The application of bioremediation: reduction of metal concentrations in river water and COD in distillery effluent.

The major aim of this study was to evaluate and develop artificial bioremediation systems to reduce or remove metal pollutants from contaminated river water and to decrease the chemical oxygen demand (COD) in distillery effluent. Metals were extracted using the nitric acid digestion method, and the concentrations determined using inductively coupled plasma-atomic emission spectrometry. A decrease in metal concentrations was observed for most of the metals analysed in the river water after being pumped through the bioreactor system for approximately two weeks, e.g. Al concentration decreased from 0.75mg.l(-1) to 0.18mg.l(-) and for Ni, from 0.19mg.l(-1) to 0 mg.l(-l). In addition, the COD counts decreased from 2255 mg.l(-1) to a final value of < 150 mg.l(-1) in the distillery effluent. It could thus be concluded that the bioreactor system decreased the COD and metal concentrations in the distillery effluent as well as the river water, respectively. A bioreactor is being evaluated on-site at a wine cellar to reduce COD and will be constructed at a site along the Plankenbrug River.

Response of the microbial community to copper oxychloride in acidic sandy loam soil.

AIMS: Determining the response of different microbial parameters to copper oxychloride in acidic sandy loam soil samples using cultivation-dependent and direct microscopic techniques. METHODS AND RESULTS: Culturable microbial populations were monitored for 245 days in a series of soil microcosms spiked with different copper oxychloride concentrations. Microbial populations responded differently to additional Cu. Protistan numbers and soil metabolic potential decreased. Experiments with more soil samples revealed that metabolic potential was not significantly affected by < or =100 mg kg(-1) additional Cu. However, a negative impact on protista was noted in soil containing only 15 mg kg(-1) EDTA-extractable Cu. The negative impact on protistan numbers was less severe in soils with a higher phosphorous and zinc content. CONCLUSIONS: Bacterial populations responded differently, and protista were most sensitive to elevated Cu levels. Protistan numbers in soil from uncultivated land were higher and seemed to be more sensitive to additional Cu than the numbers of these organisms in soil originating from cultivated land. SIGNIFICANCE AND IMPACT OF THE STUDY: Protistan sensitivity to small increases in Cu levels demonstrates the vulnerability of the soil ecosystem to Cu perturbations, especially when the importance of protista as link in the flow of energy between trophic levels is considered.