PENGARUH POROSITAS DAN PERMEABILITAS TANAH SERTA JARAK TANGKI SEPTIK TERHADAP KUALITAS AIR TANAH DANGKAL DI WILAYAH PESISIR DITINJAU DARI PARAMETER BAKTERI E. COLI

Abstract

Ground water exploitation in coastal area which have high ground water level as physically conditions, medium to high permeability and high porosity because of septic tank location not yet fulfilled safety distance to well needs to be considered because bacteria from septic tank could contaminate ground water and causes various disease. The purpose of this research was to know the E. Coli bacteria concentration in ground water at district of north Semarang as source of clean water as and to know the relationship between porosity, permeability of soil and distance from septic tank to well with E. Coli concentration. Subjects of this research were ground water well that were still being used by community. The sample total were 25 ground water wells and 13 soil sample that were collected based on purposive method. Water sampling was based on sampling method of Indonesian Health Departement (1997), while soil sample was done by soil boring in ± 1 metre depth. Data collecting was performed by using tube fermentation 3-3-3 method. Anova, regression, and correlation analysis were used in this research. The result of this research showed that 25 sample checked were not fulfilled drinking water requirements but 4 sample still fulfilled clean water requirements. Statistical analysis showed that distance variable have a strong relationship with water bacteriological quality with correlation value -83,5%. Porosity and permeability have a weak relationship to water bacteriological quality with correlation value 28,2% and 3,1%. Exponential equation from relationship between well to septic tank distance and E. Coli concentration, give recommended well to septic tank distance. The safety distance recommended should be 15 metre to avoid Fecal contamination.