Oxidation of chlorinated ethenes by potassium permanganate: a kinetics study.

The kinetics of oxidation of perchloroethylene (PCE), trichloroethylene (TCE), three isomers of dichloroethylene (DCE) and vinyl chloride (VC) by potassium permanganate (KMnO(4)) were studied in phosphate-buffered solutions of pH 7 and ionic strength approximately 0.05 M and under isothermal, completely mixed and zero headspace conditions. Experimental results have shown that the reaction appears to be second order overall and first order individually with respect to both KMnO(4) and all chlorinated ethenes (CEs), except VC. The degradation of VC by KMnO(4) is a two-consecutive-step process. The second step, being the rate-limiting step, is of first order in VC and has an activation energy (E(a)) of 7.9+/-1 kcal mol(-1). The second order rate constants at 20 degrees C are 0.035+/-0.004 M(-1) s(-1) (PCE), 0.80+/-0.12 M(-1) s(-1) (TCE), 1.52+/-0.05 M(-1) s(-1) (cis-DCE), 2.1+/-0.2 M(-1) s(-1) (1,1-DCE) and 48.6+/-0.9 M(-1) s(-1) (trans-DCE). The E(a) and entropy (DeltaS(*)) of the reaction between KMnO(4) and CEs (except VC) are in the range of 5.8-9.3 kcal mol(-1) and -33 to -36 kcal mol(-1) K(-1), respectively. Moreover, KMnO(4) is able to completely dechlorinate CEs, and the increase in acidity of the solution due to CE oxidation by KMnO(4) is directly proportional to the number of chlorine atoms in CEs.

Heavy metal mobility in biosolids-amended glaciated soils.

The mobility of heavy metals from one-time application of biosolids (i.e., compost, pellet, and cement kiln dust stabilized biosolids) onto glaciated soils (Paxton soil) was studied because previous work on metal leachate characteristics from different biosolids is limited for glaciated soils. Two types of batch tests were performed: first, a pH-edge adsorption study to evaluate the effect of pH on heavy metal adsorption to Paxton soil and, second, a pH-edge leaching study to evaluate the effect of pH on the leaching potential of heavy metals from biosolids-amended Paxton soil. Finally, a semicontinuous soil column study was performed to assess the mobility of heavy metals from biosolids-amended Paxton soil. The pH-edge leaching results showed that the leaching potential of heavy metals was lower with the compost product. Desorption concentrations for arsenic, chromium, and lead were found to be greatest in the cement kiln dust stabilized product whereas cadmium, copper, and nickel were present at the greatest concentrations in the pellets. The total organic carbon results measured during the pH-edge leaching study indicated that there is a minimum leachable concentration in the pH range of 4 to 5 for all three biosolids. Overall, the column studies indicated that heavy metals were not readily leached from the three biosolids-amended Paxton soils. The results from this study suggest that a one-time land application of these biosolids will not adversely affect groundwater quality.