Erfan Rahmani - Department of Biotechnology, University of Tehran, Tehran, Iran
Pouya Emami - Department of Chemical and Petroleum Engineering, Sharif University, Tehran, Iran,
Seyed Mehdi Borghei - Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran,

Abazar Road River is one of Tehran’s popular rivers, originated from Alborz Mountains, applied for the irrigation of parks and gardens. Unfortunately, untreated hospital and industrial wastewaters contain high concentration of organic substances are often discharged into the Abazar Road River. Chemical Oxygen Demand )COD( content was measured up to ۱۰۸۳ mg/L, followed by Total Suspended Solids (TSS) up to ۲۴۰ mg/L, and Total Dissolved Solids (TDS) reached ۱۰۳۰ mg/L. The effluent standard for the irrigation of parks and gardens sets by Environment and Water Research Center (EWRC) were ۲۰۰ mg/L for COD, ۱۰۰ mg/L for TSS, and ۴۵۰ mg/L for TDS. The effect of different dosages of calcium hydroxude in combination with aluminium sulfate studied. Removal efficiency of ۹۰, ۹۸ and ۹۶% for COD, TDS ,and TSS, respectively, were achieved with the addition of ۱۰ mg/L calcium hydroxide to ۱۰ mg/L aluminium sulfate. Moreover, the jar test was done for ۱۰ mg/L calcium hydroxide and ۱۰ mg/L aluminium sulfate by changing pH to discover which pH reaches to a maximum COD, TSS, and TDS removal. A challenge to make cheap and easy-to-operate technology lead to a combination of physical and chemical processes that designed and applied for this wastewater to meet the EWRC’s effluent standard. The wastewater treatment plant (WWTP) applied in this research composed of screening, primary sedimentation tank, coagulation-flocculation, secondary sedimentation tank, and aeration. This WWTP could decrease up to ۹۳.۹۸% of COD, ۹۸.۷۵% of TSS, and ۹۸.۲% TDS in wastewater.

High organic, Abazar Road River, COD, TSS, TDS, WWTP.