Oxygen Diffusion Rate into Trench Soil Treatment Systems and the Enhancement of the Wastewater Feed Rate per Unit Area

Abstract

A simple numerical model was constructed and the oxygen supply rate into the trench soil water treatment system was estimated as the function of the wastewater feed rate. The effects of the width of the site, the depth of the infiltration surface and the depth of the groundwater level were investigated. Three soils were examined and the soil of high hydraulic conductivity appeared to be preferable, loam soils should be avoided. By multiplying the number of trenches per unit length of width, and by making the depth of the trench shallow, the wastewater feed rate per unit area of the site is able to be improved. For andosol and silty caly loam soil, about the feed rates of 0.2m·d^-1and 0.1m·d^-1were estimated to be treated respectively.