Heat Enhanced Hydrolysis

Electrical Resistance Heating (ERH) provides two main mechanisms of contamination removal: vaporization and degradation. While many people are familiar with using ERH for contaminant source area remediation, ERH can also enhance hydrolysis. Hydrolysis is a key mechanism of contaminant degradation that breaks contaminant chemical bonds through a reaction with water. Hydrolysis occurs through either a water substitution or elimination reaction pathway. Hydrolysis is a reaction in which a molecule is cleaved in two by the addition of a water molecule.

Some hydrolysis reactions can be faster at high or low pH (alkaline or acidic). Some compounds undergo rapid neutral hydrolysis that is independent of pH. In addition, elevated temperatures speed up the hydrolysis reaction rate defined by the Arrhenius equation. ERH has been used as the method for temperature increases to escalate the rate of hydrolysis.

A half-life is how long it takes for half of a compound to be destroyed through the hydrolysis reaction. Seven half-lives produce 99% destruction; ten half-lives is 99.9% destruction. A half-life faster than 10 days is ideal and half-lives as long as about 40 days are still fast enough to be cost-effective.

Thermally enhanced hydrolysis is generally the most cost-effective remediation method for halogenated alkanes and many fumigants and pesticides. Thermally enhanced hydrolysis is also an important degradation reaction for pesticides, TNT, RDX, and trace amounts of Mustard Gas. ERH can now provide a reduced cost solution for heat enhanced hydrolysis of contaminants in soil and groundwater.

Research behind heat-enhanced hydrolysis of energetics and field case studies will be presented.