Search Results (46)

Nanomaterials (NMs) have shown broad application potential in wastewater deep treatment, but the actual application is constrained by some issues such as nanoparticle (NP) aggregation and poor recyclability. Different from previous comprehensive reviews, this article systematically synthesizes data from over 100 peer-reviewed studies (2012 to 2026) to review the preparation methods, purification mechanisms, and removal efficiencies for various pollutants, and the technical and economic feasibility of NMs, with an emphasis on carrier-assisted immobilization and NM–microbial aggregate interactions. To start with, the methods of preparation were roughly distinguished into two categories which were “top-down” and “bottom-up” methods. The advantages, disadvantages, and utilities of the physical, chemical, and eco-friendly methods of biosynthesis were investigated while paying particular attention to the function of the loading technique in preventing NP aggregation and improving recyclability. By using the technique of loading in the carrier, the growth of NPs could be restricted up to 2–50 nm. Secondly, seven basic mechanisms that underlie the process of removing pollutants by using NPs were explained: adsorption, catalytic degradation, ion exchange, surface complexation, antibacterial action, redox transformation, and waste recycling. Particular focus was placed on understanding the interactions between NMs, microbial aggregates, and extracellular polymeric substances in wastewater treatment systems. Extracellular polymeric substances (EPS) could capture >90% NMs and mitigate their toxicity. Once again, the removal efficiency and main influencing factors associated with different types of NMs, for the treatment of heavy metals, dyes, antibiotics, and pathogenic microorganisms were summarized. Removal efficiencies of the pollutants ranged from 70% to over 99%, but these values were strongly influenced by pH and matrix and often decreased substantially in real wastewater. The existing literature was used to classify the experimental substrates (single-solute systems, multi-solute synthetic systems, municipal wastewater, industrial wastewater, secondary effluent). The performance of NMs in different categories was compared, revealing the huge performance gap between ideal laboratory conditions and practical applications. Lastly, the economic viability of the methods based on the use of NMs for purifying water was assessed taking into consideration various factors such as raw materials’ prices, energy costs of the process of making materials, recyclability of the materials, and the possibility of introducing the use of NMs on a larger scale. Unlike existing reviews, this article aims to provide a quantitative mechanistic framework bridging the rational design, safe application, and engineering promotion of NMs in deep wastewater treatment. Full article

Global wastewater generated in unprecedented volumes places a significant strain on aquatic environments, challenging the municipal sector to transition from energy-heavy pollutant removal technologies towards alternative resource recovery strategies with a low carbon footprint. The aim of this work is to review microalgae-based phycoremediation as a sustainable, cost-effective alternative that extracts nutrients from municipal, agricultural, and industrial streams without generating secondary chemical pollution. By utilizing these nutrient-rich effluents, microalgal cultivation generates valuable biomass for downstream valorization into biofuels, biofertilizers, biostimulants, and high-value biopolymers, while eliminating or reducing the costs of synthetic cultivation mediums. However, integrated techno-economic analyses (TEA) and life cycle assessments (LCA) reveal critical socio-technical bottlenecks. Full article

The increasing contamination of municipal wastewater by a broad spectrum of pharmaceuticals necessitates effective quaternary treatment stages. This pilot study evaluates an innovative combined technology: physical electrostatic pretreatment (conducted using experimental equipment based on a patented design (EP 2388068)) followed by biodegradation in real secondary effluent samples (COD_(Cr) 22.0 mg·L⁻¹ to 32.0 mg·L⁻¹). A total of 17 selected micropollutants were subjected to an 8-h exposure in a high-intensity electrostatic field (20 kV) and a subsequent 20-day microbial degradation using a mixed culture of erythropolis, R. rhodochrous, and R. degradans. Results demonstrate high substance-specific efficiency. The most significant synergistic effect was observed for moderately biodegradable compounds, particularly venlafaxine (improvement up to ~44%), trimethoprim (25–36%), and tramadol (31–58%), representing a ~30–37% efficiency increase over standalone biodegradation. For readily biodegradable (e.g., metoprolol) or highly persistent substances, the impact was inconsistent. Physical pretreatment alone at 20 kV exhibited low to moderate efficiency (up to ~30%) without the biological stage. This combined approach represents a promising synergistic solution for wastewater treatment plant intensification. The primary mechanism involves enhancement of target compound bioavailability induced by the electrostatic field, which subsequently accelerates microbial metabolism. Full article

