GROUNDWATER AND LEACHATE: EX-SITU CHEMICAL/PHYSICAL TREATMENT
Advanced Oxidation
Advanced Oxidation Process
Process:
- Strong oxidisers (ozone, and/or hydrogen peroxide) are used to destroy organic contaminants & explosives as the contaminated water flows through the treatment tank.
- Usually uses low pressure lamps (at 65Watts) (slightly lower for H2O2 systems) or can be enhanced with U.V.
Note: If complete mineralisation is achieved, the final products of oxidation are CO2, H20 & harmless salts. This IS a destruction process (as opposed to air stripping or carbon adsorption where contaminants are simply 'separated').
Can be batch or continuous flow modes.
Uses:
- Most organic & explosive contaminants are completely destructed by UV/oxidation, including petroleum hydrocarbons, chlorinated hydrocarbons & TNT.
Limitations/Disavdvantages:
- Can only cope with very low concentration of heavy metal ions & insoluble oils
- If ozone is enhanced with UV, if used for VOCs the contaminants may be volatilised rather than destroyed - would require treatment of off-gas (e.g. ozone destruction unit or by activated carbon adsorption (GAC)).
- Possibly higher costs due to energy requirements.
- Pre-treatment of wastewater would reduce maintenance/replacements required.
- Special safety precautions required during storage/handling of the oxidizers.
Cost:
Generally between $0.10-$10.00 per 1,000 gallons, dependent on types & concentration of contaminants, water flow rates, and pre/post-treatment. Typical throughput per day can vary from 1,000-1,000,000gallons.