Log Removal Research Articles

The contribution of deeper layers in slow sand filters to pathogens removal

Slow Sand Filtration is popular in drinking water treatment for the removal of a wide range of contaminants (e.g., particles, organic matter, and microorganisms). The Schmutzdecke in slow sand filters (SSFs) is known to be essential for pathogen removal, however, this layer is also responsible for increased head loss. Since the role of deeper layers in bacteria and virus removal is poorly understood, this research investigated the removal of E.coli WR1 and PhiX 174 at different depths of a full-scale SSF. Filter material from top (0–5 cm), middle (5–20 cm) and deep (20–35 cm) layers of an established filter was used in an innovative experimental set-up to differentiate physical-chemical and biological removal processes. In the analysis, we distinguished between removal by biological activity, biofilm and just sand. In addition, we modelled processes by a one-side kinetic model. The different layers contributed substantially to overall log removal of E.coli WR1 (1.4–1.7 log10) and PhiX 174 (0.4–0.6 log10). For E.coli WR1, biological activity caused major removal, followed by removal within biofilm and sand, whereas, removal of PhiX 174 mainly occurred within sand, followed by biofilm and biological activity. Narrow pore radii in the top layer obtained by micro-computed tomography scanner suggested enhanced retention of bacteria due to constrained transport. The retention rates of E.coli WR1 and PhiX 174 in top layer were four and five times higher than deeper layers, respectively (kret 1.09 min−1 vs 0.26 min−1 for E.coli WR1 and kret 0.32 min−1 vs of 0.06 min−1 for PhiX 174). While this higher rate was restricted to the Schmutzdecke alone (top 5 cm), the deeper layers extend to around 1 m in full-scale filters. Therefore, the contribution of deeper layers of established SSFs to the overall log removal of bacteria and viruses is much more substantial than the Schmutzdecke.

Distribution and co-occurrence of antibiotic resistance genes and bacterial pathogens in the effluent of decentralized sewage treatment systems in China

Antibiotic resistance genes (ARGs) and bacterial pathogens (BPs) in wastewater have potential risks to human health, especially for decentralized wastewater treatment facilities (DWTFs) in rural areas where the effluent may directly expose to residents. In this study, ARGs and BPs were investigated in the effluent from five DWTFs having the Anaerobic-Oxic (AO) and AO-Membrane Bio-Reactor (AO-MBR) processes in rural areas of southeastern China. Totally 842 kinds of ARGs and 937 kinds of virulence factors (VFs) were identified. Most of the dominant ARG species (e.g., evgS, macB, and sav1866) were found to be multi-drug ARGs with antibiotic efflux pumping pathways. Most ARGs have higher relative abundances in the effluent of the AO process than the MBRs. Co-occurrence network analysis that explains the dominant pathogens (Pseudomonas, Neisseria, and Streptococcus) were supposed to carry multiple ARGs. Furthermore, typical ARGs and int1 in different ranges of particles were quantified and 51.54%–98.59% ARGs were identified in the samples filtrated in the 0.22–23 μm range, which were hard to be removed. Though AO-MBR processes were more efficient than standalone AO process, the maximum log removal value for the ARGs was only 1.9. Therefore, the results of this study might be referential for evaluating and controlling the risks of co-existed ARGs and pathogens in DWTFs.

Comparison of MBR and MBBR followed by UV or electrochemical disinfection for decentralized greywater treatment

