Performance of a sulphidogenic bioreactor inoculated with indigenous communities for treating an extremely acidic mine water.

A continuous-flow, low pH biofilm sulphidogenic bioreactor inoculated with indigenous microbial communities has been developed for treating mine impacted water. The inoculum came from an anaerobic sediment in the acidic Azufire River in northern Chile. The sulphidogenic system (2.3 litres) was operated as a continuous flow mode unit for 99 days at 30 degrees C and fed with water of pH 2.1, with Zn 0.5 mM and Fe 2 mM. The bioreactor pH was initially 4.5 and was increased in stages to 6.0. The results show that zinc concentrations in liquors draining the bioreactor were below the detection level in most of the samples analysed. By progressively increasing the glycerol concentration, it was possible to increase the removal of iron (70% of the total present), though more acetic acid (from 1 to 5 mM) was generated. Analysis of the microbial populations showed that they changed with varying operation parameters, and a known acetogenic sulphidogen (Desulphoporosinus acididurans) became more dominant. The sulphidogenic bioreactor unit was found to be robust with low complexity engineering.
A continuous-flow, low pH biofilm sulphidogenic bioreactor inoculated with indigenous microbial communities has been developed for treating mine impacted water. The inoculum came from an anaerobic sediment in the acidic Azufire River in northern Chile. The sulphidogenic system (2.3 litres) was operated as a continuous flow mode unit for 99 days at 30 degrees C and fed with water of pH 2.1, with Zn 0.5 mM and Fe 2 mM. The bioreactor pH was initially 4.5 and was increased in stages to 6.0. The results show that zinc concentrations in liquors draining the bioreactor were below the detection level in most of the samples analysed. By progressively increasing the glycerol concentration, it was possible to increase the removal of iron (70% of the total present), though more acetic acid (from 1 to 5 mM) was generated. Analysis of the microbial populations showed that they changed with varying operation parameters, and a known acetogenic sulphidogen (Desulphoporosinus acididurans) became more dominant. The sulphidogenic bioreactor unit was found to be robust with low complexity engineering.