Investigation on reducing environmental impacts of waste water from coal washery plant

About 700000 m3 of waste water is produced from Zirab coal washery plant every year. This black water not only carries about 4000 tons fine coals, it also contains waste water pollution. In this investigation by flocculation studies under optimized conditions (like concentration of flocculant, 0.0015 g/t, pH=8, concentration of silicate 0.01 g/t as depressant, and r.p.m. of 150) has been shown that it is possible to separate solid particles from black water with recovery of 93% with ash removal of40% at the same time. So, the water produced can be recycled to the washery plant with improved quality.