Research On The Treatment Of Heavy Metals In Municipal Biosolids Using Electroremediation Technique

The agricultural use of municipal biosolids as fertilizer appears to be the most alternative owing to its abundant N, P, K, and organic matters from an economic perspective in our country. The presence of the elevated concentration of heavy metals, however, represents a serious constraint to implementation of this practice. In this paper, biosolids of a waste water treatment plants in Changsha City was taken as the target experimental target. The feasibility of electrokinetic remediation on the removal of heavy metals from municipal biosolids(Experimentâ… ) were investigated. The effect of pH on electrokinetic remediation was studied in experimentâ…¡. In experimentâ…¢, the Effect of thiobacillus enhancing the removal efficiencies of heavy metals from municipal biosolids by electrokinetics was studied.Elecreoremediation technique is an advancing task of global environment science and technology. Its principle is that: application of direct electric current via electrodes immersed in a saturated soil results in oxidation at the anode, generating an acid front that cause desorption and dissolution of heavy metals. The desorped and dissoluted heavy metals are migrated toward cathode reservoir by electric field and ions concentration grads by the means of electromigration, electroosmosis and diffusing.Experiment I showed the curve of the removal efficiencies of different speciations Cd and Zn. The total removal ficiencies of Cd and Zn in municipal sewage sludge were 64.5% and 52.36% after five days electroremediation. The removal efficiencies of labile state fractions of Cd and Zn were 68.6%, 60.6% correspondingly. The labile state fractions that could be easily absorbed by plants included the exchangeable, carbonate and Fe and Mn oxides fraction. The electroremediation technique was fitted for removing heavy metals from municipal sewage sludge, and the electroremedied sludge was favorable to land utilization.Experimentâ…¡showed pH value of municipal biosolids is the major factor of dominating electroremedition, pH value of red soil can not only lead to high tank voltage and high temperature of municipal biosolids by means of decreasing electro-conductivity of soil, but also reduce remediation efficiency by precipitating Pb and then decreasing mobility of Pb. Hence, electroremediation techniques should be enhanced so as to apply to remedy heavy metals contaminated municipal biosolids.