We provide information on biological treatments whether used alone or in the combination with chemical and physical treatments. As an example we cite the following as a guide in bioremediation treatments---processes which use component microorganisms and the enzymes they produce to transform or degrade contaminants found in groundwater, surface water, soil, sediment, and sludges. Biological treatment processes include bioreactors, biofilters, ponds and lagoons, land treatment, composting, and subsurface aerobic/anaerobic treatment.