人工溼地在不同負荷及操作條件下處理效能之研究

Abstract

人工溼地已被公認為具潛力的廢污水處理設施。為探討人工溼地處理都市污水的效果，以求得人工溼地的最佳出流水質和操作條件，本研究在台北縣土城抽水站設立了一個水平流式人工溼地，從土城大排抽取都市污水，設定不同的入流量、水深、表面積污染負荷和水力停留時間等條件進行實驗。每一單元由三個小單元連接而成，分別為密植區、開放水域、密植區。選擇三種台灣的水生植物做為溼地植生物種，分別是種植於密植區的香蒲（Typha orientalis Presl）和大安水簑衣（Hygrophila pogonocalyx Hayata）以及種植於開放水域的水王孫（Hydrilla verticillata Royle）。 生化需氧量（BOD）之去除率為28~92﹪、懸浮固體（SS）之去除率為37﹪~83﹪、氨氮（NH3-N）之去除率為69~99﹪、總氮（TN）之去除率為29~93﹪、總磷（TP）之去除率為34~93﹪、正磷酸鹽（ortho-P）之去除率為45~97﹪、溶解性總磷（TDP）之去除率為34~96﹪。水深為20cm時，BOD、氨氮、總氮之去除率較水深為10cm時差，但是對總磷、正磷酸鹽、溶解性總磷之去除率則較高。 BOD和TN表面積負荷上升至 和 時，溼地系統可得BOD和TN之最大表面積去除量，而水力負荷上升至 時，溼地系統可得BOD和TN之最大去除量；本實驗未發現TP之表面積污染負荷及水力負荷極限。大安水簑衣在BOD和氮磷的去除效果上比香蒲要來的好。HRT為4天時，可得較有效且經濟之污染物去除率。

Constructed wetlands have been identified as a potential wastewater treatment facility. We investigate the effect of constructed wetlands treating municipal wastewater in order to get the best effluent water quality and operation parameters. In this research, we built up a free-water-surface constructed wetlands at Tu-cheng pumping station in Taipei County and pumped municipal wastewater from the Tu-cheng wastewater canal. We set different inflows, water depths, area pollutant loading rates, and hydraulic retention times in this experiment. Three small units, including a marsh, a pond, and then another marsh unit, were combined together. We chose three aquatic plants of Taiwan to be the roles of macrophytes in this research, including the first two planted in the marsh area, Typha orientalis Presl and Hygrophila pogonocalyx Hayata, and the last one, Hydrilla verticillata Royle, planted in the pond area. Removal rate of BOD is around 28~92﹪, SS is around 37﹪~83﹪, NH3-N is around 69~99﹪, TN is around 29~93﹪, TP is around 34~93﹪, ortho-P is around 45~97﹪,and TDP is around 34~96﹪. When water depth is 20 cm, removal rates of BOD, NH3-N, and TN are worse than when it is 10 cm water depth. But for TP, ortho-P, and TDP, removal rates are higher in 20 cm water depth than that in 10 cm water depth. When BOD and TN area loading rate are rising to and respectively, and hydraulic loading rate is rising to , we can get the highest surface removal rate of BOD and TN. We did not find out the limit of area pollutant loading rate and hydraulic loading rate of TP in this research. The performance of Hygrophila pogonocalyx Hayata of treating BOD, nitrogen, and phosphorus is better than Typha orientalis Presl. When HRT is in 4 days, we can get effective and economical pollutant removal rate.