NITRIFICATION PROCESSES IN STABILIZATION RESERVOIRS

Nitrification processes in stabilisation reservoirs have a major role in improving water quality. Wastewater effluents which enter the reser voir usually have a substantial concentration of ammonia. Oxidation of ammonia to nitrates through nitrification processes increases the opt ions of using the water for different purposes. The largest stabilisat ion reservoir in Israel,. Maale Kishon reservoir, is used to store sec ondary effluents of the Haifa treatment plant and during the summer th e water flows into an operational reservoir which is used for irrigati on. The operational reservoir contains large amounts of fish of differ ent species which serve for both commercial and algal control purposes . Thus, high ammonia concentrations in the stabilisation reservoir eff luents may cause fish mortality in the receiving water body and are ha rmful to the reclamation system. Laboratory experiments with the efflu ents of the stabilisation reservoir were conducted in order to find ou t the factors that affect nitrification processes in the reservoir and to evaluate the reasons for the inhibition of these processes. It was found that environmental factors have a decisive effect over nitrific ation in the stabilisation reservoir. The most important factors are t he temperature, solar radiation and mixing.