Abstract
Required conditions for the wastewater treatment through soil are quantitatively discussed from the kinetic point of view. In order to have satisfactory treatment of wastewater by soil both BOD and hydraulic loadings per unit effective volume of soil and per unit area of land utilized will have to be sufficiently large in order compared with conventional mechanized treatment processes. Under such low loadings; the residence time of wastewater within the effective volume of soil can be kept so long that the BOD can be removed by soil bacteria under their endogenous respiratory conditions. This will avoid the plugging of void in soil by the excess growth of the bacteria, The void fraction of soil will be an important factor which controls the transfer of oxygen consumed by bacterial activity.
