Wastewater Test Could Provide Early Warning Of COVID-19

Researchers at Cranfield University are working on a new test to detect SARS-CoV-2 in the wastewater of communities infected with the virus.

The wastewater-based epidemiology (WBE) approach could provide an effective and rapid way to predict the potential spread of novel coronavirus pneumonia (COVID-19) by picking up on biomarkers in faeces and urine from disease carriers that enter the sewer system.

Rapid testing kits using paper-based devices could be used on-site at wastewater treatment plants to trace sources and determine whether there are potential COVID-19 carriers in local areas.

Dr Zhugen Yang, Lecturer in Sensor Technology at Cranfield Water Science Institute, said: “In the case of asymptomatic infections in the community or when people are not sure whether they are infected or not, real-time community sewage detection through paper analytical devices could determine whether there are COVID-19 carriers in an area to enable rapid screening, quarantine and prevention.

“If COVID-19 can be monitored in a community at an early stage through WBE, effective intervention can be taken as early as possible to restrict the movements of that local population, working to minimise the pathogen spread and threat to public health.”

Recent studies have shown that live SARS-CoV-2 can be isolated from the faeces and urine of infected people and the virus can typically survive for up to several days in an appropriate environment after exiting the human body.

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. Results are visible to the naked eye: a green circle indicating positive and a blue circle negative.

“We have already developed a paper device for testing genetic material in wastewater for proof-of-concept, and this provides clear potential to test for infection with adaption,” added Dr Yang. “This device is cheap (costing less than £1) and will be easy to use for non-experts after further improvement.

“We foresee that the device will be able to offer a complete and immediate picture of population health once this sensor can be deployed in the near future.”

WBE is already recognised as an effective way to trace illicit drugs and obtain information on health, disease, and pathogens. Dr Yang has developed a similar paper-based device to successfully conduct tests for rapid veterinary diagnosis in India and for malaria in blood among rural populations in Uganda.

Paper analytical devices are easy to stack, store and transport because they are thin and lightweight, and can also be incinerated after use, reducing the risk of further contamination.

An overview of the approach – Can a Paper-Based Device Trace COVID-19 Sources with Wastewater-Based Epidemiology? – co-authored with Hua Zhang and Kang Mao of the Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China, has recently been published in the Environmental Science & Technology journal.

Further development of the test is being sponsored by the Natural Environment Research Council (NERC) and Royal Academy of Engineering.

About Cranfield University
Cranfield University is a specialist postgraduate university that is a global leader for education and transformational research in technology and management.

Source: Cranfield University

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Study: Agricultural Wastewater Reuse Puts 800 Million People At Risk

Study: Agricultural Wastewater Reuse Puts 800 Million People At Risk

By Sara Jerome
@sarmje

Farmers around the world are spreading raw sewage all over their farms, researchers say.

A new study published in Environmental Research Letters put a spotlight on farmers who use urban wastewater to irrigate their fields. The findings highlight the need for policymakers to balance the benefits of water reuse with “the need to invest in wastewater treatment to protect public health,” according to the journal article.

The study revealed that “crops covering almost 36 million hectares — an area roughly the size of Germany — are irrigated with water from rivers and lakes used by cities within 40 km (25 miles) upstream to discharge sewage,” Reuters reported.

The study assessed health risks linked to irrigation. Situating farms near cities enables farmers to access nutrient-rich wastewater to irrigate their crops, but it also has consequences.

“According to the study, some 65 percent of all irrigated land areas are within 40 km downstream of urban areas. A significant amount of that land is in countries with very limited wastewater treatment, exposing 885 million urban consumers, farmers and food vendors to health risks,” BBC News reported.

Pay Drechsel of the International Water Management Institute, an author of the study, noted that the research registered a 50 percent uptick in land irrigated with untreated wastewater compared to previous studies.

"The previous figure was not based on science, so this new approach combines geographic information, and is the first scientific approach to get hold of the area that is irrigated with raw or diluted wastewater," Dreschsel said, per BBC News.

Anne Thebo of the University of California, Berkeley, an author of the study, stressed the importance of investment in wastewater infrastructure.

"As long as investment in wastewater treatment lags far behind population growth, large numbers of consumers eating raw produce will face heightened threats to food safety," she said, per Reuters.

