Wastewater characteristics and appropriate method for wastewater management in the hospitals

Hospitals generate relatively large quantities of wastewater that may contain various potentially hazardous materials; therefore the proper management of hospital wastewater is essential. In this cross-sectional study, the quality and quantity of wastewater in the hospitals of Tehran University of Medical Sciences [TUMS], Tehran, Iran, were studied and the suitable method for wastewater management in the hospitals was determined. Monitoring of pH, TSS, BOD5, COD and total coliforms indicated that the quality of wastewater in the hospitals was similar to domestic wastewater. The wastewater production in the hospitals was determined to be in the range of 398 to 1090 L/d/[occupied bed]. The study on wastewater treatment and disposal methods demonstrated that discharge to municipal wastewater collection system is the best alternative for wastewater management in the hospitals, but this approach is not applicable for all of the hospitals. Baharloo, Cancer Institute, Children, Farabi, Imam Khomeini, Razi, Roozbeh, Shariati and Valiasr hospitals can be connected to municipal wastewater collection system at present. It is recommended that these hospitals' wastewater be discharged to municipal wastewater collection system. Amir Alam, Bahrami, Mirza Koochak Khan and Sina hospitals will be able to discharge their wastewater into sewerage network at second phase of Tehran sewerage project [in 2010] and Arash Hospital will be able to discharge its wastewater into sewerage network at third phase of Tehran sewerage project [in 2015]. These hospitals have to select onsite separate wastewater treatment alternative

Determination of design criteria for UASB reactors as a wastewater pretreatment system in tropical small communities

A pilot scale study was set up to investigate the principle design parameters of up flow anaerobic sludge blanket [UASB] reactors for treating wastewater of small communities in the tropical regions of Iran. A steel pipe with a diameter of 600 mm and a height of 3.6 m was used as the reactor in which a digestion and a 3-phase separator element had a volume of 0.848 and 0.17 m[3] respectively. During this study, which lasted for 203 days, two distinct phases were carried out according to the ambient temperature. The temperature of the wastewater entering the reactor was naturally ranged from 22 to 26 °C and no heat exchanger was used. The hydraulic retention times including 2, 4, 6, 8, and 10 hours with various loading rates of 0.95 to 5.70 kg COD/m[3]/day for colder period and from 1.35 to 6.40 kg COD/m[3]/day for warmer period were examined. On the basis of the results the optimal hydraulic retention time for warmer period with a 2.20 kg COD/m[3]/day organic loading rate was 6 hours which BOD5, COD and TSS removal efficiency were 71, 63 and 65 percent respectively. During the colder period the removal ratio of BOD5, COD and TSS with an optimal hydraulic retention time of 8 hours and organic loading rate of 1.22 kg COD/m[3]/day were 54, 46 and 53 percent respectively