An anaerobic biogas digester tank wastewater treatment is constructed simply and ingeniously, with a settling zone located at the top of the reactor. The wastewater enters from the bottom of the anaerobic digestion tank and flows upward through the sludge bed zone, coming into contact with a large number of anaerobic bacteria. The organic substances in the wastewater are decomposed by anaerobic bacteria, resulting in biogas (primarily composed of CH4 and CO2). During the upflow process, the wastewater carries biogas and anaerobic bacteria solids.
The biogas undergoes solid-liquid separation in the gas chamber zone, and the treated purified water is discharged from the top of the reactor, completing the entire wastewater treatment process. Most of the sludge in the settling zone can be returned to the sludge bed zone, maintaining a sufficient biomass in the reactor. Therefore, the entire upper portion of the reactor integrates biological reaction with sedimentation, without mechanical stirring or filler, making the structure relatively simple and facilitating operation and management.
When treating most organic wastewater with the correct operating method, anaerobic granular sludge can generally be cultivated within the reactor. Anaerobic granular sludge has the characteristics of high removal activity for organic substances, a higher density than floc sludge, and good sedimentation performance, allowing a high biomass to be maintained within the reactor.
Due to the ability to maintain high biomass within the biogas storage tank, the sludge age is long, while the wastewater has a short HRT within the reactor. Thus, the SRT is greater than the HRT, allowing the reactor to have a high volumetric load and good operational stability. This is the biggest difference between modern anaerobic digestion tanks and traditional anaerobic digestion tanks.
Anaerobic digester for biogas production can handle not only high-concentration organic wastewater, such as alcohol, molasses, and citric acid production wastewater, but also medium-concentration organic wastewater, such as beer, slaughter, and soft drink production wastewater. Additionally, they can handle low-concentration organic wastewater, such as domestic and municipal wastewater. Sludge digesters in wastewater treatment can operate at high temperatures (55 degrees Celsius) and medium temperatures (around 35 degrees Celsius), as well as maintain stable operation at low temperatures (around 20 degrees Celsius). Apart from organic wastewater containing toxic and harmful substances, anaerobic biogas digester can adapt to various types of organic wastewater discharged from different industries.