November 18, 2016 by John Nicholson
A paper recently published in Chemical Engineering Journal describes batch experiments where persulfate was compared to hydrogen peroxide and permanganate for its ability to oxidize organic compounds in groundwater contaminated by landfill leachate. Complementary experiments were conducted to evaluate biodegradation (natural attenuation) potential for the system.
The experiments showed that persulfate was superior to hydrogen peroxide and permanganate for degradation of total organic carbon (TOC) in the groundwater, whereas biodegradation caused only partial removal of TOC in contaminated groundwater. Persulfate completely degraded the TOC in contaminated groundwater, showing no selectivity to the contaminants.
Magnetite enhanced degradation of leachate compounds in the contaminated groundwater with limited increase in persulfate consumption and sulfate production. Under dynamic flow, magnetite enhanced both biodegradation and persulfate oxidation of TOC, although the enhancement was significantly greater for persulfate oxidation.
In the batch and column experiments, magnetite by itself caused minimal consumption of persulfate and production of sulfate, indicating that magnetite is a good persulfate activator for treating CGW in heterogeneous systems. Results show that persulfate-based in situ chemical oxidation has great potential to treat contaminated groundwater.