فهرست مطالب بهاره کردستانی

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.

Hospital wastewater is among hazardous wastewater due to its composition of pathogens and toxic chemicals. Discharge of untreated hospital wastewater to environment is hazardous for human and environment. Aims of this study were to identify Operational and Maintenance problems of Extended Aeration Activated sludge process in Golestan Hospital wastewater treatment plant (WTP), Ahwaz, Iran, and to find their solutions.
Sampling period was 6 months of 2015. BOD5, COD, and TSS parameters analysed in the hospital WTP effluent. In addition, VLR, Qr/Q, MLSS, F/M, SVI, HRT, and θc parameters measured in aeration tank, then operational and maintenance parameters calculated.
Results shown that average of operation & maintenance parameters were: F/M = 0.35, HRT = 6 hour, Qr/Q = 64.28 %, VLR = 1.1 Kg BOD/m3.d, MLSS = 2819.36 mg/l, SVI = 144.89 ml/g, θc = 10.93 days.
Results of operational and maintenance parameters shown that biological process behavior of the hospital WTP was Extended Aeration Activated Sludge in past years, but converted to conventional activated sludge process due to increase in hospital beds of clinical and out patients departments , which increased water consumption lead to increase wastewater flow rate. High flow rate lead to increase hydraulic load and diluting organic matter load, so hydraulic retention time and sludge age decreased.