Smart Organic-Inorganic Polyoxomolybdates in Forward Osmosis for Antiviral-Drug Wastewater Treatment and Drug Reclamation.

The demand to effectively treat medical wastewater has escalated with the much greater use of antiviral drugs since the COVID-19 pandemic. Forward osmosis (FO) has great potential in wastewater treatment only when appropriate draw solutes are available. Here, we synthesize a series of smart organic-inorganic polyoxomolybdates (POMs), namely, (NH4)6[Mo7O24], (PrNH3)6[Mo7O24], (iPrNH3)6[Mo7O24], and (BuNH3)6[Mo7O24], for FO to treat antiviral-drug wastewater. Influential factors of separation performance have been systematically studied by tailoring the structure, organic characteristics, and cation chain length of POMs. POMs at 0.4 M produce water fluxes ranging from 14.0 to 16.4 LMH with negligible solute losses, at least 116% higher than those of NaCl, NH4HCO3, and other draw solutes. (NH4)6[Mo7O24] creates a water flux of 11.2 LMH, increased by more than 200% compared to that of NaCl and NH4HCO3 in long-term antiviral-drug wastewater reclamation. Remarkably, the drugs treated with NH4HCO3 and NaCl are either contaminated or denatured, while those with (NH4)6[Mo7O24] remain intact. Moreover, these POMs are recovered by sunlight-assisted acidification owing to their light and pH dual sensitivity and reusability for FO. POMs prove their suitability as draw solutes and demonstrate their superiority over the commonly studied draw solutes in wastewater treatment.

Effectiveness of a Water Disinfection Method Based on Osmosis and Chlorine Dioxide for the Prevention of Microbial Contamination in Dental Practices.

In dental clinics, the infections may be acquired through contaminated devices, air, and water. Aerosolized water may contain bacteria, grown into the biofilm of dental unit waterlines (DUWLs). We evaluated a disinfection method based on water osmosis and chlorination with chlorine dioxide (O-CD), applied to DUWL of five dental clinics. Municipal water was chlorinated with O-CD device before feeding all DUWLs. Samplings were performed on water/air samples in order to research total microbial counts at 22-37 °C, Pseudomonas aeruginosa, Legionella spp., and chlorine values. Water was collected from the taps, spittoons, and air/water syringes. Air was sampled before, during, and after 15 min of aerosolizing procedure. Legionella and P. aeruginosa resulted as absent in all water samples, which presented total microbial counts almost always at 0 CFU/mL. Mean values of total chlorine ranged from 0.18-0.23 mg/L. Air samples resulted as free from Legionella spp. and Pseudomonas aeruginosa. Total microbial counts decreased from the pre-aerosolizing (mean 2.1 × 102 CFU/m3) to the post-aerosolizing samples (mean 1.5 × 10 CFU/m3), while chlorine values increased from 0 to 0.06 mg/L. O-CD resulted as effective against the biofilm formation in DUWLs. The presence of residual activity of chlorine dioxide also allowed the bacteria reduction from air, at least at one meter from the aerosolizing source.

Aerosols in Ultrasonic Instrumentation: Comparison of particle spread utilizing saliva ejectors versus high-volume evacuation

Purpose: The emergence of SARS-CoV-2 has generated renewed interest in the potential transmission of viral contaminants via ultrasonic scaler-generated aerosols. The purpose of this study was to use controlled experimental conditions to quantify the range, direction, and concentration of aerosolized and splatter droplet spread across distances up to 106 inches from the source of the ultrasonic scaling procedure on a manikin patient head. Methods: A dental simulation unit (DSU) was used to facilitate ultrasonic instrumentation performed on a typodont located within a manikin patient head. A 9 x 9-foot section of white paper was placed on the floor directly beneath the DSU. White paper was also placed on the adjacent countertops for identification of possible spread. Methylene blue dye was mixed with reverse-osmosis (RO) water and placed in the reservoir of the ultrasonic scaler. Experimental tests were run with high-volume evacuation (HVE) and a with a saliva ejector. Photographs of the paper and droplets were taken and analyzed by computer software to identify all droplets captured on the paper. Results: Particle counts show that HVE use is associated with a reduction in total particle count for each zone evaluated, with the largest reduction seen in regions closest to the origin. Using HVE on the DSU demonstrated a 99% reduction in particles and 50% reduction in the range of particles. Conclusion: Dental health care providers should use HVE when generating aerosols during ultrasonic instrumentation procedures to reduce particle spread in health care settings.

