Over-the-Counter Monocyclic Non-Steroidal Anti-Inflammatory Drugs in Environment—Sources, Risks, Biodegradation

Recently, the increased use of monocyclic non-steroidal anti-inflammatory drugs has resulted in their presence in the environment. This may have potential negative effects on living organisms. The biotransformation mechanisms of monocyclic nonsteroidal anti-inflammatory drugs in the human body and in other mammals occur by hydroxylation and conjugation with glycine or glucuronic acid. Biotransformation/biodegradation of monocyclic non-steroidal anti-inflammatory drugs in the environment may be caused by fungal or bacterial microorganisms. Salicylic acid derivatives are degraded by catechol or gentisate as intermediates which are cleaved by dioxygenases. The key intermediate of the paracetamol degradation pathways is hydroquinone. Sometimes, after hydrolysis of this drug, 4- aminophenol is formed, which is a dead-end metabolite. Ibuprofen is metabolized by hydroxylation or activation with CoA, resulting in the formation of isobutylocatechol. The aim of this work is to attempt to summarize the knowledge about environmental risk connected with the presence of over-the-counter antiinflammatory drugs, their sources and the biotransformation and/or biodegradation pathways of these drugs

Nature-based units as building blocks for resource recovery systems in cities

Cities are producers of high quantities of secondary liquid and solid streams that are still poorly utilized within urban systems. In order to tackle this issue, there has been an ever-growing push for more efficient resource management and waste prevention in urban areas, following the concept of a circular economy. This review paper provides a characterization of urban solid and liquid resource flows (including water, nutrients, metals, potential energy, and organics), which pass through selected nature-based solutions (NBS) and supporting units (SU), expanding on that characterization through the study of existing cases. In particular, this paper presents the currently implemented NBS units for resource recovery, the applicable solid and liquid urban waste streams and the SU dedicated to increasing the quality and minimizing hazards of specific streams at the source level (e.g., concentrated fertilizers, disinfected recovered products). The recovery efficiency of systems, where NBS and SU are combined, operated at a micro-or meso-scale and applied at technology readiness levels higher than 5, is reviewed. The importance of collection and transport infrastructure, treatment and recovery technology, and (urban) agricultural or urban green reuse on the quantity and quality of input and output materials are discussed, also regarding the current main circularity and application challenges

Pilot-scale drinking water distribution system to study water quality changes during transport

Abstract Drinking water (DW) quality can change during distribution, leading to taste and odor events and microbial regrowth. Pilot plants mimicking distribution networks are crucial for understanding these changes. We present a new pilot plant design, including piping material, sensors, and instrumentation. The three independent loops (100 m each) of the pilot exhibit identical behavior, allowing simultaneous testing of three conditions. Monitoring includes taste and odor compound formation, microorganism regrowth, and dissolved organic carbon changes. Real-time measurements enable continuous monitoring, and inner pipe biofilm sampling is feasible. The pilot’s modularity facilitates studying climate change effects, different piping materials, and source waters on DW quality in the distribution network

High-rate activated sludge systems combined with dissolved air flotation enable effective organics removal and recovery

High-rate activated sludge (HRAS) systems typically generate diluted sludge which requires further thickening prior to anaerobic digestion (AD), besides the need to add considerable coagulant and flocculant for the solids separation. As an alternative to conventional gravitational settling, a dissolved air flotation (DAF) unit was coupled to a HRAS system or a high-rate contact stabilization (HiCS) system. The HRAS-DAF system allowed up to 78% removal of the influent solids, and the HiCS-DAF 67%. Both were within the range of values typically obtained for HRAS-settler systems, albeit at a lower chemical requirement. The separated sludge had a high concentration of up to 47 g COD L-1, suppressing the need of further thickening before AD. Methanation tests showed a biogas yield of up to 68% on a COD basis. The use of a DAF separation system can thus enable direct organics removal at high sludge concentration and with low chemical needs