| Sludge is the product of water treatment in sewage treatment plant,in which there are a large number of pollutants,of which the most serious harm is heavy metal,so the removal of heavy metals in sludge is the key.Dialysis is an electrochemical method,with environmental friendly technology,quick effect,high efficiency,simple operation and no two pollution and other advantages,and the existing forms of heavy metal sludge in the city generally have five kinds: exchangeable,carbonate bound and Fe Mn oxide bound and organic bound and residue state.The exchangeable,carbonate bound and Fe Mn oxide bound heavy metals form stability is relatively poor,these heavy metals exist in the form of ion,therefore these heavy metal ions can be removed by electrodialysis technology,but the method of heavy metal sludge in the domestic processing research is very few,in order to treatment of sludge analysis of heavy metals in electrodialysis more clearly and corresponding effects,the main content of this paper is to analyze the electrodialysis effect of heavy metals in sludge.By electrodialysis experiment on heavy metals in Xi'an sewage treatment plant sludge using electrodialysis device in this paper,and every 2h to take a sample and then use the five step processing samples by atomic spectrophotometer to detect five kinds of heavy metals and the total content of five kinds of forms and the treatment effect,get the following conclusions:(1)The conductivity of sludge increases with by electrodialysis experiment,from the original 1.38 mS/cm increased to 15.49 m S/cm;at the same time,the resistivity of sludge mixed liquor in the electrodialysis experiment gradually reduced from the original 723.Cm gradually reduced to 65.Cm showed an inverse relationship.The electrical conductivity and resistivity.At the same time,the starting current of electrodialysis experiment is 0.724 mA,the current value is more and more big,and the current value of 14 h is not changed,and the final current value is 2.18 mA.(2)The pH value of the sludge is reduced gradually,the pH of the sludge with the electrodialysis experiment was changed,the original pH value of sludge was 8.52,that is alkaline,with electrodialysis experiment of sludge mixed liquor pH value decreased gradually,about 8 hours after becoming acid.The sludge mixed liquor pH value gradually decreased to about 2.27,the relatively strong acidic sludge mixed liquor.(3)This experiment used the main heavy metals in sludge mainly has five kinds: cadmium,nickel,copper,lead and zinc,the highest content of Zn,Cd content was the lowest,namely: Pb> Zn > Cu >Ni > Ge;and electrodialysis electrodialysis experiment basically reached the balance in about after 14 hours;then analysis by electrodialysis treatment of five kinds of heavy metals are as follows:(1)the ratio of exchangeable cadmium treatment rate of 88.41%,carbonate bound treatment rate of 40.25%,Fe(MN)oxides bound processing rate of 12.66%,organic matter and sulfide bound treatment rate of 54.07%,residue processing the rate is 40.64%;(2)the heavy metal nickel exchangeable treatment rate was 60.49%,carbonate bound treatment rate of 71.05%,Fe(MN)oxides bound by the treatment rate of 28.57%,organic matter and sulfide bound treatment rate was 71.32%,the residue state at Daniel rate is 55.57%;(3)the heavy metal exchangeable treatment rate was 82.03%,carbonate bound treatment rate of 35.79%,Fe(MN)oxides bound processing rate of 39.43%,organic matter and sulfide bound treatment rate was 21.52%,the residual treatment rate of 58.47%.(4)The heavy metal exchangeable treatment rate was 81.86%,carbonate bound treatment rate of 78.13%,Fe(MN)oxides bound processing rate of 65.03%,organic matter and sulfide bound treatment rate was 65.82%,the residual treatment rate of 57.44%;(5)the heavy metal Zn exchangeable and carbonate rate was 90.32%.Bound processing rate is 81.77%,Fe(Mn)oxides bound processing rate of 85.28%,organic matter and sulfide bound treatment rate was 75.38%,the residual treatment rate of 70.22%. |
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