| 摘要: | 本研究為國內首座以在槽式礫間接觸氧化法處理新竹市南門溪之生活污水，研究之場址位於南門溪下游端，新興橋至振興橋間之河道內，探討礫間接觸氧化工法之特性、水質處理效率、與國內相關工法去除效率之比較，以及研究實場之設置成本分析等。 該實場面積約為2,400m2，設有1座沉澱槽，長為30m、寬為8m、深為1.5m，3座礫間接觸氧化槽，各槽長為35m、寬為8m、深為2.5m，以天然礫石為接觸材料，礫石粒徑為10cm~15cm，以混合粒徑之礫石採不規則排列，利用礫石表面生長之生物膜，透過接觸沉澱作用、吸附作用及氧化分解機制，將水中污染物消耗分解，以達到改善淨化水質之目標。 本研究歷經5個月的操作運轉，觀察監測水質狀況，並定期進行槽體排空清淤作業，其平均去除率生化需氧量為35.62 %、懸浮固體為41.38 %、化學需氧量為29.23 %、氨氮為-2.22 %、硝酸鹽氮為26.38 %、大腸桿菌為53.15%，pH變化趨勢介於6.73 ~7.98 之間，平均為7.38 ，溶氧變化趨勢則呈厭氧下降趨勢，介於 -72.65%~ 4.60 %之間，平均為-28.37 %。另本研究實場之水質處理效率與國內台北關渡自然公園人工礫床模場、桃園縣南崁溪河底橋、屏東縣武洛溪場作一比較分析，如以主要去除目標污染物BOD、SS和NH3-N之整體處理效率而言，以屏東縣武洛溪場較佳、台北關渡人工礫床模場次之、新竹市南門溪場及桃園縣南崁溪河底橋場之處理效率稍低。 至於本研究實場之設置總成本分析，設置佔地需求成本為0.24m2/ CMD，建造成本為3,275元/CMD，操作維護管理成本為0.38元/CMD，處理成本為每8.97元/CMD，如與人工濕地、地表漫流、土壤處理地下滲漏法之成本比較，本實場之成本均較其他工法成本低廉，有節省成本之效。運用 本工法進行河川水質改善，在國內具有推廣的指標性意義。 The research originally presents domestic wastewater that discharged into Nan-Men river in Hsinchu city by treating a packed-bed reactor containing gravels. The studied field lied in between the Xin-Xing and Zhen-Xing bridges, and located on the downstream of Nan-Men river. The comparable characteristics including size of the packed-bed reactor, removal efficiencies of contaminants, and budget will be discussed in this study. Surface area of the reactor is about 2,400 m2. The reactor comprise a settling basin, constructed with 30m of length, 8.0m of width, and 1.5m of depth, and three gravel- packed tanks, respectively constructed 35m of length, 8.0m of width, and 2.5m of depth. Natural gravel with size of 10~15 cm was used as medium. All of gravels were mixed and were irregularly arranged in the tank. Microorganisms can attach on the gravel medium and remove organic contaminants via sedimentation, adsorption and biodegradation to reduce pollution. The water quality was continuously monitored for five months. Periodically, water was discharged and sludge was drawn off. The observed results indicated that removal efficiency of BOD, SS, COD, NH3-N and NO3-N were 35.62%, 41.38%, 29.23%, 2.22%, and 26.38%, respectively. The variation in pH were ranged from 6.73 to 7.98 (average pH is 7.38). The variation in dissolves oxygen shows the anaerobic zone declines between 72.65 and -4.60%, and it can show 28.37% of average reduction. In addition, the effluent from the reactor was compared with those from natural park artificial gravel bed of Guan-Du in Taipei County, the river bed bridge of Nan-Kan river in Taoyuan County, Wu-Lo creek in Pingtung County. The removal efficiencies of target contaminants, BOD, SS, and NH3-N, exhibit as the following order: Wu-Lo creek > natural park artificial gravel bed of Guan-Du > Nan-Men river ≈ the river bed bridge of Nan-Kan river. As for the economic analysis, land demand is 0.24m2/CMD. It can be obtained that construction cost is 3,275 NT dollars/ CMD, operation and maintenance cost is 0.38 NT dollars/ CMD, and treatment cost is 8.97 NT dollars/ CMD. If the treatment way of gravel-packed reactor was compared with artificial wetland, the overland flow, and soil filtration, the cost of the gravel-packed reactor is lower than those of the other treatment ways. This indicates the gravel-packed reactor can effectively improve water quality of rivers. The treatment process should widely be propagated in Taiwan. |
