ABSTRACT A graphical summary of microalgae-based wastewater treatment, illustrating environmental factors, pollutant removal mechanisms, and high-value utilization of biomass. Environmental pollution and the growing demand for a high-quality ecological environment have become increasingly pressing global challenges. Among these, water pollution remains a major environmental issue closely linked to human development. Consequently, efforts are being made to develop efficient wastewater treatment technologies. Among them, microalgae-based wastewater treatment technology has garnered a lot of interest because of its benefits, which include low cost, high efficiency, environmental friendliness, and the capacity to concurrently create high-value products. This review systematically summarizes and analyzes the mechanisms and pathways by which microalgae remove phosphorus, nitrogen, and heavy metals from wastewater, elucidates the key environmental factors affecting treatment efficiency, and further explores the application potential of microalgal protein in the food sector, as well as the latest advances in the preparation of nitrogen-doped functional materials using microalgal biomass. Unlike previous reviews that primarily focused on biofuel production and feed applications, this paper highlights two emerging resource utilization pathways: protein utilization for the food industry and the development of nitrogen-doped functional materials. It aims to provide a theoretical framework for the high-value utilization and sustainable development of microalgal wastewater treatment technology.
ABSTRACT A flowchart showing stepwise treatment of high salinity brine by increasing pH (through the addition of caustic soda) to precipitate Mg(OH)2 for separation, then followed by the precipitation of Ca(OH)2 to form a slurry into which CO2 is subsequently injected to produce calcite to capture the gas and solidify the aqueous phase calcium. High-salinity flowback and produced water (FPW) from unconventional oil and gas operations poses significant challenges for reuse and disposal due to elevated contents of scale-forming divalent cations. This study investigated and novelly applied a sequential pH conditioning followed by CO2 mineralization treatment approach to an actual FPW from Montney tight gas operations in Western Canada, generating valuable minerals while capturing and storing CO2. Controlled NaOH addition to the brine was first performed to selectively precipitate magnesium cation (Mg2+) at pH ≈ 10.5, while retaining calcium (Ca2+) in the solution. This removed >99% of the dissolved Mg2+ (together with the trace amount of iron) in the water, substantially clarifying the brine. The pH of the residual FPW was then raised to >11.5 to form Ca(OH)2 suspensions. Subsequent CO2 injection into the slurry induced rapid solid CaCO3 formation. Within 20 min, 75–85% of Ca was converted into solid carbonate, yielding a calcite-dominant CaCO3-rich solid after water washing. Strontium (Sr2+) and alkali cations (Na+, K+) remained largely in solution with limited co-precipitation. Overall, approximately 14 g of CO2 was solidified by each liter of the used FPW. The results demonstrate that sequential pH conditioning combined with carbonation significantly reduces scaling potential and enables the recovery of Mg(OH)2-rich solids and production of a recoverable calcite-dominant CaCO3-rich solid. This approach provides a practical pathway for integrating mineral recovery and CO2 capture, storage, and utilization into the disposal and reuse of high salinity produced water in the oil and gas industry.
ABSTRACT Graphical abstract illustrating the dynamics of wastewater that is used in the Mezquital Valley. The diagram shows the water types analyzed through bacterial determination and susceptibility tests, highlighting the presence of extended-spectrum beta-lactamase-producing E. coli. Antibiotic-resistant bacteria (ARB) in water sources constitute an important public health challenge; consequently, monitoring is necessary to mitigate their dissemination. We describe the resistance profile of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli in two zones from the Mezquital Valley, Hidalgo, where wastewater is reused for irrigation. Three sampling campaigns were conducted between 2016 and 2017 in this area. Household water and irrigation samples were processed through membrane filtration and cultured on antibiotic-supplemented media (n = 105). Presumptive E. coli colonies were isolated, after which we performed susceptibility profiles and identification using the MicroScan system. The presence of E. coli was confirmed in 96.6% of isolates, and 82.4% of them were ESBL producers. Household water from Zone A showed higher ESBL-E. coli counts compared with Zone B (p = 0.0247), likely due to its proximity to wastewater canals. Similar profiles between household water and wastewater isolates were observed (p = 0.81). Multidrug resistance (MDR) was detected in domestic and wastewater isolates. No resistance was determined for groundwater. Household water with the presence of ARB suggests wastewater contact with water supplied for human use. This case reinforces the need to meet standards and use risk assessments to mitigate negative effects of wastewater on the environment, human populations, and animals.
