Removal of polycyclic aromatic hydrocarbons from municipal sludge using UV light

Trace organic contaminants in biosolids: Impact of conventional wastewater and sludge processing technologies and emerging alternatives

“…It also has potential to enhance biodegradation by oxidising persistent TrOCs into smaller, more biodegradable products [147]. Varying TrOC removal has been observed depending on UV treatment conditions (Table 2) [9,146,147]. Salihoglu et al [146] found that UV treatment caused only 15-21% removal of polycyclic aromatic hydrocarbons from sludge through volatilisation.…”

“…Varying TrOC removal has been observed depending on UV treatment conditions (Table 2) [9,146,147]. Salihoglu et al [146] found that UV treatment caused only 15-21% removal of polycyclic aromatic hydrocarbons from sludge through volatilisation. On the other hand, UV/TiO 2 treatment with 0.5 and 20% by weight TiO 2 (Degussa P25) resulted to 77 and 63% removal of polycyclic aromatic hydrocarbons, respectively.…”

“…Exposure of sludge to heat has been reported to induce degradation and evaporation of TrOCs [30,146], but thus far thermal treatment has been found to have varying impact on TrOC removal from sludge (Table 2). Mcnamara [149] reported that thermal hydrolysis of raw sludge at 150°C and 5.1 bar for 2 hours deteriorated the biodegradation of nonylphenol ethoxylates in a laboratory-scale mesophilic anaerobic digester, probably due to an increase in volatile fatty acids that inhibited nonylphenol ethoxylate-degrading microorganisms or competed with nonylphenol ethoxylates as substrate [149].…”

“…UV only, UV/H 2 O 2 , and UV/TiO 2 ) can result to the removal of TrOCs through oxidative degradation [9,150], and also through the evaporation of volatile or semi-volatile TrOCs when temperature rises during UV irradiation [146,150]. It also has potential to enhance biodegradation by oxidising persistent TrOCs into smaller, more biodegradable products [147].…”

“…TiO 2 particles absorb UV light and produce numerous electron-hole pairs that react with oxygen and water molecules to generate hydroxyl radicals. The addition of TiO 2 can enhance TrOC removal, but an excessive addition of the particles causes UV scattering in the suspension and decreases treatment efficiency [146]. UV/TiO 2 has high potential to treat polycyclic aromatic hydrocarbons in particular because it results to minimal evaporation of the compound into air since photodegradation is faster than evaporation [150].…”