Cold Plasma Technology for Water Treatment: Design, Assembly and Technical Evaluation of A Pilot Plant

The development of innovative oxidation process methods for wastewater treatment remains a major challenge worldwide. Cold discharge plasma is considered a promising remediation technology because it is a low-cost and easy-to-operate process. In this work, a system with a reactor for water treatment using plasma technology was designed, assembled and experimentally evaluated. The water to be treated was circulated by spraying under controlled conditions through a borosilicate glass cylindrical reactor at room temperature and a flow rate of 2.5 liters/min; to which a potential of up to 10,000 volts and a relatively high electrical frequency were applied. Under these conditions, the water is converted into a plasma state, in which ultraviolet light, hydrogen peroxide, H2O2, ozone, O3, and hydroxyl radicals, OH∙, are generated. Organic materials, viruses and bacteria present in the water are oxidized. When synthesized samples were processed with treated water, ethyl alcohol and some coliforms, it was possible to quantify that their Chemical Oxygen Demand (COD) was reduced by 49% in best, and the microorganisms disappeared. It was found that the degradation of ethanol depended on the initial concentration of the synthesized samples, being more efficient for lower concentrations, so present system is proposed as a tertiary treatment.