Sanitary Wastewater Research Articles

Singular Spectrum Analysis of Pathogenic Microorganisms in a Sanitary Wastewater Treatment System

Singular Spectrum Analysis of Pathogenic Microorganisms in a Sanitary Wastewater Treatment System

Assessment of Drainage Capacity of a Surface Drain in Rajshahi, Bangladesh

One of the most important components of a community's sustainable environment system is its drainage capacity. The drainage capacity of a community is essential to maintaining environmental resilience, effective water management, and encouraging a healthy urban lifestyle. The surface drains in Rajshahi City receive a mix of waste, including sanitary wastewater, stormwater runoff, and solid waste from roadsides and households. To improve the drainage facilities of Rajshahi, some new drains have been constructed. This study considered a recently constructed drain in the Rajshahi City Corporation (RCC), running from Talaimari to Chowddopai. The primary objective of this study is to assess the drainage capacity of this drain during both dry and monsoon seasons, ensuring its capability to contain the generated waste. Additionally, the investigation encompasses observing the sludge depth, and clear space of the drain. A field survey was conducted, employing a measuring rod and scale to precisely measure the depth, width, and sludge accumulation. A map was created in ArcGIS providing all the data collected from field surveys. By examining these parameters, this study seeks to contribute valuable information for enhancing the resilience and functionality of the drainage system, thereby promoting a sustainable urban environment.

Yard phytoarchitecture for onsite sanitation of household wastewater containing copper

Copper can be found in various equipment, building materials, and consumer products. When buildings are used, copper can enter wastewater in different ways. It is challenging for occupants to remove copper physically or chemically since they can potentially reduce copper levels through yard phytoarchitecture. This study aims to formulate houseplants' suitability to become decorative plants for the yard phytoarchitecture, simultaneously as onsite sanitation. This study identified the copper deconcentration pathway in wastewater by studying published works-based research. Literature was collected and selected based on recency, accessibility, and the relationship among copper, wastewater, and plants. The study findings show that processing copper by plant has the greatest opportunity to be implemented on a building scale. The yard phytoarchitecture system involves arranging plants in the yard, which serves both as a decorative feature and a way to treat the building's wastewater. It can be used on dry yards or ponds and only requires a small amount of land. The plants used should have low leaf density and high root density. It plays a dual role consisting of onsite sanitation infrastructure and yard aesthetics, which mutually strengthen the environmental health locally and positively effect on a larger scale.

Impact of electrode arrangement and electrical connections on the power generation of ceramic membrane microbial fuel cell

AbstractSome of the most popular technologies for wastewater sanitation, still face serious limitations related to high energy consumption requirements. In this context, microbial fuel cells (MFCs) constitute a promising approach since they do not require aeration and produce electricity at the same time. Limitations for these devices, however, are related to the cost of the constituents and the functionality of the arrangement. In this work, a semi‐cylindrical ceramic MFC was designed and constructed using a low‐cost commercial ceramic handcraft as a membrane, carbon felt, carbon cloth, and carbon cloth/activated carbon in different arrangements for the anode and cathode components. The best results were obtained using carbon felt as an anode and a cathodic zone built with carbon felt in which void regions were filled with activated carbon. This arrangement produced 85 mWm−2 for each cell. Evaluating the performance of the MFC in a modular system with eight cells using a different number of separations inside the module and different electrical connections, resulting in a 4‐compartment module that produced 90 mWm−2 with one single module and 95 mWm−2 with a serial arrangement of two modules.

