THE TEMPERATURE-PHASED ANAEROBIC BIOFILTER PROCESS

The ''temperature-phased anaerobic biofilter'', or TPAB process (U.S. Patent pending), is a new high-rate anaerobic treatment system that in cludes a thermophilic (56 degrees C) biofilter connected in series wit h a mesophilic (35 degrees C) biofilter providing for two-temperature, two-phase treatment. Three TPAB systems of different thermophilic:mes ophilic reactor size ratios were operated at system HRTs of 24 hrs, 36 hrs, and 48 hrs to characterize performance and to determine if an op timum size ratio exists between the thermophilic and mesophilic phases . The three TPAB systems achieved SCOD reductions in excess of 97% and TCOD reductions in excess of 90% for a synthetic milk substrate over a range of system COD loadings from 2 g COD/L/day to 16 g COD/L/day. T here was little difference in performance between the three TPAB syste ms based on COD reduction and methane production. The 1:7 ratio of the rmophilic:mesophilic phase TPAB system performed as well as the 1:3 an d 1:1 size ratio TPAB systems. In applications of the process, a relat ively small thermophilic first-phase can be used without sacrificing o verall two-phase system performance. The TPAB process is a promising n ew anaerobic treatment technology with the ability to achieve higher e fficiencies of organic removals than is generally possible for single- stage anaerobic filter systems operated at equivalent HRTs and organic loadings.