Abstract

The objective of this study was to study the pollution indexes [biochemical oxygen demand (BOD₅) and chemical oxygen demand (COD)] variations in domestic wastewater after treatment with agronomical soil. In this experiment, 15 lysimeters were used, 1 to 5 lysimeters were irrigated by domestic wastewater and primary drainage water was accumulated from these lysimeters, 6 to 9 lysimeters were irrigated by primary drainage water and secondary drainage water was accumulated and 10, 11 and 12 lysimeters were irrigated by secondary drainage water. In order to compare soil properties, 13, 14 and 15 lysimeters were irrigated by agronomical water. Finally, soil and water properties were measured at the end of irrigation. The results showed that soil could filter the domestic wastewater and reduce pollution indexes of domestic wastewater. Also, irrigation with domestic wastewater increased electrical conductivity (EC), potassium (K), phosphorus (P), calcium (Ca) and magnesium (Mg) of soil. The findings may give applicable advice to commercial farmers and agricultural researchers for management and proper use of water.

Key words: Biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), domestic wastewater, agronomical soil