Thermophilic methane fermentation with an anaerobic fixed bed reactor containing a porous ceramic carrier

Abstract

In the previous work concerned with the anaerobic fixed bed reactor containing the porous ceramics (CAFBR), we found that highly loaded operation with up to 40kg -BOD/m³/D was possible at the thermophilic anaerobic treatment of a boiled soybean waste water. In this paper, we examined the tolerance of the CAFBR for BUD fluctuation of the waste water and for the alternation of fermentation temperature. We verified that stable themophilic methane fermentation was able to proceed for the wide BUD fluctuation of the waste water from 28, 000mg/l to 58, 000mg/l, and; that the performance of the CAFBR was scarcely affected by the temperature fluctuation untill ±3°C from the ordinaly thermophilic fermentation temperature: 54°C. We demonstrated thermophilic methane fermentation of the waste water, using a pilot plant which was constructed as CAFBR for the waste water. This plant had 0.5m³of reactor volume and had the ability to process the waste water untill 250l/day. The relation between BOD reduction rate and suspended solid produsing rate was investigated with this plant, and we determined that the growth-yield coefficient was 0.15kg-ss/kg-rBOD and microorganism-decay coefficient was 0.17 1/day at the thermophilic methane fermentation of the waste water.