Determination of inert chemical oxygen demand (COD) fractions of Cumhuriyet University wastewater

Some amounts of inert products are given into environment due to biological degradation of substrate in activated sludge system. The effluent of biological wastewater treatment consists of inert substrate in influent flow, soluble microbial products and non degradable or slowly degradable organic products. Soluble inert COD (SI) must be determined for discharge standards since it did not give any reaction in activated sludge system and was given with wastewater discharge. However particular inert COD (XI) accumulated in system depending on sludge retention time due to it is only wasted from system by wasted sludge. In this study, in order to determine inert COD fractions in Cumhuriyet University campus wastewater, three aerobic batch reactor systems were used. At the end of approximately 381 h operation, COD composition of campus wastewater were found to be C-T0=372 mgl(-1), X-S0=56 mgl(-1), S-S0=104 mgl(-1), C-S0=149 mgl(-1), S-I=12 mgl(-1), X-I=211 mgl(-1), respectively.