BIOREMEDIATION SYSTEM

A bioremediation process employing an improved bioreactor comprises pumping contaminated ground water from a recovery well in a contamination site, passing the water through a fully pressurized bioreactor wherein the water is enriched with nutrients and oxygen and treated with microorganisms native to the contamination site, and returning the enriched and treated water and microorganisms in a finely dispersed state to the contamination site, thereby enhancing bioremediation in a subsurface bioactive zone. The recirculation is accomplished with only the recovery well pump. The bioreactor is a fully pressurized fluidized bed bioreactor. The bioreactor includes a recirculation loop driven by a fluidization pump. The loop has a first branch that returns a portion of the recirculating water directly to the bioreactor inlet. A second branch of the recirculation loop includes a venturi/shearing nozzle driven by the fluidization pump that siphons biomass and attached particulate solids from an upper portion of the bioreactor and shears the biomass from the particulate solids and breaks up the biomass into fine particles. The fine particles pass through the bioreactor and outlet filter and well screen and are returned along with treated ground water to the contamination site. Computer controls provide a means for monitoring and adjusting operation from a remote location. Passive sparge and vent wells contribute to the in place bioremediation as well as serve to strip and remove volatile contaminants from the contamination site.