本研究乃利用校區構築之實驗型人工溼地(面積為3m × 5m ;以不銹鋼板分隔成寬50㎝之水道;並區分為表面流動式系統(FWS)、表面下流動式系統(SSF)及生態池三區,各區水道總長約為10公尺),探討其處理校園污水之能力,逐步針對有關項目做深入之探討;收集相關數據、求得各項設計及動力參數,以作為校園污水整治的參考資料,可做為未來大規模場設計及操作的參考。研究項目包括去除各項污染物之處理效能、各項操作變數對系統效能的影響、污染物在人工濕地系統中的轉換,以及人工濕地取代校園污水處理廠與處理水再利用的可行方式等。所取污水水源為化糞池直接所排放之污水;檢測水質項目包括水中有機物、氮磷營養物、大腸桿菌等污染物為主,探討在不同溫度、及不同流量(滯留時間)之差異性。
兩年操作的數據顯示,CW系統對廢污水中各項污染物均有明顯的去除效果,生化需氧量(BOD5)、化學需氧量(COD)的平均去除率分別為68%及66%,氨氮(NH3-N)、正磷酸鹽(PO4-P)的平均去除率分別為46%及60%,大腸菌落(E-coli)與總懸浮固體物(TSS)的去除率也分別可達89%及86%。此外,在CW系統中各項污染物去除速率的增加均有隨單位面積負荷增加而趨緩的現象,而一階面積去除速率常數(K20)對溫度的校正係數方面,本系統中除NH3-N外,各項污染物溫度校正係數(θ)均趨近於1,顯示本系統中污染物的去除速率受溫度變化之影響不大,然文中提及之K20及θ值是由操作兩年的數據計算而得,並不具絕對的代表性,未來仍有隨著操作參數的改變而有變動的可能性。 This project is based on some research results accumulated in past three years using constructed wetland systems (CW) to treat various types of wastewater and build a pilot scale CW on campus. This system has an area about 15 m2, and uses stainless steel plates to form a 10 m long water channel with a width of 50 cm. This CW system contains a free water surface wetland (FWS), a subsurface wetland (SSF), and an ecotype pond. The main goal of this project is to investigate the treatability of CW on campus wastewater and collect related data and parameters for designing full scale CW, hence the research work will gradually involve more detailed part in the future. The research work includes removal efficiencies of various pollutants, different operating parameters, the transformation and fate of pollutants in the CW, evaluation of ecosystem of the CW, and the feasibility of replacing traditional wastewater treatment plant by CW system. Meanwhile those data may be used as important reference for constructing and operating a full scale CW system in the future. The wastewater used in this study is directly conducted from sewage system, which combines wastewater from septic tank and some kitchens. The monitoring terms of water quality include organics, nutrients, coliforms, etc. Other parameters on treatment efficiency investigated are seasonal effects, impact of summer and winter vacation, various hydraulic loadings, and different macrophytes.
The data show that the CW system could remove most of the contaminants in the wastewater. The average removal rates of BOD5 and COD are 68% and 66%. The average removal rates of NH3-N and PO4-P are 46% and 60%, and the average removal rates of E-coli and TSS could be 89% and 86%. Moreover the increasing of removal rates would diminish while the various hydraulic loadings is increasing. Besides NH3-N, the other temperature correction factors(θ)are close to 1. It show the effect of temperature to removal rates is not conspicuous. All the K20 and θ were computed by the data in the passed two years, and they could be change when we change the parameters for designing.