COVID-19 in Wastewater or Wastewater Treatment Plants
Introduction
The current global pandemic that is taking the world by storm is not unknown to anyone, the coronavirus disease 2019 (COVID-19), it is caused due to severe acute respiratory syndrome (SARS COV-2). It has raised health emergency concerns at a global level and the World Health Organization has declared it as a World Public Health Emergency of 2020. This disease is caused by the virus belonging to the family Coronaviridae that comprises of viruses with RNA genome resulting in causing common colds to severe respiratory syndrome. A great deal of research has been conducted on SARS-COV 2 and it has been found out that the transmission routes are mostly through inhalation of droplets or through person-to-person contact. As research is progressing, it is also being found out that this RNA is also present in wastewater and it is suggesting that wastewater can actually pose risks to the human health and increase risks of COVID-19 in the future [i].
This paper will be reviewing the existing pools of research that are reflecting towards the presence of COVID 19 in wastewater or other water bodies. Further, the study will discuss in detail the transmission mediums of COVID and look into the ways or methods through which it is likely to get transmitted through water. Lastly, it will also evaluate technologies that can help in detecting COVID in water and wastewater by listing out disinfectant technologies used for preventing of this virus in its transmission.
Transmission modes of COVID-19
A great deal of evidence is present on COVID-19, its way of transmission from person to person, its treatments and its prevention methods. Many researchers are now focusing their attention towards gaining knowledge on transmission of corona virus through drinking water, sewer water and other mediums of water. Corona virus is considered as an extremely infectious and fatal source of viruses ever to be born [ii]. Research has found out that viruses do have a direct link with wastewater when they are excreted through faeces or urine but there is still limited evidence to support this as the faeces or urine may be concentrated with other hidden particles as well[iii]. In Hong Kong, a research carried out on SARS-COV outbreak was related with a leaking sewage line in the country that was held responsible for causing a cluster of Covid cases via aerosolization. The outcomes of the research were later published by microbiologists in China that showed that SARS-CoV RNA can be traced in the wastewater. It was later proposed that this deadly coronavirus can easily be replicated through human gastrointestinal tract as the infectious virus could be traced through stool samples as well. Since the Covid-19 virus belongs to the same family of viruses, it may not be clearly indicated yet but the gastrointestinal tract can be a possible route of infection [iv].
Since the pandemic is still very much here in the world, the awareness regarding Covid-19’s presence in wastewater is still crucially being looked at but still due to a lack of research, it cannot be concluded as one of the possible routes of infection. Sewage water or wastewater is likely to have many different viruses and it cannot be overlooked as a major pathway for transmission, if research looks into it closely, the traces of the virus may be detected through examining human faeces and urine [v]. In a COVID-19 study based in Netherlands, in order to determine whether or not COVID-19 traces can be found in the sewage system[vi]. The research made use of binary RT- qPCR data and indicated the presence of COVID-19 virus in the wastewater. In a similar study carried out in India and Australia, the authors made use of similar model (RT- qPCR) that indicated the same, the occurrence of RNA of SARS-CoV2 in the wastewater. Many similar studies have been initiated on similar research grounds making use of RT- qPCR to closely investigate the presence of SARS-CoV2 RNA in wastewater in Spain, USA and France as well. These models are also helping in determining effective treatment plans for the COVID affected patients. Currently there are studies underway in Canada that are being carried out in collaboration with the Canadian Water Network[vii].
A great deal of evidence is trying to focus its findings on faecal viral shedding that can be seen in studies carried out by Xu, et al. (2020) and Holshue. et al. (2020). The infective novel coronavirus has not yet been confirmed in any of the stool samples of the infected patients but the SARS-CoV2 RNA shedding patterns do recommend that the virus extracts can be found out in the Gastrointestinal tract. There are more studies based upon determining whether COVID-19 is transmitted through air but even that is not proved. According to Gormley et al. (2020), there is a potential for airborne transmission of the virus as it goes through aerosolization that is also responsible for the significant load of viruses present within the wastewater plumbing system, thus, suggesting that the virus is likely to be transmitted through the wastewater as well. Although researchers do worry at the same time that if COVID-19 is confirmed to get transferred through faeces and urine, as reported by the healthcare and laboratory testing facilities, this could potentially target for anticipating future spread of this particular disease that will be out of the control in the long-term. The health specialists are recommended to treat the stool and faecal samples more carefully now due to these implications by scientific researchers worldwide [viii]. COVID-19 is evidently the single most researched disease in the current year, where one end is trying to identify its long term economic side-effects, on the other end the medical sector is concerned about gaining effective control over its widespread around the world[ix].
