DETERMINATION OF TRANSFER RATE CONSTANTS AND PARTITION-COEFFICIENTS FOR AIR PHASE BIOFILTERS

The determination of transfer rate constants (k) and concentration par tition coefficients (k(h)) is required for biofilter mathematical mode ls. A bench-scale technique was developed and used to evaluate k and k (h) values for four different packing materials: (1) compost; (2) a mi xture of compost and diatomaceous earth (DE); (3) Calgon granular acti vated carbon (GAC); and (4) Westates GAC. Two vapor phase contaminants were used: ethanol and carbon dioxide. Experimental results showed th at this technique produced estimated kh values that were similar to bo th ''batch'' and ''spike test'' results, indicating the accuracy of th e procedure. Calculated k(h) values for carbon dioxide were two orders of magnitude less than those for ethanol. The water content of the pa cking material strongly affects k(h) values. High water content increa sed k(h) values for ethanol and decreased k(h) values for carbon dioxi de.