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Wastewater Surveillance Increasingly Important in Monitoring Public Health


Wastewater surveillance has gained prominence across the world since its use during the Covid-19 pandemic. Also known as Wastewater-Based Epidemiology – (WBE for short), it can give fast and cost-effective insight into; the spread of infection diseases; emergence of new pathogens/variants; community drug use; and markers of antimicrobial resistance for local authorities and national governments and their public health planning.


There are clear wins in the use of wastewater surveillance, but its widespread adoption relies on investment in the required infrastructure, reporting systems and processes to make its data of real value, both at a local and an international level.


In this article we discuss the growth of wastewater surveillance, its applications & benefits and its potential for future use.

Wastewater surveillance

Introduction to Wastewater Surveillance

A simple yet effective method

Wastewater surveillance has existed for decades, with one of the first widely-reported uses of WBE being a project to understand the spread of polio led by team of scientists in the 1930s. It is typically used not only to monitor infectious pathogens, but also the use of pharmaceuticals (both prescribed and illicit) within local communities.



It works by analysing chemicals, pathogens and biomarkers that are shed through urine and faeces into public wastewater systems – using their concentrations to understand trends and patterns in any given population. Samples are taken from the wastewater flow before they are analysed and the associated data processed, interpreted and reported.

Wastewater Surveillance During Covid-19

An unexpected ally in the testing strategy

The Covid-19 pandemic ignited the use of wastewater monitoring across the world, with many countries using it to understand patterns and trends in the spread of the virus and some using WBE for the first time.  Some governments even introduced formal national wastewater surveillance systems.


As vaccinations led to more asymptomatic cases and testing schedules were loosened, WBE played an increasing role in ongoing tracking of virus levels in populations – giving consistent data in a way that did not rely on individual testing and even provided early warning indicators in advance of an outbreak.  It also allowed for early detection of new variants. 


The UK Health Security Agency announced early in 2023 that it would cease the weekly household Covid infection testing report, instead replacing it with “Wastewater-based epidemiology…likely to be of significant importance in the future, both domestically and internationally….exploring further opportunities for this technology.”

wastewater surveillance

Why Wastewater Surveillance?

A cost-effective solution with reliable and unbiased data.

The Covid-19 pandemic ignited the use of wastewater monitoring across the world, with many countries using it to understand patterns and trends in the spread of the virus and some using WBE for the first time.  Some governments even introduced formal national wastewater surveillance systems.


As vaccinations led to more asymptomatic cases and testing schedules were loosened, WBE played an increasing role in ongoing tracking of virus levels in populations – giving consistent data in a way that did not rely on individual testing and even provided early warning indicators in advance of an outbreak.  It also allowed for early detection of new variants. 


The UK Health Security Agency announced early in 2023 that it would cease the weekly household Covid infection testing report, instead replacing it with “Wastewater-based epidemiology…likely to be of significant importance in the future, both domestically and internationally….exploring further opportunities for this technology.”


The cost of testing individuals can be extremely costly. During the pandemic, the UK government spent almost 30bn on the Test & Trace scheme. Wastewater surveillance, by comparison, is extremely cost effective, allowing more reliable and consistent testing of a whole population at one time.   


Wastewater can be sampled anonymously and without any reliance on human interaction.  This not only removes the barrier of perceived stigma from data subjects, but also means multiple people can be tested simultaneously without any effort on their part. 


Individual testing relies on the consent of data subjects, which can cause bias in not only the selection of people, but also the analysis of conjunctive health-related data of the subjects.  Wastewater epidemiology, by contrast, is an unbiased testing method, with no individual data available.  


The sheer ability to sample and analyse multiple subjects (sometimes up to hundreds of thousands) through one test, rather than individual ones, drastically reduces the required resources and processing time involved to collate widespread data.  Its ability to detect pathogens even when subjects are asymptomatic means it is faster at identifying outbreaks, and data outputs can be quickly connected to alert systems for those responsible for acting.

Reliable Data

Relying on individuals to carry out and report on individual tests leaves the data open to inaccuracy.  Wastewater surveillance is set up and processed by expert teams, who understand their field and the importance of data controls.  WBE is also able to give more detailed data than some traditional monitoring methods.  For example, monitoring the consumption of prescribed drugs through prescription levels does not take into account those drugs that are not consumed.  Conversely, WBE only measures the metabolites of those drugs that have actually been taken.

