The GPC Filter Process from Ground Penetrating Carbon consists of a specially stratified sand filter modeled after coastal outwash plains and sandy alluvial soils. The final denitrified effluent from a treatment plant is mixed with a carbon source and then periodically dosed onto the filter, creating the proper microbial environment for the soil bacteria within the sands of the filter to metabolize differing compounds. By establishing the correct carbon-to-nitrogen ratio within the dosed mixture, the soil bacteria within the sands will metabolize differing contaminants. The process can be installed as an inline system and dosed to an existing leaching field, or it can be built as a bottomless filter and continue to enlist the surrounding soils to attenuate certain contaminants. It has been shown to reduce the dissolved total nitrogen of denitrified effluent by over 50 percent, and reduce BOD and TSS to levels near or below detection. 508/548-3564; www.groundpenetratingcarbon.com.