Removal of grease and oil by biological treatment processes

TLDR: There was no evidence that the grease and oil removal performance of treatment plants was related to influent grease andOil concentrations in the range normally received at municipal treatment plants.

Abstract: A study was conducted to identify wastewater characteristics and operating parameters of full-scale wastewater treatment plants affecting grease and oil removal. Laboratory tests were conducted to supplement field observations. Grease and oil removal by biological treatment plants normally is equal to or better than BOD removal, regardless of the BOD load to the plant or the resulting low BOD removal efficiency. Effluent BOD concentrations at most surveyed plants exceeded 30 mg/l. in 20-80Vertical Bar3< of the samples. Corresponding grease and oil concentrations exceeded about 6 mg/l. No single type of biological process gave consistently high or low grease and oil removal. Polar and nonpolar fractions in effluents varied greatly, but on the average, the percentage of the total grease and oil in effluent samples occurring as polar material was about the same as in influent samples. There was no evidence that the grease and oil removal performance of treatment plants was related to influent grease and oil concentrations in the range normally received at municipal treatment plants.