Treatment Performance of Water Purification Unit for Reclaimed Wastewater of Independent Toilet

The objective of this study is to develop a toilet independent of infrastructure, that is, electricity, water and sewerage. The treatment performance of the water purification unit to reclaime wastewater for toilet usage with minimum running energy for the circulation of water was tested. The chromaticity of reclaimed wastewater was maintained at less than 30 degrees after the total number of times of toilet use reached 897 (218 excremental and 679 urinal uses). Since the complete elimination of Escherichia coli using only the water purification unit was difficult, it was found that some disinfection countermeasure would be necessary to maintain hygienic safety. The removal efficiencies for CODMn, total nitrogen and total phosphorus estimated from the total number of times of toilet use and the final water quality of reclaimed wastewater were approximately 99%, 83% and 98%, respectively, despite the frequency of toilet usage. These results confirmed that the water purification unit consisting of a multistage filtration bed could stably reclaim wastewater for reuse in the toilet.