Magnetotactic bacteria posses a magnetic moment due to the presence of membrane bounded crystals of magnetite, Fe₃O₄, within their structure. Magnetotactic bacteria accumulate heavy metal ions from wastewater and are then removed from the treatment chamber by applying a low intensity (~0.1mT) focusing magnetic field. The principle benefit of this process is that the magnetic field is used only to orientate the bacteria and not to magnetically attract them, in contrast to more traditional magnetic separators. A magnetotactic spirillum from a salt marsh pan was isolated and grown in pure culture. The variation in size, shape, magnetic moment and swimming speed of individual bacteria was measured by studying their motion in switching magnetic fields. Determination of the variation of these characteristics with growth showed that a five day 'window' exists during which a culture satisfies the two criteria of motility and magnetic moment enabling it's use in low field, orientation magnetic separation. The uptake of heavy metal ions from solution by the magnetotactic spirillum has been studied at the parts per million (ppm) level using radiolabelling techniques. It was found that certain heavy metals were toxic at these concentrations, rapidly leading to loss of bacterial motility. Therefore, orientation magnetic separation studies were limited to solutions containing specific metals, at concentrations which the bacteria remained viable. The results indicate that for effluents which meet the toxic limitations of the bacteria, orientation magnetic separation can provide a high efficiency treatment process. However, these restrictions are so severe that it is difficult to envisage orientation magnetic separation, being used as a large scale treatment process in its current form.