Dhaka North City Corporation (DNCC) is going to take action against building owners who connected their sewerage lines to lakes, canals or storm-water drains.

They will start taking measures from September 1 and have already identified 28 such connections in Gulshan and Banani areas.

"We have identified 23 lines at Gulshan and five at Banani, connected to Gulshan-Banani lake, and are working to identify more," said DNCC chief waste management officer Commodore SM Sharif-ul Islam.

DNCC Mayor Md Atiqul Islam said they are going to start the drive in posh areas like Gulshan, Banani, Baridhara and Niketan and will gradually cover all DNCC areas, to save aquatic life in lakes and canals.

"We have already held meetings with the societies of Gulshan-Banani-Baridhara and Niketan in this regard before taking action and have also given them solutions," the mayor said.

"I have set up a soak pit for my house around four months ago, so that no one can point fingers at me and others will be encouraged to do so. The water my house now releases is not harmful for aquatic life," he said.

A soak pit or soakaway is a closed, porous chamber that is  directly connected to the primary treatment unit of a residential or  commercial building. It serves the function of letting wastewater coming  from the septic tank to slowly soak into the ground.

Former general secretary of Bangladesh Institute of Planners Adil Mohammad Khan said building owners have violated their Rajuk-approved plans in regards to sewage management, and thereby, are polluting waterbodies.

In modern cities, this type of violation is penalised with a high "pollution fee". This should be introduced in the country's cities immediately, said Adil, also executive director of Institute for Planning and Development.

In addition, city corporations and development authorities should provide appropriate engineering and planning support for building owners to build septic tanks and soakaways, he added.

DSCC Mayor Sheikh Fazle Noor Taposh said they are not allowing any new sewerage-line connections to surface drains or canals from July 1, but will implement installation of septic tanks and soak pits in old buildings gradually.

In the capital, Dhaka Water Supply and Sewerage Authority (Wasa) only has the capacity to treat sewage water in Pagla area, and even then, a large part of the system is not functioning.

Earlier at a programme, Prof Md Mujibur Rahman of Bangladesh University of Engineering and Technology said although 20 percent areas of Dhaka are connected to the sewerage network that connects to Pagla Wastewater Treatment Plant, the plant treats sewage that is far lower than its capacity.

He said 71 percent household latrines (85 percent in slums) directly or indirectly discharge waste into open drains, leading to pollution of lakes and canals.

Mujibur said septic tank-soakaways do not work in Dhaka, because the soil's ability to allow water movement is low. Septic tanks in most households are not designed and constructed properly, resulting in less sludge deposition in the tanks.

Iqbal Habib, joint secretary of Bangladesh Poribesh Andolon, said when one-storey buildings were abundant, setting up septic tanks and soak pits was conceptually valid. But for a building that houses 20 to 40 families, the system is inadequate.

In foreign countries, city corporations pump out sewage water from soak pits and into treatment plants twice a week. They then release the water after treatment. But in Dhaka, there is no such system.

"Before taking steps, city corporations and Wasa will have to develop this system first. And for this, they will have to set up sewage-treatment plants at different locations," Habib said.