Human viral pathogens in the wastewater-source water-drinking water continuum: Evidence, health risks, and lessons for future outbreaks in low-income settings.

Human viral pathogens, including SARS-CoV-2 continue to attract public and research attention due to their disruption of society, global health, and the economy. Several earlier reviews have investigated the occurrence and fate of SARS-CoV-2 in wastewater, and the potential to use such data in wastewater-based epidemiology. However, comprehensive reviews tracking SARS-CoV-2 and other viral pathogens in the wastewater-water-drinking water continuum and the associated risk assessment are still lacking. Therefore, to address this gap, the present paper makes the following contributions: (1) critically examines the early empirical results to highlight the occurrence and stability of SARS-CoV-2 in the wastewater-source water-drinking water continuum, (2) discusses the anthropogenic and hydro(geo)logical processes controlling the circulation of SARS-CoV-2 in the wastewater-source water-drinking water continuum, (3) discusses the risky behaviour, drivers and high-risk settings in the wastewater-source water-drinking water continuum, (4) uses the available empirical data on SARS-CoV-2 occurrence in the wastewater-source water-drinking water continuum to discuss human health risks from multiple exposure pathways, gendered aspects of SARS-CoV-2 transmission via shared on-site sanitation systems, and (5) develops and risk mitigation strategy based on the available empirical evidence and quantitative human risk assessment data. Finally, it presents a comprehensive research agenda on SARS-CoV-2/COVID-19 to guide the mitigation of future similar outbreaks in low-income settings.

A review of microalgae biofilm as an eco-friendly approach to bioplastics, promoting environmental sustainability.

In this comprehensive review, we delve into the challenges hindering the large-scale production of microalgae-based bioplastics, primarily focusing on economic feasibility and bioplastic quality. To address these issues, we explore the potential of microalgae biofilm cultivation as a sustainable and highly viable approach for bioplastic production. We present a proposed method for producing bioplastics using microalgae biofilm and evaluate its environmental impact using various tools such as life cycle analysis (LCA), ecological footprint analysis, resource flow analysis, and resource accounting. While pilot-scale and large-scale LCA data are limited, we utilize alternative indicators such as energy efficiency, carbon footprint, materials management, and community acceptance to predict the environmental implications of commercializing microalgae biofilm-based bioplastics. The findings of this study indicate that utilizing microalgae biofilm for bioplastic production offers significant environmental sustainability benefits. The system exhibits low energy requirements and a minimal carbon footprint. Moreover, it has the potential to address the issue of wastewater by utilizing it as a carbon source, thereby mitigating associated problems. However, it is important to acknowledge certain limitations associated with the method proposed in this review. Further research is needed to explore and engineer precise techniques for manipulating microalgae biofilm structure to optimize the accumulation of desired metabolites. This could involve employing chemical triggers, metabolic engineering, and genetic engineering to achieve the intended goals. In conclusion, this review highlights the potential of microalgae biofilm as a viable and sustainable solution for bioplastic production. While acknowledging the advantages, it also emphasizes the need for continued synthetic studies to enhance the efficiency and reliability of this approach. By addressing the identified drawbacks and maximizing the utilization of advanced techniques, we can further harness the potential of microalgae biofilm in contributing to a more environmentally friendly and economically feasible bioplastic industry.

Automated machine learning-based models for predicting and evaluating antibiotic removal in constructed wetlands.

Machine learning models can improve antibiotic removal performance in constructed wetlands (CWs) by optimizing the operation process. However, robust modeling approaches for revealing the complex biochemical treatment process of antibiotics in CWs are still lacking. In this study, two automated machine learning (AutoML) models achieved good performance with different sizes of the training dataset (mean absolute error = 9.94-13.68, coefficient of determination = 0.780-0.877), demonstrating the ability to predict antibiotic removal performance without human intervention. Explainable analysis results (the variable importance and Shapley additive explanations) revealed that the variable substrate type was more influential than the variables of influent wastewater quality and plant type. This study proposed a potential approach to comprehensively understanding the complex effects of key operational variables on antibiotic removal, which serve as a reference for optimizing operational adjustments in the CW process.

Enhanced nutrient removal in agro-industrial wastes-amended hybrid floating treatment wetlands treating real sewage: Laboratory microcosms to field-scale studies.

