Human enteric viruses in a wastewater treatment plant: evaluation of activated sludge combined with UV disinfection process reveals different removal performances for viruses with different features

Relative abundance and the fate of human rotavirus in wastewater during treatment processes: identification of potential infectious rotavirus in the final effluents and receiving aquatic milieu in Durban area, South Africa

The occurrence and persistence of rotaviruses in raw and treated wastewater and their discharge into rivers represent a significant health risk for humans and animals, worldwide. In this study, samples were collected monthly from each of the four Durban wastewater treatment plants (DWWTPs) and receiving rivers for a period of 3 months. Rotavirus was quantified by real-time quantitative PCR (RT-qPCR), and viability was assessed using integrated cell culture (ICC)-qPCR. Rotavirus was detected consistently in 100% of influent wastewaters (mean concentration range, 4.36-4.46 log10 genome equivalent (GE) copies/L) and final effluent samples of three DWWTPs (range, 3.35-3.61 log10 GE copies/L). Overall, 94% (45/48) of the wastewater analyzed and 95% (20/21) of the associated river water samples were positive for rotavirus (range, 2.04-6.77 log10 GE copies/L). The activated sludge process with 0.10-0.43 log10 reduction values (LRV) only moderately reduced the viral loads. Similarly, one of the DWWTPs that operated the biofilter modality produced 0.20 LRV. Though the additional treatment with chlorine produced higher LRV (range, 0.31-0.53) than the corresponding activated sludge or biofilter process, the difference in viral removals was not significant (p > 0.05). The equivalent treatment efficiencies of the four DWWTPs varied from 19 to 43% decay in the population of rotavirus. Further, infectious rotavirus ranging from 66.67 to 100%, 50 to 100%, and 66.67 to 100% were detected in the post-activated sludge, final effluents, and river water samples, respectively. In conclusion, the findings of infectious rotavirus in both the final effluents and associated rivers represent an infection risk for humans or animals during contact. Thus, close monitoring for rotavirus and risk assessment studies under distinct exposure scenarios may further shed light on the health-related risks associated with water recovery and reuse in urban settings.

Global investigation of the presence of adenovirus in different types of water resources: a systematic review

Waterborne viruses such as adenoviruses cause major health problems in the world. Human adenoviruses are the second leading cause of childhood gastroenteritis worldwide. In recent years, the presence of the virus in aquatic resources has been shown in several studies. In this paper, the global presence of adenovirus in different types of water resources are reviewed through studying several surveys conducted in different countries worldwide. We designed one search study to collect the maximum number of related articles to this subject in international databases search engine via relevant keywords. After reviewing the articles, the most relevant ones were selected, and after classification and extracting the required information, they were reported in the tables presented in this study. In general, it was found that the highest rate of the presence of adenoviruses has been reported in sewage water, inlet, and outlet of the treatment plant while the lowest rate of the presence of adenovirus in the dam water. These findings demonstrate that treatment plant system has weakness in removing the adenovirus and are strongly recommended for treatment plants to use new and better protocols to remove this virus. In addition, appropriate diagnostic methods that combines molecular biological technique with infectivity assay should be implemented for detection of adenoviruses in water resources.

A 20-year shift in China's sewage sludge heavy metals and its feasibility of nutrient recovery in land use

Recycling resources from wastewater is even more important for developing a more sustainable society. Disposing sewage sludge, which accumulates most pollutants and resources in sewage, is the main challenge in wastewater pollution control and resource utilization. Heavy metals (HMs) are the greatest constraint limiting the application of sewage sludge to land as a sustainable use of this material. We conducted a meta-analysis of the concentrations of HMs in Chinese sewage sludge by combining data from studies published from 2000 to 2019 (N = 8477). Over this period, the reported concentrations of HMs in sewage sludge declined in three stages (a fluctuating stage, a slight decrease stage, and a rapid and stable decrease stage). The results revealed that economic development and environmental policy implementation were the main factors mitigating HM pollution in sewage sludge in China. Moreover, if environmental regulations were strengthened and HM pollution-mitigation strategies were made consistent, such that the proportion of sewage sludge applied to land in China could be increased from 18.6% to 48.0% (the proportion applied to land in the United States), the ecosystem services analysis showed that huge ecological-economic benefits could be realized (3.1 billion Chinese Yuan) and the use of fertilizers could be substantially reduced (the use of nitrogen fertilizers by 8.5% and the use of phosphate fertilizers by 18.1%). This review shows that China should formulate a unified policy and interdepartmental committee for sustainable application of sewage sludge to land and wastewater resource recycling management.

Effect of pH on UV/H2O2-mediated removal of single, mixed and halogenated parabens from water

Adjusting pH values in aqueous environments can significantly improve the efficiency by which parabens and halo-parabens are removed. In this study, 20 neutral and deprotonated species were selected as models to investigate their pH-dependent removal mechanisms and kinetics by a UV/H2O2 process using density functional theory (DFT). Compared to neutral species, deprotonated species exhibit higher reactivity to HO• due to their high electron cloud density. H atom abstraction (HAA) reactions on the substitution groups are the most favorable pathways for neutral species, while radical adduct formation (RAF) reactions are the most favorable for deprotonated species. Single electron transfer (SET) reactions can be neglected for neutral species, while these reactions become a viable route for deprotonated molecules. The total reaction rate constants range from 1.63 × 109 to 3.74 × 1010 M- 1 s- 1 at pH 7.0, confirming the experimental results. Neutral and weakly alkaline conditions are favorable for the degradation of MeP and halo-parabens in the UV/H2O2 process. The order of removal efficiency at optimum pH is dihalo-parabens > mono-halo-parabens ≈ F, F-MeP > MeP. Furthermore, the transformation products must undergo oxidative degradation due to their high toxicity. Our findings provide new insights into the removal of parabens and their halogenated derivatives from wastewater.