Greywater is an attractive source for water reuse at the household or building level, particularly for non-potable applications. Two greywater treatment approaches are membrane bioreactors (MBR) and moving bed biofilm reactors (MBBR), yet, their performance has not been compared so far within their respective treatment flowsheets, including post-disinfection. Two lab-scale treatment trains were operated on synthetic greywater: a) MBR with either polymeric (chlorinated polyethylene, C-PE, 165 days) or ceramic (silicon carbide, SiC, 199 days) membranes coupled with UV disinfection; and b) single-stage (66 days) or two-stage (124 days) MBBR coupled with an electrochemical cell (EC) for in-situ disinfectant generation. Water quality was constantly monitored, and Escherichia coli log removals were assessed through spike tests. Under low-flux operation of the MBR (<8 L·m − 2·h − 1), the SiC membranes delayed the onset of membrane fouling and needed less frequent cleaning compared to C-PE membranes. Both treatment systems met most water quality requirements for unrestricted greywater reuse, at a 10-fold lower reactor volume for the MBR than the MBBR. However, neither the MBR nor the two-staged MBBR allowed adequate nitrogen removal, and the MBBR did not consistently meet effluent chemical oxygen demand and turbidity requirements. Both EC and UV provided non-detectable E. coli concentrations in the effluent. Although the EC provided residual disinfection, scaling and fouling decreased its energetic and disinfection performance over time, making it less efficient than UV disinfection. Several outlines to improve the performance of both treatment trains and disinfection processes are proposed, thus, allowing a fit-for-use approach that leverages the advantages of the respective treatment trains. Results from this investigation will assist in elucidating the most efficient, robust, and low-maintenance technology and configurations for small-scale greywater treatment for reuse.

Preserved subsurface morphology in NIPS and VIPS laser-induced graphene membranes affects electrically-dependent microbial decontamination

Laser-induced graphene (LIG) is a graphitic material that can be easily formed by CO2-laser irradiation on a variety of carbon-based substrates, including porous polymeric membranes. LIG-membrane formation involves lasing the top surface of a polymeric membrane, and converts essential polymer separation structures to porous LIG foam. However, in previous studies, separation properties could be partly recovered by forming LIG polymer composite layers or by coating the polymeric membrane substrate with trimethylaluminum (TMA) or graphene oxide (GO) to avoid melting or damaging the membrane pore structure and the subsurface polymeric structures during the lasing process. Herein, by optimizing the laser settings and fabrication conditions, we made LIG directly on uncoated porous PES membranes, while preserving the subsurface polymer. The effects of lasing on membrane properties were studied by comparing porous polymeric PES membranes fabricated using the non-solvent induced phase separation (NIPS) or the vapor-induced phase separation (VIPS) method. Membrane fabrication conditions such as the polymer concentration of the casting solution and the exposure time to the non-solvent were varied, and the NIPS method resulted in membranes with a finger-like polymer substructure morphology while the VIPS method resulted in membranes with an asymmetric cellular morphology. LIG-membranes prepared on NIPS membranes resulted in large permeability changes, while LIG on VIPS membranes gave only very minor changes. The antimicrobial activity of these LIG-membranes as porous electrodes was dependent on applied voltage and solution contact time and 4–6 log removal of bacteria at 10 V was achieved. Understanding LIG formation on porous polymeric membranes will minimize processing steps and might lead to electrically conductive membranes with controlled separation properties.

Inactivation of antibiotic resistant bacteria and elimination of transforming ability of plasmid carrying single and dual drug resistance genes by electro-oxidation using Ti/Sb-SnO2/PbO2 anode

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are one of the major components of environmental antimicrobial resistance (AMR). Wastewater treatment plant is an important source and a contributor of AMR components in environment. The existing tertiary treatment technologies viz., chlorination, ultraviolet treatment and ozonation are not effective in ARB disinfection or ARG removal. Therefore, it is important to evaluate the potential of advanced wastewater treatment technologies in removing ARB and ARGs. In this study, the potential of Ti/Sb-SnO2/PbO2 anode in disinfecting single ARB (pUC19-ampR), dual ARB (pBR322-ampR and tetR), regrowth inhibition, removal of intracellular and extracellular ARGs and loss of transformation efficiency were evaluated. Upto 7 log (99.99 %) removal of single ARB (0.212 min−1) and dual ARB (0.185 min−1) was achieved in 40 min and 35 min, respectively at an applied current density 30 mA cm−2. Scanning electron microscopy images confirmed extensive and irreparable cell damages. Therefore, no re-growth was observed upto 30 days. Agarose gel electrophoresis and qubit analysis confirmed degradation of intracellular and extracellular genetic material. Upto ∼7.5 log (53.14 ± 1.23 %) of intracellular and ∼5.3 log (41.43 ± 0.89 %) of extracellular ampR (pUC19) reduction was observed. Similarly, reduction of intracellular ampR and tetR (pBR322) were ∼6.5 log (55.19 ± 0.92 %) and ∼7.5 log (64.89 ± 2.39 %). While, extracellular ampR and tetR (pBR322) were ∼4.1 log (41.85 ± 1.62 %) and ∼4.9 log (52.49 ± 1.35 %), respectively. Despite low ARG removal efficiency, complete loss of transformation ability of intracellular and extracellular pUC19 and pBR322 was observed. From the results, it is evident that electro-oxidation is effective in disinfecting both the ARB, removal of intracellular and extracellular ARGs. Therefore, EOP is proposed as an effective and promising tertiary treatment technology.

