The Biodegradation Characteristics of Proposed Fuel Systems Icing Inhibitors (FSII)

The biodegradation characteristics of three fuel system icing ihhibitors FSII were evaluated. FSII are jet fuel additives that partition into water readily and are present in the water drained from storage tank bottoms in concentrations approaching 40. These concentrations raise concerns as to the disposal and handling of these wastes. The current FSII, DiEGME was evaluated along with two new candidates, dipropylene glycol and glycerol formal. DiEGME appeared to be moderately but not completely biodegradable. It is likely that much of it would be removed in a wastewater treatment plant. Dipropylene glycol only showed signs of degradation after more than three weeks at which point it degraded moderately well. The third FSII, glycerol formal did not show any signs of biodegradability during the five week period of testing. Preliminary toxicity and inhibitory tests were carried out for these chemicals at high and low concentrations. DiEGME appeared to be most toxic to microorganisms at high concentrations, dipropylene glycol show moderate toxicity, and glycerol formal showed little. At low concentrations, none of the chemicals appeared to inhibit the activity of microorganisms.