Abstract

Pandemics present major challenges not only to public health, but also to economies and the environment. While the direct health consequences of pandemics are well recognized, their indirect impacts on essential infrastructure, like wastewater systems, are less explored. This study examines the intricate connections between pandemics and wastewater management to develop effective mitigation strategies. A qualitative analysis of existing research highlights significant difficulties wastewater utilities face during pandemics, including increased wastewater volume, changes in wastewater composition, operational pressures, staff shortages, and disruptions in the supply chain. The most pronounced issues are the heightened volume and altered composition of wastewater, which can overwhelm treatment facilities, degrade effluent quality, and heighten pathogen transmission risks. Furthermore, operational pressures and staffing issues can hinder treatment effectiveness and maintenance, worsening environmental and health dangers. To tackle these challenges and bolster the resilience of wastewater systems during pandemics, strategies such as capacity planning, infrastructure enhancements, operational preparedness, data-driven approaches, and improved environmental protections are crucial. These strategies encompass anticipating demand, upgrading infrastructure, ensuring staff safety, leveraging wastewater-based epidemiology for decision-making, and enhancing disinfection protocols, ultimately enabling communities to create more robust and sustainable wastewater management systems.

1 Introduction

As the world navigates the challenges posed by global health crises, the intricate relationship between public health and environmental sanitation has become increasingly evident. For example, the catastrophic floods in Pakistan in 2022 led to widespread contamination of water sources, resulting in a sharp increase in waterborne diseases, including typhoid fever (Schultz 2024). This outbreak underscores the severe consequences of inadequate sanitation and the urgent need to address wastewater management issues, especially during crises (Fuhrmeister et al. 2023; Gorgij et al. 2017; Silva et al. 2023). The COVID-19 pandemic highlighted the critical importance of wastewater management in protecting public health. Such events emphasize the urgency of tackling wastewater management challenges, particularly during pandemics. The pandemic served as a stark reminder of how interconnected our health systems are with our infrastructure, particularly in the sewage sector. This essential area of public health infrastructure is vital for safeguarding communities against waterborne diseases and environmental pollution.

However, the rise in wastewater production and the introduction of new contaminants during pandemics have revealed vulnerabilities in these systems, necessitating a renewed focus on resilience. Pandemics typically lead to a significant increase in both the volume and load of wastewater due to factors such as greater domestic water use, heightened hygiene practices, and the disposal of personal protective equipment (PPE). This surge can put considerable strain on existing infrastructure and treatment processes (Amoah et al. 2024; Ekanayake et al. 2023). Additionally, the introduction of new contaminants into wastewater—such as pharmaceuticals, disinfectants, and pathogens—presents unique challenges for traditional treatment methods, often leading to adverse environmental and health implications. Compounding these issues are disruptions in supply chains for essential equipment, which hinder the operational efficiency of sewage utilities and exacerbate the challenges of managing and treating wastewater effectively. Wastewater-based epidemiology (WBE) offers a powerful tool for tracking disease spread, particularly during pandemics. By analyzing viral genetic material in wastewater, WBE can provide early warning signals of outbreaks, identify geographic hotspots, and monitor the emergence of new variants. Throughout the COVID-19 pandemic, WBE was successfully used to track the virus's spread and inform public health interventions in various regions, including Paris, France. Moreover, WBE has played a crucial role in monitoring the global eradication of poliovirus by detecting the virus in wastewater samples. By leveraging WBE, public health agencies can make data-driven decisions to protect community health and allocate resources effectively (Gorgij et al. 2023; Maida et al. 2023; Paracchini et al. 2024).

This research aims to address several critical questions at the intersection of pandemics and the wastewater sector: How do pandemics impact wastewater characteristics and volumes? What challenges do sewage utilities face during these crises, including operational disruptions and resource constraints? How can wastewater-based epidemiology (WBE) be effectively utilized for public health surveillance during pandemics? What are the environmental and health risks associated with inadequate wastewater management during such times? What strategies can be implemented to improve the resilience of wastewater systems, ensuring they are better equipped to handle future public health emergencies? By exploring these questions, this study aims to provide valuable insights into enhancing wastewater management practices and strengthening public health responses in the face of future pandemics.

The article is organized into several key sections. First, it presents a comprehensive overview of how pandemics affect wastewater characteristics and volumes. Next, it examines the challenges that sewage utilities face during crises, including operational disruptions and resource constraints. Following this, the role of wastewater-based epidemiology as a public health surveillance tool is discussed. Then, the environmental and health risks associated with inadequate wastewater management during pandemics are considered. Finally, actionable strategies for improving the resilience of sewage systems are proposed, ensuring they are better equipped to manage future public health emergencies. Through this structured approach, the article aims to highlight the critical role of sewage management in safeguarding public health and environmental integrity during times of crisis.

