Influence of mineral nutrients on high performance during anaerobic treatment of distillery wastewater from barley- shochu making

The influence of the mineral nutrients Ni 2+ and Co 2+ was studied in order to improve the reaction rate in the anaerobic treatment of distillery wastewater. Wastewater from barley- shochu making, supplemented with mineral nutrients, was treated by a thermophilic single-phase methane fermentation process using an anaerobic fluidized-bed reactor. A maximum TOC volumetric loading rate of 42 g/ l·d, with a TOC removal efficiency of 78%, was achieved. This rate was 4-fold higher than that without the addition of the mineral nutrients. The gas yield was 1.7 l/g TOC consumed, which corresponds to 90% of the theoretical yield. In mesophilic single-phase methane fermentation, the addition of mineral nutrients also accelerated the reaction rate 5-fold compared to that without the addition of mineral nutrients.