Biodesulphurization of coal: effect of pulse feeding and leachate recycle

Biodesulphurization of coal was carried out under four modes of operation n amely: conventional batch, constant volume pulse feeding (CVPF), increasing volume pulse feeding (IVPF) and leachate recycle. The effects of different pulse feeding strategies and leachate (product) recycle on biological perf ormance were studied and compared with a conventional batch process. The su lphur removal rates for each of the four processes were 0.04 g/day (batch), 0.09 g/day (CVPF), 0.19 g/day (IVPF) and 0.05 g/day (leachate recycle). Th e values of iron solubilization rate (batch-83 mug/ml/day; CVPF-136 mug/ml/ day; IVPF-198 mug/ml/day; leachate recycle-133 mug/ml/day) also followed th e same trend. The percentage sulphur removal on the 30th day using batch, C VPF, IVPF and leachate recycle processes was 72%, 93%, 97% and 90%, respect ively. IVPF was found to be the best operational strategy for biodesulphuri zation process at enhanced rates for longer duration. (C) 2001 Elsevier Sci ence Inc. All rights reserved.