Surveillance of SARS-CoV-2, rotavirus, norovirus genogroup II, and human adenovirus in wastewater as an epidemiological tool to anticipate outbreaks of COVID-19 and acute gastroenteritis in a city without a wastewater treatment plant in the Peruvian Highlands

The coronavirus disease 2019 (COVID-19) pandemic has demonstrated that Wastewater Based Epidemiology is a fast and economical alternative for monitoring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the community level in high-income countries. In the present study, wastewater from a city in the Peruvian Highlands, which lacks a wastewater treatment plant, was monitored for one year to assess the relationship between the concentration of SARS-CoV-2 and the reported cases of COVID-19 in the community. Additionally, we compared the relationship between rotavirus (RV), norovirus genogroup II (NoV GGII), and human adenovirus (HAdV) with the number of reported cases of acute gastroenteritis. Before commencing the analysis of the samples, the viral recovery efficacy of three processing methods was determined in spiked wastewater with SARS-CoV-2. This evaluation demonstrated the highest recovery rate with direct analysis (72.2 %), as compared to ultrafiltration (50.8 %) and skimmed milk flocculation (5.6 %). Wastewater monitoring revealed that 72 % (36/50) of the samples tested positive for SARS-CoV-2, with direct analysis yielding the highest detection frequency and quantification of SARS-CoV-2. Furthermore, a strong correlation was observed between the concentration of SARS-CoV-2 in wastewater and the reported cases of COVID-19, mainly when we shift the concentration of SARS-CoV-2 by two weeks, which allows us to anticipate the onset of the fourth and fifth waves of the pandemic in Peru up to two weeks in advance. All samples processed using the skimmed milk flocculation method tested positive and showed high concentrations of RV, NoV GGII, and HAdV. In fact, the highest RV concentrations were detected up to four weeks before outbreaks of acute gastroenteritis reported in children under four years of age. In conclusion, the results of this study suggest that periodic wastewater monitoring is an excellent epidemiological tool for surveillance and can anticipate outbreaks of infectious diseases, such as COVID-19, in low- and middle-income countries.

Quantification and molecular characterization of intact rotavirus species A (RVA) in municipal solid waste leachate

AIMS

Leachate comprises a solid waste decomposition product found fresh in collection trucks or as an effluent in landfills. This study aimed to assess the occurrence, concentrations, and genetic diversity of intact rotavirus species A (RVA) in solid waste leachate.

METHODS AND RESULTS

Leachate samples were concentrated by ultracentrifugation, treated with propidium monoazide (PMA), and exposed to LED photolysis. Treated and untread samples were extracted using the QIAamp Fast DNA Stool mini kit, and nucleic acids were screened for RVA employing a Taqman® Real-time PCR. The PMA RT-qPCR method detected RVA in eight out of nine truck samples and in 15.40% (2/13) of the landfill leachate samples. The RVA concentrations in the PMA-treated samples ranged from 4.57 × 103 to 2.15 × 107 genomic copies (GC) 100 mL-1 in truck leachate and from 7.83 × 103 to 1.42 × 104 GC 100 mL-1 in landfill samples. Six truck leachate samples were characterized as RVA VP6 genogroup I2 by partial nucleotide sequencing.

CONCLUSIONS

The high intact RVA detection rates and concentrations in truck leachate samples indicate potential infectivity and comprise a warning for solid waste collectors concerning hand-to-mouth contact and the splash route.

Norovirus, Hepatitis A and SARS-CoV-2 surveillance within Chilean rural wastewater treatment plants based on different biological treatment typologies

During the COVID-19 pandemic, wastewater from WWTPs became an interesting source of epidemiological surveillance. However, there is uncertainty about the influence of treatment type on virus removal. The aim of this study was to assess viral surveillance within wastewater treatment plants (WWTPs) based on different biological treatments. Seasonal monitoring (autumn-winter and spring-summer) was conducted in 10 Chilean rural WWTPs, which were based on activated sludge, aerated lagoons, bio-discs, constructed wetlands, vermifilters and mixed systems. Viruses were measured (influent/effluent) by the RT-qPCR technique, using a commercial kit for SARS-CoV-2, NoV GI, NoV GII, and HAV. The detection of SARS-CoV-2 viral variants by genotyping was performed using SARS-CoV-2 Mutation Assays (ThermoFisher Scientific, USA). JC polyomavirus detection (control), as well as a qPCR technique. Results showed that SARS-CoV-2, NoV GI and GII were detected in influents at values between <5 and 462, 0 to 28, and 0 to 75 GC/mL, respectively. HAV was not detected among the studied WWTPs. The monitored WWTPs removed these viruses at percentages between 0 and 100 %. WWTPs based on activated sludge with bio-discs demonstrated to be the most efficient at removing SARS-CoV-2 (up to 98 %) and NoV GI and GII (100 %). Meanwhile, bio-discs technologies were the least efficient for viral removal, due to biofilm detachment, which could also adsorb viral aggregates. A correlation analysis established that solids, pH, and temperature are the most influential parameters in viral removal. Wastewater-based surveillance at WWTP allowed for the detection of Omicron before the Chilean health authorities notified its presence in the population. In addition, surveillance of viruses and other microorganisms could help assess the potential public health risk of wastewater recycling.

