ACS ES&T engineering最新文献

Efficient nutrient management is critical for crop growth and sustainable resource consumption (e.g., nitrogen and energy). Current approaches require lengthy analyses, preventing real-time optimization; similarly, imaging facilitates rapid phenotyping but can be computationally intensive, preventing deployment under resource constraints. This study proposes a flexible, tiered pipeline for anomaly detection and status estimation (fresh weight, dry mass, and tissue nutrients), including a comprehensive energy analysis of approaches that span the efficiency-accuracy spectrum. Using a nutrient depletion experiment with three treatments (T1-100%, T2-50%, and T3-25% fertilizer strength) and multispectral imaging, we developed a hierarchical pipeline using an autoencoder for early warning. Further, we compared two status estimation modules of different complexity for more detailed analysis: vegetation index features with machine learning (random forest, RF) and raw whole-image deep learning (vision transformer, ViT). Results demonstrated high-efficiency anomaly detection (73% net detection of T3 samples 9 days after transplanting) at substantially lower energy than embodied energy in wasted nitrogen. The state estimation modules show trade-offs, with ViT outperforming RF on phosphorus and calcium estimation (R ² 0.61 vs 0.58, 0.48 vs 0.35) at higher energy cost. With our modular pipeline, this work opens up opportunities for edge diagnostics and practical opportunities for agricultural sustainability.

Achieving high biochemical production in biotransformations of renewable resources requires using concentrated cultures that not only generate the product of interest but also produce abundant microbial cell waste. We explored the concept of gaining value from microbial cells by producing intracellular products in tandem with a desired extracellular product. Specifically, we engineered a strain ofNovosphingobium aromaticivorans to extracellularly produce 2-pyrone-4,6-dicarboxylic acid (PDC) from aromatic substrates and to intracellularly accumulate astaxanthin along with coenzyme Q₁₀, all of which are products of industrial interest. Achieving the goal of concurrent production of intracellular and extracellular products required the creative application of bioreactor engineering principles. Although a continuously fed membrane bioreactor (MBR) maximized extracellular product biosynthesis, it had a negative effect on intracellular product accumulation. However, operating the MBR as a sequencing batch reactor (MBR-SBR) with a step-feed resulted in stable concurrent production of both extracellular and intracellular products. With aromatics extracted from poplar biomass, we achieved productivities of 1.14 g of PDC/L-h for the extracellular product and 0.04 mg of astaxanthin/L-h and 0.64 mg of CoQ₁₀/L-h for intracellular products, respectively. Our findings demonstrate that the mode of operation of a bioreactor impacts the simultaneous production of intracellular and extracellular products byN. aromaticivorans.

Donnan dialysis (DD) is a promising approach for selectively recovering ammonium ions from wastewater, owing to its simplicity and low energy consumption. However, the role of ion sorption and desorption in cation exchange membranes (CEMs), particularly interactions between ammonium ions (NH₄ ⁺) and competing ions (e.g., sodium Na⁺), has often been overlooked. Our experimental results revealed a shift in the Donnan equilibrium caused by the preoccupied counterions in the CEM. For example, when the feed and draw solutions were in a 1:1 concentration ratio, the expected ammonium recovery efficiency was 50%. However, the NH₄Cl-presoaked membrane resulted in an increase of 19.1 ± 0.5% in the solution NH₄ ⁺ concentration and a decrease of 18.8 ± 0.6% in the Na⁺ concentration. Conversely, the NaCl-soaked membrane showed an 18.9 ± 1.6% reduction in NH₄ ⁺ and a 23.0 ± 1.3% increase in Na⁺. The difference indicated that the ion exchange capacity of the membrane and counterion uptake could shift the equilibrium of the DD process. We further analyzed the process kinetics and developed a nonsteady-state model incorporating ion sorption capacity to describe the behavior. Our results confirmed that presoaked ions shifted the final DD equilibrium, potentially due to differences in their affinity and geometry. To summarize, this study provides new insights into the mechanisms of Donnan dialysis by accounting for ion sorption and offers insights for the design of more efficient and effective separation processes for ammonium recovery.

