BROOKFIELD, CT – South Kent School, established in 1923, is a college preparatory school for boys in grades nine through 12 nestled in the hills of picturesque northwestern Conn. The facility, which houses dormitories, classrooms, a gymnasium, a hockey rink, several athletic fields and a library, is located 45 miles west of Hartford, Conn. and 90 miles northeast of New York City.
In recent years, the school has observed an expansion of its student and faculty population, creating a need for the facility to expand as well. As such, an analysis of the existing subsurface sewage disposal system (SSDS) was conducted as part of the planning stage for the larger facility. The population currently generates an estimated 15,000 gallons of sewage per day (GPD) with a future estimate of 18,300 GPD. The analysis revealed that the existing system has inadequate capacity to handle the projected future flow. Engineers from DYMAR, Corp. of Southbury, Conn., believed that an entirely new SSDS would need to be constructed to handle all of the school’s current and future sewage flow.
Discharge is regulated by the Connecticut Department of Energy and Environmental Protection (CTDEEP). Engineers chose to use CULTEC’s Contactor® 100 plastic subsurface leaching chambers, arranged side –by-side in each trench. Each chamber measures 8” x 36” x 12.5” and has an effective leaching area of 5.90 SF/ft. The chambers have repeating support panels to add strength, feature a patented overlapping rib connection and have a greater contact with the primary leaching area, which promotes maximum infiltration.
“The CULTEC chambers we used for this project were not only lightweight and simple to install, but they are durable and very reliable,” said Mark Green, owner of Green Construction Management, LLC, a full service environmental construction company specializing in septic system designs and installations. “A different product was originally specified for this project, but in working closely with DYMAR in value engineering options, we agreed a CULTEC chamber was the best solution to satisfy the project and the school requirements. In addition, CULTEC provided us with field inspections, and a representative from the company was present to oversee the installation.”
The new system consists of over 1,100 CULTEC Contactor 100 chambers arranged in a side-by-side configuration in 56 rows. They are located beneath the school’s existing lower athletic field, which is being reconstructed into a regulation-size soccer field. The system covers 4,329 linear feet of trenching, 8,658 linear feet of CULTEC Contactor 100 chambers, occupying a surface of area of 59,400 sq. ft. The subsurface chambers are being used for storage and dispersion of sewage effluent as it seeps into the native soils after conventional treatment to recharge the groundwater. In addition, there are approximately 240 linear feet of chambers being used as infiltration rechargers for the surface drainage of the soccer field and to provide nitrogen dilution. All of the chambers were placed on native material, and processed stone was placed above and on the sides of the chambers and topped off with common fill and topsoil.
A traditional septic system consists of a solid pipe from the building structure, the septic tank, a drain field and soil treatment. The school’s wastewater management system consists of gravity collection piping from numerous buildings and pretreatment septic tanks. Sewage water flows from the tanks to a centralized effluent pump station and meter pit that doses the CULTEC chambers using an electromagnetic flow meter to regulate valves and the flow controller. Flows to the CULTEC chambers are based on preset daily volumes to individual dispersal cells based on real time that is adjusted for temperature change for greater accountability of the flow. The metered flows are transmitted from a data logger to desktop computer and meter software that is customized for the school to obtain greater flow control, operational efficiencies and reporting to the CTDEEP. The CULTEC disposal system operates passively, supported by the latest instrumentation technology to provide the school with flexibility, ease of operation and long-term performance. The modeling of the groundwater response to the new CULTEC disposal bed was based on a three-dimensional MOD-Flow model. DYMAR furnished the CTDEEP with technical assistance from Shelton, Conn. based-Leggett, Brashears & Graham, the oldest Hydro-Geological consultant in the country.
South Kent School occupies approximately 350 acres of land, and the area where the CULTEC system is being installed is the size of a baseball and football field combined. Because the site is so large, engineers chose to install the technically advanced metering system that includes a splitter box, which includes multiple outlets to disperse the flow to set CULTEC trenches, segmenting the trenches into dispersal cells. This method provides better control of the effluent flow and long-term effect on the groundwater mound beneath the system. In this case, two three-inch lines from the pump station deliver water to the splitter box, alternating each line to distribute a set amount of flow. The flow then uses pressure to distribute the water through seven different lines to receiving distribution boxes. It is beneficial to use such a system on a large site because it allows extra control and manipulation over water flow and individual sections can be manually shut off if necessary. This option is especially useful since the entire system will not be in use at the same time while South Kent School prepares for construction of future housing on the premises.
CULTEC’s Contactor 100 leaching chambers replace conventional pipe and stone or concrete leach fields and may be installed in trench or bed configurations according to acceptance by local regulations. The contact area is maximized by the fully open bottoms, perforated sidewalls and the use of CULTEC No. 410. Filter Fabric. In this case, the CULTEC chambers size is based on CTDEEP regulations, which restrict the height of the chamber to a maximum of 12” high. The side by side Contactor 100 configuration has an equivalent rating to a 12” high concrete gallery trench system.
“We have specified CULTEC’s chambers in a number of other septic system and stormwater management projects and have always been very pleased with the results,” said Mark E. Lancor, P.E., Principal Engineer at DYMAR Corp. “CULTEC’s products have a great reputation and we will continue to use them in the future.”
For more information about CULTEC plastic septic chambers and other products, please call (203) 775-4416 or visit www.cultec.com.
In 1986, CULTEC introduced its Contactor® and Recharger® HDPE septic and stormwater chambers and helped begin a revolution toward the use of plastic construction products. Since then, several product developments and strategic alliances have made CULTEC a cutting-edge R&D-based manufacturer. CULTEC chambers can be used as subsurface retention or detention systems and as replacements for ponds, concrete structures or pipe and stone installations.
CULTEC manufactures several chamber sizes ranging from 8.5” - 48” to accommodate almost any site parameter. The Contactor® Chamber series consists of lower profile, lower capacity chambers used for septic installations with depth restrictions or where larger units are may not approved by the local authority. The Recharger® Chamber series consists of higher profile, higher capacity chambers. Fewer units are required resulting in a smaller overall footprint, where approved. The chambers’ perforated sidewalls and fully open bottoms promote maximum infiltration capability and allow for the transfer of high volumes of water at a low velocity. The units can be installed singularly or in series in single- or multi-layer beds for stormwater management designs.
CULTEC’s technical staff offers free design assistance including preliminary calculations and job-specific CAD details. A free CULTEC StormGenie™ -- AutoCAD® Plug-In for designing CULTEC stormwater systems and a free HydroCAD CULTEC custom edition are also available from the company. In addition, CULTEC products can contribute to the U.S. Green Building Council's credits, under the LEED rating system, when the project is designed per LEED requirements.
Melissa Lo Parco
Catalyst Marketing Communications, Inc.