ENHANCED BIODEGRADATION OF ORGANIC NITROGENOUS COMPOUNDS IN RESIN MANUFACTURING WASTE-WATER BY ANOXIC DENITRIFICATION AND OXIC NITRIFICATION PROCESS

In this study, a stream of resin manufacturing wastewater with high co ntents of organic nitrogenous compounds was treated by a conventional activated sludge process with extended aeration and a modified anoxic denitrification unit followed with two oxic activated sludge units res pectively. Performance comparison of these two processes showed that t he enhanced biodegradation of organic nitrogen in the modified process was attained with 69.0 % of organic nitrogen removal that related to 39.0 % removal in the conventional process. The anoxic/oxic process al so promoted the removal efficiencies of COD, TKN and TN (total nitroge n) from 91 %, 49.6 % and 7.4 % to 95.3 %, 83.8 % and 74.4 % respective ly, in comparison with the conventional extended activated sludge proc ess. These cheerful results also corresponded to the acceptable averag ed effluent quality: 82 mg/l of CODs, 48 mg/l of Org.-N, 11 mg/l of NH 4+-N, and 42 mg N/l of NO3--N, that could meet the national effluent s tandard of ROC-EPA in 1998. The successful investigation also demonstr ated that about 50 % of the total organic nitrogen removal was achieve d in the anoxic unit associated with denitrification, while the residu al organic nitrogen was removed in the oxic unit. The pilot-study resu lts suggested that the resin manufacturing wastewater containing high concentration of organic nitrogen should be treated by the anoxic deni trification and oxic nitrification process instead of the conventional activated sludge process with extended aeration. Copyright (C) 1996 I AWQ.