This module sketches out the impact of sewage organic matter on soils. For convenience, that organic matter is separated into the readily decomposable compounds and the more resistant material (volatile suspended solids, refractory organics, and sludges). The fates of those organics are reviewed along with loading rates and recommended soil conditions. Laboratory studies indicate that some soil systems are capable of oxidizing as much as 8000 lbs COD/acre-day if surface clogging is avoided, macropore space is sufficient, optimum moisture levels are maintained, and adequate soil aeration is assured. More stable organic matter generally is not present in quantities that are significantly greater than the normal losses from productive soils. Usually the actual amount of organic matter that is added through land application is small compared to the amount of native organic matter present. Also, the newly added organic matter decomposes more rapidly than native organic matter. These factors, combined with the restrictive load limits imposed by the nitrogen content of wastes, keep the net accumulation of organic matter quite low in highly productive soils. (Author/BB)