The Dasherkandi Sewage Treatment Plant in Bangladesh, a project undertaken by PowerChina, has greatly improved local environment.
Beautiful beaches along the Balu River flowing through Dhaka, capital of Bangladesh, attract increasing numbers of visitors this year. The number of cruise ships, tourists, and residents is rising significantly during weekends. The once dirty and smelly river has turned clear, and villagers have begun to fish in the river, while children are having a great time swimming and playing in the water.
The drastic improvement in water quality has been brought about with help from the Dasherkandi Sewage Treatment Plant on the river’s west side. The China-funded project adheres to Chinese standards, and its construction was undertaken by Power Construction Corporation of China (PowerChina). The plant officially went into operation on April 1, 2022. The domestic sewage generated by some 5 million people in downtown Dhaka can be treated daily, which has greatly improved the water quality of the city.
Largest in South Asia
When Chinese President Xi Jinping visited Bangladesh in October 2016, the two heads of state witnessed the signing of the first intergovernmental cooperation document on jointly building the Belt and Road between China and Bangladesh. At the same time, leaders of both countries also witnessed the signing of the loan agreement for the Dasherkandi Sewage Treatment Plant Project.
Being the largest city in Bangladesh, Dhaka is one of the major cities in South Asia, with a population of more than 20 million, and a daily water supply capacity of about 3 million tons. Without large-scale sewage treatment facilities, Dhaka was afflicted with serious water pollution due to aggregation of sanitary sewage and industrial sewage.
Located in the southeastern suburbs of Dhaka, about 10 kilometers from the city center, the plant was designed, procured, and constructed by Hydrochina Corporation (a company of PowerChina), which has also undertaken operations and maintenance work for a year. This is the first modern large-scale sewage treatment facility in Bangladesh and the largest single sewage treatment plant in South Asia, with a sewage treatment capacity of 500,000 cubic meters per day.
“Plants at the same level in China are generally available in metropolises like Beijing, Shanghai, Guangzhou, or other large provincial capitals. As most of the current sewage is treated nearby, it is unlikely that a single sewage treatment plant of this scale would be built again in China,” said Pan Dengyu, vice president of PowerChina Eurasia, adding that such a huge project is of great significance to Bangladesh. The capital suffers from water pollution — the only old sewage treatment plant built in the 1990s is dilapidated — and the treatment capacity (120 million Ltrs per day) seriously insufficient. Its ecological environment was in urgent need of improvement. Although the country has rich water resources, there are no domestic sewage treatment plants in other cities except the capital, and the construction of the first large-scale modern sewage treatment plant was going to open a new chapter in its water resources management sector.
The construction of the plant officially started on August 1, 2017, which mainly included the sewage lift station outside the plant, the sewage conveyance pipelines, the main plant area, and the sludge dry & incineration plant. The project provided more than 1,000 jobs and corresponding business training for the locals, and the total value of local equipment and materials purchased was about US $45 million, effectively driving local economic development.
The plant so far has treated more than 45 billion Ltrs of sewage from the municipal sewage network, and the domestic sewage of the five surrounding regions has been collected at the plant through the drainage system and effectively treated. The treated up-to-standard water is then discharged into a nearby river to further improve the local water environment. More residents nearby have also benefitted from environmental improvement. They sincerely thank the Chinese builders involved in the construction, and often warmly invite Chinese engineers to visit their homes.
Main Plant Area of Dasherkandi Sewage Treatment Plant built by PowerChina.
From Chinese Standards to Local Models
According to the contract, the project adopts the standards of the country where the project is located; the standards of Western Europe or the United States; or the equivalent of China. It was challenging to incorporate Chinese standards in the implementation process. When the contractor applied for the adoption of Chinese standards, the foreign consultant engineers were more familiar with and trusted the European and American standards, and required the submission of comparative data between Chinese standards and European and American standards to prove that the proposed Chinese standards were higher than or equivalent to European and American standards, thus a lot of standard comparison and communication work generated. “This was quite different from the traditional Chinese design model; making the design drawings was very demanding, and the approval process turned out to be difficult,” said Zhang Chengbo, project manager of the Dasherkandi Sewage Treatment Plant. “We organized experienced designers, and adopted the on-site design model, greatly promoting the approval progress of the design drawings as a result.”
