Treatment of saline, acidic, metal-contaminated groundwater from the Western Australian Wheatbelt

Abstract

Managing acidic, metal-containing saline ground and drainage waters in the Wheatbelt of Western Australia is an environmental and economic challenge. Sulfate-reducing fluidised bed bioreactors are shown to be technically capable of treating high salt, low pH, metal containing waters from the town of Narembeen in the Wheatbelt so as to reduce acidity and to remove most of the undesirable metal contaminants. The hydraulic residence time (HRT) limit for a stable process with groundwater from the region of Narembeen was >16 hours. The maximal rate of sulfate reduction in the laboratory system treating Narembeen groundwater was similar to rates observed in comparable applications of the process at other sites, ca. 3 g sulfate (L-reactor)(-1) day(-1). Salts that are relatively free of metal contaminants can be produced from water that has been treated by the sulfate-reducing fluidised bed bioreactor. It is unlikely that metal precipitates, captured from Wheatbelt waters by the process, would be of economic value. If sulfate-reducing fluidised bed reactors were considered technologically appropriate at larger scale, the decision to use them would be based on the necessity to take action, the comparative effectiveness of competing technologies, and the relative costs of competing technologies.