2 Methodology

This study utilized a qualitative content analysis approach to systematically evaluate scientific literature regarding the impact of pandemics on wastewater systems. A comprehensive search strategy was designed to identify pertinent peer-reviewed articles published in the last decade across several databases, including PubMed, Scopus, Web of Science, and Google Scholar, utilizing keywords such as pandemic, COVID-19, wastewater, sewage, epidemiology, public health, environmental impact, water pollution, wastewater treatment, and resilience. The inclusion criteria were strictly defined, focusing on English-language peer-reviewed articles that specifically addressed the effects of pandemics on wastewater systems and were available in full text. Data extraction involved a structured coding sheet to gather critical information regarding each study’s objectives, methodology, findings, and conclusions. The coding scheme was developed after an extensive literature review, centering on key themes: characteristics of the pandemic (type, geographic location, duration, and severity), wastewater impacts (changes in flow, composition, and quality), challenges faced by sewage utilities (operational disruptions, staffing shortages, and infrastructure limitations), wastewater-based epidemiology (monitoring for disease surveillance and early warnings), and associated environmental and health risks (water pollution, pathogen transmission, and ecological effects). To ensure reliability and validity, inter-coder reliability was measured through independent coding and result comparison, with member checking performed to confirm data interpretation with field experts. The qualitative data analysis software MAXQDA was employed to enhance the coding, categorization, and thematic analysis of the collected data. A total of 863 research articles from various scientific sources that examine the effects of pandemics on the water and sewage industry have been identified. Relevant information from each selected article was extracted, focusing on key themes and concepts (The complete database and titles of all research studies can be provided upon request).

3 Results and Discussion

Figure 1 presents the results of our content analysis, which revealed that research on the water and sewage sector during pandemics primarily focused on three key aspects: public health, changes in water demand, and water pollution. The analysis indicates that researchers exhibited a greater emphasis on public health concerns, followed by changes in water demand and water pollution. Key concerns include potential contamination of water and sewage due to the pandemic, its implications for disease transmission, and the need for safe water access. Researchers have focused on pandemic characteristics, wastewater impacts, sewage utility challenges, wastewater-based epidemiology, and environmental health risks. The interaction of these factors highlights the urgency for resilient wastewater infrastructure. Increased hygiene practices and home isolation during pandemics raise the demand for wastewater treatment, potentially straining existing systems. Additionally, changes in wastewater composition, including higher levels of pharmaceuticals and pathogens, can hinder treatment processes and elevate public health risks.

Figure 1 COVID-19 impact on wastewater sector.

3.1 Water pollution

Numerous studies have confirmed the presence of SARS-CoV-2 in wastewater and sewage, raising significant concerns about the potential for virus transmission through contaminated water (Amoah et al. 2022; Rume and Islam 2020). Infected individuals shed the Virus through various bodily fluids, including feces, leading to the contamination of wastewater with SARS-CoV-2. Given the virus's persistence in wastewater, there is a risk of transmission through contact with contaminated water or surfaces. While the primary mode of transmission remains through respiratory droplets, the potential for waterborne transmission, especially in areas with inadequate sanitation, cannot be ignored (Hart and Halden 2020; La Rosa et al. 2020).

The pandemic has had both short-term and long-term effects on water pollution. While the short-term impacts of water pollution have been mixed, the long-term consequences remain uncertain. Addressing these challenges will require a comprehensive approach that considers both environmental and social factors, as well as the sustainable management of water resources While some regions experienced temporary improvements in air and water quality due to reduced industrial activity and transportation, the increased use of medical waste and challenges in wastewater treatment have introduced new pollution risks (Bhardwaj et al. 2025; Kataki et al. 2021; Lüdtke et al. 2021).