ABSTRACT The graphical abstract displays generalized information regarding the source and application of phages. According to the figure, natural water bodies and wastewater treatment plants are considered to be the major sources of lytic phages. These phages can be utilized for various activities, including lowering the bacterial load of wastewater treatment plants, which will minimize the contamination of the environment with pathogenic bacteria. With this, the microbial ecological balance will be maintained. Additionally, lytic phages can be used as an alternative therapeutic agent for bacterial disease in humans and have a significant contribution in maintaining public health. Bacteriophages (phages), the viruses that infect bacteria, are the most abundant biological entities in the biosphere and constitute a fundamental component of aquatic microbial ecosystems. They are ubiquitously distributed across diverse environments, including oceans, rivers, lakes, wastewater systems, coral reefs, mangroves, and sediment water interfaces, where they strongly influence bacterial abundance, diversity, and ecosystem functionality. Aquatic environments provide highly favorable ecological niches for both bacterial hosts and their associated phages, making these ecosystems important reservoirs of enormous but still insufficiently explored viral diversity. Marine ecosystems, particularly coastal tropical waters, coral reefs, and mangrove habitats, harbor highly dynamic phage populations that actively shape microbial community structures and ecological stability. In freshwater ecosystems, sediment–water interfaces represent critical hotspots for viral–bacterial interactions, where phages regulate bacterial population dynamics and contribute substantially to nutrient turnover. Beyond their ecological importance, aquatic lytic phages possess considerable therapeutic potential against pathogenic and multidrug-resistant bacteria. Their high host specificity, self-replicating capacity, and biofilm-disrupting activity make them promising and sustainable alternatives to conventional antimicrobial approaches. Moreover, their ability to reduce bacterial contaminants highlights their potential for wastewater bioremediation and water quality management, underscoring the value of aquatic phages as an underutilized resource for antimicrobial therapy and environmental sustainability.
ABSTRACT Measurements of contaminants in runoff are essential for stormwater management. Sampling accuracy is difficult to assess due to the cost and labor of field studies and the large variation in runoff behavior between sites, rain events, and pollutants. Stormwater sampling requires autosamplers to be programmed based on weather forecasts to accurately sample events, and forecasting errors will affect results in ways that have not been thoroughly examined. We developed an easily interpretable idealized model for runoff pollution and applied the model to sampling methods for a variety of typical conditions observed in small watersheds with moderate to high runoff potential. We examined forecast errors and found a large impact on sampler accuracy, in some situations leading to biases in concentration estimates of greater than 20% along with substantial uncertainty. We found time-paced samplers to generally underestimate concentrations. We analyzed sampler robustness to pollutant and watershed parameters and found that runoff volume had a large effect on sampler accuracy. We developed a novel sampler timing approach that outperformed conventional strategies for overforecast events, and a novel cost-free change to sample compositing that can improve accuracy for underforecast events.
