ACS ES&T water最新文献

Growing concern over plastic pollution has intensified research on biodegradable alternatives, such as polyhydroxybutyrate (PHB), a biopolymer produced by cyanobacteria. Despite their sustainability advantages, photoautotrophic PHB production remains limited, and cultivation strategies need optimization. In this study, five cyanobacterial strains were isolated from environmental microbiome cultures to evaluate their PHB production potential. The goal was to identify the most productive strains and optimal conditions for polymer synthesis. Cultures were grown in modified BG11 media (without nitrogen, phosphorus, or inorganic carbon) and in a secondary effluent from treated urban wastewater, both supplemented with acetate (0, 0.6, or 4 g/L) and incubated for 7 days in darkness. The biomass remained stable in most strains but declined to 0.28 g/L in the secondary effluent, except for one Leptolyngbya sp. strain that increased the biomass with acetate. The highest PHB yield per acetate consumed was achieved by Synechocystis sp. from an agricultural pond, reaching 3.1% dry cell weight in modified BG11 with 0.6 g/L acetate. In the secondary effluent, the maximum PHB content reached 2.9% in another Leptolyngbya sp. strain with 4 g/L acetate. These findings highlight strain-specific responses and the potential of wastewater-based cultivation for sustainable bioplastic production.

Ultraviolet C light-emitting diodes (UV C LEDs) have demonstrated effectiveness in disinfection applications and proven suitability at scale for disinfection of municipal wastewater and drinking water. Technological advances in materials design and electrical efficiency have made high-intensity light delivery by UV C LEDs a reality and now poise these traditionally disinfection systems to serve a dual purpose for targeted remediation of trace organic contaminants (TrOCs). This work investigated the effectiveness of UV C light emission tailoring on the photodegradation dynamics of select TrOCs. Degradation kinetics and quantum yields of target compounds under 275 nm irradiation were governed by molar absorbance and chemical structure, and kinetics followed estrone (E1) > tryptophan > caffeine ≈ pCBA > urea. Secondary experiments compared the efficacy of a 275 nm UV LED and a medium-pressure mercury vapor (MP UV) system for photodegradation of two steroid estrogens, E1 and 17β-estradiol (17β-E2). Use of the 275 nm UV LED system substantially reduced fluence requirements and, in the case of 17β-E2, energy requirements, to achieve 90% degradation of the target compounds. Liquid chromatography-tandem mass spectrometry analysis of an E1 photodegradation product showed that the UV C LED system was more effective in eliminating both E1 and its associated photoproduct as compared to the MP UV system. This work demonstrates the effective use of UV LEDs for tailored photolysis of TrOCs and provides evidence for their use potential in applications outside of water disinfection.

Per-and polyfluoroalkyl substances (PFAS) present significant challenges for remediation due to their persistence in nature. Activated carbon is a widely used adsorbent for removing PFAS. In this study, three forms of activated carbon, granular activated carbon (GAC), powdered activated carbon (PAC), and ball-milled colloidal activated carbon (CAC_BM), are compared for their effectiveness in removing short and long-chain PFAS. Physical modification through ball-milling process enhanced the adsorptive properties of activated carbon, resulting in smaller particle size (d ₅₀ = 0.318 μm), increased surface area (968.59 m² g^-1), and improved suspension stability compared to conventional GAC and PAC. Kinetic experiments showed that CAC_BM demonstrated superior removal efficiencies of long-chain PFAS (up to 89% for perfluorooctanesulfonic acid (PFOS) and 73% for perfluorooctanoic acid (PFOA)), and moderate removal of short-chain PFAS (55% for perfluorobutanesulfonic acid (PFBS) and 30% for perfluorobutanoic acid (PFBA)). The pseudo-first-order model adequately described adsorption trends; however, the pseudo-second-order model provided a better fit, with intraparticle diffusion identified as the rate-limiting step. Isotherm studies indicated that PFAS adsorption aligned well with the Freundlich model. Competitive adsorption experiments revealed a hierarchical pattern. Overall, the study demonstrates CAC_BM as a promising adsorbent for remediation of PFAS-contaminated water systems.

