| 摘要 |
PURPOSE:To perform treatment of waste water at a low cost, by causing a large amount of waste water in a high concentration produced by non-evaporative dehydration of low grade coal to be adsorbed by dust coal, followed by surplus sludge mixing and biological treatment processes. CONSTITUTION:Low grade coal is separated into granular coal and dust coal in a crusher-classifier 1. The granular coal is dehydrated with saturated steam, etc. in a non-evaporative heat dehydrator 5 and dehydrated coal is taken out. The resultant waster water is mixed with the dust coal in a contact tank 6 for adsorption of organic components dissolved in the waste water, followed by separation into sludge and supernatant liquid by spontaneous sedimentation in a settling tank 7. The supernatant liquid is mixed with surplus sludge from a biological treatment tank 11 in a mixing tank 8 that dust coal may be contained in the sludge. The mixture is separated into sludge and supernatant liquid by spontaneous sedimentation in a settling tank 10. The supernatant liquid is purified in the biological treatment tank 11 by decomposition and removal of organic substances. The sludge from the settling tank 10 is dehydrated 12 and mixed 13 with sludge from the settling tank 7. Heat is recovered from the mixture in a boiler 14, etc. for use as a part of heat source for the non-evaporative heat dehydrator 5. |
