Batch experiments using the Hungate serum bottle technique were used to determine the anaerobic treatability of phenolic (7600 mg/1 by 4-aminoantipyrine) wastewater from an H-coal conversion pilot plant. Methane production above controls was achieved at up to 6% V/V dilution. At these levels, inhibitory components in the wastewater retard but do not stop volatile organic acid (VOA) fermentation to methane.
Ether-extracted wastewater was tested at up to 50% V/V on cultures receiving 200 mg/1 phenol and was found not to be inhibitory, suggesting that inhibitory components in the wastewater are ether-extractable. Finally, a “reconstituted H-coal” which contained pure phenolic constituents added to ether-extracted H-coal exhibited batch methanogenesis above controls at H-coal dilutions up to 10% V/V. These findings indicate that the ether-extractable inhibitory substances are not one of the major phenolic compounds present in the H-coal wastewater.