A "layer cake" treatment area is basically a leach field that is placed in layers, using materials that allow for the successive nitrification and denitrification of septic tank effluent as it percolates through the layers. In this excavation 18 inches of a sand-sawdust mix is first placed over a two-inch layer of washed pea stone followed by 18 inches of "Title 5" sand. Atop the sand layer, the distribution system will be placed (shallow pressurized drain field product, drip dispersal).
Layer Cake Pilot Program
A property on State Highway received piloting approval for a "layer cake" septic system. The property is upgradient of Town Cove's Sentinal monitoring station. At the property, Samples will be taken monthly for two years. Samples will be taken from the pump chamber as well as from a series of pan lysimeters under the system. In addition, water use and pump-run counters will be checked during each sampling event. Following the period of the grant, the homeowner will be responsible for causing an annual inspection of the system and any monitoring required by the Commonwealth's DEP. We anticipate that annual monitoring will be required and annual inspection and adjustment of the low-pressure distribution system will be needed.