Water Resources Research Act Program

Details for Project ID 2019NV169B

Improving wastewater treatment using biofilms that degrade phenolic and aromatic contaminants

Institute: Nevada
Year Established: 2019 Start Date: 2019-06-01 End Date: 2020-05-31
Total Federal Funds: $27,050 Total Non-Federal Funds: $52,554

Principal Investigators: Henry Sun

Abstract: At present, wastewater treatment facilities use oxidation ponds to eliminate organic materials. Despite this step, harmful phenolic and aromatic compounds are still present in treated wastewater and, as a result, pollute our environment. Aromatic rings are resistant to microbial degradation because they must be linearized first, and linearization happens only by oxidation with radicals. This proposal will test the concept for a biotechnology that combines some bacteria’s ability to oxidize amino acids and produce hydrogen peroxide with their ability to form biofilms. In the presence of dissolved iron, hydrogen peroxides disproportionate into radicals. When the same bacteria grow as biofilms, these powerful chemicals, along with extracellular hydrolytic enzymes secreted by the bacteria, are concentrated in the organic matrix or pockets within the biofilm and protected from dilution. We hypothesize that in these pockets phenolics are oxidized, and the resultant carboxylic acids are absorbed by the surrounding bacteria and mineralized to carbon dioxide. The proposed research will begin with raising a mono-species biofilm using a Bacillus species, B. mojavensis, that we isolated from local soil and demonstrated to be a biofilm-former and a prolific hydrogen peroxide producer. This biofilm’s ability to degrade phenol, bisphenol, and Congo Red, representing increasing aromaticity (number of rings) and recalcitrance, will be tested. Next, a complex natural biofilm will be raised using Las Vegas Wash water as a source of bacteria to maximize degradation efficiency. Assays for monitoring contaminants and hydrogen peroxide are routine in our laboratories at Desert Research Institute. If validated, this research would lead to a new technology for improved wastewater treatment in Nevada. This proposal would enhance the career of a young female postdoc and provide an opportunity for training an undergraduate student in a multidisciplinary research environment.