Todd Willis and his team install septic systems mainly on 1/4- and 1/2-acre lots with severe space constraints.
That makes compact drainfields essential for New London County Septic & Excavation, serving southeast Connecticut and southwest Rhone Island. The company’s go-to drainfield solution is the GST Leaching System from Geomatrix Systems.
The technology is an adaptation of traditional stone-filled leaching trenches. It uses a removable form that enables installers like Willis to shape and construct leaching “fingers” along the sides of a central distribution channel.
The fingers are created with 1/4-inch to 1/2-inch washed stone and are surrounded with ASTM C-33 sand. The configuration increases the sidewall surface area by more than six times that of traditional trenches. This mitigates any negative hydraulic effect that fines introduced in dirty stone may have on the system’s bottom area.
Once the stone and sand is installed, the form is removed; crushed stone is placed on top and leveled, and the central pipe is laid atop the stone. The finished system is then covered with filter fabric and topsoil seeded with grass.
The narrow profile of the leaching fingers and the central distribution channel, along with the uniform profile of the sand treatment media, enhance oxygen transfer efficiency, leading to better treatment of septic system effluent and longer drainfield life. GST systems can be configured to work with standard gravity or pressure-dosed or time-dosed distribution. Systems are available in configurations from 6 to 30 inches tall and 36, 37 or 62 inches wide.
Each system has an inspection port on every row, consisting of a 4-inch PVC tee with two slotted openings on the T ends. A threaded plug on top keeps debris from entering. The inspection ports are designed not to move up or down over the life of the system.
If it is ever necessary to pump the system out, the inspection ports prevent postholes from forming, as can happen when an open-bottom pipe is used for pumping. The ports can be finished in a valve box to be flush with the grade.
“We often deal with well and property line setback issues, and trees or other landscape features in the way,” Willis says. “So we’re always looking for systems that are compact with a high yield. The Geomatrix systems fit the bill very well.”
Read more about New London County Septic & Excavation in a full profile in the January issue of Onsite Installer and check out more GST installation photos in the gallery below.