Uses of Wastewater Surveillance

A flexible option for public health monitoring

WBE is increasingly being seen as a cost-effective way of gathering reliable data and and there are active efforts across the globe to increase its use in public health tracking while exploring further opportunities for the sharing of data on a national and international scale. 


Some of its growing uses include:


1. Tracking infectious diseases and outbreaks

Much as with the Covid-19 pandemic, many other disease levels can be tracked through wastewater surveillance.  Any virus/bacterial infection where pathogens are reliably shed through urine and/or faeces can generate the necessary biomarkers to be sampled.  


This is important not only for new outbreaks, but also for new variants of existing pandemics and diseases – as well as to see how a particular outbreak is spreading.  By tracking not only the presence but also the concentration of the shed load, data on the severity of an outbreak can be generated.  Diseases such as polio, covid, measles, hepatitis and norovirus have all been successfully monitored through wastewater surveillance.  In 2021, India set up a wastewater surveillance system to detect cases of Mpox and influenza for example.  In the US, some aviation companies are already collaborating to test the sewage generated on flights, in an effort to understand how this could be used to monitor and restrict international spread of diseases.


Some work is still to be done in validating the reliability of all WBE for this purpose, but it is certainly proving a useful tool for many governments. 

2. Illicit drug consumption

Many drugs generate metabolites when being processed by the human body, which are then shed in urine/faeces.  Alcohol, nicotine, meth, amphetamine, cocaine and many more non-prescribed drugs give off reliable biomarkers following metabolism.  The European Monitoring Centre for Drugs & Addiction has a fascinating geographical chart to show usage across the EU https://www.emcdda.europa.eu/publications/html/pods/waste-water-analysis_en.  Reasons for tracking illicit drug consumption include; planning for public health spend; using the insight to build public health campaigns; cross-referencing the data with other sources (e.g. fatal overdoses); and feeding into law enforcement agencies to identify where and when drugs are entering society. 

3. Prescribed drugs consumption

WBE can be used to track discrepancies in the levels of prescribed drugs vs. levels of the drugs actually taken.  Many people do not finish courses/discard drugs/sell them on/access them from illegal sources – merely looking at prescription data is not always reliable in giving a picture of how populations are using drugs.  Again, much as with illegal drugs, this data can help inform public health campaigns (e.g. finish your antibiotics course) and target areas of misuse – in particular prescription drugs being sourced from non-regulated suppliers. 


The concentration levels of drugs can also give a picture into the prevalence of illnesses/conditions within local populations. For example WBE has been used to track levels of erectile disfunction in local populations through metabolites of Viagra active ingredients and the rising trend in weight loss drugs is also being monitored in some countries – all drug types that carry stigma and may force people to seek illegal supply.     

4. Detection of AMR

Antimicrobial Resistance (AMR) happens when bacteria, viruses, parasites and fungi mutate enough that they are no longer treatable with existing medicines.  This makes them much harder to treat and poses a real risk to society.   WBE can detect the presence of using metagenomic techniques to track resistomes in AM genes and give data on their prevalence, type and spread.


5. Understanding Impact of Hazardous Substances

Wastewater monitoring for hazardous and toxic materials is already widespread – being used by regulating authorities such as the Environment Agency to check that water companies and industrial operators are not polluting waters.  This type of monitoring can also be used to track levels of hazardous substances such as plastics, pesticides and chemicals that have been ingested by humans.  It can then be used in this way to measure the public exposure to potentially harmful substances – even with large-scale leaks during negative industrial events (e.g. nuclear waste/chemical spills).  The data can then be correlated to incidences of illnesses and conditions that could be linked to public exposure to these hazardous substances. 

Future of Wastewater Surveillance

A developing opportunity

The opportunity for use of wastewater surveillance in public health monitoring and planning is clear –  across a range of applications. Future disease outbreaks, drug consumption trends and levels of exposure of communities to hazardous substances and bacteria all hold the potential to be tracked through WBE. Its quick assimilation of data on large numbers of subjects makes it a cost-effective and speedy option for many countries going forward. 


