Determination of Biokinetic Coefficients for the Extended Aeration Activated Sludge System Treating Hospital Effluents in Hot Climate Conditions

Hospital effluents are regarded as a kind of municipal wastewater laden with additional pollutants due to the variety of wards and therapeutic activities in a hospital. This makes the determination of kinetic coefficients and parameters of utmost importance for the successful operation and maintenance of hospital wastewater treatment facilities. Extended aeration activated sludge is one of the most important processes employed in such facilities. The present study is an effort to determine these parameters for the operation of such a facility operating in hot climate conditions. For this purpose, samples of both hospital raw wastewater and plant effluent were taken during a 6-month period from January to June 2014 to determine their BOD5, COD, TSS, PH, and Turbidity. Moreover, MLSS, MLVSS, and DO in the aeration tank as well as the sludge return ratios were measured. Such operation and maintenance parameters as θc, F/M, and SVI were then calculated and the equations of the modified Monod Model were used to calculate the values of the kinetic coefficients such as Y, K, KS, Kd, and µmax for the extended aeration activated sludge process at the hospital wastewater treatment plant as follows: K= 2.19 d-1, Ks=90.74 mg/l, Y = 0.39 g Biomass/g BOD5, Kd = 0.06 d-1, and µmax =0.85 d-1. The results obtained can be usefully exploited for designing similar extended aeration activated sludge processes for the treatment of hospital effluents, especially for those operating in hot climates.