Low Cost, Efficient Microchannel Plasma Ozone Generator for Point of Use Water Treatment

A team of EP Purification and the University of Illinois engineer and chemists is pursuing the commercialization of low cost microchannel plasma modules capable of efficiently producing ozone for water treatment. The conservation of water resources for human consumption is a growing national priority. Contamination of ground municipal water by animal manure, fertilizer and pharmaceuticals, for example, is posing an increasing hazard for human health. Ozone is a unique purification agent as it is the strongest oxidant and disinfect available commercially. It is know to be extremely effective for neutralizing pathogens (bacteria, viruses, cysts) and some pesticides, making it ideal for the disinfection of water, grain, and vegetables. Another benefit of using ozone is the minimal disinfection byproducts or residues are produced during its use, as compared with chlorination. Also, ozonation is generally regarded as being superior to traditional disinfection through chlorination because the latter requires hazardous chemicals, produces carcinogenic byproducts when reacting with hydrocarbons in water, and leaves much to be desired from an environmental perspective. The primary drawback of ozonation for utility and consumer applications is cost and power consumption. This Phase I proposal leverages technology developed at the University of Illinois and EP Purification to realize low cost and yet robust ozone generators based on massively-parallel plasmachemical processing of O2/N2 mixtures in large arrays of microcavity plasmas. Modules producing ozone at concentrations higher than 5 wt.% on efficiency of at least 180 g/kWh will be designed in Phase I, and Phase II will demonstrate and characterize a 100g/hour ozone generator for treating water in small/medium system applications that is superior to existing technology in cost (capital and operating), efficiency and size.§The microplasma technology proposed here has several advantages over conventional large-scale corona discharge systems that are currently used for municipal water treatment. Based on microchannels fabricated inexpensively in alumina (Al2O3), this technology has already been shown to be efficient(>180 g/kWh at .3 wt.% O3) and robust but at much lower system weight and cost for equivalent production. With respect to the latter, lifetimes beyond 1600 h of continuous operation in accelerated aging test have already been demonstrated. Our design philosophy is to produce robust, inexpensive, and fully recyclable modules, comprising 200-300 microchannels, as the” building block” for O3 production, allowing the ozone production rate (kg/h) to be readily scaled to the value demanded by an application. § Key Words – Water Disinfection and Remediation, Ozonation, Microplasma, Microchannel