Covid is not transmitted thru’ Wasa-treated water: Study

Coronavirus is not transmitted through treated sewage water or supply water purified by Dhaka Wasa, but the germ exists in drains, a study has found.

The findings of the survey, conducted through joint collaboration by Dhaka Water Supply and Sewerage Authority (Wasa) and the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr'b), were released at a dissemination seminar at Wasa Bhaban in the capital's Karwan Bazar on Monday.

The study has found that of the raw sewage and sludge samples, 57.1% and 53.3% samples were found to have SARS-CoV-2 RNA – the novel severe acute respiratory syndrome coronavirus 2, respectively. There was no presence of SARS-CoV-2 in the samples collected after treatment at Wasa's sewage treatment plant in Pagla, Narayanganj.

The germ was also not found in the water and sediment samples collected from the river and pond ecosystems.

Dr Sirajul Islam, emeritus scientist at icddr,b and principal investigator of the study, presented the findings.

Local Government and Rural Development Minister Md Tazul Islam attended the programme as chief guest. He hailed the Dhaka Wasa authorities for carrying out the research.

He said, "The water that Wasa purifies is 100% safe, but there are problems with the pipeline." He also stressed the need for building public awareness on the issue.

Professor John D Clemens, former executive director at icddr,b, and Dr Shams El Arifeen, acting executive director at icddr,b were present at the press conference as special guests, while Engineer Taqsem A Khan, managing director and chief executive officer at Dhaka Wasa, presided over the seminar.

The Dhaka Wasa CEO said Wasa has partnered with many local and international institutions, including icddr,b, to strengthen its activities on the basis of scientific evidence.

"Not only has this study been carried out in the traditional way, but it has also been carried out to focus on the real situation," he said.

The shedding of the SARS-CoV-2 virus through human faeces begins within three days of infection, which ultimately goes into the sewerage system. This may lead to a contamination of the environment if the sewage is not properly treated and discharged. Thus, it is very important to understand this type of environmental contamination through sewage and other contaminated surface water sources in Dhaka city.

Accordingly, between September 2020 and January 2021, 22 sewage and 23 sludge samples were collected from Dhaka Wasa's Narinda and Bashabo sewage pumping stations and Pagla sewage treatment plant.

Additionally, two composite water and two sediment samples were collected from the Mitford point of the River Buriganga and the Abdullahpur bridge point of the River Turag. Six samples, including three water and three sediment samples, were also collected from three ponds on the Dhaka University campus. All the samples were tested to detect the presence of SARS-CoV-2 through RT-qPCR assay and different physicochemical parameters.