Real time control of stormwater biofilters improves the removal of organic chemicals.

Biofilters are among the most popular nature-based systems for treating stormwater and delivering multiple environmental benefits. However, as a passive system, their performance tends to be inconsistent in removing emerging organic contaminants produced by anthropogenic activities that can be persistent, mobile, and toxic. Thus, in this study, real time control (RTC) of stormwater biofilters is introduced to enhance the removal of a diverse range of organic chemicals.

Quantifying remediation of chlorinated volatile compounds by sulfidated nano zerovalent iron treatment using numerical modeling and CSIA.

Sulfidated nanoscale zerovalent iron (S-nZVI) has demonstrated promising reactivity and longevity for remediating chlorinated volatile compounds (cVOC) contaminants in laboratory tests. However, its effectiveness in field applications remains inadequately evaluated. This study provides the first quantitative evaluation of the long-term effectiveness of carboxymethyl cellulose-stabilized S-nZVI (CMC-S-nZVI) at a cVOC-contaminated field site.

Soluble metal porphyrins - Zero-valent zinc system for effective reductive defluorination of branched per and polyfluoroalkyl substances (PFASs).

Nano zero-valent metals (nZVMs) have been extensively utilized for decades in the reductive remediation of groundwater contaminated with chlorinated organic compounds, owing to their robust reducing capabilities, simple application, and cost-effectiveness. Nevertheless, there remains a dearth of information regarding the efficient reductive defluorination of linear or branched per- and polyfluoroalkyl substances (PFASs) using nZVMs as reductants, largely due to the absence of appropriate catalysts. In this work, various soluble porphyrin ligands [[meso‑tetra(4-carboxyphenyl)porphyrinato]cobalt(III)]Cl·7HO (CoTCPP), [[meso‑tetra(4-sulfonatophenyl) porphyrinato]cobalt(III)]·9HO (CoTPPS), and [[meso‑tetra(4-N-methylpyridyl) porphyrinato]cobalt(II)](I)·4HO (CoTMpyP) have been explored for defluorination of PFASs in the presence of the nZn as reductant.

Catalytic dechlorination of 1,2-DCA in nano Cu-borohydride system: effects of Cu/Cu ratio, surface poisoning, and regeneration of Cu sites.

Aqueous-phase catalyzed reduction of organic contaminants via zerovalent copper nanoparticles (nCu), coupled with borohydride (hydrogen donor), has shown promising results. So far, the research on nCu as a remedial treatment has focused mainly on contaminant removal efficiencies and degradation mechanisms. Our study has examined the effects of Cu/Cu ratio, surface poisoning (presence of chloride, sulfides, humic acid (HA)), and regeneration of Cu sites on catalytic dechlorination of aqueous-phase 1,2-dichloroethane (1,2-DCA) via nCu-borohydride.

A fundamental model for calculating interfacial adsorption of complex ionic and nonionic PFAS mixtures in the presence of mixed salts.

Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants that have been used extensively as firefighting agents and in a wide range of commercial applications around the world. As many of the most-common PFAS components are surfactants, they readily accumulate at interfaces, a process that can govern their environmental fate. There are thousands of PFAS compounds, and they have nearly always been used as mixtures, so it is common to find many different PFAS components present together in the environment.

The role of microbial ecology in improving the performance of anaerobic digestion of sewage sludge.

The use of next-generation diagnostic tools to optimise the anaerobic digestion of municipal sewage sludge has the potential to increase renewable natural gas recovery, improve the reuse of biosolid fertilisers and help operators expand circular economies globally. This review aims to provide perspectives on the role of microbial ecology in improving digester performance in wastewater treatment plants, highlighting that a systems biology approach is fundamental for monitoring mesophilic anaerobic sewage sludge in continuously stirred reactor tanks. We further highlight the potential applications arising from investigations into sludge ecology.

Calculating PFAS interfacial adsorption as a function of salt concentration using model parameters determined from chemical structure.

