Sloping Lateral Flow Sand Filter Trenches and Constructed Wetlands as Innovative Secondary Treatment Methods for Septic System Effluent

Raymond King and Jason Osgathorp

Lateral flow sand filters (LFSF) and constructed wetlands provide low cost and minimum maintenance biological alternatives for effective secondary treatment of septic tank effluent before final disposal into soils. Over a twelve month period research will evaluate performance and effluent quality of two or more such systems which I designed; these lateral sloping sand filter trenches and constructed wetland systems were installed as successful innovative solutions where conventional repairs repeatedly failed.

My primary objective is to demonstrate that simple gravity-flow biological sewage treatment designs are capable of producing excellent effluent quality, probably exceeding mechanical treatment systems, greatly enhancing effluent absorption into poorly suited soils. Innovative features will focus on lateral flow sand filters installed in my trench configurations. I propose that common use of these biological systems will reduce groundwater and surface water pollution, reduce failure rates of on-site systems, and protect public health much better than conventional septic systems or advanced treatment systems. My second objective is to design template models for lateral flow sand filters that encompass all the best features of my innovative designs and those of previous researchers at Dalhousie University’s Centre for Water Resources Studies. Third, I will propose that sand filtration and wetlands be added to Georgia’s Manual for On-Site Sewage Management Systems as alternative methods of secondary sewage treatment although adoption process may exceed scope of this research.