Accurate modeling of seawater thermophysical and thermodynamic properties is critical for optimizing desalination processes. This study compares three seawater property models, a Reaktoro multicomponent model, the thermophysical seawater properties library from the Massachusetts Institute of Technology, and a simplified sodium chloride model, in the context of levelized cost of water (LCOW) minimization for reverse osmosis (RO) and mechanical vapor compression systems. Process simulations and cost optimizations reveal that although all three models yield comparable LCOW and specific energy consumption (SEC) estimates under baseline conditions, deviations among their predictions increase with salinity. Relative differences in LCOW and SEC reach up to 6% and 8%, respectively. RO results show greater variability due to differences in osmotic pressure predictions, which affect pressure constraints at high recoveries. Computational performance varies substantially; specifically, Reaktoro simulations are up to 28 times slower than empirical models due to their detailed equilibrium calculations. These results suggest that empirical models offer acceptable accuracy for routine desalination process design, while Reaktoro provides advantages in scenarios requiring detailed speciation, such as scaling or pH adjustment studies. These findings underscore the importance of selecting appropriate property models based on the modeling objective of desalination applications and motivate future work integrating thermodynamic rigor with empirical efficiency.

As energy, environmental, supply chain, and economic risks escalate in today's linear fertilizer manufacturing processes, there has been growing interest in developing technologies that enable a circular nitrogen-based fertilizer economy. Achieving this goal requires significant advancements in wastewater treatment, with a specific focus on the design of technologies and complete systems that can capture and recycle waste nutrients into usable fertilizers. Every year, millions of tons of nitrogen and phosphorus remain untapped in global municipal and industrial wastewater, presenting a significant opportunity for fertilizer utilization. Herein, we explore current and future opportunities for nutrient recovery systems to provide recycled fertilizers for agricultural use. We first quantify recoverable nutrient wastewater sources, examine current nutrient management processes (e.g., nitrification-denitrification, EBPR), and highlight the performance and limitations of current nutrient management processes. We also review the current commercialization landscape for nutrient recovery systems and detail efforts made in advancing full-scale deployments. Finally, we review emerging electrified technologies and compare nutrient recovery technologies in terms of technology readiness, scalability, optimal feedstock, and environmental trade-offs, pairing them with optimal wastewater feed streams. A gap analysis is also conducted to guide future research and development efforts in nutrient recovery.

Selenium (Se) contamination in flue-gas desulfurization (FGD) wastewater from coal-fired power plants poses significant environmental and regulatory challenges. Here, we developed and optimized a three-dimensional electrochemical reactor (3DER) with carbon-based particle electrodes (PEs) to remove Se-(IV). Compared with conventional two-dimensional systems, the 3DER provides an enlarged electrode surface area, enabling faster removal kinetics and higher resilience without regeneration. Reactor performance was systematically evaluated as a function of PE geometry, recirculation rate, cell potential, and anode-to-cathode (A:C) chamber ratio. The optimized configuration (A:C = 1:2, E _cell = -2.1 V, recirculation rate 3.3 mL min^-1) balanced cathodic efficiency while minimizing anodic parasitic reactions. In synthetic wastewater containing 0.1 mM Se-(IV), the single-pass 3DER achieved steadily increasing performance, with hourly removal improving from 61.3% in the first hour to 68.1% by the 12th hour. Applied to real FGD wastewater, the system maintained an average hourly removal of 51.7% (4.2 mg of Se L^-1 h^-1) without regeneration and reached a specific energy consumption as low as 0.03 kWh g^-1 Se despite high chloride levels. Competing ions, including Mn and Si, further enhanced the Se reduction by forming oxide layers and rejecting Cl^- from the electrode surface. Enhanced kinetics under elevated Se-(IV) loadings yielded a peak removal of 74.4% (17.5 mg of Se L^-1 h^-1). These results demonstrate robust and efficient removal performance of the 3DER, supporting its promise for selenium-rich wastewater treatment and future scale-up.

Azelaic acid is a renewable monomer conventionally produced via the energy-intensive ozonolysis of oleic acid. Recent advancements have enabled the use of high-oleic vegetable oils (rather than tallow-derived oleic acid) and replaced ozonolysis with two-step oxidative cleavage using hydrogen and oxygen. Although this shift would improve process safety, the financial viability and environmental implications remain uncertain. In this study, we characterized the sustainability of azelaic acid production from high-oleic vegetable oil using two-step oxidative cleavage. Process design, simulation, technoeconomic analysis (TEA), and life cycle assessment (LCA) were executed under uncertainty using BioSTEAM. The modeled system produces azelaic acid at a market-competitive minimum selling price (MSP) of 8.32 [4.93-13.34] $ kg^-1 (median 5th-95th percentiles), below the minimum estimated market price of 9.93 $ kg^-1. Further, it has the potential to approach carbon neutrality (0.0 [-5.5 to 5.6] kg of CO₂-eq kg^-1) under displacement allocation. Improvements to dihydroxylation (86 to 99%) and oxidative cleavage conversions (93 to 99%) would reduce MSP to $5.24 kg^-1 and carbon intensity to -1.90 kg of CO₂-eq kg^-1 (displacement). Additionally, increasing the feedstock triolein content (75 to 85%) lowers MSP by $0.82 kg^-1. Overall, this research demonstrates the potential for financially viable production of azelaic acid from vegetable oils and the utility of agile TEA/LCA.

