ABSTRACT
Where a site evaluation has determined that there is no problem with shallow ground water or bedrock, very loose soil, slope, a drain field comprised of a series of conventional absorption trenches is probably the most cost-effective, simple, and easily installed method of effluent disposal from the sewage treatment unit. Disposal systems, unsaturated soil can provide excellent treatment for sewage effluent. Provided that ground water is not too near the bottom of the trench, that the soil is moderately permeable, and that the rate of the sewage discharge into the soil is not too great, the concentration of particles should be reduced by many times, and the effluent should be reasonably safe as it combines with the ground water. The reason that sewage disposal systems in loose soils are not failing like matches in a rainstorm is probably because of the great safety factor built into the recommendations.
