A critical review on diverse technologies for advanced wastewater treatment during SARS-CoV-2 pandemic: What do we know?

Analysing carbapenemases in hospital wastewater: Insights from intracellular and extracellular DNA using qPCR and digital PCR

The widespread dissemination of carbapenem-resistant bacteria in wastewater systems, particularly from clinical sources, poses a significant public health risk. This study assessed the concentrations and distributions of extracellular DNA (exDNA) and intracellular DNA (iDNA) harboring carbapenemase genes in wastewater from six tertiary care hospitals in Germany. We collected a total of 36 samples, comprising six biological replicates from each hospital, and analysed them using quantitative real-time PCR (qPCR) and digital PCR (dPCR). The analysis targeted seven carbapenemase genes: blaNDM, blaKPC, blaIMP, blaVIM, blaOXA-23-like, blaOXA-48-like, and blaOXA-58-like across both DNA fractions. Our results revealed significant variability in the concentrations of exDNA and iDNA across the sampling sites, with iDNA typically present at higher concentrations. Using NanoDrop One spectrophotometry and the Qubit dsDNA kit, exDNA concentrations ranged from 2.7 to 7.7 ng/mL, while Qubit recorded lower values between 1.1 and 4.0 ng/mL. Conversely, iDNA concentrations were markedly higher, spanning from 42.3 to 191.7 ng/mL with NanoDrop and 12.0 to 46.5 ng/mL with Qubit, highlighting the variability between DNA types and quantification methods. Despite its lower concentrations, exDNA comprised up to 18.2 % of total DNA, highlighting its potential role in the horizontal transfer of antimicrobial resistance genes (ARGs). The study detected target ARGs in both DNA fractions at all sites, with notable differences in their concentrations; iDNA consistently exhibited higher levels of ARGs, with the highest concentrations reaching 10.57 ± 0.20 log gene copies per liter (GC/L) for blaVIM in iDNA and 6.96 ± 0.72 log GC/L for blaIMP in exDNA. dPCR demonstrated greater sensitivity than qPCR, especially effective for detecting low-abundance targets like blaOXA-23-like in the exDNA fraction. Additionally, qPCR's susceptibility to inhibition and contamination emphasizes the superior robustness of dPCR. This research highlights the need for improved monitoring and the implementation of advanced treatment technologies to mitigate ARG dissemination in wastewater.

Natural Clay-Modified Piezocatalytic Membrane for Efficient Removal of Coliform Bacteria from Wastewater

In the modern era, water pollution, especially from industries, agricultural farms, and residential areas, is caused by the release of a large scale of heavy metals, organic pollutants, chemicals, etc., into the environment, posing a serious threat to aquatic ecosystems and nature. Moreover, untreated sewage waste discharged directly into nearby water bodies can cause various diseases to mankind due to the high load of fecal coliform bacteria. This work demonstrates the development of a biocompatible, cost-effective, highly robust, efficient, flexible, freestanding, and reusable membrane using naturally formed biocompatible kaolinite clay-doped poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) for effective piezodynamic destruction of coliform bacteria. In this study, Escherichia coli (E. coli) and Enterococcus faecalis (E. faecalis) have been used to evaluate the mechanical stimulus-responsive antibacterial efficacy of the nanocomposite membrane. The membrane can effectively eradicate nearly 99% viable E. coli and 97% E. faecalis within a span of 40 min under mechanical stimulation (soft ultrasound ∼15 kHz). To further understand the mechanism, an evaluation of reactive oxygen species and bacterial FESEM was performed. These studies revealed that bacterial cells suffered severe visible cell damage after 40 min of piezocatalysis, elucidating the fact that the synthesized membrane is capable of producing a superior piezodynamic antibacterial effect.