Locally enhanced electric field treatment (LEEFT) has emerged as a promising chlorine-free approach for water disinfection. However, its practical deployment has been limited by challenges in electrode durability and system scalability. Herein, we report a robust stainless-steel brush designed to enable long-term operation and scalability of LEEFT electrodes. A tubular reactor with coaxial electrodes featuring the brush as the center electrode was developed to combine both macroscale and microscale electric field enhancements. Operational parameters, including waveform, frequency, voltage, and flow rate, were systematically optimized to maximize microbial inactivation while minimizing metal release. Flow cytometry and control experiments revealed electroporation, assisted by reactive oxygen species, as the primary disinfection mechanism. Under optimal unipolar pulse conditions with high duty cycle and frequency, the system achieved efficient inactivation at voltages in the tens of volts range. Notably, the LEEFT system with the brush electrode has remained effective for about half a year with minimal metal release, representing a 10-fold increase in lifespan compared to previous LEEFT configurations. This work demonstrates a scalable, durable, and chemical-free solution for decentralized and sustainable water disinfection.

Nanofiltration (NF) membranes are increasingly being used to achieve precise solute-solute separation. These membranes are commonly synthesized using interfacial polymerization, offering great potential to separate lithium from magnesium. In this study, we have developed machine learning models that relate fabrication conditions, membrane properties, and operational conditions of NF membranes to predict water permeability and lithium/magnesium selectivity. Morgan fingerprints (MFs) and molecular descriptors (MDs) are used to represent the chemical and physical properties of the monomers. Explainable artificial intelligence tools such as Shapley additive explanations (SHAP) and partial dependence plots are used to evaluate the effects of the synthesis conditions and membrane properties on membrane performance. Based on the insights obtained from SHAP analysis, we developed a material screening approach to find promising monomers from a list of amines and cation-based ionic liquids. We construct a reference MF using the functional groups that positively contribute to membrane performance and compute a screening score that favors potential candidates with more desirable MDs. Finally, the synthesizability of these monomers is assessed using the synthetic accessibility score to find the most promising candidates. We compared the performance of screened monomers against traditional ones to validate the reliability of our approach. The results of this study provide critical insights into the relationships between synthesis conditions, membrane properties, and performance and establishes a novel, strategic framework for rational screening of monomers for NF membrane synthesis. This approach holds promise to accelerate the discovery of high-performance membranes tailored for specific separation challenges, thereby advancing the field of membrane technology.

Electrode behavior was elucidated during long-term galvanostatic electrocoagulation (aluminum anode and aluminum cathode) of a hypersaline oilfield produced water rich in divalent cations. Electrode potentials progressively increased (i.e., fouling) for most operational conditions due to surface accumulation of calcite and brucite. The interfacial resistance resulting from partial insulation by electrodeposited salts was quantified by using electrochemical impedance spectroscopy. The potential drop associated with this resistance correlated strongly and positively with the increased overpotential required to maintain the galvanostatic operation and was statistically indistinguishable from the calculated ohmic drop, confirming that electrode fouling could be fully attributed to ohmic effects. This also ruled out the occurrence of electrochemical side reactions at elevated potentials, despite their thermodynamic feasibility (note that H ₂(g) evolution is a non-Faradaic chemical reaction). We evaluated polarity reversal (PR) as a fouling mitigation strategy to restore electrode performance over a 4-fold variation in current density and a 100-fold variation in PR interval. The PR interval did not significantly influence performance, and fouling was effectively mitigated only at the highest applied current density (200 mA·cm^-2). Results indicated the existence of a threshold current density and associated hydrogen bubble generation rate necessary to effectively control electrode fouling under the experimental conditions investigated. Foulant deposition also hindered the migration of electrodissolved aluminum ions away from the anode, facilitating their supersaturation, nucleation, precipitation, and entrapment, thereby decreasing the apparent Faradaic efficiency of coagulant dosing.