Technologies Detecting Covid-19 in Wastewater
Swab test is the single most widely used test for the detection of COVID-19 but as the time is progressing, researchers are able to identify capacity issues, slow turnaround and inaccurate results in this particular test. It has been found out that testing the wastewater is a much more effective technique to reach to the root cause of novel coronavirus and also a faster way to identify the rebound cases altogether. This is the main issue with COVID-19, it gets removed from single region and somehow it recurs in the same region leaving the medical practitioners and the researchers clueless regarding its occurrence. Many studies that have been carried out in the U.S.A and Netherlands have reflected towards the detection of RNA of SARS CoV-2 in wastewater. Researchers all over the world are heavily vested towards detecting traces of COVID-19 virus in sewage water as it is more likely to track its evolution and even help stopping the pandemic altogether. If the right technologies and techniques are used, it may even further guide researchers to identify the hotspots of COVID-19 and eventually prevent the public from going there and activate an early warning system. According to the CEO of KWR Water Research Institute which is research company based in Netherlands, it was able to identify traces of the virus well before the first infected person was sent to the hospital. Experts from Spain, United Kingdom and Greece had been able to find the virus residues in the sewage plants and they further stressed that it is reliable indicator of this particular disease as well. The nations all over the world are getting more and more desperate into detecting of COVID-19 virus through any possible technique that does not take much time and is effective because as the time is progressing, the stakes are even larger in the entire pandemic situation. The only way of detecting this virus is when someone reports to the emergency room and the medical practitioners and researchers are extremely curious in determining as many cases of COVID-19 by making use of different technologies and techniques that can eventually help them in stopping the virus from future spread. The U.S. health authorities have referred to wastewater epidemiology that has been used for several decades now in the region for the detection of polio cases in carrying out its tests in other countries. They are absolutely sure about this fact the SARS CoV 2 is shed in stool and hence it can be found in the sewage systems. The reason behind given wastewater preference is due to the vast opportunity it is providing through the real time data that will help in devising adequate preventive policymaking for the disease more quickly. It can alarm the region for potential second wave warnings in the different regions and can restrict its spread in time before it goes out of the hands of health authorities.
A unique methodology is being used to detect the presence of RNA of SARS CoV 2 in the sewage and wastewater and that is known as the paper device. The paper device is folded and unfolded in steps to filter the nucleic acids of pathogens from wastewater samples, then a biochemical reaction with preloaded reagents detects whether the nucleic acid of SARS-CoV-2 infection is present. The results can be seen to the naked eye, a green circle indicating positive and a blue circle negative[x].
Wastewater-based epidemiology (WBE) is identified as another significant tool to detect coronavirus in sewage systems. The researchers are using this as a potential tool for managing and assessing the level of spread of this pandemic in different regions. They are making use of computational analysis and effective modelling to examine their feasibility and the opportunities or challenges they pose in clearly identifying coronavirus infections in local regions and at a global scale as well. It has been noted that the sewage water testing can help in identifying symptomatic as well as asymptomatic cases from 100 to million people. This tool is effectively monitoring the hotspots of the pandemic like that of Wuhan, Madrid, Seattle, New Orleans and New York city. Wastewater-based epidemiology (WBE) surveillance is a cost effective method for detecting the virus and in terms of magnitude, it can screen large areas in very limited time[xi].