One-Year Surveillance of SARS-CoV-2 and Rotavirus in Water Matrices from a Hot Spring Area

The pandemic of Coronavirus Disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is still impacting not only on human health but also all economic activities, especially in those related to tourism. In this study, in order to characterize the presence of SARS-CoV-2 in a hot spring park in Uruguay, swimming pools water, wastewater, and surface water from this area were analyzed by quantitative PCR. Wastewater from Salto city located next to the hydrothermal spring area was also evaluated as well as the presence of Rotavirus (RV). Overall, SARS-CoV-2 was detected in 13% (13/102) of the analyzed samples. Moreover, this virus was not detected in any of the samples from the swimming pools water and was present in 18% (3/17) of wastewater samples from the hotels area showing the same trend between the titer of SARS-CoV-2 and the number of infected people in Salto city. SARS-CoV-2 was also detected in wastewater samples (32% (11/34)) from Salto city, detecting the first positive sample when 105 persons were positive for SARS-CoV-2. Rotavirus was detected only in 10% (2/24) of the wastewater samples analyzed in months when partial lockdown measures were taken, however, this virus was detected in nearly all wastewater samples analyzed when social distancing measures and partial lockdown were relaxed. Wastewater results confirmed the advantages of using the detection and quantification of viruses in this matrix in order to evaluate the presence of these viruses in the population, highlighting the usefulness of this approach to define and apply social distancing. This study suggests that waters from swimming pools are not a source of infection for SARS-CoV-2, although more studies are needed including infectivity assays in order to confirm this statement.

Mechanistic insights into the generation and control of Cl-DBPs during wastewater sludge chlorination disinfection process

Chlorination disinfection has been widely used to kill the pathogenic microorganisms in wastewater sludge during the special Covid-19 period, but sludge chlorination might cause the generation of harmful disinfection byproducts (DBPs). In this work, the transformation of extracellular polymeric substance (EPS) and mechanisms of Cl-DBPs generation during sludge disinfection by sodium hypochlorite (NaClO) were investigated using multispectral analysis in combination with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The microorganism Escherichia coli (E. coli) was effectively inactivated by active chlorine generated from NaClO. However, a high diversity of Cl-DBPs were produced with the addition of NaClO into sludge, causing the increase of acute toxicity on Q67 luminous bacteria of chlorinated EPS. A variety of N-containing molecular formulas were produced after chlorination, but N-containing DBPs were not detected, which might be the indicative of the dissociation of -NH₂ groups after Cl-DBPs generated. Additionally, the release of N-containing compounds was increased in alkaline environment caused by NaClO addition, resulted in more Cl-DBPs generation via nucleophilic substitutions. Whereas, less N-compounds and Cl-DBPs were detected after EPS chlorination under acidic environment, leading to lower cell cytotoxicity. Therefore, N-containing compounds of lignin derivatives in sludge were the major Cl-DBPs precursors, and acidic environment could control the release of N-compounds by eliminating the dissociation of functional groups in lignin derivatives, consequently reducing the generation and cytotoxicity of Cl-DBPs. This study highlights the importance to control the alkalinity of sludge to reduce Cl-DBPs generation prior to chlorination disinfection process, and ensure the safety of subsequential disposal for wastewater sludge.

Comparison of disinfection by-products formed by preoxidation of sulfamethazine by K2FeO4 and O3 and the influence on cytotoxicity and biological toxicity

This study researched the formation of disinfection by-products (DBPs) in sulfamethazine (SMZ) chlorination after preoxidation by K2FeO4 and O3 and the influence of preoxidation on cytotoxicity and biological toxicity. Then, the study emphatically analyzed the influencing factors such as NaClO dosage, pH value, reaction temperature, fulvic acid (FA), and bromide and iodide ions. The results showed that preoxidation by K2FeO4 effectively inhibited the formation of DBPs of haloketones (HKS) and trihalomethanes (THMs), with an average inhibition rate of over 60%. The formation of DBPs after preoxidation by O3 was higher than that by K2FeO4; preoxidation by K2FeO4 reduced the influence of NaClO dosage, temperature, and pH value on the production of DBPs after SMZ chlorination. The cytotoxicity and biological toxicity of SMZ chlorination after preoxidation were evaluated and compared by calculating the LC50 value of DBPs and the luminescent bacteria method. The results of both calculation methods showed that the toxicity of DBPs after preoxidation by K2FeO4 was lower than that by O3 preoxidation. K2FeO4 and O3 preoxidation improved the SMZ removal efficiency by 8.41 and 10.49%, respectively, and inhibited the formation of most DBPs, but the preoxidation promoted the formation of highly toxic DBPs (HANs). The toxicity of DBPs formed in SMZ chlorination after preoxidation by K2FeO4 and O3 was slightly higher than that of chlorination disinfection alone, but it was still within the safe range. This study provides more new details about the formation and toxicity changes of DBPs in the process of SMZ chlorination after preoxidation.

