With the nationwide lockdown imposed over four weeks ago and the subsequent closure of industries, there have been multiple reports of cleaner water in lakes and rivers across the country. However, a Bengaluru-based citizens’ collective has warned that coronavirus may potentially flow in them.
The report titled ‘Blindsided’, prepared by the Bangalore Environment Trust (BET), has relied upon various scientific journals and media reports published across the globe to conclude that the potentially life-threatening virus, excreted through urine and faeces of infected persons, has entered the water cycle.
Relying on the scientific literature and considering Bengaluru’s hydrology, the report noted, “SARSCoV-2 (COVID-19) has a high potential to survive for long periods in wastewater and surface waters. Can the virus, excreted in Bapujinagar make its way to Byramangala and beyond? Can the virus that hitches a ride on non-biodegradable micro-plastic, settle to the bottom of Byramangala Tank? With no light passing and plenty of solid surfaces, that the virus can stick to, will it survive longer? The chances are too high to ignore.”
The report said grossly mismanaged urban sewage ‘is at the crux of the problem’ and blamed the Bangalore Water Supply and Sewerage Board (BWSSB) for not waking up to the challenge.
Citing recent lapses in the Vrishabhavathi Valley Sewage Treatment Plant in Rajarajeshwari Nagar, it said, “The utter negligence and lackadaisical attitude of BWSSB and KSPCB (Karnataka State Pollution Control Board) in preventing the spread of the pandemic virus beats the purpose of lockdown. ‘Lock the people down and let the virus proliferate’.”
The report warned that there is high risk of a second wave of transmission via the sewage route.
“As per ICMR (Indian Council of Medical Research), 40% of the confirmed cases had no contact history and another 58% had no data on exposure. Can sewage be the source of transmission? Has the virus contaminated the groundwater we use? These are important questions to ask and seek answers,” the report read.
The report relied on researchers in the Netherlands having found traces of the virus in the sewerage system, ahead of the first reported case, in the city of Nieuwegein. Similar research done in Belgium, the United States and Sweden have found traces of the virus in their sewage systems.
Other researchers have found that the virus being shed in the faeces and urine of the infected people is common and prolonged. Only in January, the first confirmed case tested positive for the virus in stools, the BET report mentioned, relying on The New England Journal of Medicine. In fact, another report, published by The Lancet, suggested the ‘possibility of extended duration of viral shedding in faeces, for nearly 5 weeks after the patients' respiratory samples tested negative for SARS-CoV-2 RNA.’
The report mentions how this sewage surveillance system for disease control was nothing new and was done during the 2003 SARS-CoV outbreak to trace infected populations.
Since then, scientific communities have advocated the use of sewage surveillance to detect the spread of the disease, given that in many cases, the patients in early stages of the disease do not exhibit any overt symptoms. The environmental group cited a report on how the French government-owned water supply and wastewater collection company found the virus in both untreated and treated samples from three major wastewater treatment plants in Paris.
But is the spread of viruses in water a reason for worry?
Research done by KWR Water Research Institute, Netherlands, Centre for Disease Control and Prevention, USA, World Health Organisation and others have not found any significant answers. BET, however, has called for additional research for the Indian scenario.
In the meantime, the BET called for application of ‘precautionary principle’, a strategy to cope with scientific uncertainty and insufficient state of knowledge as published by the WHO in 2005.
In its report, BET said, “While our battlefield with SARS-CoV-2 is air, we seemed to have missed water. We were terrified, when the news started coming in that the virus was excreted in the faeces and urine of the infected. We were terrified because we knew where that would end up – in our sewage fed wastewater rivers and eventually to our taps.”
It added, “We tried to find out what KSPCB, BWSSB, BBMP and the CoVID-19 Task Force were doing about it. We came up empty. As we kept treading on our own, we found that some countries are using sewage surveillance to understand the nature of the pandemic and it was cutting edge. We realized that this could potentially pave the road for us to get ahead of the virus.”
