The investigation of biodegradability of dissolved organic nitrogen in slaughterhouse wastewaters

There are different fractions of dissolved organic nitrogen in domestic and industrial wastewater, and some of them may be suitable for biological use by bacteria, natural algae and plankton when discharged into the aquatic environment. In this thesis project, it is aimed to determine the amounts of nitrogen species in poultry slaughterhouse wastewater and to investigate the biodegradability of dissolved organic nitrogen by applying the incubation procedure. It is seen that dissolved ammonium nitrogen and dissolved organic nitrogen concentrations in raw slaughterhouse wastewater are 50.4 and 58.6 mg/L, respectively, and dissolved nitrite and nitrate nitrogen are below the detection limits. Low dissolved nitrite and nitrate nitrogen concentrations were also detected in the treated slaughterhouse wastewater, dissolved ammonium nitrogen was 14.2 mg/L, and dissolved organic nitrogen was detected at a very low value of 0.6 mg/L. It has been determined that the degradation of dissolved organic nitrogen in raw slaughterhouse wastewater occurs, but there is no successful nitrification. BDON/DON ratios were obtained in the range of 48-68%, and BDON/TDN ratios were obtained in the range of 26-37%. Since the chemical DAF and classical activated sludge units in the wastewater treatment plant are very successful in removing dissolved organic nitrogen, the concentration of dissolved organic nitrogen in the treated slaughterhouse wastewater is very low. Therefore, although the experimental results cannot give us information about the biodegradability of dissolved organic nitrogen, it was determined that all ammonia nitrogen was removed during incubation.