Modeling the number of people infected with SARS-COV-2 from wastewater viral load in Northwest Spain

The quantification of the SARS-CoV-2 RNA load in wastewater has emerged as a useful tool to monitor COVID-19 outbreaks in the community. This approach was implemented in the metropolitan area of A Coruña (NW Spain), where wastewater from a treatment plant was analyzed to track the epidemic dynamics in a population of 369,098 inhabitants. Viral load detected in the wastewater and the epidemiological data from A Coruña health system served as main sources for statistical models developing. Regression models described here allowed us to estimate the number of infected people (R2 = 0.9), including symptomatic and asymptomatic individuals. These models have helped to understand the real magnitude of the epidemic in a population at any given time and have been used as an effective early warning tool for predicting outbreaks in A Coruña municipality. The methodology of the present work could be used to develop a similar wastewater-based epidemiological model to track the evolution of the COVID-19 epidemic anywhere in the world where centralized water-based sanitation systems exist.

Quantification of human enteric viruses as alternative indicators of fecal pollution to evaluate wastewater treatment processes

We investigated the potential use and quantification of human enteric viruses in municipal wastewater samples of Winnipeg (Manitoba, Canada) as alternative indicators of contamination and evaluated the processing stages of the wastewater treatment plant. During the fall 2019 and winter 2020 seasons, samples of raw sewage, activated sludge, effluents, and biosolids (sludge cake) were collected from the North End Sewage Treatment Plant (NESTP), which is the largest wastewater treatment plant in the City of Winnipeg. DNA (Adenovirus and crAssphage) and RNA enteric viruses (Pepper mild mottle virus, Norovirus genogroups GI and GII, Rotavirus Astrovirus, and Sapovirus) as well as the uidA gene found in Escherichia coli were targeted in the samples collected from the NESTP. Total nucleic acids from each wastewater treatment sample were extracted using a commercial spin-column kit. Enteric viruses were quantified in the extracted samples via quantitative PCR using TaqMan assays. Overall, the average gene copies assessed in the raw sewage were not significantly different (p-values ranged between 0.1023 and 0.9921) than the average gene copies assessed in the effluents for DNA and RNA viruses and uidA in terms of both volume and biomass. A significant reduction (p-value ≤ 0.0438) of Adenovirus and Noroviruses genogroups GI and GII was observed in activated sludge samples compared with those for raw sewage per volume. Higher GCNs of enteric viruses were observed in dewatered sludge samples compared to liquid samples in terms of volume (g of sample) and biomass (ng of nucleic acids). Enteric viruses found in gene copy numbers were at least one order of magnitude higher than the E. coli marker uidA, indicating that enteric viruses may survive the wastewater treatment process and viral-like particles are being released into the aquatic environment. Viruses such as Noroviruses genogroups GI and GII, and Rotavirus were detected during colder months. Our results suggest that Adenovirus, crAssphage, and Pepper mild mottle virus can be used confidently as complementary viral indicators of human fecal pollution.

Sodium hypochlorite disinfection of SARS-CoV-2 spiked in water and municipal wastewater

Infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has the potential to be collected in wastewater from mucus, sputum, and feces of infected individuals, raising questions about the appropriate handling and treatment of the resulting wastewater. Current evidence indicates the likelihood of waterborne SARS-CoV-2 transmission is low; nonetheless, confirming the efficacy of disinfection against SARS-CoV-2 is prudent to ensure multiple barriers of protection for infectious SARS-CoV-2 that could be present in municipal and hospital wastewater. Sodium hypochlorite (free chlorine) is widely used for pathogen control in water disinfection applications. In the current study, we investigated the inactivation of SARS-CoV-2 in DI water and municipal wastewater primary influent by sodium hypochlorite (free chlorine) addition. Our results showed rapid disinfection of SARS-CoV-2, with less than 1 mg-min/L required for >3 log10 TCID50 reduction in DI water. More than 5 mg-min/L was required for 3 log10 TCID50 reduction in primary influent, suggesting potential shielding of the virus by suspended solids. These results are consistent with expected virus inactivation by free chlorine and suggest the adequacy of free chlorine disinfection for inactivation of infectious SARS-CoV-2 in water matrices.

