|摘要: ||近年來，經濟成長快速，水污染問題日趨嚴重，許多國家將溼地發展為一種污水處理新技術。而校園廢水已列為事業廢水之一，必須達到放流水標準後始得排放，有鑒於此，以校園廢水作為研究對象，透過本研究所設計之在槽曝氣生物礫石牆來提升表面流動式人工濕地(Free water surface constructed wetland, FWS CW)對污染物降解之效能。
本研究共設置2套系統；FWS-A(實驗組)、FWS-B(對照組)，其中FWS-A前端放置曝氣設備及礫石生物牆，而對照組僅是傳統之FWS CW，系統係以嘉南藥理大學宿舍區之民生污水處理廠放流水並經明溝混合鄰近工業區部分排水之廢水作為系統處理水。藉此進行新設計FWS CW之有機汙染與氮磷營養鹽的汙染降解效能特性之研究。相關實驗分為三試程進行，藉以探討溶氧、水力停留時間等操作條對件水中污染物之去除效能的影響。根據本研究之相關結果謹做以下結論；
本研究各試程的BOD進流平均濃度約為7.23-18.6 mg/L，於低濃度狀態下，FWS-B CW在HRT介於1.08~2.42 d的條件下，RUN-I~RUN-III的BOD去除率僅有5.3~8.7%，而FWS-A CW之BOD去除率明顯提升為66.8~74.3%，結果顯示本研究所加系統在低BOD進流濃度狀況下可以有效提升FWS CW的有機汙染去除效能。
而總氨氮(氨氮與銨氮之總和)進流平均濃度約為8.61-17.3 mg/L條件下，FWS-A之去除率為92.2%~99.6%，優於FWS-B (37.1~81.5%)；FWS-A之TKN去除率為79.1%~97.9%，優於FWS-B (45.2~79.9%)；就總氮而言，FWS-A在RUN-I去除率為54.4%，較FWS-B的38.6%為高，其未能大幅提高的主因是硝酸鹽累積，而在提高HRT後之FWS-A、FWS-B為81.4%與76.2%，降低DO後，FWS-A與FWS-B為60.3%與67.8%，其提升去除率較為有限；在總磷部分，去除率皆只有10%~20%，其曝氣作用對FWS-A與FWS-B沒有提升效果；綜合上述，加入曝氣設備及礫石生物牆之FWS-A系統對於水中有機污染物與總氨氮之去除效率較FWS-B系統為佳。
In recent years, water pollution becomes increasingly serious problems because of rapid economic growth. Many countries regard constructed wetlands (CWs) as one of new sewage treatment technologies. The campus wastewater has been listed as one of the cause of wastewater and must be treated before discharging into the receiving water . In this work, a modified free water flow (FWS) CWs was employed to treat the campus wastewater. An in-tank aeration and bio-gravel system was installed in FWS CWs to investigate the characteristics of pollution removal.
In this study, an experimental system (FWS-A) and a control system (FWS-B) with the same dimension were established for the experimental study. In the formal, the artificial aeration and bio-gravel wall (AABGW) was installed in the influent area. The influent wastewater mainly came from the campus wastewater of the dormitory area of Chia Nan University of Pharmacy and Science, mixed with industrial wastewater from a industrial area nearby. There were 3 runs for investigating the effects of hydraulic retention time (HRT) and dissolved oxygen (DO) on removal efficiencies of biochemical oxygen demand (BOD) and nutrients in FWS CWs.
According to the results of the study, the average concentrations of influent BOD ranged from 7.23-18.6 mg/L. In RUN-I-RUN-III, the removal ratios were only 5.3-8.7% for FWS-B. However, they increased to 66.8-74.3% in FWS-A CWs, implying that, for a rather low influent BOD concentration, AABGW was a good suggestion in improving BOD removal for low BOD influent. Total ammonia-Nitrogen (summation of ammonia-nitrogen and ammonium-nitrogen; TAN) with the average influent concentration of 8.61-17.3 mg/L was removed 92.2-99.6% in FWS-A while it was only 37.1-81.5% in FWS-B. Also, in FWS-A, total Kjeldahl nitrogen (TKN) of 79.1-97.9% was removed and the average removal ratio was only 45.2-79.9% for FWS-B. However, for the removal of total nitrogen (TN), FWS-A and FWS-B removed 54.4% and 38.6% of TN in RUN-I, respectively. As increasing HRT in RUN-II, they increased as 81.4% and 76.2%. They became 67.8% and 60.3% in RUN-III as DO had been controlled.
For the removal of total phosphorous (TP), the removal ratios ranged between 10% and 20% and implied that AABGW did not enhance the removal performance of TP. Based on the above results, it concluded that AABGW could improve the removal of BOD and TAN in a better condition.