ABSTRACT Workflow schematic summarizing the use of graphene oxide for Li+ and Sr2+ removal from water. The graphic links GO synthesis and characterization, single- and binary-ion adsorption studies, kinetic and isotherm modeling, a mechanism showing weaker Li+ electrostatic interaction and stronger Sr2+ surface complexation, and regeneration with acid treatment; the central results highlight high single-ion capacities, reduced Li+ uptake under binary competition, and reuse above 80% after three cycles. The competitive adsorption of lithium (Li+) and strontium (Sr2+) on graphene oxide (GO) was examined under single- and binary-ion conditions to clarify selective separation relevant to produced-water treatment. Most prior studies emphasize single-solute uptake, this work explicitly quantifies multicomponent interactions using advanced binary isotherm modeling. GO achieved high single-component capacities of 179 mg/g for Li+ and 131 mg/g for Sr2+. In binary solutions, capacities dropped to 32.5 mg/g for Li+ and 49.5 mg/g for Sr2+, demonstrating strong preference for Sr2+ and ∼81% suppression of Li+ uptake. Equilibrium analysis showed Li+ data were best described by the Redlich–Peterson model, consistent with heterogeneous binding, while Sr2+ followed Langmuir behavior, suggesting uniform monolayer adsorption. Under competitive conditions, the modified Freundlich model provided the most accurate fit. Kinetic analysis indicated the pseudo-second-order model described both ions, supporting chemisorption-controlled uptake. Spectroscopic evidence and capacity trends suggest electrostatic screening and site competition dominate, with higher charge density enabling Sr2+ to outcompete Li+ consistently here. Overall, the results show that adsorbent performance can change markedly in realistic ionic mixtures and underline the importance of multicomponent testing. The mechanistic and modeling insights offer a transferable framework for selective lithium recovery and divalent-ion management in complex aqueous systems.
Deoxysphingolipids (dSLs) are atypical sphingolipids that accumulate in several pathological settings, yet their impact on hematologic malignancies is poorly understood. Here, we investigate the pathways and mechanisms of deoxysphinganine (dSA) cytotoxicity in lymphoma cells and its potential as a therapeutic agent. dSA exhibited markedly greater cytotoxicity than canonical sphingoid bases in lymphoma cell lines, yet induced only cytostatic effects in normal human T cells, indicating a therapeutically exploitable window. Inhibition of ceramide synthase blocked the generation of deoxy(dihydro)ceramides, prevented mitochondrial depolarization, caspase activation, ER stress, and DNA damage, establishing CerS-dependent deoxysphingolipids as essential mediators of dSA-induced death. Mechanistically, dSA engaged a mitochondrial apoptotic pathway, with DNA damage occurring downstream of mitochondrial permeabilization and caspase activation, while PERK-driven ER stress occurred in parallel and was dispensable for cytotoxicity. Subtype-specific engagement of ER stress and DNA damage further suggests that dSL signaling is shaped by lineage context. The differential sensitivity between malignant lymphoid cells and normal T cells, together with the central role of CerS-derived deoxy(dihydro)ceramides, highlights deoxysphingolipid metabolism as a druggable vulnerability in lymphoma. These findings support further exploration of dSA-based strategies and targeted modulation of dSL synthesis as a novel therapeutic avenue for non-solid hematologic malignancies.
ABSTRACT As the mining industry shifts towards circular economy principles, a divergence emerges between coal mine and noncoal mine wastewater treatment. This study investigates this divergence from the perspectives of pollutants, treatment technologies and research characteristics, aiming to provide an analytical framework for transformation. This study compares pollutant differences in mine water and mineral processing wastewater between coal mine and four representative noncoal mines, develops process flowsheets based on engineering cases, while using a quantitative evaluation model to compare treatment technologies.Results reveal a contrasting logic: ‘platform-based’ standardization versus ‘vertical-specific’ customization. Coal mine water exhibits high compositional consistency, enabling standardized treatment trains. In contrast, noncoal mine water displays mineral-specific heterogeneity, requiring customized solutions. For mineral processing wastewater, coal mine washing wastewater is typically treated by coagulation and sedimentation, whereas noncoal mine processing effluents require advanced oxidation, ion exchange, and adsorption. A bibliometric analysis shows a shift since 2018 from resource recovery towards pretreatment and deep purification. The transformation from coal mine to noncoal mine wastewater treatment requires enterprises to reconfigure strategic cognition, technology research & development, and business models around mineral-specific customization. Policy support should prioritize differentiated standards, technology research & development funding, and the improvement of technical adaptability evaluation systems.
