EVALUATING THE TREATMENT EFFICIENCY OF THE SUBSURFACE CONSTRUCTED WETLANDS SYSTEM AND FREE FLOATING PLANTS SYSTEM FOR THE WASTEWATER FROM NOODLE HANDICRAFT VILLAGE IN HIEP HOA COMMUNE, QUANG YEN TOWN, QUANG NINH PROVINCE

Abstract

The wastewater from noodle handicraft village in Hiep Hoa commune, Quang Yen town, contain large amount of organic and nutritional compounds with high C/N ratio. Experimental treatment of wastewater from craft villages with floating plants system (system 1 was planted with umbrella sedge) and subsurface constructed wetlands system (system 2 was planted with taro) gave optimistic results. The COD, TN, TP, TSS treatment efficiency of system 1 were 80.3 - 81.1%; 52.1 - 53.8%; 59.4 - 66.4% and 63.7 - 86.8%, respectively. After 7 days, the COD value in wastewater after biogas has not reached the allowed standards. In system 2, the COD, TN, TP, TSS treatment efficiency were 88.6 - 93%; 85.4 - 86.1%; 91.8 - 93.9% and 78.5 - 95.1%, respectively. After 5 days, the wastewater quality met the permitted standards. Thus, system 2 has higher performance and processing speed than system 1, but the investment cost is higher.