Effects of Olestra on Organic and Solids Removal in Septic Tanks

Abstract

AbstractA field study was conducted to examine the fate and potential effects of olestra, a non‐caloric fat replacer, in septic tanks. The study compared the performance of parallel septic tanks, which were led domestic waste water with liquid and solid forms of olestra, against a control tank receiving waste water without olestra. Results showed that 36 g/d of olestra dosed to the tanks (a three‐fold exaggeration of expected loadings) had no adverse effect on system operation (based on visual observations and sludge accumulation) or performance (based on removal of organic content and solids) over a six‐month period. Removal efficiencies for total suspended solids (TSS), carbonaceous biochemical oxygen demand (CBOD), and chemical oxygen demand (COD) were not significantly different (p<0.05) in the olestra tanks when compared to the control tank. In addition, a relatively small amount of the total olestra added (3 to 6%) was recovered in the septic tank effluents over the course of the study. Accumulation of tank solids was not affected as measured sludge levels in the tank at the middle and end of the study showed no difference between the olestra dosed tanks and the control tank.