Evaluation of physical and chemical characteristics of wastewater and sludge of Zahedan urban wastewater treatment plant for reuse

Following the water shortage in the world, the use of wastewater as a sustainable resource has been considered in large volume. The study conducted to evaluate the physical and chemical characteristics of the wastewater and sludge of the Zahedan urban wastewater treatment plant showed that the wastewater and sludge treatment system of the treatment plant has high efficiency and effectiveness in removing the investigated parameters. The investigated parameters in the effluent included Chemical oxygen demand (COD), Biochemical oxygen demand (BOD), and Total suspended solids (TSS), turbidity, temperature, nitrate, nitrite, phosphate, pH, zinc, cobalt, lead and copper. Also, the investigated parameters in the sludge included Mixed liquor suspended solids (MLSS), Mixed liquor volatile suspended solids (MLVSS), pH, electrical conductivity and heavy metals. The results showed that the average concentration of metals in the treated effluent is Zn > Mn > Cu > Pb > Ni > Cr > Cd ،and Chemical oxygen demand and Biochemical oxygen demand in the effluent of this treatment plant are on average 171 and 44.4 mg/L, respectively, and its discharge in surface water is limited, but it can be applied for agriculture. Also, the purified sludge had the necessary standards and could be used as soil or household fertilizer and compost for agricultural land.