Background/Objectives: Water scarcity is driving the development of strategies for treating municipal wastewater (MW) to enable its safe reuse. Nonetheless, MW contains contaminants of emerging concern (CECs), such as pharmaceuticals and antimicrobial-resistant (AMR) bacteria, which require innovative treatment technologies. In this context, Corbicula fluminea, an invasive freshwater clam, presents a high biofiltration capacity, and its environmental impact could be mitigated by assigning it a beneficial role in wastewater treatment. Methods: The ability of C. fluminea to remove chemical and biological CECs from real MW secondary-treated effluents was assessed. The effects of real wastewater on the clams’ microbiome and on colony-forming unit (CFU) counts in their soft tissues were also assessed. Results: Under real conditions, the clams achieved over 73% removal for 3 chemical CECs after 24 h, with an average removal of approximately 39%. The clams showed recovery of both CFU counts and microbial community composition, dominated by opportunistic and stress-tolerant groups in the presence of pharmaceuticals. The removal of multidrug-resistant bacteria was evaluated; despite real wastewater reducing clearance rates, the clams significantly reduced these bacteria within 24 h. Conclusions: These results demonstrate that C. fluminea can serve as an effective polishing treatment, improving effluent quality, supporting control of this invasive species. Full article

Wastewater treatment plants (WWTPs) have been identified as the major sources of contaminants of emerging concern (CECs) in water bodies, as they are not designed to remove organic micropollutants efficiently. Consequently, many technologies have been explored for WWTP upgrading, including activated carbon adsorption. However, the high production cost and environmental challenges associated with activated carbon production limit its application in industrial settings. Therefore, a wide range of alternative materials has been investigated as potential replacements. In this study, biochar produced from waste raspberry biomass was evaluated as an adsorbent for the removal of pharmaceuticals and pesticides quantified in the secondary effluent of municipal WWTP. The results showed that the biochar efficiently removed almost all detected compounds, except for three compounds (clarithromycin, propranolol, and linuron). The wastewater pH (6–8) did not significantly affect removal efficiency significantly, and kinetic tests demonstrated rapid adsorption. The potential for biochar reuse was confirmed through three consecutive batch adsorption cycles. A comparative study between biochar and powdered activated carbon (PAC) revealed some differences in efficiency, primarily attributed to the larger surface area of PAC. π-π interactions, hydrogen bonding, and pore-filling were proposed as possible adsorption mechanisms based on the adsorption efficiency and biochar characterization. Full article

The non-oxidizing antimicrobial 2-Methyl-4-Isothiazolin-3-one (MIT) poses a significant environmental risk given its frequent detection in municipal wastewater. This study showed that the combination of Vacuum UV/UV (VUV/UV) and persulfate (PDS) efficiently achieved the rapid transformation and removal of 10 μM MIT within 90 s, which is much faster than UV, UV/PDS, and VUV/UV. Increasing the PDS dosage improved MIT degradation, whereas changes in pH between 4 and 10 had little effect. Radical quenching experiments showed that 93% of the MIT oxidation was attributable to the hydroxyl radical (•OH) and the sulfate radical (SO₄•⁻). SO₄•⁻ and •OH at concentrations of 8.6 × 10⁻¹² M and 1.5 × 10⁻¹² M accounted for 32% and 61% of the MIT degradation, respectively, and the greater contribution of •OH was attributed to its higher reaction rate constant with MIT compared to SO₄•⁻. Sulfate had a negligible impact on the radical concentrations. Chloride (1 mM) reduced the SO₄•⁻ and •OH concentrations by 61% and 27%, respectively. And the SO₄•⁻ contribution to MIT degradation fell to 19%. Nitrate (5 mM) readily quenched •OH but minimally affected SO₄•⁻. The •OH concentration decreased by 79%, reducing its contribution to 27%. Bicarbonate/carbonate (5 mM) simultaneously reduced the SO₄•⁻ and •OH by 26–30% and had little effect on their contributions. Because of the quenching effect of organic matter and inorganic anions on radicals, secondary effluent inhibited the degradation of MIT. After a 120 s treatment, the total organic carbon, UV₂₅₄, and fluorescence regional integration were reduced by 5%, 8%, and 17–24%, respectively. This study provides a quantitative analysis of how inorganic ions alter the concentrations and contributions of •OH and SO₄•⁻, elucidating the MIT removal mechanisms in VUV/UV/PDS for sustainable wastewater reclamation. Full article