Per- and polyfluoroalkyl substances (PFAS) are widely-detected environmental contaminants known to concentrate at surfaces and interfaces. Many of the most commonly-detected PFAS function as ionic surfactants under environmental conditions. The interfacial behaviors of ionic surfactants, including PFAS, are strongly dependent on salt concentration and composition, with interfacial affinity potentially varying by orders of magnitude for the same compound under different conditions.

Efficient Reductive Defluorination of Branched PFOS by Metal-Porphyrin Complexes.

Vitamin B (VB) has been reported to degrade PFOS in the presence of Ti citrate at 70 °C. Porphyrin-based catalysts have emerged as VB analogues and have been successfully used in various fields of research due to their interesting structural and electronic properties. However, there is inadequate information on the use of these porphyrin-based metal complexes in the defluorination of PFOS.

Removal of per- and polyfluoroalkyl substances (PFAS) from water by ceric(iv) ammonium nitrate.

Ceric(iv) ammonium nitrate (CAN) in aqueous medium acts as an excellent precipitating agent for perfluorooctanesulfonic acid (PFOS). The Ce(iv) center plays a crucial role. Interestingly, Ce(iii) chloride showed much less effectiveness under similar conditions.

A new conceptual framework for the transformation of groundwater dissolved organic matter.

Groundwater comprises 95% of the liquid fresh water on Earth and contains a diverse mix of dissolved organic matter (DOM) molecules which play a significant role in the global carbon cycle. Currently, the storage times and degradation pathways of groundwater DOM are unclear, preventing an accurate estimate of groundwater carbon sources and sinks for global carbon budgets. Here we reveal the transformations of DOM in aging groundwater using ultra-high resolution mass spectrometry combined with radiocarbon dating.

Predicting the impact of salt mixtures on the air-water interfacial behavior of PFAS.

Salts are known to have strong impacts on environmental behavior of per- and polyfluoroalkyl substances (PFAS) including air-water interfacial adsorption. Multivalent salts impact interfacial adsorption to a greater extent than monovalent salts. Models to make a priori predictions of PFAS interfacial adsorption in the presence of multiple salts with different ionic charges are needed given the need to predict PFAS environmental fate.

Silver nanomaterials released from commercial textiles have minimal impacts on soil microbial communities at environmentally relevant concentrations.

Silver nanomaterials (Ag NMs) have been used in a variety of commercial products to take advantage of their antimicrobial properties. However, there are concerns that these AgNMs can be released during/after use and enter wastewater streams, potentially impacting aquatic systems or accumulating in wastewater biosolids. Biosolids, which are a residual of wastewater treatment processes, have been found to contain AgNMs and are frequently used as agricultural fertilizer.

Factors controlling phosphorus mobility in nearshore aquifers adjacent to large lakes.

Internal P stores in offshore lakebed sediments play an important role in lake nutrient dynamics. While P stores in nearshore aquifer sediments may also be important for nutrient dynamics, it is unclear whether P accumulates in these sediments, and if so, what factors control P accumulation and its potential later release from the sediments to nearshore waters. This knowledge gap was addressed by conducting field investigations at seven nearshore sites located along the shores of Lake Erie, Lake Huron and Lake Ontario, Canada, with more detailed dissolved and sediment phase characterization completed for two nearshore sites.

A new framework for modeling the effect of salt on interfacial adsorption of PFAS in environmental systems.

Per- and polyfluoroalkyl substances (PFAS) are surface active contaminants of great environmental concern, due to their widespread historical use and their environmental persistence. Salts are known to have a profound influence on the interfacial behaviors of all ionic surfactants, including some of the most commonly detected PFAS. This work describes a new mass-action model for predicting the interfacial behavior of surfactants as a function of salt concentration.

Recent Advances in Sulfidated Zerovalent Iron for Contaminant Transformation.

2021 marks 10 years since controlled abiotic synthesis of sulfidated nanoscale zerovalent iron (S-nZVI) for use in site remediation and water treatment emerged as an area of active research. It was then expanded to sulfidated microscale ZVI (S-mZVI) and together with S-nZVI, they are collectively referred to as S-(n)ZVI. Heightened interest in S-(n)ZVI stemmed from its significantly higher reactivity to chlorinated solvents and heavy metals.

