EFFECT OF SEASONAL TEMPERATURE FLUCTUATION ON LOW-CONCENTRATION POLLUTED RIVER WATER TREATMENT BY BIO-RACK WETLAND

In this paper, a study on the efficiency of contaminant removal by bio-rack wetland (BRW) for the low-concentration polluted river water with 19 months was conducted to evaluate the effect of the seasonal variation. The results indicated that the mean removal rates of total nitrogen (TN), total phosphorus (TP), permanganate index (COD), and suspended solid (SS) were 49.11%, 72.62%, 17.74% and 71.41% during the operational period, respectively. The seasonal variation would influence the removal efficiency of TN, TP and COD. And meanwhile, the nutrient removal rate was significant higher (p<0.01) in summer and autumn than that in winter. However, there was no significant difference for SS removal with seasonal variation. During the whole operational period, the TN and TP removal rates in the BRW were determined as 385.89 g/m(2) and 24.35 g/m(2) respectively. N uptake by plants accounted for 16.77% of the total N removal and P uptake by plants accounted for 31.97% until harvesting in the BRW. The results suggest that the BRW is an effective approach for contaminant removal, and plant could grow again at suitable temperature without special protection after harvesting. And plant uptake is an effective way for nutrient removal in the BRW.