The potential of decentralised wastewater treatment in urban and rural sanitation in South Africa: lessons learnt from a demonstration-scale DEWATS within the eThekwini Municipality

The design principles of decentralised wastewater treatment systems (DEWATS) make them a practical sanitation option for municipalities to adopt in fast-growing cities in South Africa. Since 2014, a demonstration-scale DEWATS with a modular design consisting of a settler, anaerobic baffled reactor (ABR), anaerobic filter (AF), vertical down-flow constructed wetland (VFCW) and horizontal flow constructed wetland (HFCW) has been in operation in eThekwini. A performance evaluation after the long-term operation was undertaken in 2019 by comparing the final effluent with national regulatory requirements. Despite limitations in characterising the raw wastewater, a comparison of the settler and final effluent quality indicated high (≥ 85%) removal efficiencies of total chemical oxygen demand (CODt), ammonium-N (NH4-N) and orthophosphate-P (PO4-P), 75% removal of total suspended solids (TSS) and 83.3% log10 removal of Escherichia coli. Lack of exogenous and endogenous carbon and high dissolved oxygen (DO) concentrations (&gt; 0.5 mg‧L−1) inhibited denitrification in the HFCW, resulting in 12.5% of the effluent samples achieving compliance for nitrate-N (NO3-N). Moreover, mixed aggregate media and low residence times in the HFCW may have also contributed to poor NO3-N removal. During the COVID-19 lockdown, an unexpected shutdown and subsequent resumption of flow to the DEWATS indicated a 16-week recovery time based on achieving full nitrification in the HFCW. Although design modifications are necessary for the HFCW, the installation of urine diversion flushing toilets at the household will reduce the nutrient loading to the DEWATS and potentially achieve fully compliant effluent. Alternatively, the application of two-stage vertical flow constructed wetlands to improve denitrification should also be explored in the South African context. With an improved design, DEWATS has the potential to fill the gap in both urban and rural sanitation in South Africa, where waterborne sanitation is still desired but connections to conventional wastewater treatment works (WWTWs) are not possible.

Impact of low levels of silver, zinc and copper nanoparticles on bacterial removal and potential synergy in water treatment applications

AbstractBACKGROUNDPoint‐of‐use filtration units often incorporate silver as a disinfection aid. However, system performance and robustness may be increased by considering co‐application of additional transition metal nanoparticles (NPs) to support treated water disinfection. In this paper, the use of silver (Ag), zinc (Zn) and copper (Cu) NPs as disinfectants within drinking water applications was explored. Disinfection efficiency against E. coli was investigated over 72 h in batch‐phase experiments using NP concentrations within or lower than drinking water limits. Concentration ranges of the NPs were from 0 to 200 μg L−1, reflecting typical concentration reports for Ag in similar applications. Samples were examined with respect to pH and two water types. The effect of co‐application of NPs was assessed for potential synergy using the Bliss model, which compares individual treatment performance to combined treatment results.RESULTSDisinfection efficacy when applying NPs individually was Ag &gt; Cu &gt; Zn with, for instance, complete removal (≥3 log) of E. coli observed with 50 ppb Ag at 24 h, 1 log removal by Cu and no removal achieved with application of Zn. The Bliss model analysis demonstrated the co‐application of NPs resulted in synergistic behavior with the combinations. Zn‐containing combinations (Ag–Zn and Cu–Zn) were significantly more synergistic than the Ag–Cu combination.CONCLUSIONSLow‐level (0–200 ppb) concentrations of Ag, Cu and Zn demonstrated effective bacterial control and disinfection for E. coli under various water quality scenarios. In particular, co‐application of transition metal NPs increased system robustness and synergy, demonstrating potential for disinfection with water treatment applications. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley &amp; Sons Ltd on behalf of Society of Chemical Industry (SCI).