Decreased industrial activity, tourism, and transportation led to lower levels of pollutants like suspended solids and biochemical oxygen demand. The surge in medical waste, including PPE and disinfectants, poses a contamination risk if not properly managed. While wastewater monitoring is valuable for tracking COVID-19, it can also contribute to the release of pathogens and pharmaceuticals into water bodies. Specifically, the pandemic has led to elevated concentrations of various pollutants in wastewater, including pharmaceuticals and personal care products (PPCPs), disinfectants and biocides, microplastics and pathogens. Increased medication usage has resulted in higher levels of antibiotics, hormones, and other pharmaceuticals in wastewater. Widespread use of disinfectants, such as chlorine and bleach, has contributed to increased levels of these chemicals in wastewater. The increased use of single-use plastics, including masks and gloves, has led to the release of microplastics into wastewater. The presence of SARS-CoV-2 and other pathogens in wastewater poses risks to public health and the environment. Overburdened infrastructure, staffing shortages, and supply chain disruptions have strained wastewater treatment facilities, leading to reduced treatment efficiency and increased pollution risks. Increased risk of waterborne diseases is a significant issue due to pathogen transmission and disruption of sanitation services. The presence of SARS-CoV-2 in wastewater raises concerns about the potential for waterborne disease transmission although the risk remains relatively low. Also, the pandemic has exacerbated the risk of waterborne diseases in areas with limited access to sanitation and clean water. In the long term, economic recovery and increased industrial activity and resource demand following the pandemic may reverse the short-term improvements in water quality. In addition, climate change-induced droughts and floods can worsen water pollution issues and make it challenging to ensure safe drinking water supplies.

The COVID-19 pandemic has significantly impacted water quality and pollution due to the increased use of biomedical waste, wastewater treatment challenges, and pharmaceutical products. The increased use of disposable medical items, such as masks, gloves, and gowns, has led to a surge in biomedical waste, which can clog drains, contaminate water bodies, and leach contaminants into groundwater. Additionally, overburdened wastewater treatment facilities have struggled to handle the increased demand, resulting in reduced treatment efficiency and the release of pollutants into receiving waters.

Quantitative data on the impact of pandemics on water quality has shown increased levels of pharmaceuticals and personal care products (PPCPS), elevated levels of disinfection byproducts (DBPS), increased frequency of waterborne disease outbreaks and altered microbial communities in water bodies. Studies have shown significant increases in the concentration of various PPCPs in wastewater during and after the pandemic. For example, a study conducted in the United Kingdom found a 50% increase in the concentration of ibuprofen in wastewater treatment plant effluent during the COVID-19 pandemic (Ceolotto et al. 2024). The increased use of disinfectants, such as chlorine, to treat water and wastewater has led to higher levels of DBPs, which are known to have adverse health effects. A study conducted in the United States found a 15% increase in the concentration of trihalomethanes, a type of DBP, in drinking water during the pandemic (Wilburn et al. 2024). In some regions, there has been a reported increase in waterborne disease outbreaks during and after the pandemic, potentially linked to compromised water quality and sanitation. For instance, Pakistan experienced a significant surge in waterborne diseases, including typhoid fever, following the devastating floods of 2022 (Ahmed et al. 2024). The introduction of new pollutants and changes in wastewater treatment practices can disrupt the microbial balance in water bodies, leading to potential ecological imbalances and increased risks of waterborne diseases. Studies have shown that the COVID-19 pandemic has led to shifts in microbial communities in wastewater treatment plants, potentially affecting the removal of pollutants and the production of disinfection byproducts.

The pandemic has also driven up the consumption of various pharmaceutical products, including antiviral drugs, antibiotics, and disinfectants. These products can enter wastewater streams and ultimately contaminate water bodies, posing risks to aquatic life and human health. The increased use of disinfectants, PPE, and pharmaceuticals has led to a higher concentration of contaminants in wastewater, raising concerns about pathogen transmission and long-term environmental impacts.

In light of the pandemic, researchers have proposed several strategies to reduce water pollution both during and after this period. Key recommendations include the proper disposal of medical waste through dedicated collection systems and centralized disposal methods to ensure safety. Improved wastewater treatment is essential, necessitating investment in infrastructure, optimization of operations, and regular performance monitoring. Public awareness campaigns should focus on promoting hygiene practices, educating about water pollution risks, and encouraging responsible waste disposal. Sustainable water management practices, such as reducing consumption, protecting watersheds, and promoting rainwater harvesting, are also vital. Additionally, stronger government regulations and enforcement mechanisms are needed to control pollution from industrial and agricultural sources, alongside regular compliance monitoring and penalties for violations. International cooperation is crucial for sharing knowledge and coordinating efforts to tackle global water pollution challenges. Furthermore, monitoring wastewater for pathogens like SARS-CoV-2 can provide early warnings for outbreaks, emphasizing the importance of effective treatment and safe water consumption to prevent waterborne diseases. Overall, a comprehensive approach involving infrastructure investment, innovative technologies, regulatory enhancements, and public education is essential for mitigating water pollution in the context of a pandemic.

