Biocolloids, e.g. Cryptosporidium parvum oocysts, are removed from water by filtration using a packed bed of a granular filter medium, preferably MgO, establishing an electric field across the packed bed, perpendicular to the flow of the water through the packed bed. The packed bed is provided in an annular space between two concentric electrodes.

A bioremediation of subsurface soil formations contaminated with hazardous wastes is achieved by hydraulic fracturing of the subsurface soil formation with simultaneous introduction of sodium percarbonate coated with polyvinylidene chloride as a solid oxygen source (SOS) for establishing colonies of the biodegrading bacteria within the fractures of the soil formation.