Study of Septic Tank Wastewater Distribution in Soil

Abstract

In general, people use septic tanks for household wastewater management, but most of them do not meet health requirements and sni regulations, resulting in polluted shallow groundwater. Because of these issues, the author conducted a laboratory simulation of septic tank wastewater seepage on a small scale. This research was carried out in a 100 cm x 100 cm x 40 cm glass box. The aim of this study was to determine the distribution distance, flow rate, and travel time of septic tank wastewater in a horizontal direction wihtin a glass container. The study used statistical analysis to examine the horizontal spread of septic tank effluent in a glass box. The distribution simulation was performed using laboratory tests a ratio 1:10 according to the existing conditions and soil physical properties were tested. Contaminant parameters including the concentration of Escherichia coli and ammonia (NH3N) were analyzed based on distance and time. The number of samples tested in this study was 40 arranged transversely. The results of soil physical property tests included specific gravity of 2,648%, plastic limit of 16,443%, liquid limit of 25,906%, plastic index of 9,463%, sieve analysis of 17,51%, moisture content of 13%, organic matter of 6,12% and permeability 5,388 x 10−5 cm/s. The results of Escherichia coli concentration tests at showed that the concentration was 1,6 x 104 (mpn/100 ml) at the closets distance from the source of spread and 0,92 x 104 (mpn/100 ml) at the farthest distance. The ammonia (nh3n) concentration at the closest distance from the source of spread was 1,30 (mg/l) and the farthest distance was 0,97 (mg/l). The simulation results of the horizontal spread of septic tank wastewater in a glass box at a distance 81 cm required a travel time of 425 minutes (7 hours 5 minutes) with a septic tank wastewater spread speed/flow rate 8,4 x 10−5 liter/minute.