Tertiary treatment of a secondary effluent by the coupling of coagulation–flocculation–disinfection for irrigation reuse

The aim of this study was to investigate the performance of a tertiary treatment system for irrigation reuse of secondary urban effluents. The tertiary treatment units (including coagulation-flocculation-disinfection) were evaluated using a pilot-scale plant (0.24 m3 h− 1 of capacity) located in the wastewater treatment plant of Bursa in Turkey. The results showed that the highest removal efficiencies using coagulation, flocculation and disinfection of suspended solids, chemical oxygen demand, turbidity and total coliform were determined to be 64%, 39%, 81% and 5-log reduction, respectively. Additionally, the concentration of heavy metals was below the national and international standards. The results from the tertiary treatment of urban effluent suggest that it can be used as a viable water resource for irrigation.

► Various methods for wastewater treatment have been used over the past decades.
► Treatment processes are divided into primary, secondary and tertiary processes.
► The performance of a tertiary treatment system for irrigation reuse of secondary urban effluents.
► The average tertiary treatment effluent values meet irrigation standards according to both national and international guidelines.