利用不同過濾材料抑制污水廠出流水中大腸桿菌之效果

水源是人們生活不可或缺的元素之一，近年來全球人口不斷增加，水資源的需求也跟著增加，有許多地區面臨水資源不足的情況，傳統水資源取得方式可分為水庫給水、河川引水及抽取地下水，這些水資源主要供應日常生活用水、工業用水及農業用水等用途，但面對目前極端氣候的改變及全球人口數增加的情況，傳統水資源取得方式逐漸無法負荷龐大的用水量，加上隨著環境保護的觀念不斷進步，傳統水資源開發方式例如興建水庫已逐漸難以執行，因此該如何開發新興水資源以解決水資源不足仍為一亟待解決的問題，利用工業所排放的污水及人們日常生活所產生之污水進行廢污水回收再利用水，將污水經過污水處理廠後並確保水質的改善後，再進行適當之處理，便可以提供工廠或民眾取用，但由於目前污水中常含有有害物質及致病菌，為確保民眾使用安全，目前經過處理後之在生水用途仍然不應與人體有直接的接觸，而利用過濾或滲濾系統便是再處理工業及民生污水的方法之一，過濾系統具有低耗能，低成本及對環境影響較小的優勢，當水源於過濾及期間，利用過濾材料本身過濾、沈澱、化學吸附及生物處理作等作用改善水質及去除污染物，但是當水源某些致病菌而且無法被過濾及有效去除時，便可能會對將其當作日常生活用水的人們造成健康威脅，因此本研究為探討不同材料間是否有抑制微生物之效果，並以長時間過濾實驗評估將過濾材料結合土壤滲濾式工法用於實場之可能性，本研究所使用的材料為石英砂、培養土、牡蠣殼及零價鐵作為過濾材料，並以污水廠之回收水作為濾床之進流水，並探討去除微生物之效果，實驗中共使用五種過濾管柱，分別為控制組管柱(無添加任何濾料) 、培養土管柱、石英砂管柱、石英砂-牡蠣殼管柱及石英砂-零價鐵管柱，並額外添加指標性微生物-大腸桿菌，使水中大腸桿菌之菌落數為約(1.4 × 104 CFU/mL)，實驗結果顯示經過控制組管柱後，出流水之大腸桿菌數僅些微下降，進出流之平均大腸桿菌數相差約0.1 Log(CFU/mL)，於實驗前期經過培養土管柱後之出流水中之大腸桿菌數並未明顯減少，直到實驗後第18天才有其出流水中之大腸桿菌數才大幅下降，經過培養土過濾管柱平均可減少1.18 Log(CFU/mL)之大腸桿菌，石英砂過濾管柱則是呈現穩定的大腸桿菌去除效率，其出流水之大腸桿菌數可減少約可減少2.45 Log(CFU/mL)，石英砂-牡蠣殼過濾管柱於實驗期間去除大腸桿菌的表現並不穩定，但是以整體表現來看，經過石英砂-牡蠣殼過濾管柱後，水中的大腸桿菌數可減少約1.31 Log(CFU/mL)，石英砂-零價鐵管柱在所有過濾材料中具有良好抑制大腸桿菌之能力，其出流水水中之大腸桿菌可穩定維持小於20 CFU/mL，其去除率可達99.8%，由本研究之所有實驗結果來看，在不同的過濾材料中，零價鐵於所有過濾管柱中去除最多大腸桿菌，具有良好潛力用於抑制水中大腸桿菌之過濾材料。

關鍵字

生物濾床；零價鐵；牡犡殼；大腸桿菌

並列摘要

Water is one of the basic needs of human. With the increase of population, water resource has been over used for agriculture, industry and drinking water in many areas and may lead to environmental problems. It’s important to seek the way to solve the shortage of water resource. Using treated wastewater as new water resource is one of the methods. The treated wastewater effluent from wastewater treatment plants could be a stable and readily available secondary type of water resource. Although the wastewater effluent has been treated in the wastewater treatment plants, it’s still contain a lot of pollutant and microorganism. Filtration system is one of the treatments which commonly used for wastewater reuse. Filtration system has less cost and energy, it also cost less problem and pollution to environment. During the filtration, some chemical, physical and biological reactions such as adsorption, filtration, interception, oxidation and biodegradation may happen and reduce the pollutant. This study explores the pathogen inactivation abilities of three different materials (zero-valent iron(ZVI), sand and pulverized oyster shell) when used as the padding materials in soil percolation. Columns filled with these three materials were fed with recovery water from the wastewater treatment plant within fresh Escherichia coli (1 × 104 to 2.7 × 104 CFU/mL). Since the bacteria in wastewater would compete against E. coli and caused inactivation, the influent of following inactivation experiment are autoclaved before E. coli addition. Five different columns are utilized to evaluate the inactivation efficiencies of a control (C, without padding materials), a sand column (S), a zero-valent iron-sand column, and a pulverized oyster shell-sand column (OS). Inactivation efficiencies were obtained from the E. coli life counts form the influents and effluents. The changes of viable E. coli between influent and effluent in control column are less than 1 log unit. The sand column and pulverized oyster shell-sand column resulted in 2 and 1 log unit reduction, respectively. The zero-valent iron-sand column reduced more than 3 log unit in the inactivation experiment. Among three different materials, the column filled of zero-valent iron-sand has the highest E. coli inactivation efficiencies than sand filtration alone or pulverized oyster shell-sand filtration.

並列關鍵字

Biosand filtration ； Zero-valent iron ； Pulverized oyster shell ； Escherichia coli

參考文獻

Almeelbi, T., & Bezbaruah, A. (2012). Aqueous phosphate removal using nanoscale zero-valent iron. Journal of Nanoparticle Research, 14(7), 1-14

Aslan, S., & Cakici, H. (2007). Biological denitrification of drinking water in a slow sand filter. J Hazard Mater, 148(1-2), 253-258.

Auffan, M., Achouak, W., Rose, J., Roncato, M. A., Chanéac, C., Waite, D. T., Bottero, J. Y. (2008). Relation between the redox state of iron-based nanoparticles and their cytotoxicity toward Escherichia coli. Environmental Science and Technology, 42(17), 6730-6735.

Beal, C. D., Gardner, E. A., Kirchhof, G., & Menzies, N. W. (2006). Long-term flow rates and biomat zone hydrology in soil columns receiving septic tank effluent. Water Res, 40(12), 2327-2338.

Bradley, I., Straub, A., Maraccini, P., Markazi, S., & Nguyen, T. H. (2011). Iron oxide amended biosand filters for virus removal. Water Res, 45(15), 4501-4510.

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利用不同過濾材料抑制污水廠出流水中大腸桿菌之效果

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