According to Zhang, the application for approval of export materials also adopted an on-site mode to speed up the process. The main equipment and materials of the sewage treatment plant, according to the project plan, needed to be imported from China, but the technical review and approval of the equipment took around half a year. To this end, PowerChina specially organized a team working on the professional equipment approval process and technical personnel to cooperate with the consultant engineers on the scene, explain technical issues, and resubmit the revision quickly, so as to obtain the approval as soon as possible.
Since neither Dhaka nor the consultant had experience in the construction of a sewage treatment plant of this scale, China’s design scheme also had to undergo a process of adapting to the situation. Take the primary sedimentation tank as an example, the Chinese design team designed an inverted conical tank with a diameter of 50 meters based on domestic construction experience, but the consultant had only been exposed to the 30-meter diameter design and had reservations about the Chinese plan. The Chinese team patiently explained its tried and tested experience, and also led the other party to China for field investigation, visiting the sewage treatment plants in Chengdu, Chongqing, and some other cities. Seeing is believing; after seeing the normal operation of the 50-meter-diameter tank, the consultant gradually put aside their doubts.
It was even harder to persuade foreign teams to accept Chinese patented technology. The project also covered the first modern sludge dry & incineration plant in Bangladesh, making it a first in the country that a sewage treatment system and a sludge treatment system were completed and put into operation simultaneously in the same plant. It was also the first time that the “spray drying + rotary kiln incineration” technology and equipment with China’s independent intellectual property rights was applied and put into operation overseas. Among many schemes, the sludge incineration treatment process developed by Tsinghua University can achieve minimization of space requirements, stability, and safe and efficient resource utilization — especially for large cities with shortage of land resources and discarded heavy metals exceeding safety standards. According to Pan, the foreign party was not familiar with the process and scheme of Tsinghua University, insisted on using the fluidized bed technology scheme that has been widely used in developed countries. After Chinese experts were invited to Bangladesh for repeated communication, a foreign team made a field visit to Beijing and Jiangsu Province, and they finally agreed to the introduction of this mature patented technology in Bangladesh. At present, the technology is operating well, with the exhaust gas fully compliant with standards, and the daily treatment capacity hitting 580 tons, which has been fully recognized by the owner.
Since the project went into operation, clear water has flowed down from the outlet into the river, and the project plant has become a local landmark building. In the field of water governance in Bangladesh — Chinese standards, Chinese solutions, and Chinese technology are no stranger now, and have transformed into the country’s own project experience. According to Pan, all the planned sewage treatment plants in Bangladesh preparing for tenders have incorporated the design and construction plans of the Dasherkandi Plant into the tender documents as a model — from the design of the pools, the use of environmentally friendly coatings, to the design of the cable trench — all of which are based on the Dasherkandi project. During the construction, PowerChina joined hands with the locals to overcome many challenges and successfully completed the construction of the project.
The completion and operation of the project has laid a solid foundation for Chinese enterprises to further venture into the Bangladeshi market. Since entering Bangladesh in 1997, PowerChina has completed projects amounting to US $1.16 billion, and 24 projects under construction have a total contract amount of US $4.89 billion, involving the construction of the country’s electricity, water, transportation, and other facilities. Among these projects, there are three investment projects, including Bangladesh’s first transportation project, that were developed in the PPP mode.
Since the construction of the Dasherkandi Project, PowerChina has pitched similar projects to relevant ministries and cities in Bangladesh to solve the problem of urban water supply and sewage, and the mature Chinese technology is used to promote the national basin planning and further improve the water resources and water environment of Bangladesh. In addition, in the field of renewable energy, PowerChina has applied to the Bangladesh government for more than 900 megawatts of development permits. PowerChina not only wants to treat sewage into clean water, but also bring green energy to Bangladesh.