以硫酸鹽還原菌降解工業廢液及生活污水處理廠之污泥厭氧消化以回收硫化氫之可行性評估

本計畫探討化工廠廢水中二甲基亞碸(DMSO)是否能作為碳源提供化學需氧量(COD)，供硫酸鹽還原菌(Sulfate-reducing bacteria, SRB)利用，並且透過液鹼吸收、產出可回收的硫化鈉(Na2S)。同時，因民間企業與民生污水處理廠對於硫化氫有不同的見解與需求，亦將探討四間污水廠以及一間生質能源中心，建立硫平衡與評估探討污水廠常見硫化氫濃度過高問題以及是否具回收之潛力。本試驗以不同基質與不同COD/SO42--S比例下，進行兩次BSP test，第一次BSP test將碳源改為工業廢水中常見之DMSO，試驗能否供SRB菌作為碳源利用。經第一次BSP test得知DMSO因其特性無法利用COD檢測方法測得，故利用總有機碳( Total Organic Carbon, TOC )檢測方法，換算COD來得知DMSO實際COD量，而控制組蔗糖COD: SO42--S比例為10:1和5:1，COD去除率為19.2%和15.3%，SO42--S去除率分別為52.9%以及43.3%，結果說明比例10:1比5:1為佳，由於試驗期間未檢測硫化物，因此無法得知是否有硫化物抑制，第二次BSP test得知DMSO可以作為碳源供微生物利用，與SO42--S比例多寡無關，代表DMSO不是被SRB利用。厭氧濾床試驗分為兩階段，第一階段利用蔗糖作為碳源，藉SRB將硫酸鹽還原為硫化物後回收，透過屏科大後山建制的厭氧濾床模型(Anaerobic Filter, AF)，我們以兩種比例COD:SO42--S = 6,000:1,200與COD:SO42--S = 6,000:600，作為進料濃度試驗，比例為(COD:SO42--S = 6,000:600)的硫酸鹽去除率為41.4%，高於比例為(COD:SO42--S=6,000:1,200)的硫酸鹽去除率26.6%，得知SRB於6,000:600的濃度比例下去除率較佳。第二階段利用DMSO作為碳源，COD去除率與SO42--S去除率比例皆不影響，因DMSO降解速率太快，導致SRB菌還沒利用就往氣相形成DMS (Dimethyl sulfate)，因此從結果判斷純DMSO是可以被厭氧系統消耗，可是無法被SRB作為碳源利用。在相同邏輯之下生活污水中之硫酸鹽，在進行污泥厭氧消化之同時，是否可以利用汙泥中之有機物提供能量還原硫酸鹽獲得硫化氫，也是值得探討。因此本計畫亦探討四間民生污水廠以及一間生質能源中心，評估實廠消化系統中硫的影響，和污水廠潛在硫化氫濃度以及是否具回收價值問題。從五間實廠分析硫平衡說明，以污水廠原水總硫觀察，初步判斷大部分的硫，透過以溶解性硫酸鹽形式，在廢水裡往出流排放，大約占98%以上，而只有少部分不到2%的硫酸鹽，跟著污泥往厭氧消化槽，因此如果要將化工廠的模式，透過厭氧消化槽SRB菌，還原廢液裡高濃度的硫酸鹽，產出的硫化氫再經液鹼吸收，而回收硫化鈉，套用在污水廠的高廢水量，低濃度的硫酸鹽，不具有回收循環經濟價值。

關鍵字

硫酸根還原菌；異丙醇；硫化氫；厭氧生物濾床

並列摘要

This project investigated feasibility of using DMSO (Dimethyl sulfoxide) in the industrial wastewater as the electron donor for SRB to reduce sulfate into sulfide, and then through the absorption of base to recover Na2S. Under the same strategy, 4 digesters from domestic wastewater treatment plants and 1 bioenergy plant fed raw kitchen waste were investigated to study the possibility of recovering hydrogen sulfide. In this study, 2 BMP tests were conducted using different substrates under different COD/SO42--S ratios to evaluate efficiency of sulfate reduction to sulfide. The first BMP results show that, DMSO can not be measured using COD analysis. Therefore, the TOC method was used to measure the DMSO and then find out the COD of DMSO. In the control group fed sucrose, under COD: SO42--S = 10:1and 5:1, removal efficiencies of COD were 19.2% and 15.3%, and removal efficiencies of SO42--S were 52.9% and 43.3%, respectively. These show that performance of COD: SO42--S = 10:1 were better than 5:1. The second BMP results show that, DMSO can serve as the carbon source for the microbial growth, and there was no relationship between the removal efficiencies of DMSO/SO42--S ratio, indicating that DMSO might not be utilized by SRB. The anaerobic filter experiment was conducted in two stages. In the first stage, sucrose was the carbon source for SRB to reduce sulfate to sulfide. Under two dffevent ratios of COD:SO42--S = 6,000:1,200 and 6,000:600, the removal efficiency of sulfate for the later was 41.4%, better than the former of 26.6%. In the second stage of the test, DMSO was used as the carbon source. There was no relationship between removal efficiency of COD and sulfate. It was found that, degradation rate of DMSO was so fast that, before the SRB can utilize the DMSO it was transformed into gas form of DMS (Dimethyl sulfate). This indicated that DMSO might be utilized by the anaerobic microorganisms, but not by the SRB. Under the same strategy, the possibility of recovering sulfide from sulfate reduction by SRB from anaerobic digestion of domestic wastewater plants was also investigated. Four digesters from domestic wastewater treatment plants and 1 bioenergy plant fed raw kitchen waste were investigated to study the possibility of recovering hydrogen sulfide. From the cases of WWTPs, over 98% of the influent sulfate was discharged with the effluent, and only less than 2% of the influent sulfate ended up in the digester. If the chemical plant mode is going to apply in the domestic WWTP, recovery of sulfide from reduction of sulfate in the influent will not be economically feasible.

並列關鍵字

Sulfate Reducing Bacteria ； IPA ； Hydrogen Sulfide ； Anaerobic Filter

參考文獻

Google Scholar

1. Puertas, R. & Marti, L., 2021. "International ranking of climate change action: An analysis using the indicators from the Climate Change Performance Index," Renewable and Sustainable Energy Reviews, Elsevier, Volume 148, 111316

Google Scholar

2. Johnson, D. B., Hallberg, K. B., 2002. Pitfalls of passive mine water treatment. Rev.Environ. Sci. Biotechnol. 1, 335-343.

Google Scholar

3. Koster, I. W., Rinzema, A., De Vegt, A. L., Lettinga, G., 1986. “Sulfide inhibition of the methanogenic activity of granular sludge at various pH levels,” Water Res., Volume. 20, pp. 1561-1567.

Google Scholar

4. Hilton, B. L., Oleszkiewicz, J. A., 1988. “Sulphide-induced inhibition of anaerobic digestion,” Environment Engineering, Volume. 114, pp. 1377-1391.

Google Scholar

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