Treatment Using Subsurface Soil Infiltration

Abstract

Subsurface soil infiltration is a form of land-based treatment where effluent from a tank-based wastewater treatment unit is infiltrated into soil below the ground surface and treatment occurs during percolation through a soil profile and assimilation into the subsurface soil and groundwater environment. Land-based systems have been used for more than 100 years, initially for simple waste disposal but later for effective treatment purposes also. A modern version of a land-based system is a soil treatment unit that is designed to achieve tertiary treatment and natural disinfection. This Chapter presents the principles and processes involved in wastewater treatment in soil and the considerations important to design and implementation of soil treatment units that rely on subsurface soil infiltration and recharge of local groundwater.