What does a leach field do?
It accepts dissolved compounds and dissipates liquids. In a primary treatment system (septic tank only) the effluent is about 75% of full strength sewage. (The remainder is lodged in the septic tank.) The effluent passes into the leach field where the actual treatment occurs in several steps. First an anaerobic (without oxygen) microbial community forms degrading (moving to a lower energy level) various compounds. Then at the surface of the bacterial mat where oxygen is present the real decomposition occurs.
