Assessment of the efficiency of wastewater treatment from coal enterprises for suspended solids using various filtering materials

Suspended solids are the predominant pollutants in the wastewater of coal enterprises. The basic wastewater treatment system regulated in BAT No. 15 ITC-37–2017 does not ensure water quality meets the discharge standards for fishery water bodies. The gravitational sedimentation method used in this technology is effective for coarse particles. However, colloidal systems formed from fine insoluble fractions are challenging to separate in a gravitational field. As an effective method for removing suspended solids from wastewater, we recommend filtering through a stationary layer of granular filtering materials. The study investigates the kinetics and dynamics of filtering suspended particles from the wastewater of coal enterprises using various filtering materials. Sedimentation curves of suspended solids from quarry wastewater have been constructed. The dependence of wastewater treatment efficiency on the size of filtering material fractions has been identified. The study provides an evaluation of the effectiveness of using natural filtering materials for treating wastewater from coal enterprises. The experiments demonstrated that the most efficient and cost-effective granular filtering material is quartzite from the Bobrovskoye deposit, which we recommend using in a combination of fractions 20–50 and 0.7–12 mm (in a ratio of 1 : 2). The optimal flow rate of wash water during the regeneration of the granular filter is also determined.