Disinfectant Technologies for COVID-19
The world is aware of the prevention methods for COVID-19 and are fully aware of the methods in which they can avoid transmission from person-to-person. The only key to saving yourself from an infected person or catching this deadly virus is by sanitizing the human body and sterilizing the objects that are being used. There are other large scale disinfectant technologies that are being installed to cater to larger audiences of people like the Hong Kong Airport has installed a latest disinfection technology to reduce the transmission of the virus within the airport vicinity. The new technologies include a full body disinfection channel, antimicrobial coating and autonomous cleaning robots. Another common disinfecting technology that is largely being used in different regions is that of Misting cannons that are already offering unique and top notch disinfecting and decontaminating technologies. More machines are being manufactured to disinfect the surfaces by making use of a unique water atomizing technology that is being used for cleaning and disinfecting large outdoor spaces and many countries like Italy, China, Korea, Spain and Philippines are already making use of it. They make use of a pump to pressurize the solution and then a fan sprays out droplets on large areas to disinfect it[xii].
Factors Influencing the Transmission of COVID-19
A number of studies have been based upon determining the factors that are resulting in the rapid multiplication of transmission of COVID-19 from person to person in the environment. In the beginning when there were very limited cases of COVID-19 in the world, people had proposed numerous different theories regarding whether it could sit on objects for hours and how it could possibly get transferred from an infected person. Later as months passed and today after spending 7 to 8 months in this global pandemic, the assumptions and the hypothetical ideas that were left in the air can be cleared out in a minute. People are well aware of the measures they need to take to avoid getting infected by COVID-19 and how the possible transmission can be restricted. Firstly maintain cleanliness and keep yourself sanitized is what will save you from catching this deadly disease. Secondly, to avoid public spaces where there is a likely chance to get exposed to a large enclosed public space. Thirdly, cover your mouth and nose at all times as this virus enters the human body through these open pathways only.
Since it is still not confirmed whether the disease is airborne or waterborne, the people should limit themselves to being exposed to any kind of unsanitary environment. Maintaining hygiene and being surrounded with a clean environment is the key to achieving success in preventing COVID-19. Factors that have contributed majorly in the spread of COVID-19 are mostly large social gatherings where people are at close quarters with one another and have little to no knowledge about who is a possible carrier they all become victims to this deadly virus. Another significant factor that has gained the attention of researchers is that of an unsanitary environment where there is little to no consideration given to the cleanliness and hygiene of the humans who can possibly be exposed to this virus, this includes the wastewater and sewage water as well. Lastly, According to Boehm and Wiggington (2020), aerosols and droplets, on surfaces including skin and in water including seawater or wastewater are still major contributors to infecting large sums of people all over the world. Therefore, sanitation and sterilization are considered as the most effective preventive measures to fight this deadly coronavirus[xiii].
Strategies for Preventing Spread of COVID-19 in the Wastewater
Wastewater surveillance is one significant technique that can help in preventing the spread in the wastewater. The researchers can keep a track and identify hotspots through this but eventually sanitation is the key to putting a stop to COVID-19 altogether. It does propose great environmental risks to the humans in the future and it may help in alerting the authorities for the possibility of a second wave in the region but it has to be avoided. However, earlier identification of the virus’s existence in a particular region might limit the health and economic damage in the long-term. Specific COVID-19 protections need to provided to the working management involved in the wastewater management operations to protect them from catching the deadly virus. It has not been confirmed yet whether or not this virus can be transmitted through an infected person’s faeces but prevention is better than any possible health damage[xiv]. The water plants are required to be made more secure for the operating workers and it is recommended to have limited staff present on these sites to have limited exposure to the virus in any manner. The protective measures will help ensure in clear surveillance of the wastewater and also will be able to save majority of the staffs involved in the operating activities from COVID-19[xv].
Conclusion
COVID-19 is a global pandemic and research has been able to reflect upon its occurrence in wastewater and sewage water as well. The only key to preventing its spread in these water bodies is by ensuring thorough sanitation and avoiding human contact with the infected spaces as much as possible. Wastewater surveillance may be an effective tool in identifying hotspots for COVID-19 but it can be considered to be potentially infectious as well and due to limited medical research on it, it may end up in the spread of the disease at a much faster rate.
Endnotes
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