The use of natural agro-industrial materials as suspended fillers (SFs) in floating treatment wetlands (FTWs) to enhance nutrient removal performance has recently been gaining significant attention. However, the knowledge concerning the nutrient removal performance enhancement by different SFs (alone and in mixtures) and the major removal pathways is so far inadequate. The current research, for the first time, carried out a critical analysis using five different natural agro-industrial materials (biochar, zeolite, alum sludge, woodchip, flexible solid packing) as SFs in various FTWs of 20 L microcosm tanks, 450 L outdoor mesocosms, and a field-scale urban pond treating real wastewater over 180 d. The findings demonstrated that the incorporation of SFs in FTWs enhanced the removal performance of total nitrogen (TN) by 20-57% and total phosphorus (TP) by 23-63%. SFs further enhanced macrophyte growth and biomass production, leading to considerable increases in nutrient standing stocks. Although all the hybrid FTWs showed acceptable treatment performances, FTWs set up with mixtures of all five SFs significantly enhanced biofilm formation and enriched the abundances of the microbial community related to nitrification and denitrification processes, supporting the detected excellent N retention. N mass balance assessment demonstrated that nitrification-denitrification was the major N removal pathway in reinforced FTWs, and the high removal efficiency of TP was attributable to the incorporation of SFs into the FTWs. Nutrient removal efficiencies ranked in the following order among the various trials: microcosm scale (TN: 99.3% and TP: 98.4%) > mesocosm scale (TN: 84.0% and TP: 95.0%) > field scale (TN: -15.0-73.7% and TP: -31.5-77.1%). These findings demonstrate that hybrid FTWs could be easily scaled up for the removal of pollutants from eutrophic freshwater systems over the medium term in an environmentally-friendly way in regions with similar environmental conditions. Moreover, it demonstrates hybrid FTW as a novel way of disposing of significant quantities of wastes, showing a win-win means with a huge potential for large-scale application.

An updated review of the efficacy of buffer zones in warm/temperate and cold climates: Insights into processes and drivers of nutrient retention.

The transport of excess nutrients into freshwater systems constitutes a serious risk to both water quality and aquatic health. Vegetated buffer zones (VBZs) next to waterways are increasingly used in many parts of the world to successfully intercept and eliminate pollutants and other materials in overland flow, especially in warm or temperate regions. The major processes for the retention of pollutants in VBZ are microbial degradation, infiltration, deposition, filtration, adsorption, degradation, assimilation, etc. The effectiveness of the VBZ relies on several environmental factors, including BZ width, runoff intensity, slope, soil texture, temperature, vegetation type, etc. Among the reported factors, cold weather possesses the most detrimental impact on many of the processes that VBZ are designed to carry out. The freezing temperatures result in ice formation, interrupting biological activity, infiltration and sorption, etc. In the last twenty years, burgeoning research has been carried out on the reduction of diffuse nutrient pollution losses from agricultural lands using VBZ. Nonetheless, a dearth of studies has dealt with the problems and concerns in cold climates, representing an important knowledge gap in this area. In addition, the effectiveness of VBZ in terms of nutrient removal abilities varies from -136% to 100%, a range that reveals the incertitude surrounding the role of VBZ in cold regions. Moreover, frozen soils and plants may release nutrients after undergoing several freeze-thaw cycles followed by runoff events in spring snowmelt. This review suggests that the management and design of VBZ in cold climates needs close examination, and these systems might not frequently serve as a good management approach to decrease nutrient movement.

Recent advances on graphyne and its family members as membrane materials for water purification and desalination.

Graphyne and its family members (GFMs) are allotropes of carbon (a class of 2D materials) having unique properties in form of structures, pores and atom hybridizations. Owing to their unique properties, GFMs have been widely utilized in various practical and theoretical applications. In the past decade, GFMs have received considerable attention in the area of water purification and desalination, especially in theoretical and computational aspects. More recently, GFMs have shown greater prospects in achieving optimal separation performance than the experimentally derived commercial polyamide membranes. In this review, recent theoretical and computational advances made in the GFMs research as it relates to water purification and desalination are summarized. Brief details on the properties of GFMs and the commonly used computational methods were described. More specifically, we systematically reviewed the various computational approaches employed with emphasis on the predicted permeability and selectivity of the GFM membranes. Finally, the current challenges limiting their large-scale practical applications coupled with the possible research directions for overcoming the challenges are proposed.

