Kajian Sebaran Larutan Tracer NaCl pada Tanah

Abstract

Decline in groundwater quality can be caused by poor sanitation, such as seepage of wastewater from households, including in this case seepage from septic tanks whose construction is not in accordance with standards. Because of these problems, authors use glass box measuring 100 cm x 100 cm x 40 cm modeling to see seepage simulations from septic tank leaks to the ground, but in this case it is used as a comparison using a NaCl tracer solution. This tracer solution is commonly used in determining the direction of groundwater flow and in this study will be used as a comparison with other studies which using septic tank wastewater as a parameter. The aims of this study are to find out how far the spread distance, flow rate, and flow time of the NaCl tracer solution were in the glass box. The method used is the Simple Statistical Analysis method in graphical form to see the distribution of contaminants in the soil. The tests carried out were testing the physical properties of the soil, testing samples based on distance and time, and testing samples based on NaCl concentration. The number of samples tested was 40 points arranged transverselly (diagonally). The results of laboratory tests on the physical properties of the soil included permeability with a result of 5,38 x 10-5 cm/second, soil specific gravity of 2,648, liquid limit and plastic limit of 25,906% and 16,443%, sieve analysis number 200 of 17,51%, and moisture content by 13%. The results of the soil testing showed that the type of soil tested based on permeability was dense silt, which is included in low permeability (10-5). The results of the NaCl concentration test have the highest value at points 1 and 7 with a value of 4% and the lowest value is 1%. The conclusion obtained is that the NaCl tracer solution takes 431 seconds or 7,18 minutes to reach the farthest point, which is 81 cm since the solution was poured into the storage box. The flow rate is 2,3 x 10-6 liter/s.