Studi Sebaran Cemaran Air Limbah Domestik dari Tangki Septik pada Jenis Tanah Andosol

Abstract

The current increasing population growth will increase development, especially residential development. Population growth leads to surface and groundwater pollution due to limited sanitation and domestic waste management. Households generally use septic tanks to manage domestic wastewater, but these often do not comply with SNI regulations, potentially contaminating shallow groundwater. Due to these issues, the authors conducted a laboratory-scale simulation of septic tank wastewater distribution in andosol soil. This simulation was conducted using a 100 cm x 100 cm x 40 cm glass box. The purpose of this study was to determine the spread distance, travel time, and flow rate of septic tank wastewater horizontally and vertically in a glass box. The spread simulation was carried out with a test scale between the laboratory and existing conditions of 1:10. The physical properties of the soil were tested, the concentration of Escherichia coli and Ammonia (NH3N) contaminant parameters, and the concentration of contaminants based on distance and time. The number of samples tested was 20 points arranged diagonally. The results of the soil physical properties test include; soil specific gravity value of 2.6505%, plastic limit of 10.985%, liquid limit of 36.697%, plastic index of 25.712%, sieve analysis of 17.265%, water content of 20.42%, and permeability value of 5.966x 10-5 cm/s. The results of the Escherichia coli concentration test at the closest distance from the source of the spread of 18.3 x 107 (CFU/100 ml) and the furthest distance of 6.2 x 107 (CFU/100 ml) with a percentage decrease of 66%. The concentration of Ammonia (NH3N) at the closest distance from the source of the spread of 4.2 (mg/L) and the furthest distance of 1.1 (mg/L) with a percentage decrease of 74%. The simulation results of the vertical distribution of septic tank wastewater in a glass box as far as 20 cm requires 236 minutes (3 hours 56 minutes) with an infiltration rate of 5.56 cm/hour and horizontal distribution in a glass box at a distance of 80 cm requires a distribution travel time of 505 minutes (8 hours 25 minutes) with a speed/flow rate of septic tank water distribution of 9.2 x 10-3 Liters/minute.