Vegetated urban streams have sufficient purification ability but high internal nutrient loadings: Microbial communities and nutrient release dynamics.

The release of nutrients back into the water column due to macrophyte litter decay could offset the benefits of nutrient removal by hydrophytes within urban streams. However, the influence of this internal nutrient cycling on the overlying water quality and bacterial community structure is still an open question. Hence, litter decomposition trials using six hydrophytes, Typha latifolia (TL), Phragmites australis (PAU), Hydrilla verticillata (HV), Oenanthe javanica (OJ), Myriophyllum aquaticum (MA), and Potamogeton crispus (PC), were performed using the litterbag approach to mimic a 150-day plant litter decay in sediment-water systems. Field assessment using simple in/out mass balances and uptake by plant species was carried out to show the potential for phytoremediation and its mechanisms. Results from two years of monitoring (2020-2021) indicated mean total nitrogen (TN) retention efficiencies of 7.2-60.14 % and 9.5-55.6 % for total phosphorus (TP) in the studied vegetated urban streams. Nutrient retention efficiencies showed temporal variations, which depended on seasonal temperature. Mass balance analysis indicated that macrophyte assimilation, sediment adsorption, and microbial transformation accounted for 10.31-41.74 %, 0.84-3.00 %, and 6.92-48.24 % removal of the inlet TN loading, respectively. Hydrophyte detritus decay induced alterations in physicochemical parameters while significantly increasing the N and P levels in the overlying water and sediment. Decay rates varied among macrophytes in the order of HV (0.00436 g day-1) > MA (0.00284 g day-1) > PC (0.00251 g day-1) > OJ (0.00135 g day-1) > TL (0.00095 g day-1) > PAU (0.00057 g day-1). 16S rRNA gene sequencing analysis showed an increase in microbial species richness and diversity in the early phase of litter decay. The abundances of denitrification (nirS and nirK) and nitrification (AOA and AOB) genes also increased in the early stage and then decreased during the decay process. Results of this study conducted in seven urban streams in northern China demonstrate the direct effects of hydrophytes in encouraging nutrient transformation and stream self-purification. Results also demonstrate that macrophyte detritus decay could drive not only the nutrient conversions but also the microbial community structure and activities in sediment-water systems. Consequently, to manage internal sources and conversions of nutrients, hydrophytic detritus (e.g., floating/submerged macrophytes) must be suppressed and harvested.

Concentrations, bioaccumulation, and health risk assessments of heavy metals in fishes from Nigeria's freshwater: a general overview.

Heavy metals (HMs) have attracted global attention due to their toxicity, persistence, and accumulation in aquatic fish in the polluted water environment. The consumption of these fishes exposed humans to a higher risk of non-carcinogenic and carcinogenic risks. In this study, we provided a critical overview of the potential sources and concentration of HMs in Nigeria's freshwater. Furthermore, we reported their pollution level in widely eaten fish species in the country. Our findings show that effluent from anthropogenic and industrial activities is one of the major sources HMs in the country. The mean concentration of Zn (9.02 mg/L), As (7.25 mg/L), Cu (4.35 mg/L), Fe (1.77 mg/L), and Pb (1.46 mg/L) in Nigeria's freshwaters were found to be high than Nigerian Standard for Drinking Water Quality permissible limit. This study demonstrated considerable health risks associated HMs via dietary consumption of different fishes from polluted waters. Therefore, we recommended an urgent need for effective management HMs in water bodies in order to protect the lives of people living in the country.

Sustainable Use of Sewage Sludge as a Casing Material for Button Mushroom (Agaricus bisporus) Cultivation: Experimental and Prediction Modeling Studies for Uptake of Metal Elements.

