Abstract: A method for electrical treatment of a fluid medium with distributed therein cells of biological material is disclosed. The method is suitable for treatment of plant biological matter such as raw, dried, or powdered flowers, roots, algae, stems, peels, seeds, fruits and the like; animal sludge, municipal waste solids and water, including increase of methane production in digester, fish or poultry solid wastes. The method is also suitable for the purpose of extraction of intracellular matter (oil, fats, sugars, minerals, etc.) from the cells, as well as for killing bacteria, pathogen, viruses, for reduction of concentration of solids, Phosphorus, Nitrogen, microbes, or for eliminating unpleasant odor. The treatment comprises exposure the fluid medium with the distributed therein biological matter to discrete consecutive pulses, while the treated material is placed in a processing unit provided with electrodes emanating the pulses.

Abstract: A method for slowing down the increase in pressure drop across a gas filter caused by clogging as a result of a contaminant particles layer being formed on the filter. The method includes applying acoustic waves from an acoustic wave source to a gas to be filtered as it flows into the filter; thereby producing steady secondary acoustic streaming around dust particles already deposited on the filter, thus reducing pressure drop across the filter initially caused by clogging.