is characterized in that the upper part of the methanogenic zone (2) is provided with an overflow (13) to allow the liquid from this zone to flow into a decanter (16) through a deflector (15) for the separation of the liquid from carried along sludges, which sludges are recirculated toward the decanter tank (7) for feeding the acidogenic zone (3), in that the baffle comprises a cylindrical part extending to the lower part of the acidogenic zone, and in that the sludges are arranged on a supporting means formed by large surface, high weight and large absorbing power particles.