Abstract: A reactor for the biological treatment of water comprises a reactor vessel (1), a fermentation chamber (3) bounded in the vessel, inlets (10) for introducing influent into the fermentation chamber, a settling chamber (4) above the top boundary (2) of the fermentation chamber (3), for separating out sludge from treated water, a downer (5) extending downwards from the settling chamber through the fermentation chamber, for returning separated-out sludge to the fermentation chamber (3), and an outlet (11) for discharging effluent from the settling chamber. In order to improve and accelerate the separation of sludge from effluent in a simple manner, at least one supply line (8a, 9a, 17) opens out tangentially into the settling chamber. A whirlpool is produced in the settling chamber by the supply line.

Abstract: A system for purifying nitrogenous waste water by biological nitrification and denitrification, comprises at least two essentially separated reactor chambers, a liquid supply (4) and a liquid discharge (5). The first, aerated reactor chamber (1) is provided at the top with an overflow to the second, oxygen-depleted reactor chamber (2). The oxygen-depleted reactor chamber (2) is divided at the top into a degassing chamber (7) and a settling chamber (8) having an overflow (9) to the liquid discharge. The first reactor chamber is provided with an air supply (11, 18) and an air discharge (12) located above the supply. The first reactor chamber may be partly divided into a riser (14) and a downcomer (15) which allow, as a result of the air supply, mass circulation to take place in the aerated reactor chamber.

Abstract: The invention relates to a process for the biological treatment of essentially solid organic material, such as fruit, vegetable and garden waste, wherein the material is successively treated in a hydrolysis tank and in an anaerobic methane reactor, and at least a part of the solids issuing from the hydrolysis tank is treated in a second anaerobic reactor with at least one a microorganism of the rumen flora of ruminants; the liquid soluble material produced in the second reactor is further treated in the methane reactor. The material is preferably pretreated mechanically in a destructor. The invention furthermore provides an apparatus for carrying out this process.

Abstract: To avoid considerable vertical and horizontal flows in the settler formed by gas collection hoods, of the upflow anaerobic sludge blanket (U.A.S.B.) reactor, each gas collection hood (3) debouches at one or two ends into a gas collection chamber (8) via one or more openings (19), the upper boundary of said openings being situated below the inside surface of the projection or the top of the hood (3) concerned. The gas collection hoods are situated immediately below the level of the effluent discharge and the depth of the settler is shallow. As a result of the decrease in pressure only a few gas bubbles are consequently liberated and the settling of the sludge is not appreciably disturbed.

Abstract: Apparatus for purifying water containing material dissolved and/dispersed therein. The apparatus comprises an upflow reactor in which, while maintaining a sludge blanket, the water to be purified can be contacted with one or more agents bringing the dissolved and/or dispersed material into a form in which it can be separated from the water; means for the discharge of the purified water from the apparatus; and an influent distributing system to be connected to a central water supply system. The influent distributing system includes a plurality of tube members assembled to form one or more strings. The strings have outlet openings through which the water to be purified can be introduced into the reactor space at a plurality of spaced locations.

Abstract: In order to achieve an essentially turbulence-free zone near the means (11) for the discharge of purified water in an anaerobic purification plant for waste water with a fermentation chamber, a settler disposed above the latter and the said discharge means (11) disposed above the settler, the settler consists of three levels of gas-collection hoods (2, 3, 4), each gas-collection hood of the uppermost level (4) being sited directly above a gas-collection hood of the lowermost level (2), each gas-collection hood of the lowermost level (2) being connected via one or more pipes with a gas-collection hood of the uppermost level (4), and the gas-collection hoods of the uppermost and middle level (4 or 3 respectively) having a direct connection to the gas-discharge line (15).

Abstract: A considerable portion of the gas developed by fermentation in an anaerobic purification equipment for waste water, together with buoyant sludge, is collected by at least one additional collecting system (5), before it may reach the upper part of the reactor. This additional collecting system is fitted at a distance below the collecting system (6) fitted as usual just below the level of one or more overflow gutters (3; 23) for purified water. The additional collecting system (5) has a hydraulic link with one or more rising pipes (7, 7', 27, 32, 31) for raising the liquid sludge mixture by gas lift action. The rising pipes discharge into a separation device (8) from which one or more downpipes (9; 29) for returning separated liquid and sludge extend to the lower section of the reactor chamber. As a result of the tranquility at the top and the turbulence near the bottom, a substantial increase of the load capacity of the equipment can be obtained.