Wastewater treatment plants (WWTPs) play a key role in the protection of the environment and public health by reducing the levels of pollutants released into the water. Here, we evaluate the quality of water obtained from two key points of the treatment process of a municipal WWTP (León, Spain) using zebrafish (Danio rerio) embryos and larvae as sentinels. Three experimental groups were established: (1) “Control” (CTRL) maintained in embryo medium, (2) “Influent” (I) exposed to influent water before the secondary (biological) treatment (concentrations: I-100% and I-75%), and (3) “Effluent” (E) exposed to effluent water from the secondary treatment (concentrations: E-100% and E-75%). Our results confirmed that survival was subtly affected in I-100% and E-100%, as well as the hatching rate in the effluent. Larvae exposed to both experimental conditions also presented a higher rate of malformations, affecting biometry and showing reduced embryo motility, with the exception of E-75%. The I-100% condition also caused reduced heartbeat, reduced fin regeneration, and a higher number of delocalized primordial germ cells. I-100%-exposed larvae showed dysregulation of four genes (foxm1l, cenpf3b, hoxc6a, and ddit3) out of the 19 studied. Effluent dilution mitigated the observed effects, and the model proved to be an effective additional test for wastewater treatment plants. Full article

The implementation of wastewater management strategies and wastewater treatment techniques, such as reverse osmosis (RO), has been increasing to promote environmental sustainability and reduce freshwater consumption. Municipal secondary effluent is a promising source for reuse and reducing the strain on freshwater consumption. Still, its diverse foulant composition promotes the fouling of polyamide RO membranes, leading to performance decline. In this study, 3-allyl-5,5-dimethylhydantoin (ADMH) was grafted onto thin-film composite RO membranes at varying concentrations via graft polymerization. The membranes were tested against foulant solutions of E. coli and S. aureus, as well as organic and inorganic foulant solutions mimicking the fouling activity of municipal wastewater secondary effluent. Biofouling tests showed improved mortality ratios—58.9% against E. coli and 37.4% against S. aureus—along with fouling deposition rates of 3.7–8.9% and flux recovery ratios of 69.2–96.9%. Although surface hydrophilicity increased with ADMH concentration, fouling resistance was optimal at a moderate concentration. Resistance to organic and inorganic foulants did not show similar improvement, highlighting the importance of the foulant type in determining overall membrane performance. Full article

Excess phosphorus (P) and nitrogen (N) in wastewater contribute to eutrophication, driving the need for low–cost and sustainable recovery technologies. This study presents a novel adsorbent synthesized from spent coffee grounds biochar (CB) chemically modified with Mn²⁺/Zn²⁺/Fe³⁺ (oxy)hydroxide nanoparticles (CB–M) for simultaneous removal of phosphate and ammonium. Batch adsorption experiments using both synthetic solution and municipal wastewater were conducted to evaluate the material’s adsorption performance and practical applicability. Kinetic, isotherm, thermodynamic, and sequential extraction analyses revealed that CB–M achieved maximum phosphate adsorption capacities ranging from 42.6 to 72.0 mg PO₄³⁻·g⁻¹ across temperatures of 20–33 °C, reducing effluent phosphate concentrations to below 0.01 mg·L⁻¹. Ammonium removal was moderate, with capacities ranging between 2.8 and 2.95 mg NH₄⁺·g⁻¹. Thermodynamic analysis indicated that phosphate adsorption was spontaneous and endothermic, dominated by inner–sphere complexation, while ammonium uptake occurred primarily through weaker, reversible ion exchange mechanisms. Sequential extraction showed over 70% of adsorbed phosphate was associated with Fe-Mn-Zn phases, indicating the potential for use as a slow–release fertilizer. The CB–M retained structural integrity and exhibited partial desorption, supporting its reusability for nutrient recovery. Compared to other biochars, CB–M demonstrated superior phosphate selectivity at a neutral–pH, avoided the use of hazardous metals, and transformed coffee waste into a multifunctional material for wastewater treatment and soil amendment. These findings underscore the potential of CB–M as a circular economy solution for nutrient recovery without introducing secondary contamination. Full article

