Migration of polycyclic aromatic hydrocarbons (PAHs) in urban treatment sludge to the air during PAH removal applications

Abstract

In the present study, the amounts of polycylic aromatic hydrocarbons (PAHs) penetrating into air during PAH removal applications from the urban treatment sludge were investigated. The effects of the temperature, photocatalyst type, and dose on the PAH removal efficiencies and PAH evaporation were explained. The sludge samples were taken from an urban wastewater treatment plant located in the city of Bursa, with 585,000 equivalent population. The ultraviolet C (UV-C) light of 254 nm wavelength was used within the UV applications performed on a specially designed setup. Internal air of the setup was vacuumed through polyurethane foam (PUF) columns in order to collect the evaporated PAHs from the sludge during the PAH removal applications. All experiments were performed with three repetitions. The PAH concentrations were measured by gas chromatography-mass spectrometry (GC-MS). It was observed that the amounts of PAHs penetrating into the air were increased with increase of temperature, and more than 80% of PAHs migrated to the air consisted of 3-ring compounds during the UV and UV-diethylamine (DEA) experiments at 38 and 53 degrees C. It was determined that 40% decrease was ensured in sigma12 (total of 12) PAH amounts with UV application and 13% of PAHs in sludge penetrated into the air. In the UV-TiO2 applications, a maximum 80% of sigma12 PAH removal was obtained by adding 0.5% TiO2 of dry weight of sludge. The quantity of PAH penetrating into air did not exceed 15%. UV-TiO2 applications ensured high levels of PAH removal in the sludge and also reduced the quantity of PAH penetrating into the air. Within the scope of the samples added with DEA, there was no increase in PAH removal efficiencies and the penetration of PAHs into air was not decreased. In light of these data, it was concluded that UV-TiO2 application is the most suitable PAH removal alternative that restricts the convection of PAH pollution.

The Assessment of Paravertebral Ossification Progression After Cervical Disc Arthroplasty Based on CT Images: A Long‐term Follow‐up

“…The exact cause of PO formation is still unclear. Chalmers claimed that osteogenic cells, induction factors, and a proper environment are required for HO formation 25 . Some researchers surmised that the release of bone morphogenic protein during postoperative or traumatic circumstances played an important role in PO formation 26 .…”

Degradation of polycyclic aromatic hydrocarbons (PAHs) in smoked sausages by ultraviolet irradiation

“…Effect of UV irradiation power and time on PAHs in smoked sausages Electron excitation was actively induced due to UV irradiation of smoked sausages, PAHs were attacked by active electrons in an acyclic reaction, which led to the degradation of PAHs. 14 PAHs are significantly hazardous to humans and the European Food Safety Authority (EFSA) uses PAH4 (BaP, BaA, BbFA and CHR) as a marker to measure food hazards. 23 The variation of BaP, PAH4 and PAH15 contents in smoked sausages irradiated with UV are shown in times ranged from 52.1% to 82.8% at 32 W, indicating a positive correlation between radiation power and time with degradation ability.…”

“…UV radiation, which ranges from 100 nm to 400 nm and is subdivided into UVA (315-400 nm), UVB (280-315 nm) and UVC (100-280 nm), 12 has emerged as an effective technology for removing trace organic pollutants in wastewater and soil treatment. For instance, Kennedy et al 13 reported PAHs degradation rates of 41% to 91% when elution water was exposed to dark and UV light conditions for 6 h. Similarly, Karaca et al 14 examined the effect of UV irradiation on sludge and observed a significant reduction in the initial Σ5 PAHs (total of 5 PAHs). Salihoglu et al 15 discovered that when sludge was exposed to UV radiation for 2 h, PAHs were reduced 24-77% and HPAHs underwent significant degradation.…”

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

“…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]. Meanwhile, UV/H 2 O 2 treatment of sludge achieved high removal of natural hormones and bisphenol A (e.g.…”

“…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].…”