Patent ID: 7531085

Claim:
An anaerobic biological wastewater purification device, receiving wastewater through a feed pipe discharging purified wastewater through a discharge pipe and discharging built-up gas through a gas outlet pipe, said device comprising: a main chamber, having a lower area into which wastewater is fed; at least one lifting pipe through which built-up gas and purified wastewater which contains sludge particles, emerges from an area which is higher than said lower area; a return tank joined to said main chamber by said lifting pipe having an outlet thereof in the return tank being higher than an inlet thereof in the main chamber; an auxiliary chamber in communication with the return tank, the auxiliary chamber having an upper region and a lower region, said lower region being connected to the main chamber; wherein purified wastewater, which contains sludge particles and which was lifted to the return tank via the at least one lifting pipe, flows out from the return tank to the auxiliary chamber, and wherein purified wastewater flows away to the discharge pipe from the upper region of the auxiliary chamber.