Electrolytic Treatment - A great deal of interest was generated in the United States prior to 1930 in electrolytic treatment of wastewater, but all plans were abandoned because of high cost and doubtful efficiency. Such systems were based on the production of hypochlorite from existing or added chloride in the wastewater system. A great deal of effort has been made in reevaluating such techniques. Reduction in Number of Viable Microorganisms by Adsorption onto the Electrodes - Protein and microorganism adsorption on electrodes with anodic potential has been documented. Microorganism adsorption on passive electrodes (in the absence of current) has been observed with subsequent electrochemical oxidation. This does not appear to be a major route for inactivation. Electrochemical Oxidation of the Microorganism Components at the Anode -Oxidation of various viruses due to oxidation at the surface of the working electrode has been indicated, although the peak voltage used in many experiments would not be sufficient for the generation of molecular or gaseous oxygen.
Destruction of the Microorganisms by Production of a Biocidal Chemical
Species - It has been shown that NaCl is not needed for effective operation in the destruction of microorganisms. Biocidal species such as CI, HO 0, CIO, and HOCI occur but have very low diffusion coefficients. Hence, if this phenomenon occurs, the probability is that organisms are destroyed at the electrode surface rather than in the bulk solution.
Destruction by Electric Field Effects - It has been observed that some organisms are killed in midstream without contact with the electrodes. The organisms were observed to oscillate in phase with the electric field. Hence, microorganism kill can also be ascribed to changes caused by changing electromotive forces resulting from the impressed AC.
Electromagnetic Separation - In the typical operation, a magnetized fine-particle seed (typically iron oxide) and a flocculent (typically aluminum sulfate) are added to the wastewater, prompting the formation of magnetic microflocs. The stream then flows through a canister packed with stainless steel wire and a magnetic field is applied. The stainless steel wool captures the floes by magnetic forces.
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