Crude (4-methylcyclohexyl)methanol (MCHM) caused extensive contamination of drinking water, wastewater, and the environment during the 2014 West Virginia Chemical Spill. However, information related to the environmental degradation of cis- and trans-4-MCHM, the main components of the crude 4-MCHM mixture, remains largely unknown. This study is among the first to investigate the degradation kinetics and transformation of 4-MCHM isomers in activated sludge. The 4-MCHM loss was mainly due to biodegradation to form carbon dioxide (CO2), plus acetic, propionic, isobutyric, and isovaleric acids with little contribution from adsorption. The biodegradation of 4-MCHM isomers followed the first-order kinetic model with half-lives higher than 0.50 days. Nitrate augmented the degradation of 4-MCHM isomers, while glucose and acetate decreased their degradation. One 4-MCHM-degrading bacterium isolated from activated sludge was identified as Acinetobacter bouvetii strain EU40 based on 16S rRNA gene sequences. This study will enhance the prediction of the environmental fate of 4-MCHM in water treatment systems.
This work was supported by Dr. Zhang’s startup funds provided by Virginia Tech College of Engineering. Li Yuan acknowledges support from the China Scholarship Council (CSC) visiting scholarship. The work of Xi Chen was supported by National Natural Science Foundation of China (11172231 and 11372241), AFOSR (FA9550-12-1-0159), and ARPA-E (DE-AR0000396). The research was performed in conjunction with National Science Foundation, CBET Award # 1424234 in which the headspace and GC–MS methods for 4-MCHM were developed.
- Activated sludge
- Biodegradation kinetics
- Crude (4-methylcyclohexyl)methanol
- Transformation products
- West Virginia Chemical Spill