The Dasherkandi Sewage Treatment Plant (DSTP) has improved the environment of Dhaka's Hatirjheel, Rampura and Dasherkandi area. With claiming this, officials said the plant is now treating 340-520 million liters of waste water and 550 tons of sludge, which used to pollute canals and rivers around the capital.
Mustafizur Rahman, Chief Engineer of Dhaka Water Supply and Sewerage Authority (DWASA) said the waste is coming to the plant through a diversion line at Hatirjheel and due to the treatment of the sewer water and incineration of sludge, the water quality of the Balu and Shitalakshya rivers, Hatirjheel lake, and Gozaria and Rampura canals has improved.
Speaking at a program at the DSTP office, Mustafizur said, at the plant, the sewage water is treated to near drinking water level. The water is released into the Gozaria canal which flows to Balu and finally ends up at the Shitalakshya River from where DWASA sources water for the water treatment plant. Due to several layers of water treatment at the STP, the water collected from the Shitalakshya for Sayedabad Water Treatment has been found as less toxic.
He claimed that the cost of water purification with chemicals was cut by 60 percent at the Sayedabad plant as the level of ammonia in Shitalakshya has come down.
DSTP project former director Mohasain Ali Miah who is now a consultant for POWERCHINA Chengdu said people of Dasherkandi area earlier made complaints about the high presence of ammonia due to mixing of human excreta with river and canal water. Tin-roofed houses were damaged due to the pollution. Fish species went missing due to the pollution. He said DWASA is now burning 540-550 tons sludge, and producing 40-45 tons fly ash, which is being used as raw materials for the cement industry.
An engineer of DWASA said that the fly ash is being sold at Tk120 per ton and they were thinking of the diversification of the use of the fly ash such as fertilizer. The plant on 62.2 acres of land in the capital's Khilgaon area was constructed at Tk3, 482 crore with a Tk2, 366 crore (US$280 million) loan from the Exim Bank of China. The government funded Tk1, 106.42 crore and only Tk10 crore came from DWASA. The construction work on the plant started on 19 August 2018 and it was inaugurated in July 2023.
DWASA officials said that the cost of maximum operation and maintenance of the automated STP was Tk80 crore per year against no income. Momtajur Rahman , DWASA Executive Engineer who is now in charge of the plant said that the plant has been in operation for two and a half years with the technical support of HydroChina Corporation.
He said, we have been operating the plant since 2021 when it was pre-commissioned. Now, HydroChina is providing us with all technical support under a one-year contract which is going to end in June. They’re sharing with us the technical knowledge and gradually we’re taking charge of the plant.
Momtajur said, the operation of such a plant is expensive all over the world and the governments always subsidies the operation cost of the plant. Our plant also needs a subsidy for better operation.
He also said we’re bringing highly toxic water to near potable quality in the plant. We’re bringing the level of faecal coliform from 1,726,667 to 22 per 100ml water. Besides, the levels of COD, phosphate, ammonium and SS have been brought to 17mg, 1.51mg, 0.268mg and 4mg respectively per liter of water.
It should be noted that all the households of the 80 sqkm catchment area, including Gulshan, Banani, Baridhara, Baridhara DOHS, Farmgate, Tejgaon, Satarkul, Bashundhara, Badda, Kuril and adjoining areas of Hatirjheel, will be connected to the plant through sewerage network.
More significant improvement in the environment is possible once the households are connected to the network, officials of Dhaka Water Supply and Sewerage Authority (DWASA) and contractors of the project HydroChina Corporation and POWERCHINA Chengdu claimed last Sunday. However, they could not provide any report on any study in favor of their claim.
ZH