An aqueous mixture of three compounds (atrazine, carbamazepine, and p-chlorobenzoic acid) has been treated by photochemical processes including photolysis and photocatalysis with 10.7% TiO₂ supported on ceramic foams of mullite. Experiments were conducted in both ultrapure water and in a secondary effluent from a municipal wastewater treatment plant. Radiation at 365 nm was totally inefficient in the photolytic process carried out in ultrapure water; however, some sensitization phenomena were observed when municipal wastewater was used as a bulk matrix. In the latter case, conversion values in the range of 20–30% were obtained after 2 h. The photocatalytic process was much more effective experiencing conversions above 80% after just 80 min of reaction. The nature of the matrix used exerted a significant influence. Use of municipal wastewater slowed down the process due to the scavenging character of the natural organic matter content. Test runs in the presence of carbonates and t-butyl alcohol suggested that radical carbonates play some role in contaminant abatement, and secondary radicals generated after the t-BuOH attack by HO^● radicals should also be considered in the reaction mechanism. A pseudo-empirical mechanism of reactions sustains the experimental result obtained, acceptably modeling the effects of a water matrix, scavenger addition, and radiation volumetric photon flux. Full article

Effective wastewater management is critical for mitigating environmental and health impacts in ecologically sensitive regions like the Peruvian Amazon, where rapid urbanization has led to increased discharge of nutrient-rich effluents into freshwater systems. Conventional treatment methods often fail to address nutrient imbalances while generating secondary pollutants. This study aims to evaluate the bioremediation potential of a non-axenic cyanobacterium, Synechococcus sp., isolated from the Amazon Basin, for municipal wastewater treatment within a circular bioeconomy framework. The strain was cultivated in different concentrations of municipal wastewater (25%, 50%, 75%, 100%) from Moronacocha Lake in the Peruvian Amazon to assess growth kinetics, ammonium removal efficiency, and biochemical composition. The cyanobacterium exhibited optimal performance in 25% wastewater, achieving the highest specific growth rate (22.8 × 10⁻² μ·day⁻¹) and biomass increase (393.2%), exceeding even the standard BG-11 medium. This treatment also demonstrated exceptional ammonium removal efficiency (95.4%) and enhanced phycocyanin production (33.6 μg/mg, 56% higher than the control). As wastewater concentration increased, both growth parameters and removal efficiency progressively declined. Biochemical analysis revealed that higher wastewater concentrations resulted in decreased protein content and increased lipid accumulation in the biomass. These findings demonstrate the dual potential of Synechococcus sp. for effective wastewater remediation and production of valuable biomass with modifiable biochemical characteristics, offering a sustainable approach for wastewater management in the Peruvian Amazon region. Full article

The periodate/hydrogen peroxide (PI/H₂O₂) system is a recently developed advanced oxidation process (AOP) characterized by its rapid reaction kinetics, making it highly suitable for continuous-flow applications compared to conventional batch systems. Despite its potential, no prior studies have investigated its performance under flowing conditions. This work presents the first application of the PI/H₂O₂ process in a tubular microreactor, a promising technology for enhancing mass transfer and process efficiency. The degradation of textile dyes (specifically Basic Yellow 28 (BY28)) was systematically evaluated under various operating conditions, including reactant concentrations, flow rates, reactor length, and temperature. The results demonstrated that higher H₂O₂ flow rates, increased PI dosages, and moderate dye concentrations (25 µM) significantly improved degradation efficiency, achieving complete mineralization at 2 mM PI and H₂O₂ flow rates of 80–120 µL/s. Conversely, elevated temperatures negatively impacted the process performance. The influence of organic and inorganic constituents was also examined, revealing that surfactants (SDS, Triton X-100, Tween 20, and Tween 80) and organic compounds (sucrose and glucose) acted as strong hydroxyl radical scavengers, substantially inhibiting dye oxidation—particularly at higher concentrations, where nearly complete suppression was observed. Furthermore, the impact of water quality was assessed using different real matrices, including tap water, seawater, river water, and secondary effluents from a municipal wastewater treatment plant (SEWWTP). While tap water exhibited minimal inhibition, river water and SEWWTP significantly reduced process efficiency due to their high organic content competing with reactive oxygen species (ROS). Despite its high salt content, seawater remained a viable medium for dye degradation, suggesting that further optimization could enhance process performance in saline environments. Overall, this study highlights the feasibility of the PI/H₂O₂ process in continuous-flow microreactors and underscores the importance of considering competing organic and inorganic constituents in real wastewater applications. The findings provide valuable insights for optimizing AOPs in industrial and municipal wastewater treatment systems. Full article