Osmotic Processor for Enabling Sensitive and Rapid Biomarker Detection via Lateral Flow Assays.

Urine is an attractive biospecimen for in vitro diagnostics, and urine-based lateral flow assays are low-cost devices suitable for point-of-care testing, particularly in low-resource settings. However, some of the lateral flow assays exhibit limited diagnostic utility because the urinary biomarker concentration is significantly lower than the assay detection limit, which compromises the sensitivity. To address the challenge, we developed an osmotic processor that statically and spontaneously concentrated biomarkers. The specimen in the device interfaces with the aqueous polymer solution via a dialysis membrane. The polymer solution induces an osmotic pressure difference that extracts water from the specimen, while the membrane retains the biomarkers. The evaluation demonstrated that osmosis induced by various water-soluble polymers efficiently extracted water from the specimens, ca. 5-15 ml/h. The osmotic processor concentrated the specimens to improve the lateral flow assays' detection limits for the model analytes-human chorionic gonadotropin and SARS-CoV-2 nucleocapsid protein. After the treatment via the osmotic processor, the lateral flow assays detected the corresponding biomarkers in the concentrated specimens. The test band intensities of the assays with the concentrated specimens were very similar to the reference assays with 100-fold concentrations. The mass spectrometry analysis estimated the SARS-CoV-2 nucleocapsid protein concentration increased ca. 200-fold after the osmosis. With its simplicity and flexibility, this device demonstrates a great potential to be utilized in conjunction with the existing lateral flow assays for enabling highly sensitive detection of dilute target analytes in urine.

Wastewater: Novel treatment technologies and source for epidemiological studies

Treating and reusing wastewater can augment water scarcity in water-stressed regions in the world. Additionally, wastewater streams contain useful resources that can be recovered and recycled to improve the economics of the water treatment processes. Another aspect that has been reported in the past few decades is the detection of novel contaminants of concern in the wastewater samples that often escape treatment and remediation. Studies have demonstrated that the conventional wastewater treatment practices are not sufficient to address resource recovery and emerging contaminants aspects. In this chapter, first, conventional wastewater treatment process based on activated sludge is presented, and subsequently novel wastewater treatment methods have been discussed. Theoretical aspect of each method is described, and its implementation in pilot or full-scale study has been highlighted. For increasing the water recovery rate from waste streams, membrane-based treatment technologies such as reverse osmosis will be crucial. Ion-exchange, adsorption, microalgal, and bioelectrochemical systems can be advantageous from resource recovery perspective. Further, epidemiological aspects of wastewater have been highlighted and the recent spread of COVID-19 has been discussed with respect to the virus’ detection in toilet wastewater. © 2021 Elsevier Inc. All rights reserved.

Antibacterial and desalting behavior of forward osmosis membranes engineered with metal ions

The current Covid-19 aggravates membrane biofouling issue caused by bacteria and viruses which are widely present in water. Herein we synthesized a series of polyamide (PA)-based membranes engineered with distinct metal ions (Cu2+, Fe3+) via one-step metal-ligand ligation for forward osmosis (FO) separation. The antibacterial and desalting behavior of membrane were investigated by systematically varying the influential factors including the charge status, complexation ability and antibacterial mechanism of metal ions as well as testing conditions. All the newly synthesized membranes exhibit better performance with markedly increased water permeability and selectivity. Therein the Fe3+ − membrane increases water fluxes by 93% (FO mode) and 112% (PRO mode) relative to the nascent PA membrane with 0.5 M NaCl as the draw solution. Both Cu2+ and Fe3+ on membrane surface dramatically improve the membrane bactericidal efficacy against Escherichia coli via destroying the bacterial phospholipid layer. Remarkably, the metal ions on membrane surface are easily regenerated after being consumed by bacteria by simply immersing the membranes into the corresponding nitrate solutions. The separation performance and antibacterial properties of the regenerated membranes are comparable to those of the fresh membranes. When using brine from reverse osmosis process as the draw solution, the Fe3+ membrane recovers water from brackish water up to 70% higher than the nascent PA membrane. This study provides a practical strategy to develop FO membrane with sustainable antibacterial activity and desalination performance.