Whether the fecal metabolome differs according to intensive low-density lipoprotein cholesterol (LDL-C) target achievement among statin-treated patients is unclear. In this cross-sectional study, 124 statin-treated adults with chronic disease were stratified by fasting LDL-C into a target-achieved group (< 70 mg/dL, n = 52) and a target-not-achieved group (≥ 70 mg/dL, n = 72). Stool samples were profiled by untargeted ultra-high-performance liquid chromatography-tandem mass spectrometry, and multivariable models adjusted for age, sex, chronic kidney disease, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use were used to identify metabolites independently associated with target achievement. Statin dose, treatment duration and glucose-lowering therapy were also compared between the groups. Paired 16S rRNA gene sequencing data available for a subset (n = 86) were used for integrative correlation and network analyses. Partial least-squares discriminant analysis showed separation between the two groups. Eight annotated metabolites-glutamine, glutamate, phenylalanine, N-acetyl-L-phenylalanine, L-methionine, N-acetyl-L-methionine, lysine, and N-methyl-D-aspartic acid, predominantly amino acids and their derivatives-were present at lower fecal levels in participants who achieved the LDL-C target. Metabolite set enrichment analysis implicated amino acid and nitrogen metabolism, and multiomics network analysis identified an Anaerotruncus-centered amino acid module with high degree centrality. In conclusion, LDL-C target achievement under statin therapy was associated with a coherent "low fecal amino acid" signature and an Anaerotruncus-linked microbe-metabolite hub. These findings suggest that intestinal nutrient handling and gut microbial amino acid metabolism may contribute to variability in LDL-C response, and they warrant prospective mechanistic evaluation.
Metabolic dysfunction-associated liver disease (MASLD) arises from the accumulation of triglycerides within the liver. MASLD can advance to metabolic dysfunction-associated steatohepatitis (MASH), cirrhosis, and hepatocellular carcinoma. Monoacylglycerol acyltransferase 2 (MOGAT2) is essential for triglyceride synthesis and plays a significant role in regulating lipid metabolism. Here, we demonstrate the ability of a new human MOGAT 2 inhibitor, VB-85387, to inhibit the development of MASLD/MASH and further define its effects on the key metabolic pathways that progress MASH development. MASLD/MASH was induced using a methionine, choline-deficient diet (LMCD) or by streptozotocin treatment combined with high fat diet feeding (STAM-HFD). VB-85387 significantly mitigated the severity of MASLD and reduced signs of MASH in mice subjected to these two distinct diets. VB-85387-treated mice exhibited decreased fibrosis, evidenced by reduced hepatic triglyceride concentrations, hydroxyproline levels, and collagen deposition. NAS scores were consistently lower in VB-85387-treated mice across both models. VB-85387-treated mice showed induced PPARα signaling and reduced SREBP transcription, demonstrating a likely role for VB-85387 in regulating lipogenesis and fatty acid β-oxidation. STAM-HFD treated mice showed lower NF-κBp65 activation, which was associated with lower TNFα expression. IL-1β and IFNβ levels were also both reduced, suggesting VB-85387 can reduce pro-inflammatory pattern recognition receptor signaling. In addition, treatment suppressed IL-4/IL-6-dependent JAK activation. Overall, VB-85387 inhibited MASLD development by reducing liver triglyceride levels, fibrosis, and meta-inflammatory signaling. VB-85387 was as effective or superior to the MOGAT2 inhibitor phase I clinical trial drug BMS-963272 in reducing MASLD and fibrosis. VB-85387 has considerable potential for developing therapeutics targeting MASLD/MASH.
Glioma represents one of the most aggressive tumors in the central nervous system, with clinical management facing significant challenges including high recurrence rates and therapeutic resistance. Ferroptosis, an iron-dependent form of cell death, holds potential for glioma treatment, yet tumor cells frequently develop evasion mechanisms. This study elucidates the molecular mechanisms by which hypoxic microenvironment confers ferroptosis resistance in glioma cells, focusing on the pivotal role of the HIF-1α/SREBP1 signaling axis and its downstream effectors FASN and SCD1. Our experimental results demonstrate that hypoxic conditions significantly upregulate HIF-1α expression and confer resistance to RSL3-induced ferroptosis. Mechanistic studies reveal that HIF-1α promotes SREBP1 activation, which subsequently upregulates FASN and SCD1 expression to suppress lipid peroxidation.Furthermore, the HIF-1α-specific inhibitor PX-478 effectively reverses hypoxia-induced ferroptosis resistance and significantly enhances tumor cell sensitivity to ferroptosis inducers. In vivo experiments confirm the potent antitumor effects of PX-478 combined with RSL3. This study systematically elucidates the role of the HIF-1α-SREBP1-FASN/SCD1 signaling axis in ferroptosis regulation in glioma, providing important theoretical foundations and experimental support for developing HIF-1α-targeted ferroptosis therapies.
