What Is Anaerobic Wastewater Treatment?

Anaerobic biological treatment technology is an efficient wastewater treatment method in which organic matter in sewage is decomposed, metabolized, and digested by anaerobic bacteria in the anaerobic state, which greatly reduces the organic matter content in the sewage and generates biogas. As an important form of biological treatment, anaerobic treatment is successively developing a series of new anaerobic treatment processes and structures, which gradually overcomes the shortcomings of traditional anaerobic processes, and has made great progress in theory and practice.

Anaerobic wastewater treatment

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The capital investment of the anaerobic wastewater treatment process is generally higher than the oxidation ditch and SBR processes. However, as the scale increases, the capital costs of the oxidation ditch and SBR also double. The smaller the ratio, the smaller the gap between the two. When the sewage plant reaches a certain scale, the investment of conventional activated sludge process is less than that of oxidation ditch and SBR. Therefore, the larger the scale of the sewage plant, the greater the advantage of conventional activated sludge process. The main disadvantages of the conventional activated sludge method, A / O and A2 / O methods are that there are many processing units and complicated operation and management, especially the sludge anaerobic digestion requires high-level management. The biogas produced during the digestion process is a combustible and explosive gas. It also requires safe operation, which increases the difficulty of management. However, because the large-scale sewage plant is backed by a large city, with strong technical strength and high management level, it can meet this requirement. Therefore, the disadvantages of the conventional activated sludge method will not become a limiting factor.

Compared with the aerobic biological treatment process of sewage, the anaerobic biological treatment process of sewage has the following main advantages:

Significantly reduce energy consumption, and can also recover bioenergy (biogas);

In the anaerobic biological treatment process, there is no blast aeration device that provides oxygen for microorganisms, which can reduce a large amount of energy consumption. While removing a large amount of organic matter, the anaerobic treatment process is also accompanied by a large amount of biogas. And methane in biogas is a kind of combustible gas, which has high utilization value and can be directly used for boiler combustion or power generation;

The sludge output is very low;

Because most of the organic pollutants in sewage are converted into biogas-methane and carbon dioxide during the anaerobic biological treatment process, relatively few organic substances are used for cell synthesis; at the same time, the aerobic process of microbial proliferation is much higher than the anaerobic process The yield Y of acid-producing bacteria is 0.15 ~ 0.34kgVSS / kgCOD, the yield Y of methanogens is about 0.03kgVSS / kgCOD, and the yield of aerobic microorganisms is about 0.25 ~ 0.6kgVSS / kgCOD.

Anaerobic can degrade or partially degrade some organic substances that aerobic microorganisms cannot degrade; therefore, when the sewage contains hardly degradable organic substances, the effect of anaerobic process is better, or anaerobic As a pretreatment process for improving the biodegradability of sewage, the process provides a basis for the subsequent aerobic treatment process treatment effect.