Water Treatment Research Articles

Can air nanobubbles improve the swim bladder inflation in developing European perch? A pilot study of advanced water treatment.

Swim bladder inflation (SBI) is a fundamental step in larval development for both physostome and physoclist fish species. Failure of the SBI triggers higher energy expenditures of the individual, which negatively affects swimming ability, growth rate, feeding efficiency, susceptibility to predation, and survival rate. In aquaculture, the SBI failure is caused by different factors including: (a) water contamination with oil increasing the surface water tension and preventing the larvae from gulping air bubbles for inflation, and (b) bacterial aerocystitis of the swim bladder caused by gulped organic debris. Hence, novel and effective water treatment technologies such as nanobubbles can be employed in aquaculture to reduce the risk of low SBI. In the present study, we compared conventional water treatment, i.e. surface spray combined with skimmers with air nanobubbles either alone or in combination, on the SBI of European perch larvae. In the control, no water treatment technology was employed. All treatments showed higher SBI efficiency compared to the control. The control group showed the lowest percentage of swim bladder-inflated individuals associated with low body weight (BW). The highest BW and SBI efficiency was recorded with the combination of surface skimmer, spray, and nanobubbles. The current study offers the first investigation of the nanobubbles' effect on SBI promotion in larvae of European perch and gives motivation for future optimizations.

Degradation of extracellular antibiotic resistance genes using peracetic acid (PAA) and performic acid (PFA)

Antibiotic resistant bacteria (ARB) associated infections are identified as a major threat to human health in the 21st century. Wastewater contains antibiotic resistance determinants and they are discharged to aquatic environments with treated or untreated effluents. These antibiotic resistance determinants can be taken up by environmental bacteria via horizontal gene transfer (HGT) and they can become antibiotic resistant. Among antibiotic resistance determinants, extracellular DNA containing antibiotic resistance genes can be up taken by environmental bacteria via natural transformation. Therefore, we evaluated the suitability of low-cost disinfectants peracetic acid (PAA) and performic acid (PFA) on inactivating total and functional extracellular ARGs in ultrapure water and secondary wastewater effluent matrices using pUC19 as a model ARG. Performance of PAA and PFA in inactivating extracellular ARGs was compared with the performance of free chlorine disinfection. RT-qPCR results showed that inactivation of ampR gene in pUC19 plasmid suspended in ultrapure water and wastewater secondary effluent by free chlorine was higher compared to PAA and PFA. However, the reduction of functional pUC19 by PAA and PFA were comparable to free chlorine. Transformation frequency of pUC19 treated by PAA and PFA achieved the maximum possible reduction within a shorter time compared to free chlorine treatment, highlighting the possibility of having disinfection chambers with smaller footprints in wastewater treatment plants. These results suggest the suitability of PAA and PFA for inactivation of ARGs in aquatic samples as alternative disinfectants to free chlorine.

Integrated respiratory toxicity of municipal wastewater to human bronchial epithelial cells and 3D bronchospheres

Respiratory symptoms have been reported in wastewater treatment workers and residents living close to sewage treatment plant. However, toxicological research about the respiratory hazards of municipal wastewater is scarce. The present study aims to gain insight into the comprehensive respiratory hazards induced by the contaminant mixtures in municipal wastewater. The integrated respiratory hazards of effluents from four secondary wastewater treatment plants (SWTPs), a tertiary wastewater treatment plant (TTP), and a constructed wetland (CW) were evaluated using normal human bronchial epithelial cells (NHBE) bioassay, and toxicity reduction efficiency of various treatment techniques was analyzed. Effluents caused cytotoxicity, oxidative damage, inflammation response with the increased levels of IL-6 and CXCL8, and impaired barrier integrity with decreased expressions of ZO-1 and occludin in NHBE. Further, the effluents inhibited the development of 3D bronchospheres, increased irregular surface and cell debris, and suppressed the formation of luminal structures. TTP E effluent significantly increased the expression of MUC5AC in bronchospheres. The integrated biomarker response (IBR) of the influent was removed by 40.2% at SWTPs, 18.2% at TTP, and 36.6% at CW, respectively. The IBR of the final effluents from SWTPs, TTP, and CW were 7.2, 7.7, and 7.7, respectively. Significant correlation with toxicity biomarkers was frequently observed for stearyl alcohol, o-cresol, phenanthrene, butylated hydroxytoluene, and dimethyl phthalate. The present study provided human relevant evidence concerning the adverse respiratory effects associated with discharge. The necessity for deep water treatment, performance optimization, and the potential means were suggested for improving water quality and protecting respiratory health.