BACKGROUND:Lipoprotein(a) [Lp(a)] reflects inherited atherothrombotic risk, whereas the C-reactive protein-triglyceride-glucose index (CTI) integrates systemic inflammation, triglyceride-related lipid disturbance, and glucose-related metabolic stress. Their individual and joint association with angiographic coronary lesion burden in acute coronary syndrome (ACS) remain incompletely defined. We examined whether CTI complements Lp(a) in characterizing coronary lesion burden in ACS. MATERIALS AND METHODS:This retrospective, single-center study included 2,836 consecutive patients with ACS who underwent coronary angiography. Coronary lesion burden was assessed using continuous Gensini score, a high Gensini score, and multivessel disease (MVD). Multivariable regression, restricted cubic spline analyses, CTI-stratified analyses, incremental receiver operating characteristic analyses, and internally validated machine-learning analyses with SHAP interpretation were performed. RESULTS:Higher Lp(a) and CTI level were both associated with greater coronary lesion burden. Compared with Lp(a) <75 nmol/L, Lp(a) ≥175 nmol/L was associated with high Gensini score (OR, 1.51 [95% CI, 1.17-1.96]) and MVD (OR, 1.69 [95% CI, 1.27-2.26]). Each 1-SD increase in CTI was associated with high Gensini score (OR, 1.47 [95% CI, 1.35-1.60]) and MVD (OR, 1.18 [95% CI, 1.08-1.28]). Among inflammatory-lipid indices, CTI showed the most consistent associations and provided the largest numerical incremental discrimination beyond Lp(a). The associaton between ver high Lp(a) and coronary lesion burden was more pronounced at higher CTI levels, particular for MVD. Machine-learning analyses further supported the relevance of both CTI and Lp(a). CONCLUSIONS:In patients with ACS, higher Lp(a) and CTI level were associated with greater angiographic coronary lesion burden. CTI may complement Lp(a) by capturing inflammatory-metabolic status, supporting their joint assessment for more refined characterization of lesion-burden risk in ACS.
Lipoprotein metabolism is significantly different between mice and humans thus making it difficult to model disorders of human lipid metabolism in transgenic mice. Systemic lipoprotein metabolism is predominantly governed by hepatocytes, and mice with humanized livers display human-like lipid profiles. Here we report a highly efficient method to knock out genes in human hepatocytes while retaining their ability to repopulate immune deficient rodents. As proof-of-principle Fah deficient, immune compromised mice were repopulated with Apolipoprotein B (APOB) knockout human hepatocytes. Mice humanized with knockout cells recapitulated typical features of human hypobetalipoproteinemia. We conclude that at least some human lipid metabolism disorders can be modeled in liver chimeric mice using human knockout hepatocytes.
Storage and discharge are two fundamental solutions to strengthening pluvial flood resilience. Recent studies reveal that many urban catchments operate under a persistent storage-discharge imbalance, driven by urban densification. This 'imbalance' raises concerns in hydrologic, economic, spatial, and social aspects. This research aims to quantify the balanced relationship between storage capacity and discharge capacity (storage discharge balance, SDB) for pluvial flood protection and provide planning strategies for different urban topographies. We suggest and apply a quantification method using different modelling tools, hydrological and hydrodynamic models, in two cases with distinct physical and socioeconomic characteristics: one in a flat polder area in Nanjing, China, and the other in a sloping hilly area in Feldbach, Austria. By comparing these cases, insights are gained into the modelling methods, results, and proposed strategies for each context. The use of the SDB chart mapping framework supports the identification of both short- and long-term targets, as well as dynamic pathways toward enhanced flood resilience. These insights will facilitate multidisciplinary dialogue on key constraining factors, thereby enabling the co-creation of an actionable solution. While the quantitative findings are context-dependent, the novel approach can be applied to other cities to facilitate their resilience planning.