Inactivation and risk control of pathogenic microorganisms in municipal sludge treatment: A review

The rapid global spread of coronavirus disease 2019 (COVID-19) has promoted concern over human pathogens and their significant threats to public health security. The monitoring and control of human pathogens in public sanitation and health facilities are of great importance. Excessive sludge is an inevitable byproduct of sewage that contains human and animal feces in wastewater treatment plants (WWTPs). It is an important sink of different pollutants and pathogens, and the proper treatment and disposal of sludge are important to minimize potential risks to the environment and public health. However, there is a lack of comprehensive analysis of the diversity, exposure risks, assessment methods and inactivation techniques of pathogenic microorganisms in sludge. Based on this consideration, this review summarizes the control performance of pathogenic microorganisms such as enterovirus, Salmonella spp., and Escherichia coli by different sludge treatment technologies, including composting, anaerobic digestion, aerobic digestion, and microwave irradiation, and the mechanisms of pathogenic microorganism inactivation in sludge treatment processes are discussed. Additionally, this study reviews the diversity, detection methods, and exposure risks of pathogenic microorganisms in sludge. This review advances the quantitative assessment of pathogenic microorganism risks involved in sludge reuse and is practically valuable to optimize the treatment and disposal of sludge for pathogenic microorganism control.

Full-scale municipal sludge pyrolysis in China: Design fundamentals, environmental and economic assessments, and future perspectives

The increasing amount of municipal sludge in China requires safe and effective management to protect human health and ensure environmental sustainability. Pyrolysis is a thermochemical process that decomposes organic matter at elevated temperature and under anaerobic conditions, and it has attracted an increasing attention in sludge treatment in the recent years. However, comprehensive environmental and economic assessment of sludge pyrolysis in China's context is rare, due to the small quantities of full-scale sludge pyrolysis plant. In this paper, we applied our design and operation parameters of full-scale sludge pyrolysis plants to generate the material and energy consumptions of the pyrolysis system under various of conditions, including sludge organic content and moisture content, system size, system energy distribution, and whether or not heat substitution is applied. Life cycle assessment and techno-economic assessment were then applied to investigate the environmental and economic performance of the system. Our results demonstrate the significant environmental and economic impacts associated with sludge properties and system size. Generally, sludge with higher organic content and lower moisture content requires less natural gas consumption, which leads to a simultaneous improvement of the system environmental and economic performance. The system economic performance is more sensitive to the system size, and centralized sludge handling using a larger pyrolysis system is more economic favorable. In the most ideal case, the average global warming potential and minimum sludge handling price of sludge pyrolysis could be as low as -32.5 kg CO₂-Eq/t DS and 188.8 $/t DS, respectively. Based on these results, we discussed the pathways that could be taken to further optimize the environmental and economic performances of the pyrolysis system.

Occurrence of various viruses and recent evidence of SARS-CoV-2 in wastewater systems

Viruses are omnipresent and persistent in wastewater, which poses a risk to human health. In this review, we summarise the different qualitative and quantitative methods for virus analysis in wastewater and systematically discuss the spatial distribution and temporal patterns of various viruses (i.e., enteric viruses, Caliciviridae (Noroviruses (NoVs)), Picornaviridae (Enteroviruses (EVs)), Hepatitis A virus (HAV)), and Adenoviridae (Adenoviruses (AdVs))) in wastewater systems. Then we critically review recent SARS-CoV-2 studies to understand the ongoing COVID-19 pandemic through wastewater surveillance. SARS-CoV-2 genetic material has been detected in wastewater from France, the Netherlands, Australia, Italy, Japan, Spain, Turkey, India, Pakistan, China, and the USA. We then discuss the utility of wastewater-based epidemiology (WBE) to estimate the occurrence, distribution, and genetic diversity of these viruses and generate human health risk assessment. Finally, we not only promote the prevention of viral infectious disease transmission through wastewater but also highlight the potential use of WBE as an early warning system for public health assessment.

Where do we stand to oversee the coronaviruses in aqueous and aerosol environment? Characteristics of transmission and possible curb strategies

By 17 October 2020, the severe acute respiratory syndrome coronavirus (SARS-CoV-2) has caused confirmed infection of more than 39,000,000 people in 217 countries and territories globally and still continues to grow. As environmental professionals, understanding how SARS-CoV-2 can be transmitted via water and air environment is a concern. We have to be ready for focusing our attention to the prompt diagnosis and potential infection control procedures of the virus in integrated water and air system. This paper reviews the state-of-the-art information from available sources of published papers, newsletters and large number of scientific websites aimed to provide a comprehensive profile on the transmission characteristics of the coronaviruses in water, sludge, and air environment, especially the water and wastewater treatment systems. The review also focused on proposing the possible curb strategies to monitor and eventually cut off the coronaviruses under the authors' knowledge and understanding.

SARS-CoV-2 in the environment-Non-droplet spreading routes

The new coronavirus SARS-CoV-2, first identified in Wuhan (China) in December 2019, represents the same family as the Serve Acute Respiratory Syndrome Coronavirus-1 (SARS-CoV-1). These viruses spread mainly via the droplet route. However, during the pandemic of COVID-19 other reservoirs, i.e., water (surface and ground), sewage, garbage, or soil, should be considered. As the infectious SARS-CoV-2 particles are also present in human excretions, such a non-droplet transmission is also possible. A significant problem is the presence of SARS-CoV-2 in the hospital environment, including patients' rooms, medical equipment, everyday objects and the air. Relevant is selecting the type of equipment in the COVID-19 hospital wards on which the virus particles persist the shortest or do not remain infectious. Elimination of plastic objects/equipment from the environment of the infected person seems to be of great importance. It is particularly relevant in water reservoirs contaminated with raw discharges. Wastewater may contain coronaviruses and therefore there is a need for expanding Water-Based Epidemiology (WBE) studies to use obtained values as tool in determination of the actual percentage of the SARS-CoV-2 infected population in an area. It is of great importance to evaluate the available disinfection methods to control the spread of SARS-CoV-2 in the environment. Exposure of SARS-CoV-2 to 65-70% ethanol, 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite has effectively eliminated the virus from the surfaces. Since there are many unanswered questions about the transmission of SARS-CoV-2, the research on this topic is still ongoing. This review aims to summarize current knowledge on the SARS-CoV-2 transmission and elucidate the viral survival in the environment, with particular emphasis on the possibility of non-droplet transmission.

