Abstract:
This research was focused on possibility of replacing toluene and phenol with benzyl alcohol as growth substrates in biological cometabolism of trichloroethylene (TCE). Growth Yield (Y) and TCE Transformation Yield (T[subscript y]) using toluene, phenol, and benzyl alcohol as growth substrates were studied in the batch experiments. Kinetic parameters of the cometabolism processes were estimated using a computer modeling. This research started with microorganisms grown on toluene. Results showed that benzyl alcohol could be replaced for toluene and phenol as growth substrate in TCE biological cometabolism. In this study, Growth Yields (Y) of toluene, phenol, and benzyl alcohol were 0.074 mg-toluene/mg- cells, 0.056 mg-phenol/mg-cells, and 0.060 mg-benzyl alcohol/mg-cells, respectively. TCE Transformation yields (T[subscript y]) using toluene, phenol, and benzyl alcohol as growth substrates were 0.014 mg-TCE/mg-toluene, 0.015 mg-TCE/mg-phenol, and 0.012 mg-TCE/mg-benzyl alcohol, respectively. The kinetic parameters of trichloroethylene cometabolism were modeled by AQUASIM2.1b program. By using toluene as growth substrate, the maximum specific rate of substrate degradation (k[subscript g]) was 4.01 mg-toluene/mg-cell/day, the half saturation constant for the growth substrate (K[subscript sg]) was 1.29 mg/l, the maximum specific rate of trichloroethylene degradation (k[subscript c]) was 1.67 mg-TCE/mg-cell/day, and the half saturation constant for trichloroethylene (K[subscript sc]) was 7.61 mg/l. By using phenol as growth substrate, the k[subscript g] was 5.27 mg- phenol/mg-cell/day, the K[subscript sg] was 0.98 mg/l, the k[subscript c] was 1.39 mg-TCE/mg-cell/day, and the K[subscript sc] was 6.62 mg/l. And by of using benzyl alcohol as growth substrate, the k[subscript g] was 7.09 mg-benzyl alcohol/mg- cell/day, the K[subscript sg] was 0.83 mg/l, the k[subscript c] was 1.46 mg-TCE/mg-cell/day, and the K[subscript sc] was 7.06 mg/l. This research can be engineering applicative in TCE-contaminated groundwater remediation. The modelings together with batch experiments are able to estimate growth substrate quantity, remediation period, and remediation cost.