Global occurrence of organic micropollutants in surface and ground water: Highlighting the importance of wastewater sanitation to tackle organic micropollutants

The occurrence, fate and distribution of organic micropollutants (OMPs) in different water matrices is of increasing concern due to the negative effects towards flora, fauna and human health. This metadata study provides an updated picture of the global occurrence of OMPs in freshwater and wastewater in five geographical regions, and illustrates how socioeconomic factors are key elements that influence the concentration of these OMPs in the different water matrices. The study also aims to provide a collated database of OMPs removal efficiencies achieved by the different biological treatment technologies. Our findings demonstrated that OMPs like acetaminophen, ibuprofen, and triclosan are present globally in freshwater (> 500 ng/L) and wastewater (> 10, 000 ng/L), and at relatively higher concentrations than the other evaluated OMPs. Significant correlations between OMPs concentration in wastewater versus freshwater demonstrated wastewater to be a potential source of certain OMPs to the freshwater environment. This was further confirmed through correlation between OMPs concentration and socioeconomic factors like infrastructure index and governance index in both wastewater and freshwater. These results highlighted the importance of wastewater sanitation to control and reduce OMPs dissemination in the environment. Thus, various types of biological wastewater treatment processes including activated sludge processes, biofilm processes, wetland and lagoon, and membrane bioreactor were analyzed for their OMP’s removal efficiencies. Findings demonstrated that advanced processes like membrane bioreactors (MBR) may not always outperform other low-costs biotechnologies in the treatment of OMPs (e.g., bisphenol A removal by activated sludge with anoxic and oxic zone, AS-AAO was 93% versus MBR at 89%). But rather, the removal efficiency will depend on pollutant properties and certain operational parameters such as hydraulic retention time, treatment capacity, and removal efficiency of total suspended solids.

Exploring transitions of sewer wastewater infrastructure towards decentralisation using the modular model TURN-Sewers

We present a new modular model called TURN-Sewers for exploring different adaptations of centralised wastewater infrastructure towards more decentralised wastewater systems under different urban development scenarios. The modular model is flexible and computationally efficient in exploring transitions at the city scale, allowing for the comparison of different policies and management strategies for sanitary wastewater infrastructure. TURN-Sewers includes independent modules that simulate the generation, dimensioning, deterioration, management, and calculation of performance indicators for different wastewater systems. This model can use readily available spatial information to support infrastructure planners and other stakeholders in exploring different transition pathways from centralised to decentralised wastewater infrastructure. An illustrative example demonstrates how TURN-Sewers can generate multiple future alternatives, define different infrastructure management strategies regarding system expansion, rehabilitation and transition, and assess the economic, hydraulic and structural impacts.

The influence of light intensities and micropollutants on the removal of total coliforms and E. coli from wastewater in a flat-panel photobioreactor

The presence of micropollutants and pathogens in sanitary wastewater and surface water is a growing concern that impacts public health, environmental balance and the maintenance of water supply services. To improve sanitary wastewater treatment, it is necessary to develop and improve sustainable technologies. Among the available options, microalgae-based systems stand out for their efficiency and generation of value-added byproducts. To study the impact of luminosity and the presence of micropollutants (13 selected) on the removal of E. coli and total coliforms from real anaerobically treated wastewater, a pilot flat-panel photobioreactor (50 L) was operated in batch mode in a tropical climate region. This is the first study to evaluate whether micropollutants interfere with coliform groups, considering a microalgae-based system and an experiment in a tropical climate region. E. coli had better removal (from 104 to 101 CFU 100 mL−1) than did total coliforms (from 104 to 103 CFU 100 mL−1). The removal of E. coli was more strongly linked to luminosity and temperature, while the removal of total coliforms was influenced by the presence of the selected micropollutants.

The Environmental Health Risk Analysis regarding Hepatitis A Transmission among Street Food Vendor in Indonesia

