Biochemical Treatment of Wastewater. Anaerobic methods involve treatment of wastewater without access to oxygen. Instead, methane fermentation is used. The advantage of this method is the high level of converting contaminants with the formation of biogas byproduct.

Wastewater contaminated by nitrogen compounds are converted in the process of denitrification by microbes (such as Paracoccus denitrsficans) with formation of gaseous oxide (NO2) and molecular nitrogen (N2) or ammonia (NН3).

The fermentation occurs in sealed methane tanks (septic tanks). These are air tight reactors filled with immobile biological sludge, sludge ponds or similar. Methane tanks not only treat wastewaste, but also generate gas, which has high calorific value.

The main parameters of anaerobic methane fermentation are temperature, amount of waste and the intensity of mixing the water with the sludge. It should be noted that it is impossible to achieve full fermentation of organic substances in methane tanks, since the process is slow and requires stable and favorable temperature conditions. The degree of organic decomposition in the result is 40% (with methane output of 70%). An important point about the anaerobic process is the slight increase of microbial mass (by an order of magnitude less than in aerobic conditions), it also does not require the removal of large amounts of biological sludge from the reactor.

Biochemical Treatment of Wastewater.. The products of organic destruction, which are formed in the first trophic level, function as substrate for second level microbes. The characteristics of the intermediary products of anaerobic fermentation depend on the composition of the initial contaminants.

Anaerobic oxidation, as a rule, is efficient for treatment of wastewater contaminated with large amounts of organic substances (it ensures decomposition of over a hundred organic compounds).