The efficiency of sewage treatment in the ground bed under the subsurface sewage disposal field was tested in laboratory conditions using synthetic sewage. The ground bed was composed of mean sand and mean sand with assist layer with chalcedonite. The experiment determined the following indicators: suspended solids, BOD5, COD, total nitrogen, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, total phosphorus and pH. In the sewage filtered through the ground bed of mean sand as well as through mean sand with assist layer with chalcedonite, increase in the values of nitrite nitrogen and pH was observed. The values other indicators of the treated sewage, was undergo a decrease. The suspended solids, BOD5, COD, total nitro-gen, total phosphorus of the treated sewage, are meeting obligatory standards. The ground bed with mean sand with assist layer with chalcedonite is characterized by a better effectiveness of sewage treatment. ...