Microplastic pollution has been found to negatively impact water quality and ecosystem health in numerous riverine environments at different spatial and temporal scales. However, many of the underlying principles controlling microplastic transport and retention mechanisms are still poorly understood. Here, we study the deposition behavior of nylon fibers and fragments (small and large) in flow-controlled stream flume experiments with gravel or mixed sediment. We use a stochastic modeling approach and Latin hypercube sampling to optimize the parameters describing microplastic deposition and resuspension and relate deposition rates to settling rates calculated using Stoke's law. Our experiments show that lower streamflow velocity leads to faster microplastic deposition, an effect that is shape-dependent and more pronounced for fibers. In experiments with similar flow velocity, large fragments were more quickly deposited in flumes containing gravel compared to mixed sediment. Stoke's settling rates and model-based deposition rates can differ by several orders of magnitude, especially for fibers. For our flume experiments, these differences are attributed to transitional and turbulent flow near the streambed. Results emphasize that microplastic net deposition and near-bed transport cannot be well described by Stoke's law. Results will further our understanding of microplastic fate and transport in riverine environments.

Cyanobacterial harmful algal blooms (CyanoHABs) pose global risks to public health, ecosystems, and economies. Despite advancements in satellite remote sensing, monitoring gaps persist, particularly in smaller, remote, and resource-limited regions, where CyanoHABs often remain undetected. Satellite-based methods, though effective for large-scale monitoring, suffer from a low spatial resolution, cloud cover, and reliance on in situ validation data. Traditional in situ monitoring equipment, including high-precision spectroradiometers, is costly and logistically challenging, further exacerbating global monitoring inequities. Cyanosense 2.0 (CS2.0) is a low-cost system for real-time in situ CyanoHAB detection and satellite validation designed to address these monitoring voids. CS2.0 integrates two hyperspectral Hamamatsu spectrometers and a microcontroller system, recording Remote Sensing Reflectance (R_rs) with high agreement to industry-grade instruments (R ² = 0.86, Normalized Root Mean Squared Error (NRMSE) = 9.82%), at a fraction of the cost (∼$1300). During field validation in multiple CyanoHAB-prone U.S. lakes, CS2.0 showed a strong performance when tested for widely used satellite-based CyanoHAB models and indices (R ² = 0.74-0.83; NRMSE = 13%-18%). The system's weatherproof design supports long-term autonomous deployments, making it functional in remote environments. As a scalable and accessible solution, CS2.0 holds the potential to democratize CyanoHAB monitoring and improve global water quality assessments, especially in under-represented regions.

Understanding the environmental impacts and economic costs of treatment technologies is essential for developing sustainable strategies for managing per- and polyfluoroalkyl substances (PFASs). This study focuses on the treatment of PFAS-contaminated landfill leachate using foam fractionation (FF) technology. A parametrized life cycle assessment and life cycle costing analysis were conducted to evaluate the performance of one-stage and three-stage FF systems. Full-scale operational data and EPA design models were used to assess environmental and economic impacts based on a functional unit of treating 1000 m³ of PFAS-contaminated landfill leachate. The global warming potential was estimated at 818 kg CO₂ eq for the one-stage system with 20% foam fraction, 357 kg CO₂ eq for the one-stage system with 1% foam fraction, and 402 kg CO₂ eq for the three-stage system with 1% foam fraction. Life cycle costs were estimated at $77.4 and $110.6 per functional unit for the one-stage and three-stage systems, respectively, using the net present value method. Sensitivity and scale-up analyses were also performed to evaluate the influence of operational parameters and system configurations on both environmental and economic outcomes.

