DHAKA, May 30, 2022 (BSS) - The Pagla Sewage Treatment Plant was found to be
effective in removing SARS-CoV-2 RNA from the raw sewage, according to a new
study.
 
The findings of the study were disseminated at a seminar, jointly arranged by
icddr,b and the Dhaka Water Supply and Sewerage Authority (DWASA), at
Buriganga Hall, WASA Bhaban in Karwan Bazar, Dhaka.
 
The study was concluded to look into the presence of the Covid-19 virus
(SARS-CoV-2) in sewage and other contaminated surface water sources in and
around Dhaka city, an icddrib press release 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 the 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, there were 22 sewage
and 23 sludge samples collected from the DWASA's Narinda, Basabo sewage
pumping stations and Pagla sewage treatment plant (PSTP).
 
Additionally, two composite water and two sediment samples were collected
from the Mitford point of the Buriganga river and under the Abdullahpur
bridge of the Turag river.
 
A total of six samples (three water and three sediment samples) were also
collected from three ponds, namely the Institute of Public Health (IPH) pond,
Mirpur Mazar Pond and Shahidullah Hall pond on the campus of the University
of Dhaka. The Shahidullah hall pond was selected as a control pond. All the
samples were tested for the presence of SARS-CoV-2 by RT-qPCR assay and
different physicochemical parameters.
 
Dr Sirajul Islam, Emeritus Scientist at icddr,b and the Principal
Investigator of the study, presented the findings.
 
The study showed that of the raw sewage and sludge samples, about 57.1 per
cent and 53.3 per cent samples were found to have SARS-CoV-2 RNA,
respectively. There was no presence of SARS-CoV-2 in the samples collected
after treatment by the PSTP.
 
 
The SARS-CoV-2 RNA wasn't found in the water and sediment samples collected
from the river and pond ecosystems. The difference in physicochemical
parameters such as pH, temperature, total dissolved solids, dissolved oxygen,
conductivity, and dissolved solid in river and pond water samples were not
prominent, but variation was observed in treated and untreated sewage samples
collected from different sampling sites of the PSTP.
 
Local Government, Rural Development and Co-operatives Minister Md Tazul Islam
was present at the seminar as the chief guest, while Professor John D
Clemens, Former Executive Director at icddr,b, and Dr Shams El Arifeen,
Acting Executive Director at icddr,b, attended as special guests. Engineer
Taqsem A Khan, Managing Director and Chief Executive Officer at Dhaka WASA,
presided over the seminar.
 
In his speech, Tazul Islam appreciated the initiative and thanked icddr,b and
the DWASA. He said, "It was a great initiative of the DWASA to undertake this
research and generate evidence which is important."
 
Prof Clemens appreciated the leadership of the DWASA for taking up this
research at a time as there was not much knowledge about the environmental
contamination of the Covid-19 virus.
 
Dr Arifeen remarked that the findings of the study are indeed very reassuring
for the residents of Dhaka.
 
Eng Taqsem A Khan said, "The DWASA partnered with many local and
international institutions including icddr,b to strengthen its activities
based on science and evidence."
 
National public health experts, representatives from the WASA, icddr,b, and
media were also present at the seminar. The study was supported by the DWASA.