The present study focused on the use of sewage sludge (SS) as a casing material amendment and the potential uptake of metal elements by the cultivated white button (Agaricus bisporus: MS-39) mushroom. Laboratory experiments were performed under controlled environmental conditions to grow A. bisporus on the composted wheat straw substrate for 50 days. Different treatments (0, 50, 100, 150, and 200 g/kg) of casing material were prepared by mixing garden and dried SS and applied on the mushroom substrate after proper sterilization. The results revealed that SS application was significant (p < 0.05) in accelerating mushroom yield with a biological efficiency of 65.02% for the mixing rate of 200 g/kg. Moreover, the maximum bioaccumulation of selected metal elements (Cu, Cr, Cd, Fe, Mn, and Zn) was observed using the same treatment. Additionally, the multiple regression models constructed for the uptake prediction of metal elements showed an acceptable coefficient of determination (R2 > 0.9900), high model efficiency (ME > 0.98), and low root mean square error (RMSE < 0.410) values, respectively. The findings of this study represent sustainable use of SS for the formulation of mushroom casing material contributing toward synergistic agro-economy generation and waste management.

A safe haven of SARS-CoV-2 in the environment: Prevalence and potential transmission risks in the effluent, sludge, and biosolids.

The novel coronavirus, SARS-CoV-2, which has caused millions of death globally is recognized to be unstable and recalcitrant in the environment, especially in the way it has been evolving to form new and highly transmissible variants. Of particular concerns are human-environment interactions and the handling and reusing the environmental materials, such as effluents, sludge, or biosolids laden with the SARS-CoV-2 without adequate treatments, thereby suggesting potential transmission and health risks. This study assesses the prevalence of SARS-CoV-2 RNA in effluents, sludge, and biosolids. Further, we evaluate the environmental, ecological, and health risks of reusing these environmental materials by wastewater/sludge workers and farmers. A systematic review of literature from the Scopus database resulted in a total of 21 articles (11 for effluents, 8 for sludge, and 2 for biosolids) that met the criteria for meta-analysis, which are then subdivided into 30 meta-analyzed studies. The prevalence of SAR-CoV-2 RNA in effluent and sludge based on random-effect models are 27.51 and 1012.25, respectively, with a 95% CI between 6.14 and 48.89 for the effluent, and 104.78 and 1019.71 for the sludge. However, the prevalence of SARS-CoV-2 RNA in the biosolids based on the fixed-effect model is 30.59, with a 95% CI between 10.10 and 51.08. The prevalence of SARS-CoV-2 RNA in environmental materials indicates the inefficiency in some of the treatment systems currently deployed to inactivate and remove the novel virus, which could be a potential health risk concern to vulnerable wastewater workers in particular, and the environmental and ecological issues for the population at large. This timely review portends the associated risks in handling and reusing environmental materials without proper and adequate treatments.

Advances in micro interfacial phenomena of adsorptive micellar flocculation: Principles and application for water treatment.

Among various aqua remediation technologies, separation aims at cleaning pollutants by isolating them despite their destruction; solutes can also be recovered after the process. Adsorptive micellar flocculation (AMF) has been known as an important surfactant-based technique to separate poorly water-soluble hazardous pollutants from aqua media as an efficient and energy-intensive replacement for other surfactant-based techniques, as such AMF should be known. AMF is based on the partitioning of solutes gradient from bulk solution into the nanosized smart anionic surfactant micelle followed by flocculation. However, unlike coagulation/flocculation or adsorption, AMF is not viable for the production of drinking water in water utilities due to the loss of surfactant monomers. Unfortunately, it can be used as a reservoir or for the recycling/recovery of organic pollutants (intermediates) (ions, organics/bioactive, dyes, etc.), even at high concentrations. The performance of AMF depends on various parameters, and this review briefly summarizes the existing researches on different pollutants removal by AMF and material recovery/recycling. This includes operating condition factors (surfactants, flocculants, surfactant-flocculant or surfactant-pollutant concentration ratio, and water conditions chemistry). Because varieties of micro interfacial phenomena other than physical interactions occur in a versatile micellar environment in the AMF process, emphases are given to adsorptive oxidation, micellar catalysis, selectivity. Furthermore, for the first time, this review gives an overview of understanding the state-of-the-art multifunctional nano amphiphile-based AMF that behaves mimetic to aquatic organisms in the process of pollutant removal. The efficiency of AMF, including recycling concentrated solution without noticeable deterioration, as an auxiliary resource/income for the next cycle, signifies economic viability, versatility, and manifold applications in aqua remediation. Significance, ways to achieve enhanced process efficiency, as well as challenges and future opportunities in wastewater treatment, are also highlighted.

