A 75 liter immobilized microbe biological reactor with a bed retention time of 20.5 hours was used in a continuous flow mde to remediate contaminated groundwater containing ethylene dichloride (EDC), tetrachloroethylene, and trichloroethylene, with EDC being the predominant contaminant. The reactor was initially seeded with Xanthobacter autotrophicus, a demonstrated halogenated aliphatic substrate utilizer. The reactor was operated fin-forty-two days. Material balance determinations for primary volatile aliphatics of concern indicated an acerage of 90.2% mineralization of EDC, 81.7% of the trkhlorethylene (TCE) and 64.0% of the tetrachlorethylene (TeCE). In addition to Xan thobacter autotrophicus, four indigenous bacterial species from the groundwater had successfuUy acclimated to the reactor bed.
The application of adapted microbial populations immobilized on a porous diatomaceous earth carrier to pre-treat and reduce toxic concentration of volatile organics, pesticides, petroleum aliphatics and aromatics has been demonstrated for several industrial sites. In the pre-treatment of industrial effluents and contaminated groundwaters, these bioreactors have been used to optimize and reduce the cost of conventional treatment systems, i.e. steam stripping, carbon adsorption and traditional biotreatment. Additionally, these systems have been employed as seeding devices for larger biotreatment systems. The cost effective utilization of an immobilized microbe reactor system for water supply regeneration in a microgravity environment is presented. The feasibility of using immobilized biomass reactors as an effluent treatment technology for the biotransformation and biodegradation of phenols, chlorinated halocarbons, residual oils and lubricants was evaluated. Primary biotransformation tests of two benchmark toxicants, phenol and ethylene dichloride at concentrations expected in life support effluents were conducted. Biocatalyst supports were evaluated for colonization potential, surface and structural integrity, and performance in continuous flow bioreactors. The implementation of such approaches in space will be outlined and specific areas for interfacing with other non-biological treatment approaches will be considered for advanced life support, tertiary waste water biotreatment.
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