At-Grade System

The At-Grade is similar to a mound system in operation, however it does not require sand fill. They are installed on sites where the limiting factors (bedrock and high groundwater) prevent a conventional system but are deep enough to not require additional sand fill to achieve the minimum 36" seperation. The At-Grade is installed by tilling the soil and placing the bed directly at the original grade, (hence the name) and covering with synthetic fabric and topsoil. Effluent from the treatment tanks is pumped to the system similar to a mound.