Electrode potential difference in standing water over sludge set to selectively oxidize or reduce impurities in sludge and water

摘要

A process for reducing or preventing the admission of harmful impurities in standing water (2) over sludge (1) comprises using electrodes (4,5) in the water and sludge to from a barrier at the phase boundary between the water and sludge. Especially the potential difference between the electrodes is set to selectively oxidize or reduce impurities. A process for reducing or preventing the admission of harmful impurities in standing water (2) over sludge (1) comprises using electrodes (4,5) in the water and sludge to from a barrier at the phase boundary between the water and sludge. Especially the potential difference between the electrodes is set to selectively oxidize or reduce impurities. The process immobilizes or mobilizes impurities without allowing dissolved oxygen or hydrogen to escape from the sludge to the water. Immobilized water impurities are enriched within the sludge, and mobilized impurities are discharged from the water. The voltage applied is the redox pair specific half level potential of the impurity in question. This is derived from the U-I graph, power loss and electrical resistance between the electrodes. The working voltage applied first concentrates impurities in the sludge. The impurities are then expelled from the sludge in concentrated form and drawn from the water. The barrier between the water and sludge (2/1) is operated as a redox and/or pH barrier.