Engineered column treatment of greywater using raw and pyrolyzed coconut husk powder

Reclaimed water from wastewater has become a prominent water source option to manage water scarcity. This study explores the potential of coconut husk biomass, a common waste material in Ghana, as a valuable low-cost resource for greywater treatment. Engineered column treatment was applied to investigate the influence of pyrolysis and biochar properties of coconut husk biomass waste on greywater treatment. Coconut husk biomass waste was pyrolyzed at 600°C and characterized using SEM, FTIR, and XRD. Three engineered columns with 1) raw coconut husk powder (RCHP), 2) charred coconut husk powder (CCHP), and 3) sand-gravel filters (control setup) were used. A hydrostatic head of greywater with a throughput of 8.0 ml/min and a hydraulic retention time of 45 min was maintained for engineered columns. The SEM image suggested an increased surface area and pores due to the pyrolysis of the husk biomass. RCHP and CCHP contributed to 63% and 95% turbidity removal, respectively. Experimental results showed high removal efficiencies of 71% COD for CCHP. The nitrate removal efficiency of 78.93%, 88.38%, and 28.65% was observed for RCHP, CCHP, and control respectively. The log removal of faecal coliform by CCHP was two orders of magnitude higher than RCHP. Faecal and total coliform removal was 2.87 log units for CCHP. Significant differences were observed between CCHP and RCHP, p &amp;lt; 0.05 for electrical conductivity and total dissolved solids of effluents. CCHP showed a promising potential for greywater treatment. Pyrolyzed coconut husk powder is a promising adsorbent applicable to greywater treatment.

Efficiency of a new hybrid multi-soil-layering eco-friendly technology for removing pollutants from domestic wastewater under an arid climate

The goal of this research is to assess and track the efficacy of hybrid multi-soil-layering (MSL) plant in treating domestic wastewater for reuse in landscape irrigation. The investigated wastewater treatment plant is composed of a solar septic tank followed by a vertical flow MSL (VF-MSL) unit in series with a subsurface horizontal flow MSL (HSSF-MSL) unit. Wastewater samples were taken bimonthly from the plant's influent and effluent, respectively. The two-stage MSL units are composed of gravel layers alternated with soil-based layers, which are arranged in brick-like patterns, although they are operated under an HLR of 250 L m−2 day−1, which corresponds to 125 g COD/m2/d, 52 g TN/m2/d, and 2.70 g TP/m2/d. The mean removal efficiency was 75 %, 42 %, 67 %, and 47 %, respectively, for TSS, COD, NH4+, and TP for the VF-MSL system. Moreover, the VF-MSL combined with the HSSF-MSL system resulted in significant nitrogen removal as well as a significant reduction (p < 0.05) in organic matter and phosphorus with an abatement of 97 %, 79 %, 76 %, and 27 %, respectively, for TSS, COD, TP, and TN. For fecal bacteria indicators, the hybrid MSL system achieved high log removals, reaching 2.88 log units during two years of monitoring. Principal component analysis (PCA) was done on the positive correlation between COD, NH4+, TP removal, and summer seasons. Nonetheless, the winter season significantly influenced TN removal in the MSL system. The investigated hybrid multi-soil-layering plant has been shown to be effective in terms of water quality for the irrigation of green spaces in urban areas.