This study aimed to conduct hazard identification and risk assessment for the transmission of hepatitis A among street food vendors (SFVs), whereas risk management was generated. This observational analytic study was conducted in Jember Regency - Indonesia. Cluster random sampling was employed, wherein five distinct locus were selected representing SFVs in campus area and local market area. A total of 100 SFVs in Jember participated in this study. Data was collected using a questionnaire. The risk assessment was measured by multiplying the likelihood and consequence. Additionally, the data was subjected to descriptive analysis. This study found the identification of hazards among SFVs was found inadequate sanitation facilities, poor food processing practice (improper handling of raw ,- cooked ingredients, and poor food serving), limited availability of clean water,substandard building and layout were observed as potential hazards for the transmission of hepatitis A. The risk assessment found inadequate sanitation facilities (18 point), negative attitude (18 point), poor quality assurance (16 point), and food contamination (14 point) have high scores. The risk management including: a) location and building: providing specific location, and maintaining cleanliness of the furniture and equipment on a regular basis, b) sanitation facility: provision of sanitary waste bin, communal toilet and wastewater drainage system; fly control measures, and using piped water supply, c) food processing: increasing food handler personal hygiene, and standard food handling process.In conclusion, the risk of Hepatitis A transmission among street vendors remains high and poses a threat in Jember, indicating the need for health education for the street vendors. Additionally, the author recommends policymakers to implement regular monitoring or inspection of the food quality and the necessity of providing clean water facilities or other fundamental facilities to SFVs.

Characterization and Proposal of Technologies for The Treatment of Domestic Sewage in Ilha Grande Bay – RJ

Objective: To characterize the situation of sanitary wastewater discharge in the hydrographic basins draining into the Baía da Ilha Grande (BIG) and to propose wastewater treatment alternatives based on the literature on decentralized solutions. Theoretical framework: The BIG has been experiencing negative environmental impacts due to the urbanization process in the region, mainly due to the irregular discharge of domestic wastewater into the environment. Method: The methodology was developed in two stages, with stage 1 involving data collection from available data in the 2017 Wastewater Atlas, and stage 2 focusing on identifying the most appropriate treatment technologies for this study from the fifteen options evaluated. Results and conclusion: The characterization revealed that municipalities within the BIG are already using decentralized solutions for domestic wastewater treatment, albeit below the national average coverage rates (18-54%). The five most promising technologies identified were Septic Tanks, Compact UASB, Biodigesters, Compartmentalized Anaerobic Reactors, and Integrated Biosystems. It is concluded that the communities have a sanitation deficit and show potential for implementing decentralized solutions. Implications of the research: The study helped develop strategies for decision-makers to select the most appropriate wastewater treatment technologies to meet local needs. It also served as a model for scientific studies in other locations. Originality/value: This study aligns with the Sustainable Development Goals (SDGs), particularly SDG 6, by presenting decentralized solutions as a promising pathway to universalizing household wastewater treatment in developing countries.

When does infrastructure hybridisation outperform centralised infrastructure paradigms? – Exploring economic and hydraulic impacts of decentralised urban wastewater system expansion

We explore the dynamics of centralised and decentralised wastewater infrastructure across various scenarios and introduce novel insights into their performance regarding structural vulnerability, hydraulic capacity, and costs. This study determines circumstances under which infrastructure hybridisation outperforms traditional centralised infrastructure paradigms. We combined system analysis to map out the modelling problem with the model-based exploration of the transition space using the novel TURN-Sewers model. System diagramming was used to identify the parameters or combinations of parameters that significantly influence the performance indicators being assessed. This allowed the creation of relevant simulation scenarios to identify circumstances where a decentralised sewer system could outperform a centralised one. TURN-Sewers was applied to model the infrastructure maintenance and generation of new infrastructure over 20 years for a municipality on the Swiss Plateau, considering a population growth rate of 0.03 a−1. Results show that decentralisation in expansion areas with higher densification can outperform the hydraulic performance and structural vulnerability of expanding centralised sanitary wastewater infrastructure. Decentralised systems can also offer economic advantages when capital expenditure costs for small-scale wastewater treatment plants are significantly reduced compared to current costs, particularly at higher discount rates, e.g. reaping effects of economies of scale. The findings of this study emphasise the potential of transition pathways towards decentralisation in urban water infrastructures and the value of models that allow the exploration of this transition space.