3.2 Water demand changes

The COVID-19 pandemic has brought about notable changes in water demand, shaped by a variety of factors such as regional differences, government policies, and individual behaviors. One significant trend is the increase in domestic water use, driven by heightened hygiene practices emphasizing handwashing and sanitization, as well as a rise in home cooking due to more people staying at home (Carducci et al. 2020). Increased handwashing and hygiene: studies from the UK and US have shown significant increases in domestic water consumption during lockdowns. For instance, a study in the UK reported a 15% increase in household water use during the peak of the first lockdown (Abu-Bakar et al. 2021). Also, with more people working from home, there was a noticeable rise in water demand for activities like laundry, dishwashing, and personal hygiene. A survey conducted in New York City indicated a 10% increase in household water consumption during the lockdown period (Nemati and Tran 2022).

Conversely, industrial and commercial water use has seen a mixed impact; sectors like hospitality and tourism faced a sharp decline in demand due to closures and restrictions, while industries such as pharmaceuticals and cleaning product manufacturing experienced an uptick in water usage to meet increased production needs (Kalbusch et al. 2020; Venugopal et al. 2020). Hospitality and tourism sectors, heavily reliant on in-person services, experienced a sharp decline in water demand. A study in Spain revealed a 30% decrease in water consumption by hotels and restaurants during the pandemic (Rodríguez-Antón and Alonso-Almeida 2020). But industries producing essential goods, such as pharmaceuticals and cleaning products, saw an increase in water demand to meet heightened production needs. A report from India showed a 20% increase in water consumption by the pharmaceutical industry during the pandemic (Sahoo et al. 2022).

In agriculture, the effects have also been varied—some activities suffered from supply chain disruptions or reduced demand for specific crops, while others saw an increase in water requirements due to shifts in crop patterns or new government policies. Certain agricultural sectors, particularly those supplying to the hospitality and food service industries, faced decreased demand, leading to reduced water usage for irrigation. For example, in California, the demand for table grapes decreased by 25%, resulting in a 15% reduction in irrigation water needs (Beatty et al. 2020). The pandemic led to a surge in home gardening and urban agriculture initiatives, particularly in urban areas. This trend resulted in increased residential water consumption for outdoor irrigation. A study in Chicago found a 20% increase in residential water use for gardening during the pandemic (Knudson 2022).

3.3 Public health

Wastewater can serve as a valuable surveillance tool for tracking the spread of diseases and detecting new variants. Additionally, improper management of wastewater can pose significant health risks. Studies in this context can be divided into two categories:

1. Wastewater as a surveillance tool, and
2. Risks associated with improper wastewater management.

In the wastewater as a surveillance tool category, three topics have been taken into consideration in various studies including early detection, variant tracking, and community-wide assessment. Several studies have demonstrated the effectiveness of wastewater-based epidemiology (WBE) in tracking the prevalence and spread of COVID-19. By analyzing wastewater samples for the presence of SARS-CoV-2 RNA, researchers can identify areas with high viral loads and inform public health interventions. Continued research and implementation of WBE programs can provide valuable data for public health decision-making (Bhardwaj et al. 2024; Dong et al. 2021; Liu et al. 2020).

In the risks associated with improper wastewater management, three topics have been taken into consideration in various studies including pathogen transmission, waterborne diseases, and environmental pollution. Findings have shown while the risk of direct transmission of COVID-19 through wastewater is considered low, the presence of the virus in wastewater has raised concerns about the potential for indirect transmission through contaminated water sources. For example, while the risk of traditional waterborne diseases like cholera and typhoid has not been significantly exacerbated by COVID-19, the potential for the emergence of new or resistant pathogens remains a concern (Forés et al. 2021; Paul et al. 2021). Also, contaminated wastewater can indirectly affect public health through contact with contaminated surfaces or by inhalation of aerosolized water droplets. Increased wastewater flow and changes in treatment processes during the pandemic may have affected water quality in some regions. Studies have investigated the potential for increased levels of pollutants and pathogens in treated wastewater. In general, the potential for wastewater-related public health risks, such as the spread of waterborne diseases, has been a focus of research during the pandemic. The cholera outbreak in Haiti following the 2010 earthquake serves as a stark reminder of the devastating consequences of inadequate wastewater management. The outbreak, linked to contaminated water sources, resulted in over 820,000 cases and nearly 10,000 deaths. This tragic event highlights the crucial role of effective wastewater treatment and sanitation in preventing the spread of waterborne diseases, particularly in vulnerable populations.