A chronicle of SARS-CoV-2: Seasonality, environmental fate, transport, inactivation, and antiviral drug resistance

In this review, we present the environmental perspectives of the viruses and antiviral drugs related to SARS-CoV-2. The present review paper discusses occurrence, fate, transport, susceptibility, and inactivation mechanisms of viruses in the environment as well as environmental occurrence and fate of antiviral drugs, and prospects (prevalence and occurrence) of antiviral drug resistance (both antiviral drug resistant viruses and antiviral resistance in the human). During winter, the number of viral disease cases and environmental occurrence of antiviral drug surge due to various biotic and abiotic factors such as transmission pathways, human behaviour, susceptibility, and immunity as well as cold climatic conditions. Adsorption and persistence critically determine the fate and transport of viruses in the environment. Inactivation and disinfection of virus include UV, alcohol, and other chemical-base methods but the susceptibility of virus against these methods varies. Wastewater treatment plants (WWTPs) are major reserviors of antiviral drugs and their metabolites and transformation products. Ecotoxicity of antiviral drug residues against aquatic organisms have been reported, however more threatening is the development of antiviral resistance, both in humans and in wild animal reservoirs. In particular, emergence of antiviral drug-resistant viruses via exposure of wild animals to high loads of antiviral residues during the current pandemic needs further evaluation.

Disinfection by-products in drinking water: Occurrence, toxicity and abatement

Disinfection means the killing of pathogenic organisms (e.g. bacteria and its spores, viruses, protozoa and their cysts, worms, and larvae) present in water to make it potable for other domestic works. The substances used in the disinfection of water are known as disinfectants. At municipal level, chlorine (Cl₂), chloramines (NH₂Cl, NHCl₂), chlorine dioxide (ClO₂), ozone (O₃) and ultraviolet (UV) radiations, are the most commonly used disinfectants. Chlorination, because of its removal efficiency and cost effectiveness, has been widely used as method of disinfection of water. But, disinfection process may add several kinds of disinfection by-products (DBPs) (∼600-700 in numbers) in the treated water such as Trihalomethanes (THM), Haloacetic acids (HAA) etc. which are detrimental to the human beings in terms of cytotoxicity, mutagenicity, teratogenicity and carcinogenicity. In water, THMs and HAAs were observed in the range from 0.138 to 458 μg/L and 0.16-136 μg/L, respectively. Thus, several regulations have been specified by world authorities like WHO, USEPA and Bureau of Indian Standard to protect human health. Some techniques have also been developed to remove the DBPs as well as their precursors from the water. The popular techniques of DBPs removals are adsorption, advance oxidation process, coagulation, membrane based filtration, combined approaches etc. The efficiency of adsorption technique was found up to 90% for DBP removal from the water.

Development, current state and future trends of sludge management in China: Based on exploratory data and CO2-equivaient emissions analysis

This study statistically reported the current state of sludge treatment/disposal in China from the aspects of sources, technical routes, geographical distribution, and development by using observational data after 1978. By the end of 2019, 5476 municipal wastewater treatment plants were operating in China, leading to an annual sludge productivity of 39.04 million tons (80% water content). Overall, 29.3% of the sludge in China was disposed via land application, followed by incineration (26.7%) and sanitary landfills (20.1%). Incineration, compost, thermal hydrolysis and anerobic digestion were the mainstream technologies for sludge treatment in China, with capacities of 27,122, 11,250, 8342 and 6944 t/d in 2019, respectively. Incineration and drying were preferentially constructed in East China. In contrast, sludge compost was most frequently used in Northeast China (46.5%), East China (22.4%) and Central China (12.8%), while anaerobic digestion in East China, North China and Central China. The capacities of sludge facilities exhibited a sharp increase in 2009-2019, with an overall greenhouse gas emissions in China in 2019 reached 108.18 × 10⁸ kg CO₂-equivaient emissions, and the four main technical routes contributed as: incineration (45.11%) > sanitary landfills (23.04%) > land utilization (17.64%) > building materials (14.21%). Challenges and existing problems of sludge disposal in China, including high CO₂ emissions, unbalanced regional development, low stabilization and land utilization levels, were discussed. Finally, suggestions regarding potential technical and administrative measures in China, and sustainable sludge management for developing countries, were also given.

