Occurrence of pharmaceuticals and plasticizers in leachate from municipal landfills of different age.

Contaminants of emerging concern (CECs), such as pharmaceuticals and plasticizers, are present in leachate due to disposal of pharmaceuticals and plastic waste. Leachate is usually released to publicly owned treatment works, but CECs could pass through and be discharged into water resources. Landfills generate leachate for many years after closure, but it is currently unknown whether CECs continue to leach over time or dissipate soon after the waste is deposited.

Significant improvement in biodegradability of a real Optical Brightening Agent (OBA) wastewater using small doses of Fenton's reagent.

Optical Brightening Agent (OBA) wastewater (OBAW) has been reported to be highly resistant to biodegradation. In this study, a real OBAW from an industry which was already treated using primary and secondary treatments (residual COD of secondary clarifier overflow (SCO): 3400-3700 mgL) was further treated by Fenton's treatment (FT). Zahn-Wellens biodegradability test revealed that using small doses of HO and Fe, the biodegradability of SCO improved to 90% as compared to ∼18% without FT.

Using size-exclusion for improved extraction of trace organic compounds from landfill leachate.

Pharmaceuticals, plasticisers and other trace organic contaminants have been reported in landfill leachates, with most methods using hydrophilic-lipophilic balance cartridges for solid phase extraction. However, leachate has a high organic load and can quickly coat the cartridge media and prevent target compounds from being extracted. There are several solid phase extraction cartridges that offer size exclusion in addition to adsorption, where only small molecules are allowed to diffuse into the resin pores where adsorption in happening.

Methods of Responsibly Managing End-of-Life Foams and Plastics Containing Flame Retardants: Part II.

This is Part II of a review covering the wide range of issues associated with all aspects of the use and responsible disposal of foam and plastic wastes containing toxic or potentially toxic flame retardants. We identify basic and applied research needs in the areas of responsible collection, pretreatment, processing, and management of these wastes. In Part II, we explore alternative technologies for the management of halogenated flame retardant (HFR) containing wastes, including chemical, mechanical, and thermal processes for recycling, treatment, and disposal.

Methods of Responsibly Managing End-of-Life Foams and Plastics Containing Flame Retardants: Part I.

Flame retardants (FRs) are added to foams and plastics to comply with flammability standards and test requirements in products for household and industrial uses. When these regulations were implemented, potential health and environmental impacts of FR use were not fully recognized or understood. Extensive research in the past decades reveal that exposure to halogenated FRs, such as those used widely in furniture foam, is associated with and/or causally related to numerous health effects in animals and humans.

Characterisation of ultraviolet-absorbing recalcitrant organics in landfill leachate for treatment process optimisation.

Organics in leachate from municipal solid waste landfills are notoriously difficult to treat by biological processes. These organics have high ultraviolet absorbance and can interfere with the ultraviolet disinfection process at the wastewater treatment plant that receives leachate if the leachate flow contribution is large enough. With more wastewater treatment plants switching to ultraviolet disinfection, landfills face increased pressure to treat leachate further.

Biodegradability of iopromide products after UV/H₂O₂ advanced oxidation.

Iopromide is an X-ray and MRI contrast agent that is virtually non-biodegradable and persistent through typical wastewater treatment processes. This study determined whether molecular transformation of iopromide in a UV/H2O2 advanced oxidation process (AOP) can result in biodegradable products. The experiments used iopromide labeled with carbon-14 on the aromatic ring to trace degradation of iopromide through UV/H2O2 advanced oxidation and subsequent biodegradation.

Degradation pathways of lamotrigine under advanced treatment by direct UV photolysis, hydroxyl radicals, and ozone.

Lamotrigine is recently recognized as a persistent pharmaceutical in the water environment and wastewater effluents. Its degradation was studied under UV and ozone advanced oxidation treatments with reaction kinetics of lamotrigine with ozone (≈4 M(-1)s(-1)), hydroxyl radical [(2.1 ± 0.

Identifying the factors that influence the reactivity of effluent organic matter with hydroxyl radicals.

Advanced oxidation processes (AOPs) are an effective treatment technology for the removal of a variety of organic pollutants in both water and wastewater treatment. However, many background constituents in water are highly reactive towards hydroxyl radicals (HO) and decrease the efficiency of the process towards contaminant oxidation. Up to 95% of the HO scavenging can come from dissolved organic matter (OM).

Degradation of antibiotic activity during UV/H2O2 advanced oxidation and photolysis in wastewater effluent.

Trace levels of antibiotics in treated wastewater effluents may present a human health risk due to the rise of antibacterial activity in the downstream environments. Advanced oxidation has a potential to become an effective treatment technology for transforming trace antibiotics in wastewater effluents, but residual or newly generated antibacterial properties of transformation products are a concern. This study demonstrates the effect of UV photolysis and UV/H2O2 advanced oxidation on transformation of 6 antibiotics, each a representative of a different structural class, in pure water and in two different effluents and reports new or confirmatory photolysis quantum yields and hydroxyl radical rate constants.

Dimer formation during UV photolysis of diclofenac.

Dimer formation was observed during ultraviolet (UV) photolysis of the anti-inflammatory drug diclofenac, and confirmed with mass spectrometry, NMR and fluorescence analysis. The dimers were combinations of the two parent molecules or of the parent and the product of photolysis, and had visible color. Radical formation during UV exposure and dissolved oxygen photosensitized reactions played a role in dimer formation.

Re-engineering an artificial sweetener: transforming sucralose residuals in water via advanced oxidation.

Sucralose is an artificial sweetener persistently present in wastewater treatment plant effluents and aquatic environments impacted by human activity. It has a potential to accumulate in the water cycle due to its resistance to common water and wastewater treatment processes. This study examined UV/H2O2 advanced oxidation and found that hydroxyl substitution of the chlorine atoms on the sucralose molecule can form a carbohydrate consisting of fructose and sugar alcohol, very similar to environmentally benign sucrose.

The role of effluent nitrate in trace organic chemical oxidation during UV disinfection.

Most conventional biological treatment wastewater treatment plants (WWTPs) contain nitrate in the effluent. Nitrate undergoes photolysis when irradiated with ultraviolet (UV) light in the 200-240 and 300-325 nm wavelength range. In the process of nitrate photolysis, nitrite and hydroxyl radicals are produced.

Enhanced biodegradation of carbamazepine after UV/H2O2 advanced oxidation.

Carbamazepine is one of the most persistent pharmaceutical compounds in wastewater effluents due to its resistance to biodegradation-based conventional treatment. Advanced oxidation can efficiently degrade carbamazepine, but the toxicity and persistence of the oxidation products may be more relevant than the parent. This study sets out to determine whether the products of advanced oxidation of carbamazepine can be biotransformed and ultimately mineralized by developing a novel methodology to assess these sequential treatment processes.