Biogas technologies for wastewater treatment
For sewage treatment and utilization of generated organic waste (activated sludge and primary sediments) for the purpose of obtaining biogas and subsequent generation of electric and thermal energy, the following stages exist:
Mechanical stage. The incoming wastewater is cleaned from large solid parts (plastic, glass, etc.) by means of mechanical nets and screens. • With sandals, it is cleaned of sand, slag, broken glass, etc. The resulting solid parts are transported to the landfill for subsequent disposal.
Biological and physicochemical stage. Further, the wastewater enters the primary settler, where water and primary raw sludge are separated. The primary sediment is fed to the methane tanks, where the process of anaerobic digestion and the formation of biogas occurs. The separated water enters the aeration tank, where further biochemical treatment of wastewater takes place by aeration. After the aerotank, the sewage enters the secondary settling tank, where the active sludge is deposited. Surplus of activated sludge is also used as raw material for biogas production. After the secondary settling tank, the water passes through the ultraviolet irradiator, where the final purification and disinfection of wastewater takes place, which is then discharged into a nearby pond.
After passing through the cycle of anaerobic digestion of primary raw sludges and activated sludge, biofertilizer is formed, which can not be used in agriculture, but can be used for landscaping, parks, squares, green areas.