廢棄活性污泥與廚餘厭氧共消化減量及能源回收之研究

A Study on Waste Reduction and Energy Recovery of Wasted Activated Sludge and Kitchen Waste by Anaerobic Co-digestion Process

卓聖育(Sheng-Yui Cho)

指導教授 ： 林信一

長榮大學/健康科學學院/職業安全與衛生研究所/碩士(2008年)

https://doi.org/10.6833/CJCU.2008.00142

摘要

本研究利用廚餘與廢棄活性污泥混合做為厭氧共消化基質，以單相式於中溫35℃下反應，探討污泥減量及產氣效益，控制有機廢棄活性污泥TS = 10,000 mg/L，廚餘TS = 200,000 mg/L，實驗過程分三階段，第一階段以批次實驗進行條件測試，找出較適的操作條件如混合比、有機濃度、pH值、反應時間等，第二階段則利用連續進流方式了解不同有機負荷下的反應情況，並與以單純污泥為基質的消化結果互相對照比較，最後則利用共消化基質的反應槽出流水，及單純污泥為基質的反應槽出流水，投入好氧消化SBR反應槽進行反應，了解在經過厭氧消化反應後，在好氧消化是否能更進一步的減量。
由實驗結果得知當廢棄活性污泥添加廚餘做為共消化基質時，確實比以單純廢棄活性污泥為基質之反應槽的去除效果佳，單純污泥為基質的反應槽最佳TVS去除率約為20％，而共消化反應槽TS濃度45,000 mg/L、60,000 mg/L及30,000 mg/L反應槽的TVS去除率在反應至最後第60天皆有50％以上，但有機濃度超過80,000 mg/L的TVS去除率在反應最終僅有45％，由此看出當共消化基質的有機濃度超過80,000 mg/L且有機負荷率超過 4300 mg TS/L/day時，反應效果開始產生抑制。
試程中曾將基質TS濃度80,000 mg/L及30,000 mg/L的兩個反應槽在反應至第25天時將pH值調整至6.5，試圖讓反應完全的甲烷化，以達較佳的TVS去除率及最佳的減量效果，但結果並不如預期，可能原因是高濃度廚餘的添加以及污泥的老化，使得基質成分的C：N太低，造成營養不均衡的情況，且抑制了反應的效率。
廢棄活性污泥與廚餘共消化的結果，可能因為廚餘本身易酸化，造成反應槽內pH值偏低，使得反應槽處於相當不穩定的情況，酸化相產氫的時間較長，進入甲烷相時，卻又使甲烷化不完全，故需更長的反應時間才能使反應槽穩定並完全甲烷化，未來若仍以廚餘為共消化基質，可朝提高產氫效率方面進行研究。

關鍵字

廢棄活性污泥 ； 廚餘 ； 厭氧共消化 ； 廢棄物減量

並列摘要

This study is aimed to investigate the digestion rate and biogas production rate of wasted activated sludge by using the substrate with wasted activated sludge and kitchen waste in anaerobic co-digestion in a single phase under a temperature condition of 35℃. The total solid (TS) of wasted activated sludge was controlled to be 10,000 mg/L and kitchen waste 200,000 mg/L. Batch tests were run in the first stage to obtain the maximal condition for substrate admix ratio, organic loading, pH, reaction time. Experiments were carried out to study the digestion behavior in different organic loading of substrates in the second stage. Then the results were compared with those from the reaction using single substrate. Lastly, digestion efficiency in feeding substrates during anaerobic digestion was studied by using aerobic sequential batch reactor (SBR). The results of this study indicate that the removal rate of total volatility solid (TVS) is greater in co-substrate with kitchen waste and wasted activated sludge. The best TVS removal rate in substrate with wasted activated sludge is about 20%, and that in co-digestion reactors is usually higher than 50% if reaction spans for 60 days. However, TVS removal rate is only 45% when TS concentration is over 80,000 mg/L. This suggests that the digestion declines when the TS concentration is over 80,000 mg/L and the organic loading rate is over 4,300 mg TS/L/day. The pH value of the two reactors with TS concentration of 80,000 mg/L and 30,000 mg/L was adjusted to 6.5 in order to obtain the best TVS removal rate. Yet, due to the aging of wasted activated sludge as well as the high concentration of kitchen waste, C/N ratio was too low and the maximal condition was not obtained. As the pH value in reactor was too low, stable condition in the reactor is not easily achieved. Therefore, future study on the co-substrate of kitchen waste should be focused on the increase of hydrogenation efficiency.

並列關鍵字

wasted activated ； kitchen waste ； anaerobic ； waste reduction

參考文獻

王鍾錡（2008）廚餘廢水與廢棄活性污泥厭氧共消化之研究，長榮大學職業安全與衛生研究所。

李篤中 朱敬平（2001a）污泥前處理對微生物與有機物型態之影響，生化工程專刊，第48卷第5期，pp. 35-51。

李篤中、朱敬平（2002）污泥處置策略與永續利用，化工 49(2)：32-41

賴俊吉（2003）厭氧生物產氫技術發展近況，中華民國環境工程學會會刊，第14卷 第二期，pp.24-29。

APHA （1995）Standard Methods for the Examination of Water and Wastewater, 19th edition. American Public Health Association, New York, USA.