The Effectiveness of Activated Sludge Procedure and UV-C254 in Norovirus Inactivation in a Tunisian Industrial Wastewater Treatment Plant

The molecular detection of Norovirus GI and Norovirus GII in the Tunisian industrial wastewater treatment plant of Charguia I was conducted to test the effectiveness of secondary biological treatment using the activated sludge procedure and the UV-C₂₅₄ tertiary treatment radiation using a UV disinfection prototype to upgrade the quality of the purified wastewater. A total of 140 sewage samples were collected from the two lines of sewage treatment procedures. Norovirus GI and Norovirus GII have been found and quantified using Real-Time Reverse Transcription Polymerase Chain Reaction (qRT-PCR) in 66.4 and 86.4% of the collected wastewater samples. The Norovirus GI and GII mean concentration values got in the treated effluents showed a significant decrease of Norovirus viral content rates detected from upstream to downstream of activated sludge procedures and at the output of UV-C₂₅₄ treatment. These findings characterise and denote for the first time the effectiveness of biological and UV-C254 treatment for Norovirus GI and Norovirus GII removal in Tunis City, northern Tunisia. Also, these data underlined the fact that purified sewage makes up a route of gastroenteritis virus transmission and a cause of viral gastroenteritis associated with water-borne and food-borne outbreaks.

Disinfection technology of hospital wastes and wastewater: Suggestions for disinfection strategy during coronavirus Disease 2019 (COVID-19) pandemic in China

Hospitals are important sources of pollutants resulted from diagnostic, laboratory and research activities as well as medicine excretion by patients, which include active component of drugs and metabolite, chemicals, residues of pharmaceuticals, radioactive markers, iodinated contrast media, etc. The discharge of hospital wastes and wastewater, especially those without appropriate treatment would expose the public in danger of infection. In particular, under the Coronavirus Disease 2019 (COVID-19) pandemic context in China, it is of great significance to reduce the health risks to the public and environment. In this study, technologies of different types of hospital wastes and wastewater disinfection have been summarized. Liquid chlorine, sodium hypochlorite, chlorine dioxide, ozone, and ultraviolet irradiation disinfection are commonly used for hospital wastewater disinfection. While incineration, chemical disinfection, and physical disinfection are commonly used for hospital wastes disinfection. In addition, considering the characteristics of various hospital wastes, the classification and selection of corresponding disinfection technologies are discussed. On this basis, this study provides scientific suggestions for management, technology selection, and operation of hospital wastes and wastewater disinfection in China, which is of great significance for development of national disinfection strategy for hospital wastes and wastewater during COVID-19 pandemic.

Quantum Leap from Gold and Silver to Aluminum Nanoplasmonics for Enhanced Biomedical Applications

Nanotechnology has been used in many biosensing and medical applications, in the form of noble metal (gold and silver) nanoparticles and nanostructured substrates. However, the translational clinical and industrial applications still need improvements of the efficiency, selectivity, cost, toxicity, reproducibility, and morphological control at the nanoscale level. In this review, we highlight the recent progress that has been made in the replacement of expensive gold and silver metals with the less expensive aluminum. In addition to low cost, other advantages of the aluminum plasmonic nanostructures include a broad spectral range from deep UV to near IR, providing additional signal enhancement and treatment mechanisms. New synergistic treatments of bacterial infections, cancer, and coronaviruses are envisioned. Coupling with gain media and quantum optical effects improve the performance of the aluminum nanostructures beyond gold and silver.

The performance of biological and tertiary wastewater treatment procedures for rotaviruses A removal

Enteric viruses, generally found in sewage, are recognized as the main cause of waterborne and foodborne public health outbreaks. Among leading enteric viruses, the Rotavirus A (RVA) detection in wastewater appeared to be a novel approach to monitor the emergence of these viruses in some countries where the viral gastroenteritis surveillance is almost absent such as in Tunisia. The RVA detection and quantification in an industrial sewage purification plant of Charguia I (Tunis, Tunisia) were achieved to evaluate the performance of activated sludge procedures coupled to a macrofiltration monolamp ultraviolet irradiation type C (UV-C₂₅₄) disinfection reactor. This UV-C₂₅₄ system was preceded by a fiberglass cartridge filter system with an average porosity of 45 μm to clarify the water and thus increase its UV transmittance. A total of 140 composite sewage samples was collected from this line of treatment and analyzed for RVA detection. The detection and the viral load quantification of RVA were performed using real-time reverse transcription polymerase chain reaction (RT-PCR). The virological results showed in general that RVA were detected at high frequency of 98% (137/140). In fact, the RVA detection rates at the exit of the two studied wastewater treatment were about 100% at the exit of the activated sludge procedure. It means that all wastewater sampled at this last step of treatment was positive for RVA detection. On the other hand, 92.5% of the wastewater samples taken at the exit of the monolamp UV-C₂₅₄ reactor were positive for the RVA. However, the RVA quantification results expressed as viral load showed a significant reduction in the means of RVA viral loads at the exit of the biological activated sludge procedure and the tertiary UV-C₂₅₄ treatment, showing in general an improved treated wastewater virological quality. Therefore, the RVA load removal rates recorded at the two successive stages of treatment, the activated sludge and the UV-C₂₅₄ treatment, were around 85% and 73%, respectively, as compared to the one with 100% registered for the raw wastewater. In addition, good physical-chemical and bacteriological qualities of the treated sewage were found at the exit of the two considered wastewater treatment procedures. The present investigation represents the first Tunisian environmental report showing the good effectiveness and performance of the biological and the tertiary treatments for RVA removal. Therefore, an improved and an optimized tertiary disinfection treatment was needed since it could be a good means for getting better viral water quality and for minimizing the transmission and dissemination of human infectious viral diseases.

