Citation:

Zaluski, M. H., B. Park, AND D R. Bless*. ASSESSMENT OF SULFATE REDUCTION RATES IN LABORATORY EXPERIMENTS. Presented at 13th Annual West Coast Conf. on Contaminated Soils, Sediments & Water, San Diego, CA, 03/17-20/2003.

Description:

Two successful field demonstrations of sulfate reducing bacteria (SRB) bioreactors showed needs for research: 1) improve the understanding of the processes in the bioreactor and its longetivity and 2) improve and quantify the design of the bioreactors. An important component of this research was determining the rate of sulfate reduction by the SRBs. The organic substrate used for this experiment consisted of walnut shells and cow manure. Six mini-bioreactors (5-gallon bucket each) were used to determine sulfate reduction rates. Two synthetic acid mine drainage (AMD) solutions at three different temperatures were used. The buckets contained 6" high lift of walnut shells and cow manure mix (50% to 50% by bulk volume).The feed rate was 2.7 ml/min. and corresponded to the 24hr residence time. Four bioreactors were fed with medium strength AMD (two operated at 58oF; one operated at 55oF; one operated at 77oF); two bioreactors were fed with strong AMD both operating at 58oF. The bioreactors operated for 5.5 months. Dissolve metals, sulfate, alkalinity and pH in the influent and effluent were sampled monthly. The total metals in the organic matter at the start and end of the experiment were sampled. The SRB population and total organic carbon (TOC) in the organic matter were sampled at the start and end ot the experiment. Gas production rates were measured at the vent pipe of each bioreactor.

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