PHOTOLYSIS, OZONATION AND CHLORINATION OF FLAME RETARDANTS IN WATER TREATMENT

Flame retardants (FR) are added to different materials to reduce the risk of fire. They save lives, prevent injuries and property losses, and protect the environment by helping to prevent fires. In Western Europe, the average annual growth rate for 2007–2012 for all flame retardant chemicals is expected to be just over 3% in volume terms. The benefits of flame retardants must necessarily be balanced with the risks posed by these high production volume chemicals for human health and ecosystems. Several studies have determined that these compounds can lead to the emergence of several diseases as hormonal problems, neurological deficit, allergies and even cancer. These compounds are difficult to biodegrade in wastewater treatment plants (WWTP), and they can absorb to the sludge and/or be discharged by the WWTP effluent in the river basin. The dynamic of the adsorption equilibrium in the environment through the adsorption soil and sediments can promote the entrance in the urban water cycle, through the surface and groundwater and reach the drinking water system. Many studies reported the detection of FR in surface and groundwater used often for drinking water source. The degradation of triphenylphosphate (TPP), Hexabromocyclododecane (HBCD), Dibromoneopenthyl glycol (DBNPG), tetrabromobisphenol A (TBBPA) and the bisphenol-A (BPA) under three different oxidation/disinfection technologies (e.g. photolysis, ozonation and chlorination) as an ex-situ water treatment (WT) technology is the main goal of this study. The degradation of the target compounds are incomplete for the hydraulic retention time normally applied for the oxidation and disinfection purposes and an additional polish step with activated carbon is convenient in the water treatment. The use of photolysis, ozone and chlorine can promote the formation of by-products, in some cases, more toxic than the target compound. This study shows an important contribution for the determination of the kinetic parameter to help in the design of the WT facilities and the by-products generated during the oxidation process can be also removed with the activated carbon and reduces the impact in human health when these compounds are present in surface and groundwater, source for drinking water systems.