Performance of wastewater reclamation systems in enteric virus removal

Analysis of virus removal by tertiary or advanced sewage treatment processes is an emerging topic due to importance of reusing water on a global level. This study aimed to monitor important human viral pathogens: the human adenovirus (HAdV), JC polyomavirus (JCV) and Species A rotaviruses (RVA) in urban sewage, secondary effluents and reclaimed water from metropolitan São Paulo (MSP), Brazil. Four large wastewater treatment plants (WWTPs) in MSP were sampled monthly during a one-year period (April 2015 to March 2016). The viruses were quantified by quantitative PCR (qPCR), and HAdV viability was tested by the integrated cell culture (ICC)-qPCR assay. WWTPs are composed of activated sludge processes and different tertiary treatments (coagulation/sedimentation, sand-anthracite filters, membrane bioreactors (MBRs)/reverse osmosis (RO) and disinfection by chlorination). Physicochemical parameters were also evaluated to verify association with density of viruses detected in different treatment stages. HAdV, JCV and RVA were consistently detected (100%) in the sewage influent samples (range: 10⁶-10⁸ genome copies GC/L). In the secondary effluent, HAdV was detected in 100% (48/48) of the analysed samples, JCV in 85.4% and RVA in 97.9% (range: 10⁴-10⁷ GC/L for all viruses tested). HAdV was the most frequently detected virus in the tertiary effluent (62.2%) (28/45), exhibiting a viability between 0 and 44% of the tested samples in the wastewater reclamation systems. The MBR/RO systems demonstrated better virus removal efficiencies (range: 2.3-2.9 log₁₀). Temperature, pH, turbidity and total organic carbon presented association with the viral density in the reclaimed water samples. Presence of viruses in treated effluents can indicates health risks depending on uses of recovery water. Further risk assessment studies should be conducted to better assess health risks under different exposure scenarios for water recovery in urban settings.

Molecular detection and genotyping of group A rotavirus in two wastewater treatment plants, Iran

In different countries especially developing countries, treatment of urban wastewater might be ineffective removal of pathogens such as group A rotavirus. The objective of this study is to evaluate the efficiency of rotavirus removal in two wastewater treatment plants (WWTPs) in Isfahan, Iran. To meet the study objectives, 96 sewage samples from influent (n = 48) and final effluents (n = 48) were collected by grab sampling. Two different concentration methods included pellet and two-phase used for concentrating sewage samples. The presence of rotavirus antigens in all concentrated sewage samples was screened by enzyme-linked immunosorbent method. To analyze the study samples, real-time PCR technique with SYBR Green I fluorescent dye and nested multiplex PCR for rotavirus genotyping were utilized respectively. Result indicated positive rotavirus percentage in two methods of ELISA and real-time PCR was equal to 61.45% (59 cases) and 44.79% (43 cases). In addition, analyzing seasonal distribution of rotavirus shows different distributions as below: in spring (18.64%), summer (20.33%), autumn (35.60%), and winter (25.42%). Finally, rotaviruses illustrate significantly higher frequency in cold seasons. G10 and G1 types are considered the most, among common genotypes which identified in 11 (25.58%) and 5 (11.62%), out of the 43 positive samples in WWTPs, followed by non-typeable genotypes (13.95%) and mix genotypes (11.62%); and different genotypes including G2, G3, G4, G8, G9, and G12 were equal to 2.33, 9.30, 9.30, 2.33, 7, and 7% in the WWTPs, respectively. Such high prevalence underlines the significance of environmental surveillance. Also, to eliminate potential pathogens especially enteric viruses from sewage, the improvement of treatment systems is essential.

Inactivation and Loss of Infectivity of Enterovirus 70 by Solar Irradiation

Enterovirus 70 (EV70) is an emerging viral pathogen that remains viable in final treated effluent. Solar irradiation is, therefore, explored as a low-cost natural disinfection strategy to mitigate potential concerns. EV70 was exposed to simulated sunlight for 24 h at a fluence rate of 28.67 J/cm2/h in three different water matrices, namely, phosphate-buffered saline (PBS), treated wastewater effluent, and chlorinated effluent. In the presence of sunlight, EV70 decreased in infectivity by 1.7 log, 1.0 log, and 1.3 log in PBS, effluent, and chlorinated effluent, respectively. Irradiated EV70 was further introduced to host cell lines and was unable to infect the cell lines. In contrast, EV70 in dark microcosms replicated to titers 13.5, 3.3, and 4.2 times the initial inoculum. The reduction in EV70 infectivity was accompanied by a reduction in viral binding capacity to Vero cells. In addition, genome sequencing analysis revealed five nonsynonymous nucleotide substitutions in irradiated viruses after 10 days of infection in Vero cells, resulting in amino acid substitutions: Lys14Glu in the VP4 protein, Ala201Val in VP2, Gly71Ser in VP3, Glu50Gln in VP1, and Ile47Leu in 3Cpro. Overall, solar irradiation resulted in EV70 inactivation and an inhibition of viral activity in all parameters studied.