Research on heavy metal passivation treatment technology for urban sludge
In response to the problem of excessive heavy metal content in urban sludge,a new passivation agent DTG-3 was developed as the passivation material to carry out heavy metal passivation treatment experiments on urban sludge.The focus was on investigating the effects of the dosage and passivation treatment time of the new passivation agent DTG-3 on the distribution of different types of heavy metal forms in sludge,and calculating the heavy metal stability coefficient under different treatment conditions.The experimental results show that the higher the mass fraction of the new passivation agent DTG-3,the longer the passivation treatment time,and the better the passivation treatment effect of heavy metals in urban sludge;When the passivation treatment time is 28 days,the residual content of different types of heavy metals in urban sludge increases compared to before passivation treatment.In addition,with the gradual increase of the mass fraction of the new passivation agent DTG-3 and the extension of passivation treatment time,the stability coefficients of different types of heavy metals after urban sludge passivation treatment have decreased.After comprehensive consideration,the recommended optimal mass fraction of the new passivation agent DTG-3 is 15%,and the optimal passivation treatment time is 28 days.At this time,the stability coefficients of heavy metals Cu,Pb,Cr,and Zn in the target city sludge after passivation treatment can be reduced to 5.17,0.68,4.13,and 11.99,respectively,indicating good passivation treatment effects.
new passivating agentsurban sludgeheavy metalsdistribution morphologystability coefficient
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NSTL
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