The efficiency of microalgae biofilm in the phycoremediation of water from River Kaduna.

This study is aimed at investigating the efficiency of microalgae biofilm in the phycoremediation of water from a polluted river. Freshwater microalgae biofilm inherent in a contaminated petrochemical stream was employed to remediate water from the River Kaduna, which is the largest river in Kaduna town, Kaduna State, Nigeria, and serves as the primary water source in Kaduna town. The results indicate high reduction efficiency of some physicochemical parameters and pollutants (turbidity (71%), conductivity (9.8%), sulfate (37.5%), alkalinity (62.5%), chloride (11.5%), TDS (9.9%), TSS (66.7%), nitrate (42.9%), COD (24%), and BOD (33%), Cd (70.0%), Ni (74.0%) and Pb (71.0%)), indicating the effectiveness of microalgae biofilm in the phycoremediation of water from River Kaduna. According to scanning electron microscope (SEM) observation, the microalgae biofilm has rough surface morphology after the treatment of the river water, which implies that the biofilm was capable of removing the pollutants in water via biosorption. Other characterizations such as XRF, XRD, and FTIR also buttressed that biosorption was the primary removal mechanism of pollutants by microalgae biofilm. Besides, the results also show the production of ROS during the treatment of water from the River Kaduna by the microalgae biofilm. This high concentration of ROS produced during the treatment correlates significantly with pollutant degradation. The GC-MS analysis of the microalgae biofilm shows the involvement of some phytochemicals in the process of pollutant degradation. As a result, microalgae biofilm is a simple and cost-effective method of polluted water phycoremediation with promising applications and future prospects.

Monitoring the presence and persistence of SARS-CoV-2 in water-food-environmental compartments: State of the knowledge and research needs.

The recent spread of severe acute respiratory syndrome coronavirus (SAR-CoV-2) and the accompanied coronavirus disease 2019 (COVID-19) has continued ceaselessly despite the implementations of popular measures, which include social distancing and outdoor face masking as recommended by the World Health Organization. Due to the unstable nature of the virus, leading to the emergence of new variants that are claimed to be more and rapidly transmissible, there is a need for further consideration of the alternative potential pathways of the virus transmissions to provide the needed and effective control measures. This review aims to address this important issue by examining the transmission pathways of SARS-CoV-2 via indirect contacts such as fomites and aerosols, extending to water, food, and other environmental compartments. This is essentially required to shed more light regarding the speculation of the virus spread through these media as the available information regarding this is fragmented in the literature. The existing state of the information on the presence and persistence of SARS-CoV-2 in water-food-environmental compartments is essential for cause-and-effect relationships of human interactions and environmental samples to safeguard the possible transmission and associated risks through these media. Furthermore, the integration of effective remedial measures previously used to tackle the viral outbreaks and pandemics, and the development of new sustainable measures targeting at monitoring and curbing the spread of SARS-CoV-2 were emphasized. This study concluded that alternative transmission pathways via human interactions with environmental samples should not be ignored due to the evolving of more infectious and transmissible SARS-CoV-2 variants.

Assessment of socioeconomic inequality based on virus-contaminated water usage in developing countries: A review.

Water is an essential resource required for various human activities such as drinking, cooking, and other recreational activities. While developed nations have made significant improvement in providing adequate quality water and sanitation devoid of virus contaminations to a significant percentage of the residences, many of the developing countries are still lacking in these regards, leading to many death cases among the vulnerable due to ingestion of virus-contaminated water and other waterborne pathogens. However, the recent global pandemic of COVID-19 seems to have changed the paradigm by reawakening the importance of water quality and sanitation, and focusing more attention on the pervasive effect of the use of virus-contaminated water as it can be a potential driver for the spread of the virus and other waterborne diseases, especially in developing nations that are characterized by low socioeconomic development. Therefore, this review assessed the socioeconomic inequalities related to the usage of virus-contaminated water and other waterborne pathogens in developing countries. The socioeconomic factors attributed to the various waterborne diseases due to the use of virus-contaminated water in many developing countries are poverty, the standard of living, access to health care facilities, age, gender, and level of education. Some mitigation strategies to address the viral contamination of water sources are therefore proposed, while future scope and recommendations on tackling the essential issues related to socioeconomic inequality in developing nations are highlighted.

