Description of Technology

he system is an alternative subsurface Soil Absorption System (SAS) that replaces a conventional SAS designed in accordance with 310 CMR 15.000. GeoMat™ is a low profile leaching system which consists of an approximately 1–inch thick core of fused, entangled plastic filaments fully wrapped in a hygroscopic membrane. A distribution pipe is placed inside the fabric on top of the core. The distribution laterals for gravity systems can either be 2 or 3 inch SCH40 pipe with minimum ½ inch perforations or 4 inch SDR35 perforated pipe. Pressure Distribution laterals are typically 1-2 inch SCH40 PVC. Size will vary depending on design and site conditions. Distribution laterals that are at different elevations should have flow equalization valves installed to provide equal head/flow of effluent to all rows. Orifice holes should be oriented in a downward (six ’clock) direction and can be spaced according to the dosing requirements of the system. The GeoMat system can be installed in trench and bed configurations and function in a gravity and pressure distribution system configuration. GeoMat with gravity distribution and 6” of ASTM C33 sand is NSF standard 40 certified treatment systems. Pressure distribution is required when the GeoMat is installed directly into native soil; gravity or pressure distribution is possible when GeoMatTM is installed in Title 5 fill. In a pressure distribution configuration, diffusers are installed over the orifices.

Both gravity and pressure distribution configurations utilize a transmissive core and a hygroscopic membrane that is in contact with the native soil or imported sand/soil medium to further distribute the water. Water is sent to the GeoMatTM, emitted from perforations or the diffusers by the pressure differential, into the transmissive core where it contacts the hygroscopic membrane. Water is subsequently moved by hygroscopic and capillary force between the diffusers and around the membrane surface of the GeoMatTM. Once the hygroscopic and capillary forces are overcome by head, the dose is released into the surrounding soil. The capillary force of the soil then draws the water away from the GeoMatTM.

Massachusetts Alternative Soil Absorbtion System Approvals

General - Disposal Only	General - Treatment and Disposal	Remedial - Disposal Only	Remedial - Treatment and Disposal

Please check the Title 5 Innovative/Alternative Technology Approval Letters webpage at Massachusetts DEP for the most up-to-date information.

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