Permeable pavement systems are a key low-impact development strategy for mitigating rainfall runoff in urban environments. However, their long-term effectiveness is often compromised by clogging from particulate matter, which progressively reduces permeability. This study evaluates long-term permeability of PPs installed at 13 sidewalk locations in Seoul, South Korea, over 38 months (May 2018-June 2021) using in-situ tests (KS F 2394). Results show that by the end of monitoring, eight sites had declined to Grade 5 (lowest classification), while five sites maintained Grade 3. According to Seoul guidelines, the minimum recommended permeability is Grade 3. These findings indicate that more than half of the sites fell below the recommended standard within 3 to 5 years of installation, highlighting the critical need for regular maintenance. The study aligns with recent research demonstrating that pressure washing can effectively restore permeability in clogged pavements. Based on these results, a guideline revision is proposed: adding a new top category (Grade 0) for superior permeability (≥1.5 mm/sec) and raising the minimum recommended permeability to Grade 2 to ensure longer-term performance before maintenance is required. Future research should develop more efficient cleaning techniques to sustain the hydrological function of existing permeable pavement installations in urban areas.
For decades, activated sludge has been utilized to remove organic components from wastewater. In this process, required oxygenation is typically energy-intensive. Hydrogen peroxide (H2O2) poses an energy-saving alternative to generate catalase-driven oxygen (O2). However, assessing its viability in activated sludge has been limited to stoichiometric respiration demands. In this study, specific H2O2 concentrations were tested on artificial wastewater to obtain predictable kinetic rates for peroxide addition, O2 production, and substrate removal by a native sludge community. Batch injections of 25-50 mg H2O2/L result in fast conversion to O2 whose response could be modeled through Michaelis-Menten kinetics. Calculated production rates are at least tenfold higher than oxygen uptake rates, with the latter comparable to typical AS systems. Based on consumption rates, continuous feeding (28 mg H2O2/g MLSS-h) achieved complete substrate conversion at 1.1 g COD/L-d. Higher feeding rates eventually resulted in minimal O2 uptake and incomplete substrate removal, which recovered after stopping H2O2 feeding. Comparatively, nitrification was not inhibited by increased peroxide feeding. Our results provide consistent O2 generation and direct responses to leverage direct H2O2 utilization in existing WWTPs, where the experimental framework determines relevant feeding rates to be met by in situ H2O2-producing technologies during activated sludge treatment.
Textile industries generate large volumes of wastewater, containing high concentrations of organic pollutants, dissolved solids, and suspended particles, requiring eco-friendly and cost-effective treatment technologies. This study developed a gravity-driven bio-based batch filtration system using sugarcane bagasse fiber and coconut fiber to investigate textile wastewater treatment performance and economic feasibility. Five bagasse-to-coconut fiber ratios (100:0, 0:100, 50:50, 75:25, and 25:75) were evaluated in a multilayer filtration system. Scanning electron microscope and Fourier transform infrared analyses were performed to characterize the fiber morphology and adsorption-active functional groups before and after filtration. Among all filter configurations, the 50:50 fiber ratio demonstrated the best overall performance, achieving removal efficiencies of 79.33% for biological oxygen demand, 75.75% for chemical oxygen demand, 80.00% for total dissolved solids (TDS), 46.51% for turbidity, 77.45% for electrical conductivity (EC), and 4.82% for pH after a single filtration cycle, while maintaining pH within the Bangladesh Department of Environment permissible range. Sequential treatment cycles further enhanced treatment efficiency, achieving an overall removal of 89.17% for TDS, 81.52% for turbidity, and 88.63% for EC after five filtration cycles. Economic evaluation demonstrated a unit treatment cost of approximately 90.71 BDT/m3, significantly lower than activated carbon-based systems. These findings suggest that the proposed bio-based filtration system provides an economical, energy-free, and sustainable alternative for resource-limited regions such as Bangladesh.
