Experimental Study On Treatment Of Acid Coal Gangue Leaching Wastewater By Permeable Reactive Barrier

The problem of coal gangue accumulation is serious.The waste water from Coal Gangue Leaching contains a lot of heavy metals,which pollutes the environment seriously.Permeable reactive barrier(PRB)technology can effectively treat heavy metal wastewater.In this paper,through leaching experiments,the changes in p H,sulfate and heavy metal content in coal gangue leaching wastewater were explored,and the leaching characteristics of coal gangue under different experimental conditions were analyzed;PRB was used to treat coal gangue leaching wastewater,the effect of different PRB filling materials on the removal of heavy metals in coal gangue leaching wastewater was screened out,and the better PRB filling materials were screened.The PRB reaction tank was used to explore the effect of filling materials on the removal of heavy metals in different compounding methods.In the static leaching process,the p H value of waste water leached from coal gangue is about 3.0,and the content of sulfate and heavy metals is high.Reducing the solid-liquid ratio can increase the leaching of sulfate and heavy metals from coal gangue;During dynamic leaching,the p H value of waste water from coal gangue leaching increased gradually with time,while the content of sulfate and heavy metals decreased;The acute toxicity test of luminescent bacteria showed that the toxicity of acid coal gangue leaching wastewater was strong.The comprehensive treatment effect of PRB filling material on Acid Coal Gangue Leaching wastewater is as follows: garbage pyrolysis ash > fly ash > limestone > zeolite.The p H value can be increased from 3.0 to 9.0,and the removal rate of heavy metals is higher than 95%,and the operation effect is stable.Considering the permeability coefficient of the material,limestone and garbage pyrolysis ash are selected as PRB filling materials.The results show that the sandwich PRB and mixed PRB have better treatment effect on the waste water from Coal Gangue Leaching,and the operation effect of PRB decreases with the increase of operation time.After running for 10 days,the p H value of the effluent of the sandwich PRB and the mixed PRB was higher than 6,and the removal rates of Fe,Zn and Cu by the sandwich PRB were still higher than 90%,and the operation effect of the sandwich PRB was more stable than that of the mixed PRB.