Currently, the management of domestic solid waste is a hot issue, which is paid special attention to by the public. The overloaded domestic landfills and outdated technology incinerators lead to high risk of environmental pollution and affect public health.
In this context, finding a solution for solid waste treatment is a challenge for many localities. Cần Thơ has solved this difficult problem since the waste-to-energy plant in Trường Xuân Commune (Thới Lai, Cần Thơ City) went into operation (December 2018). In order to learn about the Plant's waste treatment technology, as well as its development orientation in the near future, the Vietnam Environment Administration Magazine (VEM) had an interview with Mr. Shao Qi Chao - Chief Representative of China Everbright International Limited in Việt Nam (the project owner of the Cần Thơ waste-to-energy plant project) on this issue.
Mr. Shao Qi Chao - Chief Representative of China Everbright International Limited in Việt Nam
VEM: Could you please introduce briefly about the Plant, as well as the advantages of the waste-to-energy technology that the Plant is using compared to other technologies?
Mr. Shao Qi Chao: Cần Thơ Project is the first modern waste-to-energy project to be developed and operated by the China Everbright International Limited (China) in Vietnam. The Plant has a treatment capacity of 400 tons of domestic waste/day and generates about 150,000 kWh of electricity (equivalent to 60 million kWh/year) into the national grid. The Plant applies the technology with flipped-type incinerators and 7,5 MW condensate steam turbine generators developed by the Company itself and SNCR emission treatment technology (NOx treatment technology after combustion by chemical reaction).
Based on some European standards, the Company has improved and perfected the Plant's incineration technology, helping to reduce more than 90% of waste volume and 80% of waste amount, without the need for additional fuel. The Plant's emission treatment system is installed in a synchronous manner, meeting the European Standard BU2000 and the Vietnam Regulation No. 61 - MT:2016/BTNMT, the National Technical Regulation on biological solid waste incinerator, the main technology of emission treatment system is: The SNCR nitrogen removal equipment (selective non-catalytic reduction) shall conduct dry and semi-dry treatment and use activated carbon to remove heavy metals and dioxins. Simultaneously, the Company also installs dust filter bags and dioxin treatment in the 3T + E method to control temperature, time and excess air, in which the furnace temperature is maintained above 950°C. The emission treatment system is fully automated, the emission indices all meet the environmental standards. For leachate, the Plant uses A/O + UF + Chemistry Softener + MicroFilter + Reverse Osmosis technology, after the treatment, and it is reused through the circulating system in the Plant. Through the above treatment process, all the indicators meet the environmental standards of Vietnam.
Cần Thơ waste-to-energy plant
Compared to landfilling or composting, waste-to-energy technology is the preferred method of waste treatment, helping to treat a large amount of waste, saving land area and avoiding negative impact on the environment. Prior to investing in the Plant in Việt Nam, the Company had studied Việt Nam's environmental issues and decided to select the waste-to-energy technology. In addition, the features of domestic waste of the two countries are similar in low calorific value, high water level, high ash and impurities content. Therefore, the Company has invested in a waste-to-energy plant in Cần Thơ, helping the locality solve the problems of domestic waste and protect people's health. The waste generated during incineration will turn into a source of electricity to serve the daily life of people.
VEM: Could you tell us the commissioning operation results of the plant in the past time?
Mr. Shao Qi Chao: The Cần Thơ waste-to-energy plant is a project in which Cần Thơ City uses international bidding to select the investor to be the China Everbright International Limited. On June 30th, 2017, the project began construction and the operation license was granted on November 26th, 2018. By the end of July 2019, more than 120.000 tons of domestic waste were treated (about more than 60% of the City's waste). Since the Plant was put into operation so far, the operation has been guaranteed continuously and stably. Up to now, all the indicators on emissions and wastewater have met environmental standards and regulations. Outside the Plant's gate, LED screens are installed, showing the parameters of the Plant and clear operating time for local environmental managers and communities to know. Emission indicators are stored in the computer system of the Plant to provide all data when a competent authority requires to check. During the commissioning period, the Plant used an independent third party to check and monitor the indicators to ensure 100% of the indicators meeting the requirements. At the same time, the Plant also regularly welcomes the management agencies, enterprises and people to visit, which shows the objectivity and transparency of the plant's operation information. Starting from April 2019, on the first Friday of each month, the Plant is open for everyone to visit. Up to now, there has been more than 2,000 people to visit the plant and give a lot of compliments on the Green - Clean - Beautiful grounds and the system of modern and advanced machinery and equipment of the Plant.
VEM: How is slag and fly ash treated by the Plant?
Mr. Shao Qi Chao: After the treatment by waste-to-energy technology, the rate of furnace slag accounts for about 16% of the waste amount put into the furnace (about 480 tons of waste/day). The furnace slag is treated by sorting, screening, grinding and then collected to produce bricks or road construction materials and sold to units in need of leveling. The Plant has been licensed by the authorities to produce construction materials from slag in accordance with the law. In addition, the fly ash content of the Plant is currently about 3%, which is stabilized, collected and then covered with tarpaulins and temporarily stored in the warehouse area of the Plant. After that, it will be taken to the designated area by the local Government. Cần Thơ City is currently constructing a fly ash landfilling and treatment area for the Plant to treat fly ash as prescribed.
VEM: In your opinion, what are the biggest difficulties for the investors of the waste-to-energy plant projects? What suggestions do you have for making this technology widely available in Việt Nam?
Mr. Shao Qi Chao: In order to invest in a waste-to-energy plant in Việt Nam, investors must spend a lot of time applying for approval of the Project with a lot of procedures, making it difficult for investors to fulfill their schedule commitments with the local authorities. Currently, the China Everbright International Limited is investing in a number of waste-to-energy plant projects in some localities and conducting technology transfer for some Vietnamese enterprises. However, the policies of each locality are different, making it difficult for enterprises in the process of applying for project investment.
In order to meet the development of the waste-to-energy sector in Việt Nam, the Plant would like to propose some solutions: Unifying and perfecting various standards on construction and operation of waste-to-energy plants; There should be a unified national regulation on procedures for investment in waste-to-energy plants to avoid each locality requiring a different regulation; For small provinces and cities with low population, the relevant agencies should coordinate to construct waste-to-energy projects in some neighboring provinces to ensure the project feasibility and the economic scale to attract investors.
The company expects that the Cần Thơ waste-to-energy plant will be a model for the management agencies and the local authorities to refer to, thereby replicating to other localities in Việt Nam.
VEM: Thank you very much!
Hương Trần (Implemented)
(Source: Vietnam Environment Administration Magazine, English Edition III - 2019)