The COVID-19 crisis has affected access to safe water in many countries, especially in low-income and vulnerable areas. Lack of access to clean water can lead to increased cases of infectious diseases and deaths. It is very important to prevent water pollution and ensure that water sources are clean and safe for consumption (Singh et al. 2020; Varbanov et al. 2021). One example of the impact of water pollution on public health was the cholera outbreak in South Africa in 2000. The outbreak was caused by contaminated water sources and more than 120,000 people contracted cholera and more than 200 deaths were reported. During the COVID-19 pandemic, wastewater has been crucial for public health. However, by improving wastewater treatment, using wastewater-based epidemiology, and implementing public health measures, the associated risks can be effectively managed. It is essential to adopt regulations for wastewater treatment and management to safeguard public health and the environment.

The COVID-19 pandemic highlighted the crucial role of effective wastewater management in safeguarding public health and the environment. While it did not fundamentally alter the trajectory of sewage development, it underscored the necessity for resilient infrastructure, especially in densely populated areas. The increase in domestic and commercial activity has spurred investments in upgrading sewage systems, even amid temporary disruptions. Given the challenges brought by pandemics and other emergencies, it is essential to develop a robust and adaptable wastewater management strategy. Extensive research has explored various aspects of the pandemic's impact on the water industry. In synthesizing and integrating these studies, the urgent need for a comprehensive and resilient approach becomes clear. By considering the insights from these studies within a holistic framework of resilience, five key themes have been identified. Addressing these themes will facilitate the development of a comprehensive and resilient wastewater management strategy that effectively tackles the challenges posed by pandemics and other emergencies (as depicted in Figure 2 and Table 1).

Figure 2 Wastewater management challenges during pandemics.

Table 1 Key factors affecting wastewater during pandemics.

Main theme	Factors
Increased wastewater volume	Increased handwashing, disinfection practices, changes in household behavior, public health interventions
Changes in wastewater composition	Increased pathogen shedding, changes in dietary habits, disinfectant residue, pharmaceuticals and personal care products (PPCPs)
Operational challenges for sewage utilities	Increased workload, staffing shortages, infrastructure limitations, supply chain disruptions
Wastewater-based epidemiology	Early detection, community-level surveillance, variant tracking
Environmental and health risks	Waterbody contamination, soil contamination, air pollution, pathogen transmission

Increased wastewater volume

The surge in wastewater volume during pandemics is a direct consequence of increased water consumption driven by public health measures, changes in household behavior, and public health interventions. This increased volume can strain sewage treatment facilities, leading to potential overflows and environmental pollution.

Changes in wastewater composition

The altered composition of wastewater during pandemics, including increased pathogen shedding, disinfectant residue, and pharmaceuticals and personal care products (PPCPs), can pose significant challenges for wastewater treatment processes. These changes can impact treatment efficiency, increase the risk of pathogen transmission, and contribute to environmental pollution.

Challenges for sewage utilities

Pandemics can impose significant operational challenges on sewage utilities, including increased workload, staffing shortages, and supply chain disruptions. These challenges can hinder the ability of sewage utilities to provide effective wastewater treatment and management services.

Wastewater-based epidemiology

Wastewater-based epidemiology (WBE) offers a valuable tool for tracking the spread of diseases, providing early warning signals, and informing public health interventions. However, WBE faces challenges such as data interpretation, sampling and analysis, data quality, and ethical considerations.

Environmental and health risks

The environmental and health risks associated with wastewater pollution during pandemics are significant. Wastewater can contaminate water bodies, soil, and air, leading to the transmission of diseases, ecosystem degradation, and public health hazards.

The interconnectedness of factors

The factors influencing wastewater systems during pandemics are interconnected and mutually reinforcing. For example, increased wastewater volume can exacerbate the challenges faced by sewage utilities, while changes in wastewater composition can impact treatment efficiency and increase the risk of environmental and health hazards.

3.4 Increased wastewater volume

During pandemics, there has been a notable increase in wastewater volume due to several contributing factors (Table 2). Firstly, domestic wastewater has surged as heightened handwashing and sanitization practices lead to increased water consumption—evidenced by a UK study reporting a 15% rise. Healthcare facilities have been significantly impacted as well, with a 30% increase in wastewater flow during the COVID-19 pandemic, driven by higher patient numbers and the disposal of medical waste, including personal protective equipment (Hillary et al. 2021).

Table 2 Increase in wastewater volume due to the pandemic.