Quantitative models and potential surrogates for rapid evaluation and surveillance of chlorine disinfection efficacy in reclaimed water

Chlorine disinfection has become the most widely applied and indispensable technology in wastewater treatment and reuse to mitigate microbial risk and guarantee water safety. However, owing to complexities and high concentrations of contaminants in reclaimed water, rapid evaluation of chlorine disinfection efficacy is a crucial but challenging issue. Based on intensive experimental and statistical analyses, this study has established kinetic models and potential surrogates for rapid indication of the inactivation of microbial indicators and opportunistic pathogens during chlorine disinfection in different reclaimed waters. Overall, the constructed Selleck models performed very well to simulate log removal values (LRVs) of fecal coliforms, Pseudomonas aeruginosa and heterotrophic plate counts in all reclaimed water samples (R2 = 0.877–0.990). Moreover, total and Peak A fluorescence intensity as well as fluorescence integral intensities in Regions II and IV were found to have high response sensitivities during the chlorination process. Nevertheless, their effectiveness to act as potential surrogates of LRVs of microbial indicators needs to be further validated. The results from this study can provide valuable information on microbial safety surveillance of disinfection toward sustainable and long-term water reuse.

Uptake without inactivation of human adenovirus type 2 by Tetrahymena pyriformis ciliates.

Human adenoviruses are ubiquitous contaminants of surface water. Indigenous protists may interact with adenoviruses and contribute to their removal from the water column, though the associated kinetics and mechanisms differ between protist species. In this work, we investigated the interaction of human adenovirus type 2 (HAdV2) with the ciliate Tetrahymena pyriformis. In co-incubation experiments in a freshwater matrix, T. pyriformis was found to efficiently remove HAdV2 from the aqueous phase, with ≥4 log10 removal over 72 hours. Neither sorption onto the ciliate nor secreted compounds contributed to the observed loss of infectious HAdV2. Instead, internalization was shown to be the dominant removal mechanism, resulting in the presence of viral particles inside food vacuoles of T. pyriformis, as visualized by transmission electron microscopy. The fate of HAdV2 once ingested was scrutinized and no evidence of virus digestion was found over the course of 48 hours. This work shows that T. pyriformis can exert a dual role in microbial water quality: while they remove infectious adenovirus from the water column, they can also accumulate infectious viruses.

Facile preparation of all cellulose composite with excellent mechanical and antibacterial properties via partial dissolution of corn-stalk biomass

All-cellulose composite (ACC) was directly fabricated by the partial-dissolution welding of cellulose microfibers from agro-residual corn stalks treated with low-concentration ZnCl2 solvent (10–40 %). The solvent infiltrated deeply into nano/micro-scaled pores of cellulose fibers to facilitate the free migration of the disordered chains among the cellulose network while leaving the fiber core undissolved. Then, these disordered chains would entangle and regenerate to serve as a welded layer to bond the undissolved microfibril core in the solvent removal process. Such welding achieved exceptional mechanical (the tensile strength and Young's modulus of 49.9 MPa and 6.6 GPa, respectively), antibacterial (log removal value (LRV) of 4.8 and 3.0 for E. coli and S. aureus, respectively) and biodegradable properties of the multifunctional ACCs. It is worthwhile noting that the excellent antimicrobial effect is attributed to the sufficient contact of these microbes with ZnO NPs that were converted from the residual Zn2+ in ACCs. After five recycling processes, the elimination efficiency could still maintain a high LRV of 2.0–3.8. This high durability of ACC microbicidal activity was originated from strong twining interactions of cellulosic fibrils with in-situ synthesized ZnO NPs. This strategy was proven to be a facile and economical pathway to fabricate functional all-cellulose composites.

