Abstract

Before the reuse of treated wastewater in irrigation, supplementary treatment could be used for controlling pollution index. In order to evaluate the filtration and subsurface drip irrigation (SDI) application on wastewater quality index, the SDI system based on wastewater reuse and three treatments (three replications) was applied. These treatments were controlled by; drip irrigation with drinking water (CH), surface drip irrigation with treated wastewater (DI) and subsurface drip irrigation with treated wastewater (SDI). There was also a SDI filtration to improve biological index of wastewater. The results showed that the values of BOD₅, TSS and nitrogen component adequately decrease during filtration, but ideally the microbiological factors did not improve. Under this condition, injection of treated wastewater below the soil surface (SDI system) could decrease the surface microbiological pollution significantly in comparison to CH. In overall, the SDI system which applies wastewater reuse can be introduced as a substitute system for supplementary treatment unit.

Key words: Filtration, subsurface drip irrigation, biological index, treated wastewater.