Rosemary Falcon and Evanie Devi Deenanath
Department of Chemical and Metallurgical Engineering, University of the Witwatersrand, South Africa
Background: Contamination by acid mine drainage (AMD) from the mining industry is an on-going environmental concern. The generation of AMD, unfortunately cannot be entirely prevented, however it can be treated in order to minimize and control the harmful effects caused by AMD metals with a growing interest in biological aspects towards AMD treatment. In Middelburg, Mpumalanga-a popular mining area in South Africa, an isolated site known as the NET Energy site was established to investigate the large-scale harvesting of algae biomass to be implemented for carbon sequestration. Other than this carbon technology there is an interest in utilising algae biomass for AMD neutralization. For this research, 'algae' growing in an open-pit, close to the Net Energy site, was collected and harvested on site and the neutralising potential of the 'algal' biomass (as a mixed culture or multiple species culture) will be investigated.
Method: A bioassay was carried out which consisted of acid mine water (collected from Muhanga Mines) inoculated with the harvested culture (open-pit algae). Basic measurements of pH and dry mass were monitored.
Results: During the duration of the bioassay, an increase in pH from 3.3 to 6.8 was recorded and dry weight of biomass ranged from 0.30 to 0.35 g/L.
Conclusion: The biomass, presumably algae, collected from this particular area has a neutralizing ability and can easily sustain its growth within an AMD environment.
Future Work: Experimental work is currently underway to confirm these preliminary results and identify species population of the culture. Additionally, concentration of AMD metals and sulphur will be determined and other analytical methods will be performed to understand the interaction between the AMD metals and the biological cells and the effect of sulphur removal for the utilization of biomass for mine land rehabilitation.
Keywords: Acid mine drainage, Neutralization, Biomass.