Almost 55 years after its inception, Chittagong Water Supply and Sewerage Authority (CWasa) has taken up a sewerage treatment project for the first time as it bids to reduce pollution in the port city.
With the successful implementation of the massive project, contaminants will be removed from the household wastewater of over 1.2 million residents.
According to information provided by Chittagong City Corporation (CCC), the country’s second city is now inhabited by 6,000,000 people, while the total number of holdings stands at 182,248.
Of these, 72,502 households located in the Halishahar, Agrabad, New Market, Lalkhan Bazar, Jamal Khan and Kotwali areas, will come under the sewerage treatment coverage.
The project, titled “First Ever Sewerage Project of Chittagong City”, will begin in July with the approval of the government, and is slated to be completed by June 2025.
“The Development Project Proposal (DPP) has been sent to the Local Government Division for approval,” Superintendent Engineer (Planning and Construction) Mohammed Ariful Islam told the Dhaka Tribune.
With a total budget of Tk3,978 crore, the treatment plant of the gargantuan project will be set up over 165 acres of land in Halishahar area, owned by CWasa.
Of late, CWasa has drafted a drainage and sanitation master plan, recommending a total of six sewerage plants,” Ariful said. “As per recommendations, CWasa has undertaken the initiative to install the first sewerage treatment plant.”
‘Long overdue’ project
This massive project includes a sewerage treatment plant, fecal sludge treatment plant, 189km-long gravity pipeline, 3,602 manholes and chambers, and various pipelines and pump stations.
Terming the project “long overdue”, Chittagong chapter Vice President of Poribesh Bachao Andolon Prof Dr Md Edris Ali said the plant will clean sewage and water for their safe return to the environment.
“Untreated sewage of the city is contributing to a sharp fall in dissolved oxygen level of Karnaphuli River and endangering the underwater biodiversity,” he said. “The project will help improve the environmental hygiene of the port city.”
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According to a report of Department of Environment (DoE), as many as 50,000 sanitary and 24,000 unhygienic traditional latrines are feed directly into the Karnaphuli River.
With an aim to reduce pollution and improve navigability of Karnaphuli River, a master plan was drafted comprising 50 recommendations, including 100% sewerage coverage for the port city.
According to the draft master plan, the absence of sewerage treatment plants was one of the major causes behind the river pollution.
Following this, an action plan was set as per the government’s directive.
How will the sewerage be treated?
In the treatment cycle, physical, chemical and biological processes are used to remove contaminants and produce treated wastewater that is safer for the environment.
Two types of wastewater will be collected for the project: black water, which is waste deposited at the septic tanks of households; and grey water, which is water used for bathing and cooking.
The two types of wastewater will be deposited at a station through household pipelines, from where it will be channelled to the treatment plant through a larger pipeline.
A by-product of sewage treatment is usually a semi-solid or slurry, called sewage sludge.
After processing the wastewater, the liquid effluent will be dumped into the sea and solid waste will be used to produce compost manure.
Waste will be collected from canals and drains in the hilly and the slum areas, where the pipeline installation will not be possible.