Effective stabilization of electrochemically prepared ecological oxidizing agent-ferrate(VI)-by encapsulation in zeolite and its application to water containing SARS-CoV-2 virus

Improper and insufficient treatment of infectious hospital wastewater could seriously endanger public health and the environment. Ferrate(VI), a strong oxidizing, disinfecting, and coagulating agent, has the potential as a green solution for decontamination of water and wastewater. In this paper, electrochemically prepared potassium ferrate (K2 FeO4 ) with high purity was successfully encapsulated and applied to the water contaminated by SARS-CoV-2. Natural zeolite was chosen as an appropriate ecological material for ferrate encapsulation. The stability of encapsulated ferrate (in tablet form) was monitored for an extended time period (290 days) and has significantly increased in contrast with free potassium ferrate by almost 30%. Subsequently, the K2 FeO4 encapsulated with zeolite in tablet form was applied to the water and municipal water samples containing the SARS-CoV-2 virus. The removal efficiency reached up to 98.5% and 86.7%, respectively, under natural conditions. Combination of environmentally friendly oxidizing agent and natural excellent adsorbent leads to the creation of very effective water treatment matter. These findings are essentially immediate and especially important for immediate water treatment in urgent situations such as natural disasters or military conflict. PRACTITIONER POINTS: Electrochemical preparation of oxidizing agent, K2 FeO4 , in high purity by own constructed electrolyzer. Encapsulation of ferrate(VI) to natural zeolite threefold improving the stability during 9 months. SARS-CoV-2 virus was successfully removed from various contaminated types of water. High degradation efficiency of virus fragments by Fe(VI) was achieved without additional water adjustment, in natural pH range.

A critical assessment of SARS-CoV-2 in aqueous environment: Existence, detection, survival, wastewater-based surveillance, inactivation methods, and effective management of COVID-19

In early January 2020, the causal agent of unspecified pneumonia cases detected in China and elsewhere was identified as a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was the major cause of the COVID-19 outbreak. Later, the World Health Organization (WHO) proclaimed the COVID-19 pandemic a worldwide public health emergency on January 30, 2020. Since then, many studies have been published on this topic. In the present study, bibliometric analysis has been performed to analyze the research hotspots of the coronavirus. Coronavirus transmission, detection methods, potential risks of infection, and effective management practices have been discussed in the present review. Identification and quantification of SARS-CoV-2 viral loads in various water matrices have been reviewed. It was observed that the viral shedding through urine and feces of COVID-19-infected patients might be a primary mode of SARS-CoV-2 transmission in water and wastewater. In this context, the present review highlights wastewater-based epidemiology (WBE)/sewage surveillance, which can be utilized as an effective tool for tracking the transmission of COVID-19. This review also emphasizes the role of different disinfection techniques, such as chlorination, ultraviolet irradiation, and ozonation, for the inactivation of coronavirus. In addition, the application of computational modeling methods has been discussed for the effective management of COVID-19.

Integrating Water Purification with Electrochemical Aptamer Sensing for Detecting SARS-CoV-2 in Wastewater

Wastewater analysis of pathogens, particularly SARS-CoV-2, is instrumental in tracking and monitoring infectious diseases in a population. This method can be used to generate early warnings regarding the onset of an infectious disease and predict the associated infection trends. Currently, wastewater analysis of SARS-CoV-2 is almost exclusively performed using polymerase chain reaction for the amplification-based detection of viral RNA at centralized laboratories. Despite the development of several biosensing technologies offering point-of-care solutions for analyzing SARS-CoV-2 in clinical samples, these remain elusive for wastewater analysis due to the low levels of the virus and the interference caused by the wastewater matrix. Herein, we integrate an aptamer-based electrochemical chip with a filtration, purification, and extraction (FPE) system for developing an alternate in-field solution for wastewater analysis. The sensing chip employs a dimeric aptamer, which is universally applicable to the wild-type, alpha, delta, and omicron variants of SARS-CoV-2. We demonstrate that the aptamer is stable in the wastewater matrix (diluted to 50%) and its binding affinity is not significantly impacted. The sensing chip demonstrates a limit of detection of 1000 copies/L (1 copy/mL), enabled by the amplification provided by the FPE system. This allows the integrated system to detect trace amounts of the virus in native wastewater and categorize the amount of contamination into trace (<10 copies/mL), medium (10-1000 copies/mL), or high (>1000 copies/mL) levels, providing a viable wastewater analysis solution for in-field use.

