Many landfills in cities and provinces have become “hot spots” due to serious pollution. The situation is so serious that local residents sometimes have blocked roads to prevent trucks from entering landfills and have asked local authorities to remove the dumping grounds.
Mr. Đặng Huy Đông, former Deputy Minister of Planning and Investment
Domestic waste treatment technological solutions include sanitary landfills and waste-to-electricity, i.e incinerating waste to generate electricity. The first, popular in the US, has been used in many cities in Việt Nam, including Hồ Chí Minh City. The second, popular in Europe, is used at Lam Sơn landfill in Hà Nội City. The third solution is technology that regenerates clean electricity and organic carbon from solid waste with pyrolysis and gasification methods. This is new technology which has been tested and recognized by Ministry of Science & Technology (MST) and Ministry of Natural Resources and the Environment (MONRE). However, more tests are needed for assessment.
Regarding the sanitary landfill method, waste is gathered in treatment complex and buried under the ground with protection layers to prevent penetration. However, according to Mr. Đặng Huy Đông, former Deputy Minister of Planning and Investment, when it rains, the waste water leaks and produces a bad odor.
In Việt Nam, waste is not sorted at source, and organic and plastic waste is buried together. It takes hundreds of years to decompose plastic. And the method requires large land space and does not prevent pollution. In the incineration method, burning of waste which includes plastics will produce furan and dioxin, two very toxic substances.
Mr. Đặng Huy Đông said that waste cannot be sorted before treatment in these methods. Trial programs on sorting of waste at source was applied in Hà Nội and Hồ Chí Minh City, but did not develop further. Hồ Chí Minh City authorities recently released a regulation on classifying solid waste at source. However, enforcement is unclear. Sorting waste at source is the major solution to the landfill method. As for incineration, furan and dioxin will be emitted into the environment when waste is burned at 500ºC. At the temperature of 1.200ºC, the two kinds of gas will no longer exist if the gas emitted at the top of the chimney is less than 70ºC.
Mr. Đặng Huy Đông suggested setting up a set of national standards on waste treatment, allowing investors to compete with each other with different technological solutions. The owners of the more effective solutions will be chosen.
Scientists say pyrolysis is one of the best technological solutions now available. The technology especially works well in treating plastic waste.
Duy Bạch (Vietnamnet Bridge)