Modeling of two-stage anaerobic onsite wastewater sanitation system to predict effluent soluble chemical oxygen demand through machine learning

The present research aims to predict effluent soluble chemical oxygen demand (SCOD) in anaerobic digestion (AD) process using machine-learning based approach. Anaerobic digestion is a highly sensitive process and depends upon several environmental and operational factors, such as temperature, flow, and load. Therefore, predicting output characteristics using modeling is important not only for process monitoring and control, but also to reduce the operating cost of the treatment plant. It is difficult to predict COD in a real time mode, so it is better to use Complex Mathematical Modeling (CMM) for simulating AD process and forecasting output parameters. Therefore, different Machine Learning algorithms, such as Linear Regression, Decision Tree, Random Forest and Artificial Neural Networks, have been used for predicting effluent SCOD using data acquired from in situ anaerobic wastewater treatment system. The result of the predicted data using different algorithms were compared with experimental data of anaerobic system. It was observed that the Artificial Neural Networks is the most effective simulation technique that correlated with the experimental data with the mean absolute percentage error of 10.63 and R2 score of 0.96. This research proposes an efficient and reliable integrated modeling method for early prediction of the water quality in wastewater treatment.

Wastewater management from municipal slaughterhouses in Mexico: quantities produced, existing legislation, treatment processes applied and future challenges

Wastewater from municipal slaughterhouses remains a persistent issue in the world, owing to its inherent characteristics it has been categorized as one of the most environmentally detrimental water sources. Mexico has 972 registered facilities dedicated to meat processing, so it is necessary to establish the best treatment options in order to achieve efficient control of the wastewater produced, reduce water consumption and enhance the utilization of natural resources. The objective of this study was to estimate the quantities of municipal slaughterhouse wastewater produced in Mexico and to provide information on the legislation applicable to the disposal and discharge of these effluents. It also presents the nature-based solutions that could be applied and that are technically and economically feasible, as well as future opportunities for the sustainable management of this type of wastewater. The state of Jalisco is the largest generator of wastewater and solid waste in the country, and significant progress has been made in the transition of public policies toward a sustainability model nationwide. These advancements are supported by legal foundations, institutional frameworks, and governmental bodies. The competitive advantages of nature-based solutions such as constructed wetlands over other treatment technologies include low operation and maintenance costs, ease of implementation, low energy consumption, and the fact that they are not harmful to nature and receiving bodies. While significant progress has been made in the management and sanitation of slaughterhouse wastewater, challenges persist with regard to the technologies employed (design and operation parameters, scaling up, biochemical processes involved, etc.) which in turn become excellent areas of opportunity for future research.

Sanitation facility mapping at Kalideres District, West Jakarta

Poor sanitation has various impacts on human health, such as the risk of contracting diseases like diarrhoea, typhoid, polio, and worm infections. The government has set targets in the National Medium-Term Development Plan (RPJMN) 2020 - 2024, with the goal of achieving 90% access to proper sanitation, including 15% of households having access to safe sanitation, and reducing the rate of open defecation to 0% by the end of 2024. The objective of this mapping is to recommend wastewater sanitation technologies in Tegal Alur Subdistrict. Data collection will be carried out through interviews and questionnaires, determining the number of respondents using the Slovin formula. Interviews and questionnaires will be conducted in 4 densely populated neighbourhoods (RW) with a high rate of open defecation, namely RW 01, RW 02, RW 03, and RW 13. Based on the results of interviews and questionnaires, 71% of the population in Tegal Alur Subdistrict have toilets, but only 24% have septic tanks, leading to environmental pollution due to wastewater discharge. The type of septic tank used is individual septic tanks, and 88% of the population in Tegal Alur has never desludged their septic tanks. The condition of wastewater sanitation in Tegal Alur Subdistrict can be described as poor, characterized by a lack of septic tanks to manage wastewater, resulting in wastewater pollution of the environment, which can lead to various diseases.

