慢砂濾池生物膜生物總量與含鹵乙酸降解之關係

Biofilm Formation and Haloacetic Acids Degradation in Slow Sand Filtertaion Units

黃永定(Yong Ting Huang)

指導教授 ： 王根樹

國立臺灣大學/公共衛生學院/環境衛生研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.00549

摘要

自來水處理流程中，以含氯消毒劑進行消毒程序為最方便有效，也是最多國家所使用的方法，然而使用加氯消毒亦衍生消毒副產物之問題。人體可能經由各種接觸與吸收途徑，增加消毒副產物的暴露風險。在飲用水水質標準越趨於嚴格的同時，更突顯消毒副產物對民眾健康及自來水處理的重要性。
慢濾池是最天然的淨水程序，與一般過濾不同之處，在於除經由過濾之一般物理、化學程序外，還有生物作用進一步將水質淨化。而慢濾池之生物作用的相關研究甚少，尤其針對降解含鹵乙酸等消毒副產物的生物降解程序相關研究更是缺乏。
本研究進行實驗室模擬管柱與水廠實場操作，探討慢濾池操作期間微生物生長量、含鹵乙酸濃度之變化情形，分別以不同的進流水進行實驗，並於不同深度及操作時間時間進行採樣。研究目標在於觀察及比較不同的進流水對慢濾池微生物膜生成情形與含鹵乙酸的去除之影響，並且討論不同濾砂深度之影響。
研究結果顯示，在操作初期濾砂表層微生物量與操作時間成顯著相關，而中、底層的微生物量低於表層微生物量；以不同進流水進行慢濾池管柱試驗，MCAA皆可去除；但DCAA與TCAA等此類含較多鹵素之含鹵乙酸，則需較長時間或較高鹵乙酸濃度之馴化才能有效去除。
實驗室模擬管柱在操作約16天後，即可去除大部分的含鹵乙酸；與實場的實驗比對，實場微生物受水中餘氯的影響，生物膜之生物量與模擬管柱相反，在管柱中底層的微生物數量高於表層並較為穩定，於操作3週後含鹵乙酸才有較為明顯的去除效果。且含鹵乙酸的去除量與微生物的數量成顯著相關，但依不同的進流水而有不同回歸係數，顯示馴化強度或物種組成具有一定的影響。

關鍵字

慢濾池 ； 含鹵乙酸 ； 生物降解 ； DAPI螢光染色法 ； 生物膜

並列摘要

Disinfection with chlorine in water treatments is widely used by water treatment plants because of its convenience and effectiveness. However, formation of disinfection by-products is of concern due to its potential health risk.
Slow-sand filtration (SSF) is one of the most natural processes for water clarification. This study evaluates the biodegradation of haloacetic acids (HAAs) in slow-sand filtration unit. Simulated SSF columns were setup at both laboratory bench scale and pilot scale; and the results were compared with those observed in water treatment plant with SSF units. For both bench and pilot scale columns, water samples were taken from various bed depths of the columns and HAAs were analyzed. Filter sand was also taken to analyze the microbial activities on the sand surface.
The results reveal that the microorganism mass on sand surface in the top portion of SSF and operation time have positive correlation, but the microorganism mass in the middle or in the bottom part of the columns are less than those observed in the top portion. MCAA is degradaded in all of the columns tested, but only the columns fed with higher halogen numbers HAAs (DCAA and TCAA) in influent water can effectively eliminate HAAs with high halogens. It may result from the domestication process for the microorganism to eliminate HAAs with higher halogen numbers However, after 16 days of the operation, the simulated SSF columns can eliminate most of the HAAs including TCAA. For water treatment plant with SSF units, the HAAs removal on SSF is affected by the residual chlorine in influent water, and the growth of microorganism is slower on the top portion.

並列關鍵字

slow-sand filtration ； HAAs ； biodegradation ； DAPI ； Biofilm

參考文獻

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