Demonstration scale treatment of drainage canal water in the Nile Delta through a combination of facultative lagoons and hybrid constructed wetlands

Drainage canal water (DCW), a mixture of Nile water, drainage water and municipal wastewater, is largely used for irrigation in the Nile Delta. Facultative lagoons (FL) and constructed wetlands (CWs) represent interesting options for DCW treatment before its agricultural re-use, but very few studies investigated their implementation in Egypt. This work aimed at developing at demonstration scale (250 m3 d-1) a FL+CW treatment train capable to turn DCW into an effluent reusable in agriculture. Three types of hybrid CWs were tested in parallel for 530 days. The combination of FL with a cascade hybrid CW, operated at a 200 L d-1 m-2 surface loading rate, led to medium-to-high removal efficiencies (suspended solids 90%, total nitrogen 84%, phosphate 80%, COD 67%, faecal coliforms 2.2 Log) and surface removal rates (COD 47.5 t y-1 ha-1, total nitrogen 10.9 t y-1 ha-1, faecal coliforms 1.5 1011 MPN y-1 ha-1). The effluent, compliant with class C of EU 2020/741 regulation, is potentially reusable to irrigate numerous Egyptian crops. The results show that the combination of FLs with cascade hybrid CWs has a great potential for the treatment of DCW and low-strength municipal wastewater, with near-zero energy consumption, null consumption of chemicals and a land requirement varying between 1.1% and 1.5% of the agricultural land irrigated with the treated DCW.

Chemical characterization of activated carbon derived from Napier grass, rubber wood, bamboo, and hemp

This study examines the process and analysis of activated carbons that use H2SO4, H2O2, and NaOH as activating agents. The distinct chemical methods employed by each activator impacted the ash and carbon content, surface properties, and functional groups of the activated carbons, exhibiting notable disparities. The ash level varied from 6.86% to 37.08%. H2SO4-activated carbons had the lowest ash content, suggesting better elimination of inorganic contaminants. The iodine number, which serves as a measure of adsorption capacity, was consistent among all samples, with values ranging from 800 to 950 mg g-1. This indicates that the three activating agents effectively increased the surface area and porosity. The BET surface areas varied between 9.14 and 167.42 m2 g-1, whereas the BJH adsorption surface areas ranged from 9.68 to 28.89 m2 g-1. The pore volumes ranged from 0.0071 to 0.0595 cm2 g-1, while the sizes ranged from 0.51 to 8.2 nm. These measurements suggest the presence of both micropores and mesopores. The FTIR spectra exhibited comparable functional groups among all samples, such as OH, CH, C=C, and C-O. The SEM-EDX and XPS tests showed that there was a lot of carbon. The carbon content was highest in H2O2-activated carbons because they were exposed to less severe oxidative conditions. These activated carbons comply with the requirements set by IUPAC and ASTM. They are suitable for catalytic processes and liquid adsorption, such as water and wastewater treatment. Subsequent research should aim to improve activation conditions to get the highest possible carbon content and optimise surface characteristics.

Sulfur-containing cellulose esters for selectively anchoring gold for water catalytic decontamination

The facile preparation of sustainable sulfur-containing polymer functional materials has been obtained great attention due to their chemical reactivity and metal complexing ability. In this study, taking the solution properties advantages of the newly developed cellulose solvent system of DBU/DMSO/CO2, thiol and disulfide bond functionalized cellulose ester (TDSCE) was facilely prepared via in-situ tandem transesterification and oxidation reaction by using methyl 3-mercaptopropionate, without adding any external catalyst. The synthetic protocol was featured by that the DBU not only acted as reagent for the dissolution of cellulose, but also catalysts for the transesterification of cellulose with methyl 3-mercaptopropionate to yield cellulose 3-mercaptopropionate (Cell-MP) with maximum degrees of substitution (DS) of 0.77, and an oxidant for the partial oxidation of Cell-MP to produce a cellulose methyl 3,3′-disulfanediyldipropionate (Cell-MDSP) with maximum DS of 0.36 mixed ester, respectively. With successful introduction of thiol and disulfide bond into the cellulose backbone, the TDSCEs indicated desirable selective absorption of Au3+ from mimic heavy mental ions waste water due to the sulfur-Au chemistry with maximal adsorption capacity for Au3+ of 415.2 mg/g. The subsequent reduction of Au3+ into gold nanoparticles (Au NPs) fabricated a robust TDSCE-2@Au NPs composite catalyst with high catalytic activity for the hydrogenation treatment of water pollutes, such as 4-nitrophenol (4-NP)and azo dyes.