Wastewater quality index (WWQI) as an indicator for the assessment of sanitary effluents from the oil and gas industries for reliable and sustainable water reuse

With the development of numerous industries, the increasing use of water resources and the discharge of pollutants into the environment, particularly industrial wastewater, has become extremely important. The purpose of this study was the assessment of sanitary wastewater treatment plants attributed to the oil and gas industries as reliable and sustainable water resources based on the wastewater quality index (WWQI). The findings revealed that the facilities under investigation effectively process and discharge their effluents following the Environmental Protection Organization's standards. Springtime has the maximum removal in wastewater treatment plants (WWTPs), with typical removal values of COD and BOD5 of 96.1% and 97.1%, while pH in the effluent of these WWTPs was 7.22, and DO in the range of 1–6.3 mg/L throughout this period. In addition, fecal coli removal efficiencies were 98.6%, respectively. Finally, the wastewater treatment system in the four refineries investigated has resulted in a considerable decrease in microbiological and organic pollutants in conformity with environmental regulations permitting wastewater reuse for irrigation and agriculture, as well as discharge into adsorption wells. However these treatment plants perform poorly in terms of cumulative and WWQI models (13.86–16.05), it is clear from the results and discussion of this research that the results of the treated wastewater from the under-investigation plants comply with the Environmental Protection Organization of Iran's standards required for discharge to surface water or reuse in agricultural land irrigation. Still, the treatment system should be constantly audited and improved to reach a higher rank according to the WWQI.

Recyclable adsorbent aerogels by in-situ growth of ZIF-8 on aramid nanofibers/poly(vinyl alcohol) for multiple water pollutants

Water pollution from human activities such as sanitary wastewater, agricultural run-off and industrial discharges is becoming an increasingly serious issue, which has caused immeasurable damage to human health and the ecological environment. Therefore, it is urgent to develop an effective strategy for dealing with multiple water pollutants. Herein, we designed a ZIF-8@ANF/PVA composite aerogel by in-situ growth of zeolitic imidazolate frameworks-8 (ZIF-8) on aramid nanofibers (ANF) and poly(vinyl alcohol) (PVA) networks. The utilization of PVA provided more active hydroxyl groups on ANF for the in-situ growth of ZIF-8, so as to enrich the pore structure of the composite aerogel, thus improving the mechanical property and adsorption capacity significantly. Owing to its high surface area, extensive porosity and multiple size pores, the resultant ZIF-8@ANF/PVA composite aerogel exhibited excellent adsorption capacity for Cr(VI) (230.5 mg/g), tetracycline (319.5 mg/g), Congo red (547.0 mg/g), as well as organic oils and solvents. More importantly, the composite aerogel retained its remarkable adsorption capacity even after 10 cycles, demonstrating optimal cycling stability, superior reusability, and facilitated separation operations. This study provides an effective and sustainable strategy for fabricating MOF-derived composite aerogel as a promising adsorbent for the removal of diverse pollutants from water.

Molluscicidal and Cercaricidal Effects of Myrciaria floribunda Essential Oil Nanoemulsion.

Schistosomiasis is a tropical disease transmitted in an aqueous environment by cercariae from the Schistosoma genus. This disease affects 200 million people living in risk areas around the world. The control of schistosomiasis is realized by chemotherapy, wastewater sanitation, health education, and mollusk control using molluscicidal agents. This work evaluates the effects of a nanoemulsion containing essential oil from Myrciaria floribunda leaves as a molluscicidal and cercaricidal agent against Biomphalaria glabrata mollusks and Schistosoma mansoni cercariae. The Myrciaria floribunda essential oil from leaves showed nerolidol, β-selinene, 1,8 cineol, and zonarene as major constituents. The formulation study suggested the F3 formulation as the most promising nanoemulsion with polysorbate 20 and sorbitan monooleate 80 (4:1) with 5% (w/w) essential oil as it showed a smaller droplet size of approximately 100 nm with a PDI lower than 0.3 and prominent bluish reflection. Furthermore, this nanoemulsion showed stability after 200 days under refrigeration. The Myrciaria floribunda nanoemulsion showed LC50 values of 48.11 µg/mL, 29.66 µg/mL, and 47.02 µg/mL in Biomphalaria glabrata embryos, juveniles, and adult mollusks, respectively, after 48 h and 83.88 µg/mL for Schistosoma mansoni cercariae after 2 h. In addition, a survival of 80% was observed in Danio rerio, and the in silico toxicity assay showed lower overall human toxicity potential to the major compounds in the essential oil compared to the reference molluscicide niclosamide. These results suggest that the nanoemulsion of Myrciaria floribunda leaves may be a promising alternative for schistosomiasis control.