Factor	Explanation	Implications
Increased handwashing	Public health recommendations emphasizing frequent handwashing	Higher water consumption and subsequent wastewater generation
Disinfection practices	Use of disinfectants in homes, businesses, and public spaces	Increased water consumption and wastewater production
Changes in household behavior	Stay-at-home orders and reduced travel leading to increased domestic activities	Higher wastewater volume due to changes in water use patterns
Public health interventions	Mass testing and contact tracing efforts	Increased wastewater volume associated with sample collection

While some industries like hospitality faced reduced operations during lockdowns, others, particularly the pharmaceutical sector, experienced a 20% rise in wastewater discharge, as mentioned in a study from China (González Peña et al. 2021). The implications of these trends include overburdened sewage treatment facilities, resulting in potential treatment failures and untreated wastewater contaminating water bodies, which poses serious environmental and public health risks due to the spread of waterborne diseases. Additionally, the financial burden on sewage utilities escalates with rising operational costs linked to managing increased wastewater volumes. To address these challenges effectively, investment in upgrading wastewater treatment infrastructure is essential, alongside promoting water conservation measures, integrating wastewater management into public health planning, and providing economic support to utilities during such crises.

3.5 Changes in wastewater composition

During pandemics, the composition of wastewater undergoes significant changes due to shifts in human behavior, heightened public health measures, and the emergence of new pathogens (Table 3). Notably, there is an increase in pathogen shedding from infected individuals, resulting in higher concentrations of viruses and bacteria in wastewater. For instance, during the COVID-19 pandemic, the presence of SARS-CoV-2 RNA in wastewater became a pivotal tool for tracking the virus's spread. Furthermore, the surge in the use of pharmaceuticals and personal care products (PPCPs) has led to elevated levels of these compounds in wastewater, raising concerns about their impact on human health and aquatic ecosystems. The extensive use of disinfectants and biocides, alongside the rise of single-use plastics such as personal protective equipment, has introduced additional chemicals and microplastics into the wastewater stream. These alterations not only challenge wastewater treatment processes but also pose significant public health risks, and environmental hazards, and necessitate enhanced monitoring strategies.

Table 3 Changes in wastewater composition due to the pandemic.

Factor	Explanation	Implications
Increased pathogen Shedding	Infected individuals shedding pathogens in their feces	Higher concentrations of pathogens in wastewater
Changes in dietary habits	Shifts in dietary patterns due to pandemics	Altered chemical composition of wastewater, potentially affecting treatment processes
Disinfectant residue	The presence of disinfectant residues in wastewater due to increased use	Interference with wastewater treatment processes and potential environmental impacts
PPCPS	Increased consumption of PPCPs during pandemics	Altered wastewater composition, potentially affecting aquatic ecosystems and human health

3.6 Challenges for sewage utilities

Sewage utilities face considerable challenges as they navigate these changes in wastewater composition (Table 4). Increased operational demands arise from the surge in wastewater volume and altered chemical loads, straining treatment facilities and potentially leading to treatment failures. Additionally, pandemics can result in staffing shortages due to illness, impacting the efficiency and reliability of operations. Aging infrastructure often lacks the necessary capacity to handle the increased loads, causing overflows and environmental concerns. Supply chain disruptions further complicate the procurement of essential materials and maintenance equipment, while financial strains from rising operational costs and revenue losses add to the burden on sewage utilities. The repercussions of these challenges are profound, encompassing not only public health risks associated with untreated wastewater, but also detrimental effects on aquatic ecosystems and challenges in maintaining service reliability.

Table 4 Operational challenges for sewage utilities due to the pandemic.

Factor	Explanation	Implications
Increased workload	Higher wastewater volumes and altered composition	Strain on sewage treatment facilities and potential treatment failures
Staffing shortages	Absenteeism due to illness or other pandemic-related factors	Reduced operational efficiency and maintenance
Infrastructure limitations	Aging infrastructure or inadequate capacity	Potential overflows, backups, and environmental hazards
Supply chain disruptions	Difficulties in procuring essential materials and equipment	Increased costs and potential disruptions in wastewater treatment

3.7 Wastewater-based epidemiology

Wastewater-based epidemiology (WBE) has become a valuable tool for monitoring the spread of diseases, especially during pandemics. By detecting viral genetic material in wastewater, WBE can provide early warning signals for disease outbreaks, guide public health interventions, and evaluate the effectiveness of mitigation measures. WBE plays a critical role in proactive disease surveillance. It allows for the detection of pathogens in wastewater before individuals show symptoms, enabling timely public health response. This non-invasive method assesses disease prevalence across entire communities, including asymptomatic individuals, and can identify hotspots of disease transmission through geographic mapping. When paired with genetic sequencing, WBE can track the emergence and spread of new pathogen variants, aiding in public health policy decisions such as vaccine development and mitigation strategies. Additionally, WBE can monitor changes in disease prevalence over time, offering insights into the effectiveness of public health interventions and highlighting areas where further action may be necessary. The successful use of wastewater-based epidemiology during pandemics has significant implications. It provides a more comprehensive and timely understanding of disease prevalence and spread within communities. Early detection and monitoring through WBE can inform targeted public health interventions, ultimately reducing the overall impact of pandemics. Compared to traditional surveillance methods, WBE can also be a more cost-effective approach. Moreover, WBE contributes to environmental health by monitoring pollutants and pathogens in wastewater.

