| 摘要 |
<p>This invention provides a method of treating waste effluent, particularly photographic effluent, containing reduced species such as thiosulphate or sulphite, by oxidation with hydrogen peroxide or a compound capable of releasing hydrogen peroxide, in the presence of a catalyst therefor. The invention is characterised in that the catalyst is immobilised on a substrate. The catalyst may be selected from chromate, vanadate and preferable molybdate or tungstate and the substrate may comprise an ion exchange material, especially an anion exchange material. The invention further provides a holding tank apparatus (10) or a conduit apparatus (20) for carrying out this method. The invention is particularly appropriate for use with fixer from redox-amplification processes. With conventional solutions with higher concentrations of fixer a soluble alkali, especially potassium bicarbonate, may be combined with the oxidising agent and stored for at least 4 weeks without decomposition, whereby the pH of the final effluent is rendered environmentally acceptable. <IMAGE></p> |
