Effect of HRT and HLR on removal efficiency for livestock wastewater treatment in constructed wetland planted with Phragmites australis

Dairies and livestock industries generate wastewater which is high in nutrients and can impressed water resources. Constructed wetlands are one of alternatives for livestock wastewater treatments because of its pollution removal efficiency and low cost in construction and operation. The goal of this study is determination of constructed wetland efficiency at organic matter and nutrient removal at different Hydraulic Loading Rate (HLR) and Hydraulic Retention Time (HRT).
The removal efficiency of BOD5, COD, TSS, NO3-N and PO4(orthophosphate) from livestock wastewater in constructed wetlands at different HLR and HRT at a 6-months period are investigated.
Findings: The highest efficiency of BOD, COD, TSS, NO3 and PO4 removal at lowest HLR and highest HRT in temperature above 15 °C were 74%, 62%, 69%, 61% and 23% respectively.
Constructed wetlands can improve effluent quality from secondary wastewater treatment plant of livestock industry to meet the environmental organization of Iran to reuse in irrigation.