An eco-friendly strategy for emerging contaminants removal in water: Study of the adsorption properties and kinetics of self-polymerized PHEMA in green solvents

Water contaminants severely affect human health and aquatic ecosystems, and adsorption poses an economic, available, and feasible technology for remediation that needs to be accompanied by eco-friendly and sustainable materials. This study proposes an eco-friendly strategy for removing emerging contaminants using polyhydroxyethyl methacrylate polymers synthesized by self-polymerization with hydrophilic first-generation deep eutectic solvents. The polymers were characterized using structural and physical characterization techniques and their adsorption capacity against four emerging contaminants: a non-steroidal anti-inflammatory drug, an antibiotic, a pesticide, and a non-ionic surfactant. The experimental results showed high adsorption capacity for the urea: choline chloride-derived polymer with 6.21, 7.19, 6.01, and 6.99 mg⋅g-1 for paracetamol, ciprofloxacin, glyphosate, and triton X-100, respectively; these values are comparable to those obtained for similar systems. Kinetic, isothermal, and thermodynamics were also studied using various mathematical models to understand the adsorption mechanism, further complemented by DFT analysis. Chemisorption was found to be the primary mechanism by exothermic and ordered processes, which is thermodynamically favored. The study demonstrated for the first-time the effectiveness of self-polymerized PHEMA without chemical modification as a reusable adsorbent material and its ability to remove different types of emerging contaminants, thereby offering a promising solution for water treatment in environmental science.

Enhanced photocatalytic performance of (Mg, Cu) Dual-Doped ZnS nanosheets for Solar-Driven water treatment and embedded with PVA polymer membrane for reusability

Photocatalysis uses semiconductor materials to solar energy effectively purify to water by eliminating pollutants. Organic Dye degradation serves as a standard to assess the photocatalytic effects of the materials. In this study Mg, Cu dual-doped ZnS nanosheets were synthesized using the coprecipitation method. The impact of the concentration on the structural, morphology, optical, and degradation efficiency was investigated with XRD, XPS, TEM with EDAX, and UV spectroscopy. The pure ZnS and Zn0.98-xCu0.02MgxS (x = 0, 0.01, 0.02) (ZCM1, ZCM2, ZCM3, and ZCM4) nanosheets, exhibited cubic structure with high phase purity. The average crystalline size was calculated as 1.66, 1.60, 1.45, and 1.47 nm for the ZCM1, ZCM2, ZCM3, and ZCM4 nanosheets, respectively. TEM analysis revealed the presence of crumpled nanosheets. The bandgap of the ZCM1, ZCM2, ZCM3, and ZCM4 nanosheets were 3.99, 3.78, 4.03, and 4.09 eV respectively. This study investigated the photocatalytic activity of crystal violet dye when exposed to natural sunlight irradiation. Notably, ZCM3 nanosheets exhibited a high degradation rate of 99 % over 120 min under sunlight. Furthermore, the proposed dye degradation mechanism, effect of dosage, effect of dye variation, reusability, scavenging activity, and hemolytic activity were comprehensively discussed. The nanosheets embedded with the Polyvinyl alcohol (PVA) polymer membrane for reusability.