Problem in aerosols
The report pointed out that sewage treatment plants release microbial aerosols (suspended liquid droplets in air) into the air. And as a result, the virus can potentially be passed onto the surrounding air.
“Due to scarcity of land, all the STP (Sewage Treatment Plant) siting guidelines are flouted and the treatment plants are located in populated areas. To add to that, the concerned officials never maintain adequate tree zone as a buffer to at-least mitigate the spread of the aerosols. The unaware public around the STP and the STP operators themselves are at risk of exposure,” the report said.
It added, “The authorities need to map the confirmed and suspected cases with no contact history, to STP proximity. It can throw up some clues and help prevent spreading. Concerns have been expressed in the press about this route of transmission.”
Priyanka Jamwal, a water expert and Fellow, Centre for Environment and Development at the Ashoka Trust For Research in Ecology & The Environment (ATREE) told TNM that apart from STP workers, agriculturalists who use the same water and spray it are also at risk.
Fault in the system
Chlorination during sewage treatment
One of the easy fixes pointed out in the report said chlorination for 30 minutes has shown to inactivate the virus. But as it happened, the report said chlorination as a general practice is not done in our treatment plants as revealed to by BWSSB engineers on several occasions.
Further, they have stated that in the past, KSPCB inspection data of various STPs collected by filing RTIs have revealed that pathogens are not eliminated by the treatment process as carried out by the authorities.
The report cautioned that the process of dechlorination is equally important since residual chlorine is highly toxic and reacts with organic compounds in the wastewater to form dangerous carcinogens.
Sludge management
Sludge or concentrated solid waste stream of sewage is where higher quantities of the virus settle in the sewage networks. The report noted that sludge provides a conducive habitat for the virus to be active for longer and can protect them from inactivation. But in Karnataka and elsewhere in the country, sludge is often kept in open land and left untreated. When applied on land, it can become airborne, said the report, and can potentially infect nearby communities.
Other dangers due to reuse of partially treated water and diverting sewage
The report noted that partially-treated wastewater is pumped to far-off places from Bengaluru to address unsustainable groundwater exploitation. The water-parched Kolar District receives partially-treated wastewater from the Koramangala Challaghatta (KC) valley STP near Bellandur tank.
“Our enquiries have confirmed that pumping is on-going. Even during normal conditions, the KC valley STP was unable to treat water as per standards and eliminate all pathogens. To that mix, is the presence of this new virus. By pumping, we are needlessly and knowingly spreading the virus far and wide, exposing communities to undue risks. The case is the same for Chikkballapura and Bengaluru Rural district,” the BET report said.
The delved into how recharging minor irrigation tanks with partially-treated or untreated sewage can potentially contaminate groundwater, which serves as the source of drinking water for rural communities living in Kanakapura.
Other points detailed in the report include how this untreated sewage can also lead to infection of wildlife:
The 12 solutions proposed the report are
1. Wastewater surveillance
2. Strengthen sewage treatment plants (hospital and urban local bodies)
3. Strengthen drinking water treatment plants
4. Safe disposal of pandemic sludge
5. Investigate mysterious cases of diarrhea
6. Protect farming communities
7. Pause wastewater pumping
8. Wildlife surveillance
9. Wastewater epidemiology research
10. Issue advisories to apartments
11. Constitute pandemic control and prevention committee
12. Democratise information
Sewage surveillance scenario Given the present situation in Bengaluru, Bapuji Nagar and Padarayanapura wards in the city have been sealed due to the high rate of infection. The report stated sewage from both these wards flow into the Vrishabhavathi river. 24-hour composite samples can be taken at location ‘A’, before the river enters the wards and then again at location ‘B’ after the river exits the ward.
It said, “Viral Load can be calculated for each location. The difference in loads between locations, can indicate the scale of infection in the hotspots. Continued surveillance can tell if infections are increasing or decreasing. Decision to advance or scale back quarantine can be based on these data points coupled with data from clinical testing.”