Biochemical processes for geothermal brine treatment

As part of the DOE Geothermal Energy Program, BNL`s Advanced Biochemical Processes for Geothermal Brines (ABPGB) project is aimed at the development of cost-efficient and environmentally acceptable technologies for the disposal of geothermal wastes. Extensive chemical studies of high and low salinity brines and precipitates have indicated that in addition to trace quantities of regulated substances, e.g., toxic metals such as arsenic and mercury, there are significant concentrations of valuable metals, including gold, silver and platinum. Further chemical and physical studies of the silica product have also shown that the produced silica is a valuable material with commercial potential. A combined biochemical and chemical technology is being developed which (1) solubilizes, separates, and removes environmentally regulated constituents in geothermal precipitates and brines, (2) generates an amorphous silica product which may be used as feedstock for the production of revenue generating materials, (3) recover economically valuable trace metals and salts. Geothermal power resources which utilize low salinity brines and use the Stretford process for hydrogen sulfide abatement generate a contaminated sulfur cake. Combined technology converts such sulfur to a commercial grade sulfur, suitable for agricultural use. The R and D activities at BNL are conducted jointly with industrial parties in an effort focused on field applications