Machine learning modeling of polycarbonate ultrafiltration membranes at different temperatures, Al2O3 nanoparticle volumes, and water ratios

The efficacy of novel polycarbonate ultrafiltration, aluminum oxide nanoparticle (Al₂O₃-NPs) volume fraction, temperature, and water/ethylene glycol (EG) ratio were evaluated to determine the thermophysical properties of the membrane. 5%-10% of Al₂O₃-NPs have been added to the PC. A machine learning approach was used to compare the volume fraction of Al₂O₃-NPs, the temperature, and the water-to-ethylene glycol (EG) ratio. To determine the impact of Al2O3-NPs loading on the Response Surface Method (RSM), DOE, ANOVA, ANN, MLP, and NSGA-II, the number of aluminum oxide nanoparticles (Al₂O₃-NPs), temperature, and water/ethylene glycol (EG) on membranes in PC ultrafiltration are evaluated. Based on the Relative Thermal Conductivity Model (RSM), the regression coefficient of Al₂O₃ in water and EG was 0.9244 and 0.9170 with adjusted regression coefficients. A higher concentration of EG enhances the thermal conductivity of the membrane when the effective parameters are considered. The effect of temperature on the relative viscosity of the membrane led to the conclusion that Al₂O₃ water/EG can cool at high temperatures while providing no viscosity change. When Al₂O₃ is dissolved in water and EG, more EG is necessary to optimize the mode of reactivity. Using the MLP model, the calculated R-value is 0.9468, the MSE is 0.001752989 (mean square error), and the MAE is 0.01768558 (mean absolute error). RSM predicted the average thermal conductivity behavior of nanofluid better. The ANN model, however, has proven to be more effective than the RSM in simulating the relative viscosity of nanofluids. The NSGA-II optimized results showed that the minimum relative viscosity and maximum coefficient of thermal conductivity occurred at the lowest water ratio and maximum temperature.

Mega-scale desalination efficacy (Reverse Osmosis, Electrodialysis, Membrane Distillation, MED, MSF) during COVID-19: Evidence from salinity, pretreatment methods, temperature of operation

The unprecedented situation of the COVID-19 pandemic heavily polluted water bodies whereas the presence of SARS-CoV-2, even in treated wastewater in every corner of the world is reported. The main aim of the present study is to show the effectiveness and feasibility of some well-known desalination technologies which are reverse osmosis (RO), Electrodialysis (ED), Membrane Distillation (MD), multi effect distillation (MED), and multi stage flashing (MSF) during the COVID-19 pandemic. Systems' effectiveness against the novel coronavirus based on three parameters of nasopharynx/nasal saline-irrigation, temperature of operation and pretreatment methods are evaluated. First, based on previous clinical studies, it showed that using saline solution (hypertonic saline >0.9% concentration) for gargling/irrigating of nasal/nasopharynx/throat results in reducing and replication of the viral in patients, subsequently the feed water of desalination plants which has concentration higher than 3.5% (35000ppm) is preventive against the SARS-CoV-2 virus. Second, the temperature operation of thermally-driven desalination; MSF and MED (70-120°C) and MD (55-85°C) is high enough to inhibit the contamination of plant structure and viral survival in feed water. The third factor is utilizing various pretreatment process such as chlorination, filtration, thermal/precipitation softening, ultrafiltration (mostly for RO, but also for MD, MED and MSF), which are powerful treatment methods against biologically-contaminated feed water particularly the SARS-CoV-2. Eventually, it can be concluded that large-scale desalination plants during COVID-19 and similar situation are completely reliable for providing safe drinking water.

SARS-CoV-2 removal by mix matrix membrane: A novel application of artificial neural network based simulation in MATLAB for evaluating wastewater reuse risks