Application of photocatalytic proxone process for petrochemical wastewater treatment

Industrial wastewaters are different from sanitary wastewaters, and treatment complications due to their unique characteristics, so biological processes are typically disrupted. High chemical oxygen demand, dye, heavy metals, toxic organic and non-biodegradable compounds present in petroleum industry wastewater. This study intends to optimize the photocatalytic proxone process, utilizing a synthesized ZnO–Fe3O4 nanocatalyst, for petroleum wastewater treatment. The synthesis of ZnO–Fe3O4 was done by air oxidation and layer-by-layer self-assembly method and XRD, SEM, EDAX, FT-IR, BET, DRS, and VSM techniques were used to characterize the catalyst. Central composite design (CCD) method applied to investigated the effect of pH (4–8), reaction time (30–60 min), ozone gas concentration (1–2 mg/L-min), hydrogen peroxide concentration (2–3 mL/L) and the amount of catalyst (1–0.5 g/L) on the process. In the optimal conditions, biological oxygen demand (BOD5) and total petroleum hydrocarbon (TPH) removal, reaction kinetic, and synergistic effect mechanisms on the process were studied. Based on the ANOVA, a quadratic model with R2 = 0.99, P-Value = 0.0001, and F-Value = 906.87 was proposed to model the process. Based on the model pH = 5.7, ozone concentration = 1.8 mg/L-min, hydrogen peroxide concentration = 2.5 mL/L, reaction time = 56 min, and the catalyst dose = 0.7 g/L were proposed as the optimum condition. According to the model prediction, an efficiency of 85.3% was predicted for the removal of COD. To evaluate the accuracy of the prediction, an experiment was carried out in optimal conditions, and experimentally, a 52% removal efficiency was obtained. Also, at the optimum condition, BOD5 and TPH removal were 91.1% and 89.7% respectively. The reaction kinetic follows the pseudo-first-order kinetic model (R2 = 0.98). Also, the results showed that there is a synergistic effect in this process. As an advanced hybrid oxidation process, the photocatalytic proxone process has the capacity to treat petroleum wastewater to an acceptable standard.

Cleaner production of iron-coated quartz sand composites for efficient phosphorus adsorption in sanitary wastewater: A design of experiments (DoE) approach

Phosphorus (P) adsorption and recovery from sanitary wastewater is a promising route to produce more sustainable fertilizers. Multivariate Design of Experiments (DoE) techniques were used to develop a cleaner process to produce Fe-coated quartz sand composites with applications in Phosphorus (P) adsorption from sanitary effluents. Nine different process parameters were investigated and correlations between process inputs and physicochemical characteristics of adsorbents were elucidated. It was found that Goethite and Magnetite phases with different degrees of crystallinity were obtained depending on the conditions applied during the synthesis by coprecipitation. Statistical models fitted to an experimental multivariate database were used to predict the best conditions for synthesizing an efficient P adsorbent. In addition, a zero-waste process for the production of the adsorbents is reported. The best adsorbent produced, an aqueous suspension containing particles of a SiO2@FeOOH composite, exhibited a P (KH2PO4) adsorption capacity of 12.4 mg P/g (C0 = 10 mg P/L, pH 6.0) and robust performance when applied in simulated sanitary effluent, reaching 97% of P removal efficiency (C0 = 5 mg P/L). Considering the value of the green star area index (GSAI), the optimized method (suspension) was 65% green, reaching the maximum score for four of the ten principles involved, denoting the greenness of the proposed method. The optimized adsorbent has appropriate characteristics to be applied in sanitary effluent treatment processes for capturing and recovering residual P, contributing to a more sustainable management of natural resources.

