Improving the clarification quality of industrial wastewater by acoustic method

Abstract

The gravity clarification method is relatively effective only for extracting coarse suspended particles from industrial wastewater. The removal of medium and fine suspended and colloidal particles and heavy metals at respective treatment facilities requires their preliminary aggregation by chemical, physical, or combined methods, with the use of additional sorbent filters. Irregular removal of bottom sediments results in secondary pollution of industrial wastewater with mineral particles and heavy metals retained by the sediments. In poorly treated industrial effluents, fish die within a few weeks. The key factor, in this case, is the dispersion rather than concentration of suspended solids in the water. The method proposed involves coagulation of finely dispersed suspended solids, colloidal particles, and insoluble heavy metals and their forced settling with simultaneous compaction of bottom sediments in acoustic fields (not only in horizontal settling tanks, but also directly in local and main water sumps of open pits and mines). The paper presents examples of successful application of the integrated acoustic method in the sumps of pits and mines at diamond and gold mining enterprises of the Russian Federation in 2015–2022. The average underground dewatering efficiency (in local and main mine dewatering) is shown to be 82.1 %, which is 20–22 % higher than the surface dewatering efficiency (via the settlement pond and two filter channels) of the mine water clarification facility.