Treatment of domestic wastewater by subsurface flow constructed wetlands in Jordan

The use of subsurface flow constructed wetlands for treating domestic wastewater in Jordan is described. The objective was to study the performance of subsurface flow constructed wetlands as a low-cost technology for treating domestic wastewater. Results show that subsurface flow constructed wetlands are capable of reducing biochemical oxygen demand (BOD), different forms of nitrogen, total suspended solids (TSS), fecal coliform count (FCC), and total coliform count (TCC). However, removal efficiencies differ from bed to bed and from month to month. Results show that there is strong correlation between BOD₅ removal efficiency and BOD₅ loading in kg/ha, which is defined as BOD₅ loading rate in kg/ha.d multiplied by residence time. The coefficient of determination (R²) for the six beds varied from 0.827 for bed number one to 0.608 for bed number four. Total nitrogen, ammonia nitrogen, and nitrate nitrogen reductions were observed, which suggestthat, nitrification as well as denitrificationtookplace in the beds. TSS reduction was observed in all beds. However, removal efficiency differed from bed to bed and for the same bed from month to month. Total and fecal coliform counts were reduced by one to three logs, because influent was high in total and fecal coliform counts were still high.