Despite its potential, WBE faces several challenges and limitations. Interpreting wastewater data requires expertise in epidemiology, microbiology, and wastewater engineering. The collection and analysis of wastewater samples can be resource-intensive, particularly in remote or underserved areas. Furthermore, the quality of wastewater data may be influenced by factors such as sampling methods, laboratory procedures, and wastewater treatment processes. There are also privacy and ethical concerns regarding collecting and analyzing wastewater samples.

Table 5 Wastewater-based epidemiology due to the pandemic.

Factor	Explanation	Implications
Early detection	Monitoring wastewater for pathogens to identify outbreaks early	Timely implementation of public health interventions
Community-level surveillance	Assessing disease prevalence within entire communities	Informed decision-making for targeted interventions
Variant tracking	Analyzing wastewater for the presence of new variants	Development of tailored public health measures

3.8 Environmental and health risks

Wastewater pollution during pandemics poses significant environmental and health risks when treatment and disposal systems are inadequate. This analysis focuses on two primary risk categories as shown in Table 6.

Table 6 Environmental and health risks due to the pandemic.

Factor	Explanation	Implications
Water body contamination	Improperly treated wastewater contaminating rivers, lakes, and other water bodies	Eutrophication, pathogen transmission, ecosystem disruption
Soil contamination	Wastewater leaking into the soil	Soil pollution, groundwater contamination, and agricultural impacts
Air pollution	Emissions from wastewater treatment facilities	Respiratory problems and climate change

Firstly, improperly treated wastewater can contaminate water bodies, leading to eutrophication, pathogen transmission, and ecosystem disruption. Secondly, wastewater that leaks or is improperly disposed of can contaminate soil, resulting in soil pollution and groundwater contamination. Furthermore, wastewater treatment processes can emit air pollutants, contributing to air pollution and climate change. These risks have severe implications, including public health crises, significant economic impacts, and exacerbation of social and environmental injustices, particularly for vulnerable communities.

4 Conclusion

Wastewater resilient management during pandemics refers to the ability of wastewater systems to maintain their essential functions and services, even in the face of extraordinary challenges posed by disease outbreaks. This includes the capacity to handle increased wastewater volumes, adapt to changes in wastewater composition, ensure operational continuity, monitor public health indicators, and protect the environment. Pandemics pose significant challenges for wastewater systems, requiring a comprehensive and coordinated approach to address the interconnected impacts. By understanding the factors driving increased wastewater volume, changes in composition, operational challenges, and environmental and health risks, policymakers and wastewater utilities can develop effective strategies to mitigate these impacts and ensure the sustainability of wastewater infrastructure.

The findings of this analysis highlight the complex and interconnected nature of the impacts of pandemics on wastewater systems. Increased wastewater volume, altered composition, operational challenges, wastewater-based epidemiology, and environmental and health risks are all interrelated factors that must be considered in developing effective responses. The findings indicate that a resilient approach is necessary to tackle the challenges and risks linked to wastewater management during pandemics. Therefore, several important strategies can be drawn to ensure the resilience of wastewater management. Capacity planning and infrastructure are fundamental aspects of resilient wastewater management, especially during pandemics when demands can surge unexpectedly. In this context, four strategies can be considered: peak flow estimation, capacity expansion, stormwater management, and water conservation.

Historical data needs to be analyzed to identify peak flow periods, estimate potential increases during pandemics, and develop models to simulate various scenarios, such as different infection rates and public health measures. Policymakers should consider temporary solutions like equalization basins or additional treatment units to handle surges in flow and invest in infrastructure upgrades to increase treatment capacity and accommodate future growth. It seems necessary to implement measures to reduce CSOs, such as green infrastructure, storage tanks, or flow control devices. This can be achieved by repairing and upgrading aging sewer systems to minimize infiltration and inflow (I&I) which can contribute to increased volume. Promoting water conservation practices among the public, such as reducing water usage for non-essential purposes and implementing efficient leak detection and repair programs to minimize water loss, are important water conservation actions.