Insights into hazardous solid waste generation during COVID-19 pandemic and sustainable management approaches for developing countries.

The recent emergence of the COVID-19 pandemic has contributed to the drastic production and use of healthcare and personal protective equipment, leading to the release of a huge quantity of hazardous medical and solid wastes in the environment. Meanwhile, these solid wastes may contribute to the spread of the SARS-CoV-2 viral particles when disposed of without proper treatment and care. Since SARS-CoV-2 could persist on different material surfaces including plastic, steel, paper, cardboard, cloth, and wood, proper management of these hazardous solid wastes has become a challenging task during the COVID-19 pandemic. In this paper, an overview of the consumption of COVID-19-related healthcare and personal protective equipment along with the production of hazardous solid waste is presented. The efficient management of these wastes is necessary to prevent the entering of SARS-CoV-2 in various environmental compartments. Therefore, some preventive measures including the use of biodegradable materials for manufacturing personal protective equipment, minimizing the use of non-biodegradable materials, efficient pre- and-post planning, careful segregation, and disposal are, therefore, proposed for their sustainable management. The findings reported in this paper contribute to tackling the problems associated with hazardous solid waste management, particularly for low- and middle-income countries.

Utilization of electrochemical treatment and surface reconstruction to achieve long lasting catalyst for NOx removal.

The development of catalysts has seen tremendous growth recently but most strategies only report utilization of catalysts for a few initial cycles without taking into account the influence of oxygen poisoning. Here, the magnetic Fe3O4@EDTA-Fe (MEFe, having a core Fe3O4 particle with EDTA-Fe coating) was investigated as a model catalyst for long-term recycling for the removal of nitrogen oxide (NOx) from NO/O2 mixture, followed by N2O recovery. The concentration of oxygen in the flue gas was found to have a strong impact on NOx absorption and catalytic response. To circumvent the oxygen poisoning, the MEFe was subjected to electrochemical treatment in the presence of neutral red (N.R.) and NO removal efficiency was ∼95 % noted. Furthermore, the surface of the catalyst degraded significantly (p < 0.05) after 6-7 repetitive cycling due to surface catalytic reactions, surface poisoning, oxidation of metallic species as well as residual stresses. The MEFe surface was reconstructed after 7 cycles using EDTA solution and Fe source to achieve similar surface coating as the fresh MEFe catalyst. The reconstructed MEFe exhibited similar NOx absorption capability as the fresh MEFe and the reconstruction loop was repeated several times to achieve long term cycling, which make the catalyst cost-effective. Hence, it is proposed that a successful regeneration process can be employed for promising, sustainable and long-lasting catalytic treatment of air pollutants.

Evaluating the health risks of heavy metals from vegetables grown on soil irrigated with untreated and treated wastewater in Arba Minch, Ethiopia.

Available freshwater scarcity significantly affects sustainable food production for the rapidly growing population. This problem has forced people in most parts of the world to use wastewater as a viable solution. However, wastewater reuse has some deleterious effects on human and environmental health. This study was designed to investigate the health risks (HRs) of heavy metals (HMs) from vegetables irrigated with untreated and treated wastewater. The composite wastewater was collected at various sites in Arba Minch town and subjected to aerobic-anoxic treatment. Treated and untreated wastewater (UTW) was used to irrigate vegetables (lettuce, cabbage and tomato), and HM results were compared with the control (tap water) and standards. Water, soil and vegetables were investigated for various physical and chemical properties. Human health effects due to vegetable consumption were analyzed using HR- index (HRI), target hazard quotient (THQ) and hazard index (HI). The results revealed that most of the water quality indexes were significantly enhanced after aerobic-anoxic treatment, suggesting that wastewater collected from different sites was suitable for biodegradation. Soil physicochemical analyses also showed that pH, cation exchange capacity, organic carbon and organic matter were higher for UTW irrigated soil. Heavy metal concentrations were relatively greater in soils than water used for irrigation purposes and vegetables. The HM concentration in vegetables was higher for UTW than for treated and tap water irrigated vegetables. In vegetables, the order of HM content was Fe > Mn > Zn > Pb > Cu > Cd. Tomato followed by cabbage and lettuce accumulated significant amount of HMs (Fe > Mn > Zn > Pb > Cu > Cd) in their different organs (fruit/leaf>root>stem). The individual and combined health indexes (HRI, THQ and HI) showed that Pb and Cd have values greater than unity for wastewater irrigated vegetables, which could result in non-carcinogenic disease for short/lifetime exposure in adults and children. Overall, consumption of vegetables can be safer when grown with treated effluent than with UTW.

