Location: Agricultural Systems ResearchTitle: Analysis of the effects of in-situ chemical oxidation on microbial activity using Pseudomonas putida F1
|DANGI, MOHAN - California State University|
|URYNOWICZ, MICHAEL - University Of Wyoming|
|SCHULTZ, CHRISTOPHER - University Of Wyoming|
|BUDHATHOKI, SAMIR - University Of Wyoming|
|Rana Dangi, Sadikshya|
Submitted to: Heliyon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2021
Publication Date: 12/27/2021
Citation: Dangi, M.B., Urynowicz, M.A., Schultz, C.L., Budhathoki, S., Rana Dangi, S. 2021. Analysis of the effects of in-situ chemical oxidation on microbial activity using Pseudomonas putida F1. Heliyon. 7(12). Article e08665. https://doi.org/10.1016/j.heliyon.2021.e08665.
Interpretive Summary: The overall goal of the study was to evaluate the effects of a feasible technique that uses chemical agents in subsurface environment to treat pollutant on subsequent microbial activity by measuring carbon dioxide production. For the most part, the oxidation of the soil significantly affected microbial activity, and each chemical agents affected microbial activity differently. Some changes in microbial activity were not significantly different, and some clearly increased or decreased considerably. The results can interpret that microbes could better utilize the carbon in the soil with chemical [toluene] using it as a sole carbon source.
Technical Abstract: In-situ chemical oxidation (ISCO) has been an experimental process in delivering oxidants to the subsurface environment where various contaminants of concern and the natural organic matter and other reduced species within the soil consume the oxidants. The addition of the oxidants alters microbial activity changing the physical and chemical structure of the soil. This paper studied the effects of chemical oxidation on microbial activity by the toluene's biodegradation. Several oxidants were used as part of the study: sodium percarbonate, hydrogen peroxide, potassium permanganate, and sodium persulfate evaluated at low, medium, and high concentrations. A series of biometer experiments seeded with microbe Pseudomonas putida F1 and soil sample and aqueous toluene solution for each oxidant was monitored by CO2 production as a function of incubation days to evaluate the oxidation effects on the microbial activity. Experiments showed that permanganate oxidation resulted in the highest increase in microbial activity post oxidation based on CO2 production both with and without the addition of toluene. Experimental observations concluded permanganate oxidized soils revealed the strongest direct correlation between increasing oxidant concentration and CO2 increased output other than other oxidants. Only permanganate oxidation yielded a correlation between permanganate chemical oxidant demand (PCOD) removal and microbial activity. Oxidants (hydrogen peroxide, sodium persulfate, and sodium percarbonate) exhibited a correlation between oxidant concentration and PCOD removal during the oxidation process. However, there was no correlation between the oxidant concentration and microbial activity. Each oxidant affected the microbial CO2 yield triggering an overall increased CO2 output except for sodium percarbonate, which resulted in a decrease in CO2 quantity. ISCO process adversely affected the microbial activity only while using percarbonate.