二仁溪流域承受來自於台南、高雄市流域之工業廢水、畜牧廢水、衛生掩埋場污水及中下游地區生活污水排放。流域內之工廠、畜牧、養殖場數量雖多,但普遍規模不大,也因規模小及操作處理成本問題,常常發生廢污水未經妥善處理便排放至二仁溪之偷排與暗管事件,造成污染排入量遠超過河川自淨能力負荷量,導致二仁溪水不適用於流域內之民生、農業及漁牧業用水,故行政院環保署將二仁溪列為重點整治河川之一。 本研究主要針對二仁溪流域進行水文水質之採樣及分析,結果顯示於枯水期,主流除二層橋屬於中等(WQI 51-70)水質外,其餘主流測點多位在中下(WQI 31-50)及不良(WQI 16-30)水質之間,營前排水、三爺溪、函口圳等三條排水為惡劣(WQI 0-15)水質,其餘支流位於中下至不良水質之間。分析結果可用於評估河川現況,並以進行Water Quality Analysis Simulation Program (WASP)水質模式之模式建立,經由率定和驗證及模式建立後,可用於二仁溪流域水質管理策略之水質改善程度預測。 本研究以二仁溪公告丙類水體作為水質改善目標,進行污染削減量分析,結果顯示各支流、排水之BOD、NH3-N所需削減量皆偏高,其整體總削減率之BOD及NH3-N至少需分別達83.23%和97.61%,方能使二仁溪整體河段達到丙類水體水質標準。執行加強管制措施後,民生污水及畜牧廢水之BOD須分別減少1107.63和3532.16 kg d-1;NH3-N須分別減少1035.35和549.48 kg d-1,其BOD和NH3-N總削減率分別至少需達80.88%和97.38%,才能使二仁溪流域符合丙類水體水質標準。針對污水截流進行40%、60%、80%水質模擬,結果以80%截流率效果最佳。下游污水截流80%時,二仁溪下游BOD及NH3-N整體削減率需各達19.69%及89.02%時,其水質可達丙類水體標準。進行潔淨養豬措施評估時,假設豬廁所設置率達80%進行水質模擬,結果指出,BOD及NH3-N整體削減率需各達78.29%和96.91%時,可達丙類水體水質標準。由上述三項管理策略可發現,支流排水截流及潔淨養豬措施可使二仁溪流域下游水質得到較顯著的淨化效果。本研究結果可做為各水質管理策略對二仁溪水質改善成效之預測參考。
The Erhjen River bears the discharges of industrial, livestock, sanitary landfill, and municipal wastewaters from Tainan and Kaohsiung watershed in Taiwan. Within the Erhjen River basin, there are numerous factories and farms, but generally their scales are small. Because of the small scales and cost considerations, improperly processed wastewaters were often illegally discharged into the Erhjen River through the underground pipes, so that the amounts of pollutant loadings discharged far exceeded the river self-purification capacity resulting in the water of Erhjen River not applicable to the uses for livelihood, agriculture, and farms. Therefore, Taiwan Environmental Protection Administration (EPA) is working on the remediation of the Erhjen River.
In this study, hydrology and water quality of the Erhjen River was sampled and analyzed. The results indicated that water quality of the sampling stations along mainstream was classified as lower (31