Removal of Environmentally Harmful and Hardly Degradable Pharmaceuticals Sulfamethoxazole, Diclofenac, and Cetirizine by Adsorption on Activated Charcoal

The removal of three environmentally harmful and hardly degradable pharmaceuticals, namely sulfamethoxazole, diclofenac, and cetirizine, from aqueous solution by the adsorption onto two types of activated charcoals (WSCl2 and HWOH) was investigated. The volume of micropores and mesopores in two charcoals was the main property affecting removal efficiencies. Using microporous WSCl2 as an adsorbent, higher removal efficiencies were achieved for all chosen pharmaceuticals. The highest removal efficiency was recorded in the case of sulfamethoxazole (79%). A direct correlation between log Kow and removal efficiencies and between the solubility of pharmaceuticals and removal efficiencies was not found. The adsorption behavior of individual pharmaceutical solutions can be described by the pseudo-second order kinetic model. The parameters obtained from the kinetic model show that the adsorption rate on HWOH was higher than on WSCl2. However, the amounts of adsorbed pharmaceuticals were lower on HWOH than on WSCl2, which can be linked to the textural difference between the charcoals. In the mixture consisting of all three compounds, overall removal efficiencies were lower than in the case when individual pharmaceuticals were present in the solution. Results also indicate that a certain fraction of the micropores can only be occupied by the smallest compound in the mixture (sulfamethoxazole).

Strong anti-viral nano biocide based on Ag/ZnO modified by amodiaquine as an antibacterial and antiviral composite

In this paper, we synthesized Ag/ZnO composite colloidal nanoparticles and the surface of nanoparticles was improved by amodiaquine ligand. The synthesized nanoparticles were characterized using the XRD diffraction pattern, FT-IR Spectroscopy, TEM image, and UV–Vis spectroscopy. The antibacterial, antifungal, and antiviral effects of the synthesized colloid were examined on E.coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus hirae bacteria, and Candida Albicans and form spore aspergillus fungi, also influenza, herpes simplex, and covid 19 viruses. The results indicate more than 7 log removal of the bacteria, fungi, and viruses by synthesized colloid with a concentration of 15 μg/L (Ag)/50 µg/ml (ZnO). This removal for covid 19 virus is from 3.2 × 108 numbers to 21 viruses within 30 s. Also, irritation and toxicity tests of the synthesized colloid show harmless effects on human cells and tissues. These colloidal nanoparticles were used as mouthwash solution and their clinical tests were done on 500 people infected by the coronavirus. The results indicate that by washing their mouth and nose three times on day all patients got healthy at different times depending on the depth of the disease. Almost all people with no signs of infection and using this solution as a mouthwash didn’t infect by the virus during the study.

Magnéli-Phase Ti4O7-Doped Laser-Induced Graphene Surfaces and Filters for Pollutant Degradation and Microorganism Removal.

Laser-induced graphene (LIG) has recently become a point of attraction globally as an environmentally friendly method to fabricate graphene foam in a single step using a CO2 laser. The electrical properties of LIG are studied in different environmental applications, such as bacterial inactivation, antibiofouling, and pollutant sensing. Furthermore, metal or nonmetal doping of graphene enhances its catalytical performance in pollutant degradation and decontamination. Magnéli phase (TinO2n-1) is a substoichiometric titanium oxide known for its high electrocatalytic behavior and chemical inertness and is being explored as a membrane or electrode material for environmental decontamination. Here, we show the fabrication and characterization of LIG-Magnéli-phase (Ti4O7) titanium suboxide composites as electrodes and filters on poly(ether sulfone). Unlike undoped LIG electrodes, the doped Ti4O7-LIG electrodes exhibit enhanced electrochemical activity, as demonstrated in electrochemical characterization using cyclic voltammetry and electrochemical impedance spectroscopy. Due to the in situ generation of hydroxyl radicals on the surface, the doped electrodes exhibit increase in methylene blue degradation and microorganism removal. Effects of voltage and doping were examined, resulting in a clear trend of degradation and decontamination performance proportional to the doping concentration and applied voltage giving the best result at 2.5 V for 10% Ti4O7 doping. The LIG-Ti4O7 surfaces also showed biofilm inhibition against mixed bacterial culture. The flow-through filtration using a LIG-Ti4O7 conductive filter showed complete bacterial killing with 6 log removal in the permeate at 2.5 V, an enhancement of ∼2.5 log compared to undoped LIG filters at a flow rate of ∼500 L m-2 h-1. The facile fabrication of Ti4O7-doped LIG with enhanced electrochemical properties can be effectively used for energy and environmental applications.

