Community Research and Development Information Service - CORDIS

Design and Control of solar photocatalytic wastewater treatment plants

The inability of conventional biological wastewater treatments to effectively remove many toxic pollutants shows that new treatment systems are needed. Rigorous pollution control and legislation in many countries has resulted in an intensive search for new and more efficient water treatment technologies. The adoption of the Water Framework Directive provides a policy tool that enables this essential resource to be protected. Among other measures, surface water deterioration must be prevented and bodies of water enhanced and restored, good chemical and ecological status of such water must be achieved and pollution from discharges and emissions of hazardous substances reduced by 2015.

In the near future, Advanced Oxidation Processes (AOPs) may become the most widely used water treatment technologies for organic pollutants not treatable by conventional techniques due to their high chemical stability and/or low biodegradability. The use of AOPs for WW treatment has been studied extensively, but UV radiation generation by lamps or ozone production is expensive. Photo-Fenton has been demonstrated to be effective for treating wastewater containing pollutants at concentrations of > 10 mg L-1, as the reaction rate is usually much higher and separation of iron is very often not necessary. Despite its obvious potential for the detoxification of polluted water, there has been very little commercial or industrial use of the solar photocatalysis technology so far.

The proposed technology could be applicable to different organic hazardous contaminants, such as pesticides, solvents, detergents and a variety of industrial chemicals, which are capable of substantial contamination of the environment due to their toxicity and persistency.

In this context, treatment of industrial waste water seems to be one of the most promising fields of application of solar detoxification. There is no general rule at all, each case being completely different. Consequently, preliminary research is always required to assess potential pollutant treatments and optimize the best option for any specific problem, on a nearly case-by-case basis. Solar photocatalytic degradation technology might be feasible for the treatment of waste water containing hazardous contaminants at medium or low pollutant concentrations when biological treatment is impossible. The technology is dependent on the energy flux, as is the associated investment contingent on the collector surface. In general, the types of compounds which have been degraded include alkanes, haloalkanes, aliphatic alcohols, carboxylic acids, alkenes, aromatics, haloaromatics, polymers, surfactants, herbicides, pesticides and dyes.

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ECOSYSTEM ENVIRONMENTAL SERVICES SA
Travesia Turo d'en Llull, 12
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