Hydrothermal Oxidation of Liquid Organic Waste

With the increase in annual waste production and the scarcity of landfill options, the elimination and/or recycling of the materials making up this waste has become an imperative necessity for our industrial societies. The management of organic waste generally involves thermal treatment (e.g. [G 2 051] ), which in particular makes it possible to recover the calorific energy released by the mineralization of waste.

Since the first developments in 1980, a number of innovative processes for treating organic waste have emerged, including hydrothermal oxidation processes, which are extremely effective in terms of versatility, efficiency and compactness. These processes enable mineralization in supercritical water, which is particularly well-suited to the treatment of refractory substances, hazardous or toxic organic substances present in isolation, industrial effluents or urban wastewater.

The temperatures involved (below 600°C), and the environmentally-friendly gaseous and aqueous effluents generated, position supercritical water oxidation as a relevant competitor to conventional thermal processes (temperatures between 850 and 1,100°C). Implementing oxidation under supercritical water conditions, with their high temperatures and pressures, has necessitated the design of innovative reactors to control the reaction, as well as managing the corrosion of the mineral charge precipitation. Industrial developments in this process are presented.

At the end of the article, readers will find a glossary and a table of acronyms and notations.