| Summary: | 碩士 === 明志科技大學 === 環境與安全衛生工程系環境工程碩士班 === 103 === Previous study has shown that bagasse compost sample could serve as microbial and electron source for anaerobic reduction of tetrachloroethene (PCE). In this study, different types and amendment methods were applied to add additional electron donors into the compost microcosms, to study their effects on the reduction dechlorination efficiency. During 180 days of incubation period, the experimental results showed that adding full amount (200 electron equivalent; EQ) of lactase in the microcosms on Day 0 would show the best PCE removal efficiency among different treatments; while adding full amount of acetate would exhibit the worst removal efficiency. If adding half amount (100 EQ) of lactase or acetate on Day 0 and Day 120 respectively, the PCE removal efficiency would be in the middle. Comparing with acetate, lactase could serve as slower electron release agents, in addition that lactase could provide greater alkalinity. Therefore, the microcosms amended with lactase would have more suitable pH environment for reductive dechlorination of PCE.
If adding total 200 EQ lactase or acetate in the microcosms on Day 120, the enhancement of microbial reduction efficient was not as signification when compared with the electron donors were amended on Day 0, probably because the microbial activity decreased during the incubation period. Overall, the results suggested that the additional amendment of lactase would have better reduction efficiency when compared with acetate. The lactase amendment could be done at full amount at the beginning of the experiment, while the acetate amendment should be half amount.
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