Enhanced Absorption Capacity and Fundamental Mechanism of electrospun MIL-101(Cr)-NH2/PAN nanofibrous Membranes for Mo(VI) Removal

Amidst the escalating global concern over heavy metal discharge from industrial effluents, Mo(VI), as a potentially toxic trace element, poses significant risks to human and environmental health. Traditional treatment methods such as biodegradation and ion exchange have low removal efficiency, hence, the efficient removal of Mo (VI) ions from industrial wastewater assumes paramount importance. Emerging materials, Metal-Organic Frameworks (MOFs), have garnered extensive attention in water treatment due to their strong adsorption properties, and MOFs membrane materials are hailed as the most promising adsorbents. Therefore, this study aims to prepare a novel membrane material with high efficiency for the removal of Mo (VI) by loading MOFs into nanofibers. Given the water stability of MIL-101, MIL-101-R(-H, -NH2, -NO2) with different functional groups were prepared and subsequently loaded into PAN nanofibrous for the adsorption of Mo(VI). Adsorption kinetics and isotherm studies revealed PAN/MIL-101(Cr)-NH2 to exhibit superior adsorption performance, achieving a maximum adsorption capacity of 171.81 mg/g. Density functional theory (DFT) calculations and molecular dynamics simulations elucidated the adsorption mechanism, highlighting the role of amino modification in facilitating Mo(VI) adsorption through electrostatic attraction and high reactivity. This work not only offers novel materials and approaches for Mo(VI) wastewater treatment but also advances the industrial application of MOF materials in the domain of heavy metal wastewater treatment.

Nano Filtration Techniques in Waste Water Treatment

Nano filters, based on nanotechnology to improve filtration processes, offer sophisticated solutions for contaminant removal from liquids and gases. The filters in this group include polymeric membranes with a pore size of 1-100 nanometres, ceramic membranes that are tolerant to chemicals, and carbon nanotube and graphene-based filters with advancedpermeability and selectivity. Recently, differentiated nanomaterials have been developed to make composite membranes with improved performance and durability. However, NF have disadvantages such as membrane fouling and high production costs. In this respect, research is currently being done to come up with solutions to the challenges, optimize the integration of nanomaterials, and realize application possibilities in water treatment, air purification, and industrial processes. On the whole, NF stand as the radical improvement filtration technology has so far achieved, and further research is bound to make them more efficient and cheaper About 17–19 million people in the world lack access to clean water. It is estimated that about 3.4 million people die every year from water scarcity, sanitation, and hygiene-related problems out of which 99% of deaths occurin developing countries. In recent years, water contamination has become a global environmental concern. The paper providesinsights into advancements in wastewater treatment through nano-filters. The paper focuses on evaluating the effectiveness ofnanomembranes in removing containments such as inorganic salts, organic compounds, and heavy metals. Additionally, the paper gives information about performance based on a comparison of the tractional filters and RO in terms of flexibility, durability, efficiency, and cost-effectiveness. Furthermore, it explores the application of NF in industries such as textile, pharmaceuticals, and agriculture and evaluates the versatility and effectiveness in these sectors.

Study of some physicochemical and bacteriological characteristics of drinking water in three selected rural communities in Wamba, Nasarawa State, Nigeria.

Access to safe drinking water remains a challenge in rural Nigeria. This study was carried out to determine physicochemical and bacteriological characteristics of drinking water in three rural communities in Wamba, Nasarawa State. A cross-sectional survey was conducted, 5 water samples were in respective cases collected from stream, well and borehole sources. Standard techniques were used for physicochemical analysis. Total viable counts, Total Staphylococcal counts, Total coliforms & Feacal coliforms in the samples were obtained using pour plate method, growth on Mannitol salt agar, growth on MacConkey agar and Eosin Methylene Blue agar respectively. Stream Water had higher values for physicochemical parameters. Stream water exhibited the highest bacterial counts, followed by well and borehole water. The Bacteria isolated were Escherichia coli, Staphylococcus aureus, Pseudomonas spp, Klebsiella spp, Proteus spp and Salmonella spp. The acid lability attributes of the isolates were determined using Nutrient Agar buffered with (4-(2- Hydroxyethyl)-1- piperazineethanesulfonic acid) and Lipase activity was assessed using Trypticase soy agar supplemented with 1% Tween 80. Statistical analysis was performed using SPSS-PC statistical package, with a p-value of < 0.05 it was considered statistically significant. These findings indicate contamination of drinking water sources, posing health risk to consumers and it shows the need for water treatment, monitoring & public health education in rural communities.

