High-Concentrated Sewage Purification Technology

Combined works (CW) can be applied for technological schemes of purification of the highly concentrated wastewater produced by sugar mills, yeast plants, distillery, chemical, and pharmaceutical industries with BOD to 50000 mg/liter.

Sorption and oxidation of the bulk organic matter of initial sewage is carried out in anaerobic bioreactors.
In the process of methane fermentation in anaerobic bioreactors sulphide and hydrosulphide content increases to 10...100 mg/l, and pH level decreases to 4-5. Hydrogen sulfide removal, hydrosulfides and organic impurities sorption and oxidation take place in CW-1. CW provides the increase of pH level due to waste water dilution by circulating activated sludge in the mixing chamber and contacting of the sludge mixture with biocoenosis biofilter adapted to metabolize hydrosulfides and low pH values. At this stage biodegradation of organic impurities by 50-70% with high loads of organic matter in the sludge occurs.
Oxidation of the rest of organic matter as well as deep processes of nitrification and partial denitrification of nitrogen-containing impurities take place in CW-2 at low loads on sludge. The sludge supply from CW-1 into CW-2 for stable discharged biomass mineralization as well as sludge supply from CW-2 into CW-1 to decrease the load of organic matters on the active biomass is foreseen in technological scheme.