Abstract

Roughing filters can be considered as a major pre-treatment process for mine water, since they efficiently separate fine solids particles over prolonged periods without addition of chemicals. A pilot plant was designed at delcoal. The design and sizing of the pilot plant was guided by wegelin design criteria. Gravel was used as a control medium since it is one of the most commonly used roughing filter media and because it was used in developing these criteria. In order to improve the performance of the roughing filters, the process has been modified by applying local available material such as charcoal as an alternative filter media. The pilot plant was monitored for a continuous 60 days from commissioning till the end of the project. The overall function of the filter in removing parameters such as iron and magnesium is accepted using charcoal. The achieved results in this study showed that, roughing filters may be considered as an efficient pretreatment process for mine water. It was also observed that in general, charcoal performed better than gravel. This observation could have resulted from the reason that charcoal has a slightly higher specific surface area and porosity, respectively to enhance sedimentation and other filtration processes like absorption, compared to gravel.

Key words: Roughing filters, sedimentation, absorption, mine water.

Abbreviation

HRF, Horizontal roughing filters; DWAF, Department of Water Affairs and Forestry; TWQR, target water quality range.