A Self-Contained, PV-Powered Toilet and Domestic Waste Water Disinfection System

A comprehensive design review, development, construction, and performance testing of a sustainable, traditional infrastructure-free approach to the handling and processing of human sanitary waste including human fecal solids control, urine processing, and liquid wastewater treatment. The treatment scheme incorporates sludge disinfection, treatment, and volume reduction. This solar toilet system has at its core unit process photovoltaic-powered (PV) electrochemical chemical reactors that generate H2 as a potentially useful byproduct obtained during anoxic wastewater and fecal matter treatment including the complete disinfection of the total cultural bacteria initially present. The system has been designed to be free of an electrical grid or from subsurface urban infrastructure. Our prototype treatment scheme can be adapted for single family use as a sanitary toilet facility or upon scale-up, the design can be enlarged in size to handle the daily wastes of 500 people with a predicted break-even operating cost when powered by a PV array in which energy is stored for use throughout 24 hours of continuous operation. The fundamental concept has been tested at the bench-scale and also at the prototype scale with synthetic feces, with urine, with domestic wastewater, and with human feces. Based on both our bench-top laboratory experiments and on our larger-scale reactor systems (20 L and 40L process volumes), and in the prototype unit testing unit. Our general concept, specific design elements, and treatment approach has proven to be viable for the treatment of raw domestic wastewater, human urine, human feces, and synthetic human waste analogues. After several hours of PV-powered electrochemical treatment, the turbid, black water influent can be clarified with the elimination of the suspended particles along with the reduction or total elimination of the chemical oxygen demand (COD), total enteric coliform disinfection via in situ reactive chlorine species generation, and the elimination of measurable protein after 3 to 4 hours of PV-powered treatment.