Image credit: "hewitt scene," william garrett © 2015, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/

Global Use of Wastewater To Irrigate Agriculture At Least 50 Percent Greater Than Thought

Global Use of Wastewater To Irrigate Agriculture At Least 50 Percent Greater Than Thought

Credit: CC0 Public Domain

July 24, 2017

The use of untreated wastewater from cities to irrigate crops downstream is 50 percent more widespread than previously thought, according to a new study published this week in the journal Environmental Research Letters.

The study relies on advanced modeling methods to provide the first truly comprehensive estimate of the global extent to which farmers use urban wastewater on irrigated cropland. Researchers analyzed data with geographic information systems (GIS) rather than depending on case study results, as in previous studies.

The researchers also assessed for the first time 'indirect reuse', which occurs when wastewater gets diluted but still remains a dominant component of surface water flows. Such situations account for the majority of agricultural water reuse worldwide, but have been difficult to quantify on a global level due to different views of what constitutes diluted wastewater versus polluted water.

Considering consumer safety the foremost priority, study authors highlight the need to mitigate public health risks through measures taken along the entire food supply chain. This includes improved wastewater treatment, but also preventive steps on farms and in food handling, since capacity for water treatment is increasing only slowly in developing countries.

According to the study, farmers' use of wastewater is most prevalent in regions where there is significant wastewater generation and water pollution. In these circumstances, and where safer water is in short supply, wastewater offers a consistent and reliable means of irrigating fields, including high-value crops, such as vegetables, which often require more water than staple foods. Where raw wastewater is available, farmers may tend to prefer it because of its high concentrations of nutrients, which can lessen the need to apply purchased fertilizers. In most cases, however, farmers' use of this water is motivated by basic needs; they simply do not have alternatives.

"The de facto reuse of urban wastewater is understandable, given the combination of increasing water pollution and declining freshwater availability, as seen in many developing countries," said Anne Thebo, a recent graduate at the University of California, Berkeley in the USA and lead author of the study. "As long as investment in wastewater treatment lags far behind population growth, large numbers of consumers eating raw produce will face heightened threats to food safety."

Results show that 65 percent of all irrigated areas are within 40 km downstream of urban centers and are affected by wastewater flows to a large degree. Of the total area of 35.9 million hectares, 29.3 million hectares are in countries with very limited wastewater treatment, exposing 885 million urban consumers as well as farmers and food vendors to serious health risks. Five countries - China, India, Pakistan, Mexico and Iran - account for most of this cropland. These new findings supersede a widely cited 2004 estimate, based on case studies in some 70 countries and expert opinion, which had put the cropland area irrigated with wastewater at a maximum of 20 million hectares.

"Gaining a better grasp of where, why and to what extent farmers use wastewater for irrigation is an important step toward addressing the problem," said second author Pay Drechsel of the International Water Management Institute (IWMI), who leads the CGIAR Research Program on Water, Land and Ecosystems. "While actions aimed at protecting human health are the first priority, we can also limit the hazards through a variety of tested approaches aimed at safely recovering and reusing valuable resources from wastewater. These include the water itself but also energy, organic matter and nutrients, all of which agriculture needs. Through such approaches, we have been helping the World Health Organisation (WHO) respond to the wastewater challenge over the years."

"We hope this new study will focus the attention of policy makers and sanitation experts on the need to fulfill Sustainable Development Goal 6, particularly target 3, which calls for halving the proportion of untreated wastewater, and increasing recycling and safe water reuse," added Drechsel.

"One major challenges is to cultivate behavior change from farm to fork, especially where risk awareness is low. Another consists of larger scale efforts to put the recovery and reuse of resources from wastewater and other waste on a business footing to make its management more attractive for the public and private sectors. Safe resource recovery and reuse have significant potential to address the health and environmental risks, while at the same time making cities more resilient and agriculture more sustainable, contributing to more circular economies."

 Explore further: Drugs in wastewater contaminate drinking water

More information: A L Thebo et al, A global, spatially-explicit assessment of irrigated croplands influenced by urban wastewater flows, Environmental Research Letters (2017). DOI: 10.1088/1748-9326/aa75d1 

Journal reference: Environmental Research Letters  

Provided by: Institute of Physics

Read more at: https://phys.org/news/2017-07-global-wastewater-irrigate-agriculture-percent.html#jCp