Dissolved humic substances for remediation of sites contaminated by organic pollutants. Binding-desorption model predictions

A process is proposed to use dissolved humic substances (DHS) which through hydrophobic binding reduce sorbability of organic contaminants and enhance desorption-remediation of contaminated sites. Computations, using sorption-desorption and binding models, predict 50- to 100-fold reductions in sorbability and retardation of highly hydrophobic organic solutes (log Kow ≥ 6) using DHS solutions of 20–50 mg/l. Solutes of medium hydrophobicity (log Kow 4–5) would require 100–200 mg/l of DHS for 90% reduction in retardation, while low hydrophobic solutes (log Kow < 3) are little affected. The high reduction in retardation results in a corresponding reduction in volumes of flushing liquid and process times, as well as in higher concentration of the released contaminant facilitating treatment and disposal. The paper includes regression correlations between binding coefficients to aqueous DHS Kb and Kow of many solutes and a sensitivity analysis to model parameters.