Sanitary installations and wastewater plumbing as reservoir for the long-term circulation and transmission of carbapenemase producing Citrobacter freundii clones in a hospital setting

BackgroundAccumulating evidence shows a role of the hospital wastewater system in the spread of multidrug-resistant organisms, such as carbapenemase producing Enterobacterales (CPE). Several sequential outbreaks of CPE on the geriatric ward of the Ghent University hospital have led to an outbreak investigation. Focusing on OXA-48 producing Citrobacter freundii, the most prevalent species, we aimed to track clonal relatedness using whole genome sequencing (WGS). By exploring transmission routes we wanted to improve understanding and (re)introduce targeted preventive measures.MethodsEnvironmental screening (toilet water, sink and shower drains) was performed between 2017 and 2021. A retrospective selection was made of 53 Citrobacter freundii screening isolates (30 patients and 23 environmental samples). DNA from frozen bacterial isolates was extracted and prepped for shotgun WGS. Core genome multilocus sequence typing was performed with an in-house developed scheme using 3,004 loci.ResultsThe CPE positivity rate of environmental screening samples was 19.0% (73/385). Highest percentages were found in the shower drain samples (38.2%) and the toilet water samples (25.0%). Sink drain samples showed least CPE positivity (3.3%). The WGS data revealed long-term co-existence of three patient sample derived C. freundii clusters. The biggest cluster (ST22) connects 12 patients and 8 environmental isolates taken between 2018 and 2021 spread across the ward. In an overlapping period, another cluster (ST170) links eight patients and four toilet water isolates connected to the same room. The third C. freundii cluster (ST421) connects two patients hospitalised in the same room but over a period of one and a half year. Additional sampling in 2022 revealed clonal isolates linked to the two largest clusters (ST22, ST170) in the wastewater collection pipes connecting the rooms.ConclusionsOur findings suggest long-term circulation and transmission of carbapenemase producing C. freundii clones in hospital sanitary installations despite surveillance, daily cleaning and intermittent disinfection protocols. We propose a role for the wastewater drainage system in the spread within and between rooms and for the sanitary installations in the indirect transmission via bioaerosol plumes. To tackle this problem, a multidisciplinary approach is necessary including careful design and maintenance of the plumbing system.

Lattice-disordered high-entropy metal hydroxide nanosheets as efficient precatalysts for bifunctional electro-oxidation

Electro-oxidation reactions (EORs) are important half reactions in overall and assisted water electrolysis, which are crucial in achieving economic and sustainable hydrogen production and realizing simultaneous wastewater treatment. Current studies indicate that the high-valence metal ions that are locally enriched in the catalysts or generated in situ during the anodic preoxidation process are active species for EORs. Hence, designing (pre)catalysts with enriched local active sites and boosted preoxidation is of great importance. In this work, with a focus on improving the EOR performance toward the oxygen evolution reaction (OER) and the urea oxidation reaction (UOR), we fabricated a lattice-disordered high-entropy FeCuCoNiZn hydroxide nanoarray catalyst that exhibits robust bifunctional OER and UOR behavior. The high-entropy feature could bring in a unique catalytic ensemble effect and remarkably improve the intrinsic OER/UOR activity. The lattice-disordered structure could not only enrich the local high-valence metal ions as active sites but also provide abundant reactive surface sites to accelerate the preoxidation process, thus leading to enriched active sites for the OER and UOR. Benefitting from the structural merits, the lattice-disordered high-entropy catalyst exhibits excellent OER and UOR activity with low overpotential, large current density and enhanced intrinsic activity, and no performance degradation but dramatic 35.3% and 88.7% enhancement in activity can be achieved during the long-term OER and UOR tests, respectively. The robust OER and UOR performance makes the lattice-disordered high-entropy catalyst a promising candidate for overall and urea-assisted water electrolysis from industrial, agricultural and sanitary wastewater.