Freshwater salinization is a threat to biodiversity conservation. Winter road deicing salt use is a dominant driver of freshwater salinization in north temperate regions that experience winter temperatures below 0 °C. In Canada, the identification and management of areas vulnerable to road salt contamination is the least-complied-with tenet of the Canadian Code of Practice for the Environmental Management of Road Salts. To aid delineation of salt vulnerable areas, we developed and applied a framework for identifying dominant road salt loading source areas relative to aquatic species at risk critical habitat. We estimated per-event road salt loading at the subwatershed scale from roads and parking areas to determine contributions from different land-use classes and road types. We spatially focused on a watershed containing Redside Dace (Clinostomus elongatus), a fish species listed as federally and provincially endangered in Canada and Ontario, respectively. Applying uncertainty analysis, we found that cumulative road salt inputs on parking areas dominated total subwatershed-scale inputs. We recommend enhanced management of smaller-scale private road salt use, as the cumulative effect of smaller-scale salt use can be the largest source of watershed road salt loading. Furthermore, we emphasize the need to include critical habitat explicitly in salt vulnerable area delineations.

Cytostatic pharmaceuticals are not completely removed in wastewater treatment plants (WWTPs) and may affect aquatic ecosystems. Their quantification is challenging due to variations in wastewater characteristics, which influence analytical performance. An analytical procedure has been developed, based on solid-phase extraction and liquid chromatography coupled with tandem mass spectrometry, for the simultaneous quantification of 15 anticancer compounds. Influent and effluent samples from 14 Spanish WWTPs were analyzed, and 11 out of 15 target compounds were found at quantifiable levels (ng/L). These findings underscore the need for new WWTP treatments and the further development of analytical techniques capable of monitoring trace contaminants, in line with new regulatory demands. To carry out a comprehensive study of matrix influence on the analytical process, a novel physicochemical clustering approach was applied to group WWTPs, facilitating the validation of the method and widening its application to assess the load of micropollutants emitted to natural aquatic environments. Results show the influence of matrix variability on determining the concentration of cytostatics at both the influent and effluent of WWTPs. The interferences due to the matrix effect can be minimized by optimizing the dilution of the different samples.

Slow sand filters (SSFs) are increasingly recognized for enhancing the biological stability of drinking water. While research has historically focused on the top layer (Schmutzdecke) of SSFs, the contribution of deeper filter depths in removing dissolved organic carbon (DOC) and ammonium (NH₄ ⁺) has recently been acknowledged. This study investigated the occurrence and potential pathways of DOC release in mature full-scale, and young laboratory SSFs. The top layer (5 cm) reduced the easily biodegradable DOC, mainly low-molecular-weight (LMW) acids and building blocks. The middle layers (20-60 cm) released DOC, particularly LMW acids and neutrals, at depths where nitrification was nearly complete. This release occurred in both mature and young SSFs and may result from bacterial activity under carbon or nitrogen limitation or from the transformation of slowly degradable DOC into labile forms. Whatever the precise mechanism of release, the bottom layers (60-90 cm) subsequently removed this released DOC and reduced PO₄ ^3- to ultralow levels, highlighting the importance of the deepest layers in maintaining effluent quality. This study provides the first evidence of biodegradable DOC release in SSFs and emphasizes the need to better understand its implications for carbon cycling and removal processes in biological filters.

Effects of copper at 0, 4, 30, 250, or 2000 μg/L on microbial communities were examined over an 11 month dosing period using triplicate 120 mL water heater microcosms with PEX-b pipes containing mature biofilms to simulate premise plumbing. Effluent total cell counts (TCCs) and Mycobacterium avium peaked at 250 μg/L, reflecting the dual role of copper as a nutrient and antimicrobial. TCCs and M. avium were relatively consistent among replicate microcosms at each dose, but Legionella pneumophila (Lp) diverged among biological triplicates at 250 μg/L, consistently producing high culturable Lp (average 2.5 log MPN/mL) in one microcosm and low/nondetectable levels in the other two. Repeated cross-inoculations and a reinoculation failed to normalize the microbial community composition across 250 μg/L and other triplicate microcosms. 16S rRNA gene amplicon sequencing revealed that the 250 μg/L replicate with a high Lp was characterized by a distinct microbial community composition relative to the two replicates. At 2000 μg/L copper, microbial diversity and TCCs initially decreased, but then TCCs subsequently increased and ultimately were not statistically different from the 250 μg/L microcosms. This study provides insight into mechanisms underlying nonlinear effects of copper dosing when applied as a disinfectant to premise plumbing for opportunistic pathogen control.