ABSTRACT Graphical abstract showing the journey of microplastics from their sources and environmental distribution to ecological impacts, plastisphere formation, microbial degradation using plastic-degrading enzymes, biotechnological enhancement, and sustainable environmental remediation. Microplastic (MP) pollution has gained increasing attention as a critical environmental concern owing to the persistent accumulation of plastic debris and its ubiquitous presence in ecological systems. The small size, high penetration potential, and potential toxicity of MPs pose high risks to ecological integrity and biological systems, including humans. The majority of scientific research has been focused on the distribution, utilization, fate, behaviour, and influence of MPs, whereas remediation studies remain underexplored. Therefore, this review provides an extensive critical synthesis of current knowledge on MP pollution and recent advances in microbes-mediated MP mitigation approaches. The primary focus is on the role of bacteria, fungi, microalgae, and their enzymes in MP degradation through plastisphere/biofilm formation, depolymerization, and metabolic assimilation pathways. Microbial degradation potential has been assessed for major polymer types, including polyethylene, polypropylene5, polystyrene, polyethylene terephthalate, polyvinyl chloride, and polyurethane. The MPs biodegradation section includes studies from 2021-2026, supplemented with previously curated literature addressing MP sources, fate, transport, and ecological impacts. The existing bottlenecks, including low degradation efficiencies, partial mineralization, and the lack of standardized protocols, are discussed. Through integration of ecological impacts, biodegradation mechanisms, and future technological developments, this review pinpoints critical knowledge gaps and proposes scalable and greener solutions formanaging MP pollution and advancing the circular plastic economy.
ABSTRACT Overview of technological developments in sewage sludge thickening, conditioning , and dewatering in Japan, including future directions for energy recovery and fertilizer utilization. This paper reviews the historical evolution and technological development of sewage sludge thickening, conditioning, and dewatering in Japan. Due to limited land availability and specific climatic conditions, sludge treatment in Japan has historically prioritized incineration; consequently, thickening, conditioning, and dewatering have been developed as essential pretreatment processes. The evolution of gravity and mechanical thickening methods, advances in conditioning using inorganic and polymer flocculants, and the diversification of dewatering machinery are examined with reference to representative case examples. Recent innovations emphasize integrating system optimization, reductions in energy consumption and labor requirements, and improvements in sludge dewaterability. Several full-scale case studies at wastewater treatment plants demonstrate measurable reductions in sludge water content. For instance, approaches such as low-temperature thermal treatment have been investigated to enhance dewaterability and overall process efficiency, with particular attention paid to the underlying mechanisms and operational feasibility. These technological and operational perspectives offer valuable insights for regions facing similar urban and environmental constraints. Furthermore, because sewage sludge utilization as fertilizer is given the highest priority and promoted in Japan, integrating emerging technologies beyond conventional processes is essential. Ultimately, these practices provide useful perspectives for the future development of sustainable sludge management on a global scale.
ABSTRACT Inorganic metal coagulants have been shown to be a viable option for treating nanoplastics (NPs) in water. However, the current research on inorganic metal coagulants has primarily focused on aluminum, iron, and titanium salts, with relatively insufficient studies on zirconium salts. This study represented the first systematic investigation of polystyrene (PS) NPs removal using zirconium chloride (ZrCl4) as a coagulant. Coagulation experiments revealed that the dosage of ZrCl4 significantly influenced the removal efficiency of PS NPs in water. When the ZrCl4 concentration reached 400 mg/L, the coagulation system achieved a maximum removal efficiency of 98.9% for 25 mg/L of NPs. Results from analytical techniques, including zeta potential measurements, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, indicated that at lower ZrCl4 dosages (200 mg/L), charge neutralization and adsorption bridging were the primary coagulation mechanisms for PS NPs. Increasing the coagulant dosage significantly enhanced the sweeping flocculation effect on NPs, thereby substantially improving the removal efficiency. Experiments investigating the influence of coagulation revealed that the optimal dosage system utilizing 400 mg/L ZrCl4 exhibited significant environmental adaptability. Additionally, the presence of Ca2+ improved the coagulation efficiency of low-dose ZrCl4 for PS NPs by strengthening charge neutralization and facilitating sweeping flocculation.