Key to adoption and ongoing success is the level of investment in collaborative, comprehensive reporting systems and the required R&D and expertise to tackle any current concerns around unreliability of data. Automation, AI and robotics may all play their part in moving forward the opportunity for wastewater surveillance to create a sustainable model of WBE that can be adopted on an international scale. 


Until then ongoing individual projects and concept testing will continue to give insight into the costs and benefits of how it could be best used going forward.  Since Covid-19, the world has had a glimpse into the opportunities that WBE presents and an ongoing curiosity will drive forward further understanding of the purposes for which it could be used. Whether as part of wider surveillance strategies, or as a stand-alone methodology, we’re sure wastewater surveillance will be here to stay.

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Where there’s muck, there’s data: How sewage epidemiology is helping in the fight against COVID-19

There has been much chatter in the industry and wider media about the use of sewage epidemiology in the ongoing tracking of COVID-19 levels.  How does this method work and how can it help in the fight against this pandemic?


Introduction to Sewage Epidemiology


Wastewater-based epidemiology (WBE) is used to measure a variety of trace substances in effluent for the purposes of public health monitoring.  Indeed, the sampling of wastewater to track disease spread is not a new concept and is commonly used to measure levels of enteric viruses such as hepatitis, rotaviruses and noroviruses.  Legal and illegal drug use is also monitored through traces found in local effluent sources.  The SCORE network (Sewage analysis CORe group Europe) is a co-ordinated project to enable European researchers to compare the use of different illicit drugs across Europe by calculating the estimated milligrams consumed per 1000 people through analysis of their waste. You can view the results of this study in this interactive online resource.



How does Sewage Epidemiology work?

If a virus “sheds” in faeces, then theoretically it can be sampled within wastewater, typically through monitoring levels of its DNA or RNA (the genetic code of the virus).  Techniques of measuring virus genetic code levels in wastewater typically fall into either quantitative polymerase chain reaction PCR (qPCR) or quantitative polymerase chain reaction PCR (qRT-PCR) approaches. Small trace amounts of DNA/RNA are amplified or elongated through highly calculated processes in order to give a reliable estimate of their equivalent real-life prevalence.  For a full and detailed explanation of these scientific methods visit this page from Enzo.  With SARS-CoV-2, although the RNA within faecal matter is no longer infectious, its concentration level in effluent still acts as a reliable guide to outbreak levels within the local population.  With very few UK wastewater treatment works, each serving multiple cities and towns, a sample as small as a litre can give information on a vast number of people at one time.


Why is the development of Sewage Epidemiology important now?

Resistance to antibiotics, an increasing population and climate change are all contributing to an increased risk of new and mutated pathogenic organisms.  Simply looking at the last two decades and the emergence of novel viruses such as SARS, MERS and Ebola shows the devastation that unrecognised viruses can bring to human existence.  Being able to quickly monitor and act on the spread of these diseases is seen as critical in managing their risk to society.  Intensive and costly monitoring systems such as track and trace are not always viable on a large scale due to virus infection and transmission rates.  A community-level measurement method of disease levels, such as WBE, can act as an effective early warning system for infectious disease outbreaks and support more individual-level testing such as track and trace.  Sampling local wastewater sources can provide comprehensive and real-time information on levels of disease in a local area, indicating when an outbreak is likely before it has even happened.


How is it being used in the fight against COVID-19?

Our current UK testing programme focuses on those already showing symptoms, meaning that asymptomatic carriers are typically not included in disease prevalence or growth estimates. With a high number of COVID-19 carriers known to be asymptomatic, the risk is that prevalence is critically underestimated when relying solely on individual testing and we could enter a second wave of exponential growth before even realising the threat.


Wastewater sampling plugs this gap through its ability to accurately gauge the threat of local or national outbreaks before they have occurred by monitoring the viral shed of both symptomatic and asymptomatic COVID-19 carriers through their faecal excretion.  Typically the virus appears in faeces much earlier (3 days after infection)* than appearance of the symptoms that we are being asked to identify, such as a cough or high temperature.  The sampling time can take as little 48 hours, quickly giving local authorities and government data to be able to take swift decisions in locking down or releasing specific areas.


