The article presents results of research carried out on four “DUOFILTER” type septic tanks. Analysed objects made first step of living sewage treatment in household sewage treatment plants. As a second step of treatment vertical flow sand filter was applied. Sewage flow through the tank in each case was less than 1,0 m3*d-1. Septic tank consisted of three chambers: first – sedimental one and two flow ones, equipped with filter made of porous structures. The research was carried out during the period from October 2003 to May 2005. Concentrations of raw sewage pollutants were analysed – taken from the first chamber of the tank, and sewage primarily treated – taken on the outflow from the tank. Three indexes from the basic group: BOD5, CODCr, total suspended solids were physicochemically analysed. On the basis of the carried out results’ analysis, mean effectiveness of BOD5 was ascertained from 25,3 to 40,2%; CODCr from 32,4 to 43,5 %; total suspended solids from 35,9 to 56%. ...
The article presents results of analyses concerning the influence of air temperature on the sewage temperature in the household sewage treatment plant. Each of the objective treatment plants (4 of them) consisted of the septic tank and vertical flow sand filter. The research was carried out from March 2003 to May 2006. Air temperature, raw sewage temperature (flowing into the septic tank), primarily treated sewage (after the septic tank) and treated sewage (on the out-flow from the septic tank) temperature was measured. The influence of the sur-rounding temperature on the raw sewage, primarily treated sewage and treated sewage temperature was statistically analyzed. On the basis of the research it was ascertained, that the temperature of the raw, primarily treated and treated sewage is influenced by the air temperature. ...
The article presents the thorough description of the vertical flow sand filters. The construction of sand filters was also presented and materials used for building filters were described. In the next part, capacities of sewage treatment in the vertical flow sand filters were presented. Vertical flow sand filters are mainly used as the second step of sewage treatment after septic tanks or after Imhoff tanks, as well as the third step after biological treatment processes when the high quality and stable outflow is required. Sand filters are useful for treatment sew-age from single households and from the group of houses, but they also can be used in bigger sewage treatment plants for the public utility objects. The article ends with the summary and conclusions where it is ascertained that the vertical flow sand filters are very good solution regarding household sewage treatment plants, in the areas where the combined sewerage system can-not be applied. Moreover the efficiency of sewage treatment in these objects is high. ...
