厭氧固定生物技術降解醣類與蛋白質合成污水之研究

Immobilized Biological Method for Anaerobic Biodegradation of Carbohydrate and Protein in Wastewater

邱明祺(Ming-Chi Chiu)

指導教授 ： 林正芳

國立臺灣大學/工學院/環境工程學研究所/博士(2021年)

https://doi.org/10.6342/NTU202101211

摘要

生活污水主要成分為醣類、蛋白質和脂質，它們是消耗河川水體中氧氣的主要化合物。現今民生污水處理廠普遍利用好氧活性污泥法處理污水，在該處理方法中，碳質成分被生物轉化為生物質和二氧化碳，活性污泥系統不僅消耗能量，而且還會產生過量的污泥，需要進一步消化和處置。而利用厭氧生物方法除了免曝氣動力外，還可將污水中的有機化合物轉化為甲烷氣的能量，並減少污泥量的產生，這種方法已在熱帶國家（如巴西和印度尼西亞）實行。惟實際操作生活廢水的厭氧處理效率主要取決於溫度、微生物濃度和水力停留時間，以及如何保留厭氧微生物在反應系統中避免被沖洗出，為此，近年來厭氧生物處理生活污水技術已得到了極大的發展。
有鑑於厭氧生物處理中微生物對於不同基質之利用率不同，反應程序與相對應產物也相異，本研究中使用AnIBPR（Anaerobic immobilized bio-plates reactor）系統研究了醣類和蛋白質的生物降解，以了解基質間厭氧生物降解率和產氣情形。實驗建立一單槽連續式反應槽處理合成污水，在水力停留時間HRT 12小時，恆溫水域35℃下，以不同濃度醣類（1000、750、500、250及0 mg/L）與固定濃度1000 mg/L蛋白質（50％植物性蛋白質與50％動物性蛋白質）混和比例之進流作為合成污水基質主要碳源，分析厭氧固定生物系統對於不同濃度混合基質之COD去除率、各基質去除率、甲烷產氣率與甲烷回收率，並探討醣類與蛋白質共降解之影響。
研究結果顯示，本實驗使用厭氧固定生物系統處理醣類與蛋白質合成污水，各階段處理效率達97.5％ - 90.1％，總甲烷回收率為81.0 % - 55.0 %，最佳甲烷產量為0.28 L CH4/g COD removed，回收率達81％，整體而言，本厭氧固定生物系統能有效地將進流有機物轉換成氣相及液相等不同形式的甲烷存於系統中，且相較於只有添加蛋白質進流之第Ⅴ階段合成污水，第Ⅰ至第Ⅳ階段添加醣類進流時對於總COD及蛋白質降解效率提升，經過計算後本實驗進流濃度下，第I至第Ⅳ各階段每添加1公克的醣類可增加0.05-0.08公克蛋白質的降解，經由本研究推測在生活廢水厭氧處理中，醣類基質的存在會促進蛋白質在COD去除和甲烷轉化作用，良好的甲烷回收率顯示厭氧固定生物系統處理污水具有產能及能源回收的可行性。

關鍵字

固定生物技術 ； 厭氧生物反應 ； 醣類 ； 蛋白質 ； 生質氣體

並列摘要

Domestic wastewaters contain carbohydrates, proteins, and lipids which are principal compounds that deplete oxygen in natural waterways. These compounds have been conventionally treated by aerobic activated sludge processes in wastewater treatment plants where carbonaceous constituents are biologically converted into biomass and carbon dioxide. Activated sludge systems not only consume energy but also generate excess biosolids that need to be further digested and disposed of. Alternatively, these organic compounds in wastewaters can be converted into energy in the form of methane gas with reduced biomass generation using anaerobic biological methods which has been practiced in tropical countries such as Brazil and Indonesia. Besides treatment temperature, the efficiency of anaerobic treatment of domestic wastewaters depends largely on biomass concentrations and hydraulic retention time in the treatment vessel. One important issue is retaining anaerobic microorganisms in the reaction system without being washed out even at short hydraulic retention times (HRTs). For this purpose, treatment technologies of domestic wastewaters under anaerobic conditions have been significantly advanced in recent years.
In this study, we have investigated the biodegradation of carbohydrate and protein using the AnIBPR（Anaerobic immobilized bio-plates reactor） system to understand the rate and extent of anaerobic biodegradability of carbohydrate and protein. At constant protein concentration with 50% isolated soy protein (Solae, LLC, North America) and 50% whey protein isolate 90 NK (Milk Specialties Global), which were mixed with different sugar concentrations of 1000, 750, 500, 250, 0 mg/L in five test modes at HRT of 12 h at 35 oC.

At this study, the AnIBPR system achieved methane yields around 0.28 L CH4/g CODremoved and methane recovery efficiencies from 81% to 55%. And also achieved 97.5% to 90.1% of total COD removal at 12 h of HRT. Under all other modes (I through IV) with higher influent total COD, the effluents showed higher overall COD and protein removals than those of Mode V. The results show with each additional gram of sugar it resulted in an additional 0.06 ~ 0.08 gram of protein removal. In domestic wastewaters, the presence of carbohydrates is likely to promote and not suppress the hydrolysis/acidogenesis of proteins with respect to COD removal and methane conversion. The AnIBPR demonstrates high anaerobic biomass retention and high biological activities, which shows potential for wastewater treatment applications and energy recovery.

並列關鍵字

Anaerobic,Immobilized bioreactor ； Carbohydrate ； Protein ； Biogas ； Waste to energy

參考文獻

田俊彥，2016，厭氧固定生物技術處理低強度合成污水：水力停留時間與進流濃度之影響，國立臺灣大學環境工程學研究所碩士論文。

Alatriste-Mondragón, F., Samar, P., Cox, H. H., Ahring, B. K., Iranpour, R., 2006. Anaerobic codigestion of municipal, farm, and industrial organic wastes: a survey of recent literature. Water Environment Research. 78(6), 607-636.

Bae, J., Shin, C., Lee, E., Kim, J., McCarty, P.L., 2014. Anaerobic treatment of low-strength wastewater: a comparison between single and staged anaerobic fluidized bed membrane bioreactors. Bioresource Technology. 165, 75-80.

Bae, J., Yoo, R., Lee, E., McCarty, P. L., 2013. Two-staged anaerobic fluidized-bed membrane bioreactor treatment of settled domestic wastewater. Water Science and Technology. 68(2), 394–399.

Borja, R. and Banks, C.J., 1995. Response of an anaerobic fluidized bed reactor treating ice-cream wastewater to organic, hydraulic, temperature and pH shocks. Journal of Biotechnology. 39 (3), 251–259.