ABSTRACT
The purpose of biochemical reactors (BCRs) is to carry out biological sulfate reduction, while converting many dissolved metal(loid)s in wastewaters into insoluble precipitates, thereby removing them from the wastewater passing through them. The organic and other substrate materials in passive treatment biochemical reactors not only serve as a carbon source but also physically retain precipitated metal(loid) sulfides and other precipitates in available pore spaces that are unlikely to clog. In the solid active media-containing substrate beds of passive treatment BCRs, populations of cellulose-degrading bacteria, acid-producing bacteria and other microbes break down the high molecular weight organics into simpler compounds that the Sulfate-reducing bacteria can metabolize. Semi-passive treatment BCRs are similar to BREW Bioreactors in that their substrates are beds of screened and washed gravel or gravel-like crushed rock. BCRs can be configured as: anaerobic Eco-engineered bioreactor cells, Stand-Alone bioreactors and backfill reactors in abandoned/disused mineshafts.