Electrokinetically-enhanced emplacement of lactate in a chlorinated solvent contaminated clay site to promote bioremediation.

Bioremediation through the injection of electron donors and bacterial cultures is effective at treating chlorinated solvent contamination. However, it has had limited application in low permeability zones where amendments cannot be delivered successfully. This field-scale study investigated the application of electrokinetics to enhance the delivery of lactate at a clay site contaminated with chlorinated solvents.

Predicting the relationship between PFAS component signatures in water and non-water phases through mathematical transformation: Application to machine learning classification.

Per- and polyfluoroalkyl substances (PFAS) are widespread in the environment, as a result of decades of use across a range of applications. While PFAS contamination often enters the environment in the aqueous phase, PFAS is regularly detected in a range of different phases, including soils, sediments and biota. Although PFAS at a given site may originate from the same sources, the compositions observed in different phases are nearly always different, a fact that can complicate source allocation efforts.

Occurrence of Arsenic in Nearshore Aquifers Adjacent to Large Inland Lakes.

Metal oxides that form near sediment-water interfaces in marine and riverine settings are known to act as a sediment trap for pollutants of environmental concern (e.g., arsenic and mercury).

Source allocation of per- and polyfluoroalkyl substances (PFAS) with supervised machine learning: Classification performance and the role of feature selection in an expanded dataset.

This work explores the use of supervised machine learning as a tool for identifying the source of per- and polyfluorinated alkyl substances (PFAS) in water samples on the basis of the detected component concentrations. Specifically, the work focuses on distinguishing between PFAS used in aqueous film forming foam (AFFF) fire suppression applications, and PFAS from other sources. The fact that many sites contaminated with legacy PFOS-based AFFF formulations are dominated by perfluorinated sulfonates can make it tempting to naïvely classify samples dominated by perfluorinated sulfonates as being of AFFF origin.

A group-contribution model for predicting the physicochemical behavior of PFAS components for understanding environmental fate.

The factors controlling per- and polyfluoroalkyl substances (PFAS) environmental fate remains the subject of considerable debate and study. As surfactants, PFAS readily partition to interfaces, a property that controls their transport and fate. A group contribution model is developed to predict the extent to which PFAS partitions to the air-water interface.

Spatiotemporal controls on septic system derived nutrients in a nearshore aquifer and their discharge to a large lake.

This study evaluates spatiotemporal variability in the behavior of septic system derived nutrients in a sandy nearshore aquifer and their discharge to a large lake. A groundwater nutrient-rich plume was monitored over a two-year period with the septic system origin of the plume confirmed using artificial sweeteners. High temporal variability in NO-N attenuation in the nearshore aquifer prior to discharge to the lake (42-96%) reveals the complex behavior of NO-N and potential importance of changing hydrological and geochemical conditions in controlling NO-N discharge to the lake.

Field test of electrokinetically-delivered thermally activated persulfate for remediation of chlorinated solvents in clay.

In situ chemical oxidation (ISCO) has demonstrated success in remediating soil and groundwater contaminated with chlorinated volatile organic compounds (CVOCs). However, its performance is often hindered in low-permeability or heterogeneous media due to an inability to effectively deliver the oxidants. This field-scale study investigated the novel approach of applying electrokinetics (EK) to enhance the delivery of persulfate in a low-permeability media and the ability of electrical resistance heating (ERH) to thermally activate the delivered persulfate.

Supervised machine learning for source allocation of per- and polyfluoroalkyl substances (PFAS) in environmental samples.

Environmental contamination by per- and polyfluoroalkyl substances (PFAS) is widespread, because of both their decades of use, and their persistence in the environment. These factors can make identification of the source of contamination in samples a challenge, because in many cases contamination may originate from decades ago, or from a number of candidate sources. Forensic source allocation is important for delineating plumes, and may also be able to provide insights into environmental behaviors of specific PFAS components.