Wastewater Surveillance of SARS-CoV-2 in Slovenia: Key Public Health Tool in Endemic Time of COVID-19

With the reclassification of COVID-19 as an endemic disease and the relaxation of measures, Slovenia needed a complementary system for monitoring SARS-CoV-2 infections. This article provides an overview of the epidemiological situation of SARS-CoV-2 in Slovenia using a wastewater surveillance system, demonstrating its usefulness as a complementary tool in epidemiological surveillance. This study found that estimated SARS-CoV-2 infections in Slovenia peaked in September 2022 and showed a declining trend with subsequent lower peaks in March–April and December 2023, mirroring the trends observed from clinical data. Based on both surveillance systems, the most prevalent variant in 2022 was BA.5. By 2023, BQ.1 and other Omicron variants increased in prevalence. By the end of 2023, XBB sublineages and the BA.2.86 variant had become predominant, demonstrating consistent dynamic shifts in variant distribution across both monitoring methods. This study found that wastewater surveillance at wastewater treatment plants in Slovenia effectively tracked SARS-CoV-2 infection trends, showing a moderate to strong correlation with clinical data and providing early indications of changes in infection trends and variant emergence. Despite limitations during periods of low virus concentration, the system proved significant in providing early warnings of infection trends and variant emergence, thus enhancing public health response capabilities.

Introducing Oxygen Vacancies into a WO3 Photoanode through NaH2PO2 Treatment for Efficient Water Splitting.

WO3, with a high light absorption capacity and a suitable band structure, is considered a promising photoanode material for photoelectrochemical water splitting. However, the poor photoinduced electron-hole separation efficiency limits its application. Herein, we report an effective strategy to suppress electron-hole recombination by introducing oxygen vacancies (OV) on the surface of a WO3 photoanode through NaH2PO2 treatment. An OV-enriched amorphous surface layer with a thickness of 4 nm is formed after NaH2PO2 treatment, which increases the charge carrier density and enlarges the electrochemical surface area of the photoanode. The charge separation and surface injection efficiencies are both improved after NaH2PO2 treatment, and the charge transfer process of the photoanode is accelerated consequently. The current density of the modified WO3 photoanode reaches 0.96 mA cm-2 at 1.23 V.

Physical and Chemical Characterization of Sustainable Green Adhesives Derived from Municipal Treatment Plant Sludges

Adhesive formulations derived from sustainable feedstocks, like waste-activated sludge and biosolids from wastewater treatment plants, are developed due to protein-based adhesives receiving attention for their low-cost, resourcefulness, and minimal ecological footprint. The protein composition and associated dynamic changes of the adhesive formulations were studied via gel permeation chromatography, which detailed a molecular size distribution of 8.72 × 105 g/mol for the adhesive formulation and 6.89 × 103 g/mol for the dewatered biosolid base fraction, which confirms the formation of multiple protein functional groups combining to form the larger adhesive molecules. Further analysis determined the types of proteins present in the dewatered biosolids as glutelin, prolamin, globulin, and albumin proteins, with the glutelin proteins as the most prevalent, as thus likely responsible for adhesive formation. The rheological properties of the novel protein adhesive were also studied to interpret the structure of the adhesives, which detailed the findings of viscoelastic properties and flow behaviors of each adhesive in relation to the wastewater treatment plant sample location, which yielded higher flow points, storage moduli, and loss moduli for the dewatered biosolids in comparison to the waste-activated sludge and biosolid adhesives, which correlates with the higher solids content of the dewatered biosolids and potentially cell rupturing when exposed to filtration stress.

Adsorption of amoxicillin by chitosan and alginate biopolymers composite beads.

