Oxidation

Advanced electrochemical oxidation processes have emerged as a promising method for the destruction of persistent organic material in variable waste streams. Although the process has been successfully employed for wastewater treatment applications, high energy requirements, and the risk of formation of undesirable by-products may limit its application in the field of leachate treatment. This study focuses on the investigation of the feasibility of removing organics and ammonia by electrochemical oxidation coupled with ozone, Fenton or lime. Landfill leachate was treated by two different bench scale electrochemical oxidation reactors coupled with ozone oxidation, Fenton coagulation or lime precipitation. The electrochemical oxidation was conducted using a titanium anode coated with multi-metal oxides (MMO) at three-different current densities for different durations. Treatment performance was determined based on the removal of COD, ammonium-N, and turbidity. A three-level factorial design was established, and response surface methodology (RSM) was introduced to determine the optimum process parameters. The results suggest that the process can remove appreciable amounts of ammonium-N and COD in a very short time, demonstrating that the process is effective in rapidly degrading recalcitrant organics in leachate.

Nitric acid can drive oxidation reactions of paraffins producing nitroparaffins and
other oxidation products. Presented here is a study on the aqueous liquid phase nitric
acid oxidation of paraffin oil supported on PTFE particles. The goals ofthis study
are:
1. To evaluate the effectiveness of nitric acid in removing paraffin oil from
PTFE particle surfaces.
2. To evaluate the effects of nitric acid driven reactions with paraffin oils
under varying reaction conditions.
3. To evaluate FTIR Diffuse Reflectance Spectroscopy, DRIFT, as a tool to
accomplish the quantitative analysis of this process. These goals have been achieved employing analysis by FTIR Diffuse Reflectance,
which provides a ready means of quantifying paraffin removal. Paraffin removal
generally increases with time, temperature and nitric acid concentration and can be
described by known kinetics including activation energy and region of unity
relationship between the log of the rate constant verses Hammett acidity function.

The objective of this research was to determine if mature landfill leachate could be treated to a level so that it was safe to discharge to the environment. The treatment method was an Advanced Oxidation Process. The process utilized Titanium Dioxide and UV. Three different reactor types were used, falling film, flow through and falling film + Electron Magnetic Oxygen Hydrogen (EMOH). To improve removal pre-treatment with titanium dioxide settling were conducted in conjunction with treatment in a reactor. The best removal was obtained with pre-treatment with titanium dioxide settling, followed by the falling film + EMOH reactor. In 8 hours, removal was 63% for COD, 53% for ammonia, 73% for alkalinity and 98% for calcium hardness. The kinetics found in this experiment show that full treatment times for safe discharge vary between contaminates. For complete removal of all tested contaminates to safe discharge regulations requires 185 hour of treatment.

A landfill is in a reserved space on land used for the disposal of refuse by utilizing the principles of engineering to confine the refuse to the smallest practical area to prevent the creation of nuisances to public health or safety (Andersen et al. 1967). However, because landfills are open to the atmosphere, rainfall can saturate them, resulting in a liquid called leachate. Leachate generated within the landfill contains suspended solids, soluble components of the waste and by-products from the degradation of the waste by various micro-organisms. Treatment of leachate is an emerging area of need. In this manuscript the main purpose is to investigate a laboratory scale batch reactor that is able to detoxify and treat leachate by using an advanced oxidation process (i.e. TiO2). Based on the results obtained from this ground breaking research, it appears that the process investigate has the potential to radically change the way landfill leachate is treated. Scale up may provide direction that can be used to improve the efficiency of the different stages of toxicity of leachate during the entire life of a landfill.