Snowballing transmission of COVID-19 (SARS-CoV-2) through wastewater: Any sustainable preventive measures to curtail the scourge in low-income countries?

In this communication, we proposed sustainable preventive measures that may be adopted by the low-income countries to forestall the potential outbreak and transmission of COVID-19 (coronavirus disease 2019) through wastewater. Most low-income countries have poor sanitation and wastewater management policies, which create potential risks of COVID 19 spread. Hence, the proposed measures include decentralization of wastewater treatment facilities, community-wide monitoring and testing of SARS-CoV-2 in wastewater samples, improved sanitation, developing point-of-use devices for wastewater decontamination, and more focused policy interventions. Therefore, this paper adds useful insights into the monitoring and management of ongoing COVID-19 outbreak in low-income countries.

Perylene pigment wastewater treatment by fenton-enhanced biological process.

Polycyclic aromatic hydrocarbons (PAHs) are regarded as priority pollutants owing to their toxic, mutagenic and carcinogenic characteristics. Perylene is a kind of 5-ring PAH with biological toxicity, and classified as a class III carcinogen by the World Health Organization (WHO). Nowadays, some of its derivatives are often used as industrial pigments. Hence, urgent attention is highly needed to develop new and improved techniques for PAHs and their derivatives removal from the environment. In this study, Fenton oxidation process was hybridized with the biological (anaerobic and aerobic) treatments for the removal of perylene pigment from wastewater. The experiments were carried out by setting Fenton treatment system before and between the biological treatments. The biological results showed that COD removal efficiency reached 60% during 24 h HRT with an effluent COD concentration of 1567.78 mg/L. After the HRT increased to 48 h, the COD removal efficiency was slightly increased (67.9%). However, after combining Fenton treatment with biological treatment (Anaerobic-Fenton-Aerobic), the results revealed over 85% COD removal efficiency and the effluent concentration less than 600 mg/L which was selected as the better treatment configuration for the biological and chemical combined system. The microbial community analysis of activated sludge was carried out with high-throughput Illumina sequencing platform and results showed that Pseudomonas, Citrobacter and Methylocapsa were found to be the dominant genera detected in aerobic and anaerobic reactors. These dominant bacteria depicted that the community composition of the reactors for treating perylene pigments wastewater were similar to that of the soil contaminated by PAHs and the activated sludge from treating PAHs wastewater. Economic analysis results revealed that the reagent cost was relatively cheap, amounting to 10.64 yuan per kilogram COD. This study vividly demonstrated that combining Fenton treatment with biological treatment was efficient and cost-effective.

Applying rhamnolipid to enhance hydrolysis and acidogenesis of waste activated sludge: retarded methanogenic community evolution and methane production.

Recently, bio-surfactants, like rhamnolipid (RL), have been used as efficient pre-treatments to enhance the accumulation of short-chain fatty acids (SCFAs) from waste activated sludge (WAS). The current study found that SCFA accumulation occurred with evolutional variation in methanogen with RL (0.04 g RL g-1 TSS), resulting in a retarded methane production over a period of 20 days. However, a slow methane production was only detected before the 18th day, while the concentration of acetic acid (HAc) accumulated to a peak at 2616.94 ± 310.77 mg L-1 in the presence of RL, which was 2.58-fold higher than the control assay. During the retarded methane production, the concentration of dissolved hydrogen also increased to 49.27 ± 6.02 µmol L-1, in comparison with 22.45 µmol L-1 of control WAS without RL. According to the analysis of archaea communities induced by RL, hydrogenotrophic methanogens, like Methanobrevibacter, had been substantially promoted at the beginning of quick SCFA and hydrogen production, but their percentage decreased from 70% to 35% with time. Intrinsically, the growth of acetotrophic methanogens were postponed but they contributed most to the methane production in this research according to the correlation analysis.