ИСТИНА

Nowadays the removal of nitrogen pollutions became a quite serious problem for treatment of strong nitrogenous industrial wastewater. The conventional way used in low nitrogen loaded sewage treatment and based on combination of two biological processes (nitrification and denitrification) is hardly applicable for these effluents because the majority of existing activated sludge systems are not designed for denitrification (e.g., in the CIS and other Eastern European countries) or already overloaded with nitrogen (in densely populated urban areas). As a consequence, the municipal wastewater treatment plants frequently put very strict ammonia limits for discharge of non-domestic effluents into their sewerage. In this situation, a dedicated nitrogen removal from strong nitrogenous industrial wastewater received a primary attention during the last decade. As a result, a number of new processes based on partial nitrification (nitritation), anaerobic ammonia oxidation, de-ammonification, nitrifier denitrification etc. have appeared in this domain of wastewater treatment. The most pioneering process of this type is so called ANAMMOX in which ammonia is oxidized to dinitrogen gas with nitrite serving as an electron acceptor under anaerobic conditions. To generate nitrite, the special process called SHARON was developed. However, the combination SHARON-ANAMMOX requires an advanced and expensive process control on both stages, which may represent a burden for application as on site treatment in conventional industries. This paper reports about the successful laboratory testing of a new nitrogen removal process called DEAMOX (DEnitrifying AMmonium OXidation) for treatment of such a strong nitrogenous wastewater as baker’s yeast effluent. The concept of this process combines the ANAMMOX reaction with autotrophic denitrifying conditions using sulphide as an electron donor for the production of nitrite from nitrate within an anaerobic biofilm. The achieved results with nitrogen loading rate of higher than 1000 mg/l/d and nitrogen removal of around 90% look very promising because they exceed (in 9-18 times) the corresponding nitrogen removal rates of conventional activated sludge systems and are comparable with those of the combination of SHARON-ANAMMOX processes. The paper describes also some characteristics of the deamox sludge as well as the preliminary results of its microbiological characterisation.