Effluent quality performance of horizontal subsurface flow constructed wetlands using natural zeolite (escott)

The objective of the present study was to assess the simultaneous removal of physiochemical parameters in moderate strength wastewater using a lab scale horizontal subsurface flow constructed wetland (CW). The wetland was constructed using natural zeolite as a substrate. In this study, high-density polyethylene tanks (0.36 m(2)) were planted with phragmites australis and scirpus maritimus. The system was subjected to two hydraulic retention times for (HRT) 4 and 3 days respectively. Averaged data reported coincided with the plant age (4 to 39 weeks) and covered the entire cold season and early part of the hot season. The physico-chemical characteristics of the wastewater changed significantly as the wastewater flowed through the respective wetland cells. Based on the 39 weeks of operation, the CW unit with zeolite achieved significantly higher removal for COD, ammonium and total nitrogen at 4 and 3 days HRT. This unit was highly effective in removing COD, NH4-N, TN, and TSS compounds which were found to be 89%, 99%, 96% and 956% respectively at 4 days HRT. At 3 days HRT, the removal was slightly changed to be 85 %, 99.6%, 91% and 91.3% for COD, NH4-N, TN, and TSS. A simple mineralogical survey of filter materials for the zeolites may render many installations of constructed wetlands successful.