The COVID-19 outbreak led to the discovery of SARS-CoV-2 in sewage; thus, wastewater treatment plants (WWTPs) could have the virus in their effluent. However, whether SARS-CoV-2 is eradicated by sewage treatment is virtually unknown. Specifically, the objectives of this study include (i) determining whether a mixed matrixed membrane (MMM) is able to remove SARS-CoV-2 (polycarbonate (PC)-hydrous manganese oxide (HMO) and PC-silver nanoparticles (Ag-NP)), (ii) comparing filtration performance among different secondary treatment processes, and (iii) evaluating whether artificial neural networks (ANNs) can be employed as performance indicators to reduce SARS-CoV-2 in the treatment of sewage. At Shariati Hospital in Mashhad, Iran, secondary treatment effluent during the outbreak of COVID-19 was collected from a WWTP. There were two PC-Ag-NP and PC-HMO processes at the WWTP targeted. RT-qPCR was employed to detect the presence of SARS-CoV-2 in sewage fractions. For the purposes of determining SARS-CoV-2 prevalence rates in the treated effluent, 10 L of effluent specimens were collected in middle-risk and low-risk treatment MMMs. For PC-HMO, the log reduction value (LRV) for SARS-CoV-2 was 1.3-1 log10 for moderate risk and 0.96-1 log10 for low risk, whereas for PC-Ag-NP, the LRV was 0.99-1.3 log10 for moderate risk and 0.94-0.98 log10 for low risk. MMMs demonstrated the most robust absorption performance during the sampling period, with the least significant LRV recorded in PC-Ag-NP and PC-HMO at 0.94 log10 and 0.96 log10, respectively.

Wastewater treatment with nanomaterials for the future: A state-of-the-art review

Aquatic and terrestrial ecosystems are both threatened by toxic wastewater. The unique properties of nanomaterials are currently being studied thoroughly for treating sewage. Nanomaterials also have the advantage of being capable of removing organic matter, fungi, and viruses from wastewater. Advanced oxidation processes are used in nanomaterials to treat wastewater. Additionally, nanomaterials have a large effective area of contact due to their tiny dimensions. The adsorption and reactivity of nanomaterials are strong. Wastewater treatment would benefit from the development of nanomaterial technology. Second, the paper provides a comprehensive analysis of the unique characteristics of nanomaterials in wastewater treatment, their proper use, and their prospects. In addition to focusing on their economic feasibility, since limited forms of nanomaterials have been manufactured, it is also necessary to consider their feasibility in terms of their technical results. According to this study, the significant adsorption area, excellent chemical reaction, and electrical conductivity of nanoparticles (NPs) contribute to the successful treatment of wastewater.

Various advanced wastewater treatment methods to remove microplastics and prevent transmission of SARS-CoV-2 to airborne microplastics

Microplastics (MPs) and SARS-CoV-2 interact due to their widespread presence in our environment and affect the virus' behaviour indoors and outdoors. Therefore, it is necessary to study the interaction between MPs and SARS-CoV-2. The environmental damage caused by MPs is increasing globally. Emerging pollutants may adversely affect organisms, especially sewage, posing a threat to human health, animal health, and the ecological system. A significant concern with MPs in the air is that they are a vital component of MPs in the other environmental compartments, such as water and soil, which may affect human health through ingesting or inhaling. This work introduces the fundamental knowledge of various methods in advanced water treatment, including membrane bioreactors, advanced oxidation processes, adsorption, etc., are highly effective in removing MPs; they can still serve as an entrance route due to their constantly being discharged into aquatic environments. Following that, an analysis of each process for MPs' removal and mitigation or prevention of SARS-CoV-2 contamination is discussed. Next, an airborne microplastic has been reported in urban areas, raising health concerns since aerosols are considered a possible route of SARS-CoV-2 disease transmission and bind to airborne MP surfaces. The MPs can be removed from wastewater through conventional treatment processes with physical processes such as screening, grit chambers, and pre-sedimentation.

A comprehensive review of various approaches for treatment of tertiary wastewater with emerging contaminants: what do we know?

In the last few decades, environmental contaminants (ECs) have been introduced into the environment at an alarming rate. There is a risk to human health and aquatic ecosystems from trace levels of emerging contaminants, including hospital wastewater (HPWW), cosmetics, personal care products, endocrine system disruptors, and their transformation products. Despite the fact that these pollutants have been introduced or detected relatively recently, information about their characteristics, actions, and impacts is limited, as are the technologies to eliminate them efficiently. A wastewater recycling system is capable of providing irrigation water for crops and municipal sewage treatment, so removing ECs before wastewater reuse is essential. Water treatment processes containing advanced ions of biotic origin and ECs of biotic origin are highly recommended for contaminants. This study introduces the fundamentals of the treatment of tertiary wastewater, including membranes, filtration, UV (ultraviolet) irradiation, ozonation, chlorination, advanced oxidation processes, activated carbon (AC), and algae. Next, a detailed description of recent developments and innovations in each component of the emerging contaminant removal process is provided.