The Relationships between Environmental Policy and Water Quality - Swine Wastewater

Abstract

[[abstract]]2011年政府推動「高屏溪離牧政策」,針對高屏溪攔河堰以上之集水區,實施養豬禁養計畫,在養豬廢水為主要污染源的高屏溪流域,削減約51萬頭豬,其成果為河川中的氨氮由4 5降為1 09mg/L,明顯改善水質,實為有具體成效之環境政策。 近10年來環保署在畜牧場的管制政策調整,分別為92 11 26 放寛畜牧(一)放流水標準COD由250降為600mg/L,及96 12 12 修訂水污法第40條,畜牧業放流水超過標準罰款由6萬至60萬降為6仟至1萬2仟元,此2次的政策調整實質減輕了養豬業者操作成本及約束,本研究即探討在政策鬆綁的同時,前後3階段河川水質的變化情形。 本研究以南部地區養豬廢水及生活污水為主要污染來源之流域,做為研究對象,經克瓦(Kruskal-Wallis)單因子等級變異數分析,檢定歷年來水質監測數據,在政策施行前後3階段的河川污染指數(RPI)、水質指數(WQI)、溶氧(DO)、生化需氧量(BOD)均有顯著的差異,再經由盒狀圖及趨勢圖分析探討,整體河川水質有改善的趨勢,代表此養豬鬆綁政策對水質改善有其成效。另探討稽查告發管制政策對水質改善亦有顯著的相關,故對污染源的管制及河川水質的維護,稽查告發手段是不可或缺。 本研究探討另一項養豬廢水指標污染物氨氮(NH3-N),雖經分析檢定未因政策的改變而有顯著的差異,可能為現階段三段式養豬廢水處理技術對氨氮的去除效果不佳,其次非點源及生活污水中的氨氮等因素,影響政策成效的的顯著性。 對於枯、豐水期河川水質特性,本研究發現就整體而言,枯水期水質較豐水期差,但豐水期的第1個月份,其降雨量有限,對污染物的稀釋效果並不明顯,且初期的降雨會將枯水期時沈積在排水道的污染物沖入河川,影響河川水質。另枯水期時若河川植物營養鹽氮、磷污染濃度增加,將促進水中植物生長,因光合作用而提高河川溶氧,甚至產生超溶氧情形。[[abstract]]In 2011 government implemented “Pig farm buy out policy in Gao-Ping River area” The policy banned pig farming in catchment area above Gao-Ping Dam Since then the pig population is lowered by 510 000 and river ammonia level is reduced from 4 5 to 1 09 mg/L which results in greatly improved water quality It is truly a successful outcome based environmental policy Environmental Protection Administration (EPA) has had several policy changes on animal husbandry in the last 10 years including 1) on 11/26/2003 Effluent Standards has reduced chemical oxygen demand (COD) from 250 to 600mg/L and 2) on 12/12/2007 Number 40 of Water Pollution Control Act was revised to decreases the fine to livestock industry from 60 000 NT - 600 000 NT to 6000 NT -120 000 NT These two policy changes substantially decrease the operating cost and loosen restrains for the pig farmers The purpose of this study is to look at the effects of the policy changes to the water quality 3 years before and after the implementation The subject of this study is the drainage area where main pollutants came from discharges from pig farmers and domestic sewage in southern Taiwan Using Kruskal-Wallis ranked one way analysis of variant this study re-examines past water quality data at 3 stages before and after the implementation of the policy including the River Pollutant Index (RPI) Water Quality Index (WQI) Dissolved Oxygen (DO) and Biochemical Oxygen Demand (BOD) all of which showed remarkable differences The data was compiled to generate box plots and discussion of trend analysis was made Overall river water quality displayed an improving trend which indicated the positive impact the deregulation of the pig livestock industry has on water quality Furthermore site inspection with the help of informant to implement the policy is important to improve water quality Therefore in order to control the source of pollutant and to maintain good river quality it’s paramount to keep doing onsite inspection and incorporate public involvement This study also looks at one of the pollutant indicators ammonia nitrogen emission from swine wastewater The changes in ammonia nitrogen emission show no significant difference from the changes in policy The reason might be that the 3-stage swine wastewater processing techniques was ineffective Secondly the ammonia nitrogen emission from the non-point source or from the domestic sewage might dampen the significance of the effectiveness of the policy As for river water quality during drought season and wet season what we found in this research is that the water quality is worse during the drought season However in the first month of the wet season due to the limited rainfall no obvious dilution of the pollutant is observed The first rainfall after the drought season tends to flush the pollutants from the sewage system to river which adversely affect the water quality If during dry season the existence of plant nutrient nitrogen together with increased phosphate concentration will promote the growth of water plant which in turn will increase the river saturated oxygen or even over saturation from the process of photosynthesi

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This paper was published in FirstTech Institutional Repository.

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