studying effluent quality of wastewater treatment plant

normal 0 false false false en-us x-none fa background: nowadays wastewater is one of the important sources of environmental pollutions and   one of the aims of wastewater treatment is to maintain a healthy environment. nonstandard wastewater discharges and their use in agriculture or discharge to surface water will follow environmental and health hazards. the aim of this study was to compare the effluent quality of three tehran, iran wastewater treatment plants (in ekbatan, sahebgharanie and south of tehran).   methods: this study was performed in 2010 on three mentioned treatment plants in tehran, iran. three samples were taken from each wastewater treatment plant. the measured parameters of the effluent include ph, do (dissolved oxygen), bod 5 (biochemical oxygen demand), cod (chemical oxygen demand), sulfate chloride, nitrate, nitrite, tss (total suspended solids), fecal coliform. then they were analyzed according to the methods described in the standard method.   findings: the results showed that the nitrite concentration in sahebgharanie, ekbatan and south wastewater treatment plants with standard deviation 10.02, 5.9 and 0.142 respectively was 17.53, 50.33 and 35.5 mg/l which were higher than the standard amount. the number of fecal coliform in each three wastewater treatment plant was higher than the standard (2400 mpn/100 ml). bod 5 concentration mean in south wastewater treatment plant effluent with standard deviation 4.58 was 65 mg/l which in comparison to the standard amount was not significant (p > 0.05). the mean cod concentration with standard deviation 5 was 121 mg/l and had a significant difference with the standard amount (p < 0.05). both of these amounts were higher than the standard.   conclusion: the quality of effluent in ekbatan and sahebgharanie wastewater treatment plants was better than south of tehran but the amount of some parameters like nitrite and fecal coliform in these treatment plants was higher than the standard. therefore, using the effluents of these wastewater treatment plants for discharging surface water or agricultural use is not recommended.