Use of tannery wastewater as an alternative substrate and a pre-treatment medium for biogas production

Abstract This study investigated biogas production as an alternative treatment of tannery wastewater (TWW) and its use as a pre-treatment medium to increase CH 4 yield from anaerobic digestion (AD) of wheat straw. The TWW had high levels of sulfate and chloride, so biochemical CH 4  potential could be estimated only when the TWW was diluted. Untreated straw yielded 255 NL CH 4 (kg VS) -1 , whereas straw that had been pre-treated with TWW yielded 314 NL CH 4  (kg VS) -1 (35% increase). Treatment of TWW by AD with a co-substrate might be possible using a controlled feedstock mixing ratio. Use of TWW as a pre-treatment medium by simple co-storage before AD would be beneficial as an inexpensive treatment of lignocellulosic biomass.