Due to its widespread use and incomplete breakdown in the human body, amoxicillin has been detected in receiving water bodies. This raises significant concerns, like the promotion of antibiotic resistance, toxicity towards aquatic life, disruption of the natural balance of microbial communities within these water bodies, and the struggle of effectively removal by the traditional wastewater treatment plants. Consequently, exploring new processes to complement the existing methods is crucial. Adsorption, a promising highly efficient, selective, and versatile technique, can effectively remove contaminants, making it useful in various industries such as water treatment, pharmaceuticals, and environmental remediation. Several adsorbents are documented in the literature for drug adsorption; however, their fabrication often involves more complex steps and substances compared to chitosan and alginate, which are natural polymers that are biocompatible, non-toxic, and biodegradable. Their tunable properties and ease of modification enhance their efficacy in environmental remediation. Therefore, the novelty of this article is to understand the interaction of amoxicillin with chitosan and alginate adsorbents easily synthetized using the dripping technique. This approach allows us to explore basic principles that can be applied to more complex systems in future studies. The optimal pH for both beads was found to be 4, with adsorption capacities of 74.2 ± 0.3mgg-1 for alginate and 80.4 ± 0.2mgg-1 for chitosan, using 1g of adsorbent. Kinetics studies indicated that external diffusion governs adsorption for alginate, while internal diffusion governs adsorption for chitosan. This approach underscores the potential of chitosan and alginate beads as effective adsorbents for mitigating antibiotic contamination in water systems, offering a sustainable complement to traditional treatment methods.

Challenges associated with access to safe water in Rhino Camp refugee settlement in Arua District, Uganda

ABSTRACT The study evaluated water access and disease prevalence in the Rhino Camp refugee settlement by mapping water sources, interviewing residents, and reviewing health centre records. Primary water sources were tanks providing 10.2 litres per person per day (l/p/d). Microbial contamination including total coliforms reaching 2.8 × 104 cfu/ml (household container – Tika), thermotolerant coliforms, and faecal enterococci were observed throughout the water supply chain, suggesting faecal contamination and posing a health risk. We attributed this to poor handling and storage related to poor sanitation in the settlement, highlighting the importance of promoting hygiene practices among refugees, particularly in the Ofua Zone, which had the highest contamination risks and the highest sanitary risk scores. Malaria and typhoid were the most prevalent diseases, with Ofua having the highest disease incidence. Water collection was mostly done by adult females and female children (34.7 and 30.3%, respectively) although water collection was generally low (<4 times a day). Boiling water was associated (p < 0.05) with the incidence of hepatitis A in Ofua. Adequate water (>20 l/p/d), water treatment, and education on hygiene practices especially for adult females are essential in lowering contamination and the incidence of diseases.

Boron nitride: Novel ceramic reductant for low‐activity waste vitrification

AbstractDuring vitrification of radioactive wastes, excessive foaming reduces processing rates within melters by hindering heat transfer from the molten glass pool to the reacting melter feed. Formulations of low‐activity waste (LAW) melter feeds, for vitrification at the Waste Treatment and Immobilization Plant at the Hanford Site, conventionally include the addition of sucrose to mitigate excessive foaming by hastening the denitration process. However, incomplete combustion of sucrose produces organics such as acetonitrile (C2H3N) that may exceed bounding limits of downstream effluent treatment facilities. Using boron nitride (BN) as an alternate reductant to sucrose, in a representative LAW melter feed reduced C2H3N production by 90% by preventing the low‐temperature sucrose–nitrate reactions. Furthermore, foaming was suppressed due to the higher decomposition temperature of BN than H3BO3 meaning a delayed reaction of a large fraction of boron with the transient glass‐forming melt until above the foam onset temperature, thus reducing the quantity and viscosity of the connected melt and trapping less gas in the foam layer.

Viral pathogen surveillance in wastewater using metagenomic approaches: obstacles and prospects