Operational resilience is crucial for ensuring the continued delivery of wastewater services during a pandemic. This involves maintaining essential operations, mitigating disruptions, and protecting the health and safety of staff. Some key challenges and strategies are staff safety and well-being, supply chain resilience, and emergency response. Staff safety and well-being should be provided adequate personal protective equipment (PPE) and training on safe work practices to protect staff from exposure to pathogens. Also, mental health support is necessary. It offers mental health support and counseling services to address the stress and challenges staff face. In supply chain resilience, the wastewater sector should develop contingency plans to ensure a reliable supply of essential equipment, chemicals, and spare parts, especially during disruptions caused by pandemics. Also, it should be considered to identify alternative suppliers to mitigate the risk of disruptions. In emergency response, wastewater resilient management develops and regularly updates emergency response plans to address equipment failures, power outages, and other operational challenges. Also, it establishes strong coordination mechanisms with local authorities, emergency services, and other stakeholders. As we discussed before, during the pandemic, many sewage utilities faced challenges with staff absences. Due to illness or quarantine, staff absences led to reduced workforce and operational difficulties. Also, shortages of PPE, chemicals, and spare parts impact treatment plant operations and cause supply chain disruptions. The increased workload and stress on equipment led to higher maintenance requirements. To address these challenges, utilities can implement strategies such as remote work and shift adjustments. In addition, emergency procurement should be considered when seeking alternative sources to obtain essential supplies.

It is crucial to have flexibility in the treatment process to adapt to changing wastewater conditions, especially during pandemics. This means being able to adjust treatment processes as needed to effectively remove new contaminants and handle increased flows. To achieve this, comprehensive monitoring programs should be implemented to identify emerging contaminants and assess their concentrations. It is also important to stay updated on research and literature related to potential contaminants associated with pandemics. Additionally, consider using advanced treatment technologies such as membrane filtration, ultraviolet disinfection, or activated carbon adsorption to remove specific contaminants. Optimizing existing treatment processes is also important to improve the efficiency of removing emerging pollutants and ensure compliance with strict effluent quality standards, which is essential for protecting public health and the environment.

Data-driven decision-making is essential for effective wastewater management, especially during pandemics. By collecting and analyzing data on wastewater composition, flow rates, and operational performance, utilities can make informed decisions to optimize treatment processes, identify potential risks, and improve resilience. For instance, during the COVID-19 pandemic, wastewater-based epidemiology (WBE) was used to track the spread of the virus in many communities. By monitoring the presence of SARS-CoV-2 RNA in wastewater, public health officials were able to identify areas with high levels of infection and implement targeted interventions. In this manner, it is recommended to implement sensor networks to monitor wastewater flow rates, quality parameters, and operational conditions in real time and use advanced data analytics techniques to identify trends, anomalies, and potential issues. Also, it is important to promote public awareness and acceptance of WBE as a valuable tool for public health surveillance and develop ethical guidelines for the collection and use of wastewater data to protect privacy and ensure transparency. Other measures to consider include:

1. Monitoring the presence of pathogens in wastewater to provide early warning signals of disease outbreaks,
2. Integrating WBE (wastewater-based epidemiology) data with traditional public health surveillance systems to gain a more comprehensive understanding of disease dynamics,
3. Using predictive modeling to optimize treatment processes, minimize energy consumption, and reduce costs, and
4. Comparing performance against industry benchmarks to identify areas for improvement.

During a pandemic, there are concerns about the possible release of harmful microorganisms into the environment through wastewater. To address this issue, wastewater treatment plants need to enhance the disinfection processes to eliminate these microorganisms and to regularly monitor and detect new contaminants. It is also crucial to assess the potential impacts of wastewater discharges on aquatic ecosystems. Finally, international collaboration can facilitate knowledge sharing, fostering the exchange of best practices and innovative solutions among countries to address global challenges. By collaborating on research and development, countries can work together to develop innovative technologies and strategies for wastewater management, ultimately improving public health and environmental outcomes.

Future research should focus on emerging contaminants and innovative technologies that can enhance wastewater treatment and resilience, as well as strengthen public health surveillance systems based on wastewater-based epidemiology. In-depth case studies of specific wastewater utilities or regions need to be conducted to understand how they have responded to pandemics. This will help identify best practices and track the effectiveness of different resilience strategies during pandemics. Additionally, emerging trends and challenges can be identified through these case studies.

It should be kept in mind that the studies have limitations, including subjectivity and a scope that is limited to the available literature. This may not capture all relevant research, especially unpublished or gray literature, and the quality of the included research can vary. This variability can affect the reliability and generalizability of the findings.

Acknowledgments

We appreciate the constructive and insightful comments of the anonymous reviewers.

Data analysis was conducted using MAXQDA 24. Grammarly was utilized for English proofreading, and graphs were created with Napkin.

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