FATE OF METHANOL IN AN ANAEROBIC TREATMENT SYSTEM IN A PAPER MILL

A paper mill has recently proposed the treatment of methanol-containing condensate in an existing anaerobic pretreatment system as an alternative control of hazardous air pollutants (HAPs) 40 CFR Part 63 Subpart S – Maximum Achievable Control Technology. There was a concern on the anaerobic biodegradability of methanol and byproducts and the potential for gas stripping from the system. A series of laboratory-scale experiments was conducted and a mathematical model was developed to evaluate the fate of methanol during anaerobic treatment. More than 99% of methanol contained in the condensate was biodegraded during anaerobic digestion. From an anaerobic digester batch test, the second order biodegradation rate constant, kb2, was estimated to range from 3.97 × 10-3 m3/g·day (when only condensate was fed) to 4.06 × 10-2 m3/g·day (when condensate was fed at the proposed rate). The losses of methanol through the Styrofoam™ cover system and volatilization were estimated to be almost zero (