Protein-imprinted particles for coronavirus capture from solution.

Molecular imprinting is a promising strategy to selectively adsorb viruses, but it requires discerning and validating epitopes that serve as effective imprinting templates. In this work, glycoprotein‐imprinted particles were synthesized for coronavirus capture. Adsorption was maximized at pH 6 (the glycoprotein isoelectric point) where the glycoprotein‐imprinted particles outperformed non‐imprinted particles, adsorbing 4.96 × 106 ± 3.33 × 103 versus 3.54 × 106 ± 1.39 × 106 median tissue culture infectious dose/mg of the target coronavirus, human coronavirus – organ culture 43, within the first 30 min (p = 0.012). During competitive adsorption, with pH adjustment (pH 6), the glycoprotein‐imprinted particles adsorbed more target virus than non‐target coronavirus (human coronavirus – Netherland 63) with 2.34 versus 1.94 log removal in 90 min (p < 0.01). In contrast, the non‐imprinted particles showed no significant difference in target versus non‐target virus removal. Electrostatic potential calculation shows that the human coronavirus – organ culture 43 glycoprotein has positively charged pockets at pH 6, which may facilitate adsorption at lower pH values. Therefore, tuning the target virus glycoprotein charge via pH adjustment enhanced adsorption by minimizing repulsive electrostatic interactions with the particles. Overall, these results highlight the effective use of glycoprotein‐imprinted particles for coronavirus capture and discern the merits and limitations of glycoprotein imprinting for the capture of enveloped viruses.

Disinfection during Iron Electrocoagulation: Differentiating between Inactivation and Floc Entrapment for Escherichia coli and Somatic Coliphage ØX174

Electrochemical water treatment is gaining increasing popularity due to its wide range of potential applications, its decreasing costs, and its suitability as a decentralized treatment alternative, but mainly due to it being considered a ”green technology”. In the field of municipal wastewater treatment, the use of iron electrocoagulation (Fe-EC) has been marginal and although disinfection has been reported, its underlying mechanisms are not fully understood, for which significant controversy remains. In this study, microbial inactivation during Fe-EC was evaluated as a two-component process, namely, physical removal by microbial floc sorption/entrapment, and inactivation by reactive oxygen species (ROS) produced by (semi)Fenton reactions. Using the fecal indicators Escherichia coli WR1 and somatic coliphage ØX174 suspended in a synthetic water matrix, the role of ROS and the role of flocculation were quantitatively evaluated. Fenton inhibitor TEMPOL was used to quench ROS production during Fe-EC. At circumneutral pH, ROS were found to be highly detrimental to E. coli, yet only mildly damaging for phage ØX174 (≈3.9 log10 and ≈0.8 log10 inactivation, respectively). Inactivation for both indicators increased under acidic conditions (pH 5.5), likely due to the formation of hydroxyl radicals (•OH), exceeding 5.1 log10 for E. coli and 1.5 log10 for phage ØX174. The ROS inactivation pathway is linked to the oxidation of ferrous iron (Fe2+), being independent of flocculation settings. Experiments involving different flocculation settings demonstrated that there is a strong positive correlation between orthokinetic-like flocculation conditions, floc sedimentation, and microbial removal, meaning that floc entrapment is a major removal pathway following Fe-EC. When compared to control experiments in which no proper flocculation stage was introduced, orthokinetic flocculation produced additional 3.1 log10 and 4.4 log10 removal for E. coli and phage ØX174, respectively. We conclude that ROS production is not a prerequisite for removal of E. coli and phage ØX174, however, it does offer an additional disinfection barrier, which increases the robustness of Fe-EC for water treatment.

Neuroprotective activity of a virus-safe nanofiltered human platelet lysate depleted of extracellular vesicles in Parkinson's disease and traumatic brain injury models.