Furazolidone, a nitrofuran antibiotic, has been broadly used in aquaculture and veterinary medicine, and its presence in water poses considerable environmental and health hazards due to its toxicity. This study investigated a hybrid photocatalytic process for the removal of furazolidone, employing graphitic carbon nitride (g-C₃N₄) and persulfate anions (PS) under both laboratory and pilot-scale conditions. The synergistic effect of g-C₃N₄ and PS enhanced the generation of reactive species, facilitating the efficient degradation of FZ in two different aqueous matrices. Through scavenging studies, positive holes were determined to be the dominant reactive species, followed by sulfate radicals. Seven transformation products of FZ were tentatively identified via UHPLC-LTQ/Orbitrap MS analysis. The optimized photocatalytic system (g-C₃N₄/PS) achieved a 100% removal of furazolidone in less than 60 min under simulated solar light, demonstrating its potential for large-scale application in wastewater remediation. Furthermore, pilot-scale experiments using real secondary treated municipal wastewater proved that the applied process is capable of achieving an 86.2% removal of furazolidone (k = 0.017 min⁻¹) as well as a 90% decrease in effluent ecotoxicity within 120 min of UV_A irradiation. This study provides insights into sustainable processes for the removal of antibiotic contaminants from wastewater and underscores the role of g-C₃N₄-based photocatalytic approaches in upper-scale applications. Full article

Investigating human pathogens in wastewater is crucial for identifying and predicting potential occupational health risks faced by wastewater treatment plant (WWTP) workers. This study aimed to determine the occurrence and levels of Legionella pneumophila, Mycobacterium spp., Arcobacter butzleri, and Aeromonas hydrophila in untreated municipal wastewater. Grab influent, activated sludge, and secondary settling tank (SST) effluent samples were collected bi-weekly over 6 months from 5 WWTPs in Tshwane, South Africa. Mycobacterium spp., A. butzleri, and A. hydrophila were detected using quantitative PCR (qPCR), while Legionella was detected using both a culture method and qPCR. The four pathogens were identified in most samples at varying levels. Legionella pneumophila had a positivity rate of 92%, ranging from 2 to 5.4 log₁₀ MPN/100 mL. Detection rates of Legionella spp., L. pneumophila, and L. pneumophila serogroup 1 were 97%, 75%, and 69%, respectively, with up to 5.3 log₁₀ gene copies (GC)/mL. Importantly, this study demonstrates molecular typing of L. pneumophila serogroup 1 in wastewater, a topic that has been rarely documented. Mycobacterium spp. were detected in all samples at varying levels (log₁₀ GC/mL) in influent (2.8–7.6), activated sludge (4.8–8.9), and SST effluent (3.8–8.9) samples. Arcobacter butzleri and A. hydrophila were detected in 96% and 82% of the samples, respectively, with GC levels in influent, activated sludge, and SST effluent ranging from 0.8 to 6.6, 1.5 to 6.5, and 0.7 to 6.6 log₁₀ GC/mL for A. butzleri, and similar levels for A. hydrophila. These findings underscore the presence of respiratory and enteric pathogens at various treatment points, suggesting potential occupational exposure for WWTP workers. This emphasises the need for microbiological risk assessments (RAs) or reviewing existing RAs and implementing necessary control measures to protect WWTP workers. Full article

The increased presence of resistant microorganisms in water promotes the need for supplementary measures to mitigate the water source’s contamination. Traditional treatments are inefficient in wastewater management at removing some emerging contaminants. Corbicula fluminea, an invasive species, can be used in the treatment due to their resistance and biofiltration capacity, working as a pest management strategy. In this study, this bivalve was used to promote the virus disinfection from the municipal wastewater treatment plant (MWTP) that enters (influent) and after the secondary treatment (effluent leaving the plant). JC virus, norovirus (GI, GII), and hepatitis A (HAV) were identified. C. fluminea promoted norovirus GI and GII removal after 72 h and a slight decrease in the JC virus concentration. These results prove the potential of this pest management approach to be used in virus removal. Furthermore, infectivity assays using mengovirus confirmed the correlation between the presence of the genome detected by PCR and the infectious virus particles. This highlights the potential of PCR as a reliable indicator of the infectious virus’s presence. However, such an infectivity assay proved that even when PCR results are undetectable, a reduced number of viruses may remain viable and able to infect susceptible cells in culture. Full article