Governments have been quick to understand and react to the potential of sewage monitoring for this critical purpose and have funded various accelerated research projects and live trials across the world.  In the UK there are many trials taking place with local water authorities, government, leading universities, Defra, the Environment Agency, the Natural Environment Research Centre, the Engineering and Physical Sciences Research Council and UK Research & Innovation all partnering to progress a range of projects.  A number of live trials are already taking place with local water authorities as of June 2020, with the data gathered feeding directly into the government’s COVID-19 Alert System.


Further Resources

As a supplier of wastewater sampling and flow measurement systems we have been closely following this industry development in the fight against COVID-19.  Some resources that we have found particularly helpful/interesting are as follows if you would like to understand more around this topic.  If you would like to speak to us about your own wastewater sampling requirements, we are continuing to provide our services during the pandemic.  Please contact us for more information.  


*Jamanetwork research,








COVID-19 Regulatory Position Statement released by Environment Agency for monitoring of air and water emissions

COVID-19 Regulatory Position Statement released by Environment Agency for monitoring of air and water emissions.


In a COVID-19 Regulatory Position Statement (RPS), released by the Environment Agency on 16th April, holders of installation, waste or radioactive substances activity permits have been advised that they “can make certain reasonable adjustments (such as delays or reschedules)” to environmental monitoring requirements should they be unable to comply due to COVID-19 restrictions.



Specifically the RPS states:

  • Written agreement must be obtained from the EA prior to making use of the COVID-19 RPS via email from your area regulatory officer or site inspector
  • The holder must be able to show that they have taken all reasonable steps to comply with monitoring conditions, with explanations for non-compliance
  • This RPS does not apply to any other activity, even if under the same legislation.  Other permits or licences must be obtained for other activities.
  • If monitoring continues and a holder becomes aware of exceeding any limit value, they should still notify the EA immediately
  • You must comply with all the other requirements in your environmental permit unless they are covered by another COVID-19 RPS.
  • This COVID-19 RPS will be withdrawn on 30 June 2020 unless we extend it. After this date you must comply with your permit.


Monitoring Emissions to Water

With regards to monitoring emissions to water, periodic monitoring may be delayed if a permit holder:

  • Has staff shortages due to COVID-19
  • Has restricted access due to infection/risk of infection to people/places
  • Has restricted access to external laboratories


Guidance has been issued that the following alternatives should be considered:

  • Use of alternative tests e.g. (onsite chemical oxygen demand or total organic carbon measurements)
  • Emissions being calculated based on other parameters
  • If no alternative monitoring solution can be found, then the holder must contact the EA to discuss options
  • Samples that can not be analysed should be kept in suitable conditions for analysis at a later date


Monitoring Effluent Flow

  • Certification/Recertification of MCERTS for flow monitoring may be delayed but it must be rescheduled as soon as possible.
  • Any QM system reassessment audit should be considered for remote auditing with your assessor.
  • On-site maintenance of flow monitoring systems should be continued wherever possible.

All delays/reschedules should be risk-assessed for their impact to human health and the environment, which the holder must demonstrate that they are continuing to protect. For any waste operations monitoring the holder is required to not cause; a risk to water, air, soil, plants or animals; a nuisance through noise or odours; any adverse effect to the countryside or places of interest such as conservations areas and Ramsar sites.


Logging and Recording of Events

Any reasons for missing samples should be noted in the next monitoring return and all reschedules should be implemented as soon as possible – though seasonal sampling to replace missed collections does not need to be carried out.  Any collected samples that can’t be analysed should be stored for later analysis where possible.

Permit holders must also maintain records for 24 months to show the reasons why the COVID-19 RPS was used.  For example, records of:

  • staff absences
  • contractors being unavailable
  • supply chain failures


What to do if you have questions

The Environment Agency intends to monitor the use and compliance of this COVID-19 RPS through inspection and monitoring activity and are available for support and guidance.


At SIRIS we are continuing to deliver service, maintenance, inspection and installation requirements for our clients.  We are able to quickly adapt our working practices to individual site social-distancing requirements, in addition to our own, in-house rigid social distancing working methodology.  We are also working with clients for flexible and innovative solutions to waste flow monitoring during these challenging working conditions. 


Please talk to us if you have any concerns or questions about how COVID-19 may impact your ability to comply with your effluent flow monitoring requirements.