Brain administration of human platelet lysates (HPL) is a potential emerging biotherapy of neurodegenerative and traumatic diseases of the central nervous system. HPLs being prepared from pooled platelet concentrates, thereby increasing viral risks, manufacturing processes should incorporate robust virus-reduction treatments. We evaluated a 19 ± 2-nm virus removal nanofiltration process using hydrophilic regenerated cellulose hollow fibers on the properties of a neuroprotective heat-treated HPL (HPPL). Spiking experiments demonstrated >5.30 log removal of 20-22-nm non-enveloped minute virus of mice-mock particles using an immuno-quantitative polymerase chain reaction assay. The nanofiltered HPPL (NHPPL) contained a range of neurotrophic factors like HPPL. There was >2 log removal of extracellular vesicles (EVs), associated with decreased expression of pro-thrombogenic phosphatidylserine and procoagulant activity. LC-MS/MS proteomics showed that ca. 80% of HPPL proteins, including neurotrophins, cytokines, and antioxidants, were still found in NHPPL, whereas proteins associated with some infections and cancer-associated pathways, pro-coagulation and EVs, were removed. NHPPL maintained intact neuroprotective activity in Lund human mesencephalic dopaminergic neuron model of Parkinson's disease (PD), stimulated the differentiation of SH-SY5Y neuronal cells and showed preserved anti-inflammatory function upon intranasal administration in a mouse model of traumatic brain injury (TBI). Therefore, nanofiltration of HPL is feasible, lowers the viral, prothrombotic and procoagulant risks, and preserves the neuroprotective and anti-inflammatory properties in neuronal pre-clinical models of PD and TBI.

Quantification of the Retention and Disassembly of Virus Particles by a PEI-Functionalized Microfiltration Membrane.

Monitoring the performance of polymer-functionalized surfaces that aim at removing and inactivating viruses is typically labor-intensive and time-consuming. This hampers the development and optimization of such surfaces. Here we present experiments of low complexity that can be used to characterize and quantify the antiviral properties of polymer-functionalized surfaces. We showcase our approach on polyethylenimine (PEI)-coated poly(ether sulfone) (PES) microfiltration membranes. We use a fluorescently labeled model virus to quantify both virus removal and inactivation. We directly quantify the log removal of intact viruses by this membrane using single particle counting. Additionally, we exploit the change in photophysical properties upon disassembly of the virus to show that viruses are inactivated by the PEI coating. Although only a small fraction of intact viruses can pass the membrane, a considerable fraction of inactivated, disassembled viruses are found in the filtrate. Fluorescence microscopy experiments show that most of the viruses left behind on the microfiltration membrane are in the inactivated, disassembled state. Combined, our fluorescence microscopy and spectroscopy experiments show that not only does the model virus adsorb to the PEI coating on the membrane but also the interaction with PEI results in the disassembly of the virus capsid.

Advanced wastewater treatment with ozonation and granular activated carbon filtration: Inactivation of antibiotic resistance targets in a long-term pilot study

The inactivation of antibiotic resistant bacteria (ARB) and genes (ARGs) in an advanced plant combining ozonation and granular activated carbon (GAC) filtration applied for effluent after conventional activated sludge treatment at a full-scale urban wastewater treatment plant was investigated for over 13 consecutive months. The nitrite compensated specific ozone dose ranged between 0.4 and 0.7 g O3/g DOC with short-time sampling campaigns (0.2–0.9 g O3/g DOC). Samples were analysed with culture-dependent methods for bacterial targets and with qPCR for genes. The log removal values were correlated with a decrease of the matrix UV absorption at 254 nm (ΔUV254) and indicated a range of ΔUV254 that corresponds to a sufficient membrane damage to affect DNA. For trimethoprim/sulfamethoxazole resistant E. coli, sul1, ermB and tetW, this phase was observed at ΔUV254 of ~30 % (~0.5 g O3/g DOC). For ampicillin resistant E. coli and blaTEM-1, it was observed around 35–40 % (~0.7 g O3/g DOC), which can be linked to mechanisms related to oxidative damages in bacteria resistant to bactericidal antibiotics. GAC treatment resulted in a further abatement for trimethoprim/sulfamethoxazole E. coli, sul1 and tetW, and in increase in absolute and relative abundance of ermB and blaTEM-1.