發酵廢棄污泥產生揮發酸以增加活性污泥PHA含量之研究

本研究利用實廠濃縮槽之廢棄污泥進行發酵產揮發性脂肪酸(Volatile Fatty Acid, VFA)實驗，再利用揮發性脂肪酸當碳源進行好氧動態進流(Aerobic dynamic feeding, ADF)餵養程序增加活性污泥中聚羥基烷酸酯(polyhydroxyalkanoate, PHA)含量之研究，本研究目的為快速提高實廠廢棄污泥中的PHA含量。本實驗第一部份為利用廢棄污泥發酵產生VFA，其過程為先將廢棄污泥調整pH11進行水解，再將水解後的污泥進入發酵，發酵溫度在40 °C下，第五天有最高產量1144 mg/L且產率為92.9 mgVFA/gVSS，發酵液中乙酸、丙酸、丁酸、異丁酸及戊酸濃度為397、290、79、140及186 mg/L。本實驗第二部分ADF實驗中，是將廢棄污泥進行曝氣活化至飽和溶氧80%後即進入ADF馴養程序，ADF實驗中碳源是取自第一部份產生之發酵液，其將VFA濃度調整為400mg/L且調整為pH9並控溫25 °C進行ADF實驗，馴養過程中何時添加VFA是由DO飽和溶氧達70%為判斷基準，在1193min時污泥中PHA含量為705 mg PHA/g VSS，活性污泥PHA含量由初始2.3%提升至70.5%，且成本僅需 23.2元。

關鍵字

廢棄污泥；揮發性脂肪酸；好氧動態進流；聚羥基烷酸酯；過飽過饑

並列摘要

This study used waste sludge in the concentration tank of a factory to conduct a fermentation experiment to derive volatile fatty acids (VFAs). Subsequently, the VFAs were employed as a carbon source to conduct aerobic dynamic feeding (AFD) and examine its effectiveness in increasing the polyhydroxyalkanoate (PHA) content of activated sludge. The purpose is to rapidly increase the PHA content of waste sludge in the concentration tanks of factories. The first experiment involved the fermentation of waste sludge to produce VFAs. Specifically, waste sludge was subjected to hydrolysis under a pH of 11 and then fermented at 40 °C. The results revealed that the highest VFA yield occurred on the Day 5, with a maximal production quantity and rate of 1144 mg/L and 92.9 mgVFA/gVSS, respectively. The fermentation broth was composed of 397 mg/L acetic acid, 290 mg/L propionic acid, 79 mg/L butyric acid, 140 mg/L isobutyric acid, and 186 mg/L valeric acid. In the second experiment, waste sludge was subjected to aerobic activation until it reached saturation and a dissolved oxygen content of 80%, after which it was used to conduct ADF. The carbon source was provided from the fermented broth in the first experiment; the VFA concentration was adjusted to 400 mg/L, and the temperature and pH to 25 °C and 9, respectively. During the feeding process, a saturated dissolved oxygen content of 70% was used as the basis for determining the timeframe for adding the VFAs. At 1193 min, the PHA content of the activated sludge was 705 mg PHA/g VSS, denoting an increase in the PHA content from 2.3% to 70.5% at a cost of only NT$23.2.