Li, Y. Master's Thesis, 73 pp, 2019

Column- and batch-scale tests were conducted to observe and measure the dechlorinating performance KB-1T™ in simulated lab-scale permeable reactive barriers (PRBs) to remediate TCE. The study also aimed to determine whether the presence of nitrate, sulfate, and RDX prevented TCE dechlorination under anaerobic conditions. The PRBs were filled with pine bark mulch substrate to serve as the electron donor to favor the growth of microbes. Butyric acid was injected to reduce oxygen and serve as extra electron donors. The analyses were conducted via gas chromatography, PCR amplification, and DNA sequencing. In column experiments, sulfate at a concentration of 0.25 mM had no obvious inhibitory impact on the dechlorination ability of mulch biobarrier when receiving 1 mg/L TCE. Batch-scale tests revealed that the presence of 1 mM nitrate decreased the dechlorination rate of chlorinated ethenes, while the presence of 1 mg/L RDX made no difference. Tests also indicated that the presence of chlorinated ethenes would inhibit the denitrification process. Results from DNA sequencing showed that significantly higher amounts of dechlorinators existed in columns without the presence of nitrate and sulfate, indicating that these two alternative electron acceptors are driving the differences of microbial diversity between control and experimental columns. https://ecommons.cornell.edu/bitstream/handle/1813/67315/Li_cornell_0058O_10544.pdf?sequence=1