Abstract Background Wastewater monitoring offers an important tool for pathogen detection and tracking within large populations at a minimized cost and labor. Untargeted metagenomic approaches for the detection and sequencing of viruses still face limitations. In this study we tested the application of the sequence-independent single-primer amplification (SISPA) protocol in conjunction with nanopore sequencing to the study of viromes in wastewater samples. Methods Influent wastewater was collected from four Wastewater Treatment Plants located in the Lisbon region and Alentejo, Portugal in 2019 and 2023. Samples were processed with different methods including filtration, flocculation, Nanotraps or absorvent tampons. We applied the SISPA protocol, that includes a random amplification step, followed by nanopore sequencing on flow cells R9.4.1. We used the CZ ID (https://czid.org) pipeline for metagenomic analysis and taxonomic reporting. Results A large heterogeneity was found between samples in sequencing output (ranging from 17 thousand to 12 million reads) and the proportion of sequence reads classified as viral (ranging from 0.06% to 4% per sample). Viral taxa with higher number of reads were Picornavirales, dsDNA and ssDNA phages, Mimiviridae and Circoviridae. Known viral pathogens included Rotavirus A, Orthopoxvirus, Human betaherpesvirus and Avian orthoavulavirus. Conclusions Metagenomic studies of environmental samples generally exhibit a low proportion of viral reads, even after viral enrichment. A substantial sequencing effort is thus required to achieve a comprehensive virome characterization. As alternative, a more targeted approach, e.g. to target families of viruses of interest, may be considered. Funding: Fundação para a Ciência e Tecnologia (FCT): GHTM - UID/04413/2020; LA-REAL - LA/P/0117/2020; https://doi.org/10.54499/CEECINST/00102/2018/CP1567/CT0040 to SGS. Research council of the Vrije Universiteit Brussel (OZR-VUB): OZR3863BOF to PL. Key messages • Enrichment for viruses in metagenomic approaches remain challenging in very complex samples as are influent wastewaters. • Virome characterization still necessitates high sequencing efforts but may be used as a complementary environmental survey tool integrated with more targeted approaches.

Evaluation of the Cytotoxicity Effects of Bacteriophage VbɸPA-1 on the Virulent Pseudomonas aeruginosa, A375 Human Skin Melanoma Epithelial, and HFSF PI3 Human Skin Fibroblast Cells

Background: Gram-negative bacteria are the most common infectious bacteria and are life-threatening in burn patients. Phage therapy studies can help the hospital community eliminate these bacterial pathogens. Objectives: This study aimed to evaluate the effects of the isolated bacteriophages from hospital wastewater against Gram-negative pathogenic bacteria and investigate their cytotoxicity on two human skin cell lines. Methods: The bacterial strains were isolated from burn wound infections. Bacteriophages were isolated from the hospital wastewater treatment plant in Isfahan, Iran. Transmission electron microscopy, spot tests, and restriction enzyme digestion were considered for phage identification. Finally, the lactate dehydrogenase (LDH) and tetrazolium-based MTT assays were used to realize the cytotoxicity impacts of the isolated phages. The statistical analysis of cell viability was performed using a two-way analysis of variance (ANOVA). Results: The results showed that among the isolated strains, P. aeruginosa strain NEG_RA1300 (GenBank accession number: MW845642) was sensitive to the isolated phage VbɸPA-1. The TEM results showed a possible viral taxonomy of VbɸPA-1 based on its morphology, which belonged to the Myoviridae (T4-like phages). The MTT and LDH experiments showed no cytotoxicity of VbɸPA-1 on two tested cell lines. Conclusions: Based on the results, the inhibitory effect of isolated phage on P. aeruginosa isolated from burn wounds with no toxic effect on cell lines was very significant. This phage can also be an acceptable selection against burn wound infections.

Simultaneous degradation of cyanobacteria and cyanotoxins by catalytic wet peroxide oxidation: Impact of morphology and growth stage

The widespread proliferation of potentially toxic cyanobacteria in source waters for drinking water treatment plants (DWTPs) presents a pressing contemporary challenge. Although catalytic wet peroxide oxidation (CWPO) has been recognized as a highly effective and environmentally friendly technology for removing cyanotoxins from water, the simultaneous degradation of cyanobacteria and cyanotoxins has been scarcely investigated. Considering their great morphological diversity, in this work, the impact of the presence of pure strains of several species of toxic and non-toxic cyanobacteria on the degradation of relevant cyanotoxins has been evaluated considering also the main stages of their life cycle. In each studied scenario, achieving a full eradication of the cyanobacteria also led to the complete elimination of the cyanotoxin, including both intra and extracellular fractions. Morphological factors, including filament and cell sizes, play a crucial role in the efficiency of the process. Small cells and long filaments entail a higher presence of particulate organic matter, which consumes hydroxyl radicals considerably in competence with the cyanotoxin degradation. Moreover, the growth stage emerges as a pivotal factor in understanding the CWPO process performance, with cyanobacteria in their early life stages, exhibiting more pronounced interference compared to later stages, probably due to their higher cell viability and accelerated metabolism. All these understandings are essential for the successful implementation of the technology in treating surface waters affected by toxic cyanobacterial blooms.