Diurnal patterns of micropollutants concentrations in domestic greywater

<p>In recent years, much interest has been given to presence of micropollutants in municipal wastewater, some of which are suspected to be endocrine disruptors, toxic or carcinogenic. Much less attention has been paid to their presence in greywater. The present research studies the diurnal patterns of micropollutants in greywater and computes their daily loads. Monitoring was carried-out using auto-controlled sampling system, designed to overcome the erratic greywater generation. Two main generation periods were identified: morning (5:00–11:00) and evening-night (18:00–2:00), contributing about 20% and >50% of daily greywater discharge, respectively. Average specific daily greywater discharge was 57 L p⁻¹d⁻¹, which matches reported value for greywater generated by showers and washbasins in Israel. The most frequently detected micropollutants in this study were methylparben (preservative), galaxolide (fragrance) and oxybenzone (UV-filter), which are common ingredients in many personal care-products. Their daily loads were 2, 840, 1, 887 and 728 µg p⁻¹d⁻¹, respectively.</p

Degradation of VX Surrogate Profenofos on Surfaces via in Situ Photo-oxidation

Surface degradation of profenofos (PF), a VX nerve gas surrogate, was investigated using in situ photo-oxidation that combines simple instrumentation and ambient gases (O₂ and H₂O) as a function of exposure conditions ([O₃], [OH], UV light λ = 185 and/or 254 nm, relative humidity) and PF film surface density (0.38–3.8 g m^–2). PF film 0.38 g m^–2 fully degraded after 60 min of exposure to both 254 and 185 nm UV light in humidified air and high ozone. The observed pseudo-first-order surface reaction rate constant (<i>k</i>_obs = 0.075 ± 0.004 min^–1) and calculated hydroxyl concentration near the film surface ([OH]_g = (9 ± 2) × 10⁷ molecules cm^–3) were used to determine the second-order rate constant for heterogeneous reaction of PF and OH (<i>k</i>^OH_PF = (5 ± 1) × 10^–12 cm³ molec^–1 s^–1). PF degradation in the absence of 185 nm light or without humidity was lower (70% or 90% degradation, respectively). With denser PF films ranging from 2.3 to 3.8 g m^–2, only 80% degradation was achieved until the PF droplet was redissolved in acetonitrile which allowed >95% PF degradation. Surface product analysis indicated limited formation of the nontoxic phosphoric acid ester but the formation of nonvolatile chemicals with increased hydrophilicity and addition of OH

Hydrothermal Processing of Multilayer Plastic Film for Cascaded Valorization of Nonrecyclable Waste

Mixed polymer plastics cannot undergo mechanical recycling, resulting in heterogeneous low-quality recycled products. Multilayered mulch film, used in agriculture, is an example of mixed polymeric product, as it usually contains a gas barrier polymer layer, which is different in composition compared to the outer layers. Thus, multilayered mulch films are considered nonrecyclable and landfilled. Hydrothermal processing (HTP) is an alternative solution for mixed plastic waste management. HTP is used here as a combined separation and treatment of a multilayer film. Low-density polyethylene (LDPE) film with a 20–25 wt % barrier layer of polyamide (PA) was treated with HTP, and analyses were performed for products in all phases (solid, liquid, and gas). After HTP, the inner PA layer had decomposed, and 22 ± 3 wt % of the original film was recovered as caprolactam monomer and similar compounds in the liquid phase. The remaining solid product, 80 ± 2 wt % of the original film, mainly comprises the LDPE fraction. Evaluation of its suitability for subsequent processing with pyrolysis and mechanical recycling was also demonstrated. This work indicates that HTP can valorize landfill-designated mixed polymer plastics and should be considered as a beneficial alternative for a circular plastic economy