Extended Thromboprophylaxis in Patients with COVID-19

Introduction Patients hospitalized with COVID-19 have an increased incidence of venous thromboembolism (VTE) and arterial thromboembolism (ATE) events. These thrombotic events increase readmission and mortality rate in COVID-19 survivors who are recently discharged from hospital. To lower the risk of VTE, a short course of post-discharge anticoagulation at either prophylactic or therapeutic dose has been variably prescribed among different facilities to COVID-19 patients. This practice, however, is challenged by less than 3% incidence of VTE in unselected patients. The net clinical benefit of extended thromboprophylaxis beyond hospitalization remains unclear. Methods We conducted a retrospective multicenter observational study of 5613 hospitalized COVID-19 patients. After applying the inclusion and exclusion criteria, 2838 patients were included in statistical analysis. Patients were excluded if they had negative SARS-CoV-2 PCR, remained hospitalized at the time of analysis, or were discharged to hospice service. The first symptomatic ATE and VTE events up to 90 days after patients' discharge from their index admission for COVID-19 were identified using ICD-10 codes, and subsequently validated by chart review. The predictors for post-discharge VTE were identified using multivariate logistic regression. The average protective effect of anticoagulation was assessed using inverse propensity score weighting. Results The mean age (SD) of our cohort was 63.4 (16.7) years old and 47.6% were male. Black, white and other races were 38.9%, 50.7% and 10.3%, respectively. Thirty-six (1.3%) patients developed post-discharge VTE events that require hospital visits (18 deep vein thromboses, 16 pulmonary embolisms and 2 portal vein thromboses). Fifteen (0.5%) patients developed post-discharge ATE events (14 acute coronary syndromes and 1 transient ischemic attack). The incidence of VTE decreased with time (p <.001) with the median event time of 16 days (Figure 1). The incidence of ATE was unchanged with time (p =.369) with the median event time of 37 days (Figure 1). Patients who had a history of VTE (OR=3.24, 95% CI 1.34-7.86), peak D-dimer >3 µg/mL (OR=3.76, 95% CI 1.86-7.57), and predischarge C-reactive protein >10 mg/dL (OR=3.02, 95% CI 1.45-6.29) were at a high risk of developing VTE after hospital discharge (Figure 2). A short course of prophylactic or therapeutic anticoagulation after hospital discharge markedly reduced VTE (OR=0, 95% CI 0-0, p<.001, and OR=0.176, 95% CI 0.04-0.75, p=.02, respectively). Conclusions Although extended thromboprophylaxis in unselected COVID-19 patients is not recommended, post-discharge anticoagulation may be considered in high-risk patients who have a history of VTE, peak D-dimer >3 µg/mL and predischarge C-reactive protein >10 mg/dL if their bleeding risk is low. Our study has provided the first evidence to guide the selection of hospitalized COVID-19 patients who may benefit from post-discharge anticoagulation. [Formula presented] Disclosures: Kaatz: Gilead: Consultancy;Novartis: Consultancy;CSL Behring: Consultancy;Bristol Myer Squibb: Consultancy, Research Funding;Alexion: Consultancy;Pfizer: Consultancy;Janssen: Consultancy, Research Funding;Osmosis Research: Research Funding.

An Assessment of Renewable Energies in a Seawater Desalination Plant with Reverse Osmosis Membranes.

The purpose of our study was to reduce the carbon footprint of seawater desalination plants that use reverse osmosis membranes by introducing on-site renewable energy sources. By using new-generation membranes with a low energy consumption and considering wind and photovoltaic energy sources, it is possible to greatly reduce the carbon footprint of reverse osmosis plants. The objective of this study was to add a renewable energy supply to a desalination plant that uses reverse osmosis technology. During the development of this research study, photovoltaic energy was discarded as a possible source of renewable energy due to the wind conditions in the area in which the reverse osmosis plant was located; hence, the installation of a wind turbine was considered to be the best option. As it was a large-capacity reverse osmosis plant, we decided to divide the entire desalination process into several stages for explanation purposes. The desalination process of the facility consists of several phases: First, the seawater capture process was performed by the intake tower. This water was then transported and stored, before going through a physical and chemical pre-treatment process, whereby the highest possible percentage of impurities and organic material was eliminated in order to prevent the plugging of the reverse osmosis modules. After carrying out the appraisals and calculating the amount of energy that the plant consumed, we determined that 15% of the plant's energy supply should be renewable, corresponding to 1194 MWh/year. As there was already a wind power installation in the area, we decided to use one of the wind turbines that had already been installed-specifically, an Ecotecnia turbine (20-150) that produced an energy of 1920 MWh /year. This meant that only a single wind turbine was required for this project.