In Bac Ninh Province, there are many occupational villages and recycling facilities currently producing non-ferrous metal, which offers a high economic value for the local population. However, as these facilities are located among residential areas, waste and emission from the manufacturing process directly affect the residents nearby, disturbing their livings.

As reported by the Bac Ninh Department of Natural Resources and Environment, dust concentration at all locations measured in Dai Bai copper-casting village is 2.6 to 4 times higher the permitted levels. Similarly, at Van Mon village, dust concentration is almost five times larger than the limit.

In order to lessen the current pollution severity in these villages, in 2009, the project to “Support 6 demonstration models of treating emission pollution at non-ferrous metal recycling villages in the province”, funded by grant aid from the Japanese Government, was carried out at 6 non-ferrous metal recycling co-operatives in 3 communes: Van Mon (Yen Phong), Dai Bai (Gia Binh), and Quang Bo (Luong Tai).

Exhaust gas treatment equipment installed at these co-operatives was provided by Environmental Equipment JSC (Ha Noi) and was undergoing examinations and practical tests at the Center for Science Technology and Environment of Vietnam. In a short period of time, the models are now complete and already in operation.

According to specialized agencies, emission treatment technology currently applied in these models is the solution of circulating absorption and diffusion with wet-type dust filtration device. Emission in the entire production process, including dust, steam, heavy metals and mixtures of CO2, SO2 … is drawn through the pipe tower due to the difference of natural pressure and pressure on the top of the tower system where the suction ball is installed.

After passing the tower, impurities such as dust, heavy metals, and toxic fumes will sink to the bottom of the tank containing the circulating solution, releasing clean air into the environment. The absorption solution will be circulated inside the towers by pumps. After every two months of operation, the sludge at the bottom of the tank will be discharged.

Analysis reveals that the discharge sludge comprise of CaCO3, CaSO4 and other Nitrogen compounds, etc and is not dangerous to the environment. They can be mixed with waste coal ash to make non-heated bricks or other products.

Mr. Nguyen Long, president of a copper and aluminum casting co-operative at Dai Bai is assisted in investing and building the environmental pollution treatment at non-ferrous metal recycling trade village treatment from the project. As he noted, this method is very effective. In the past, the workers have to work in an environment filled with exhaust gas, but since the gas treatment operation was implemented, these emissions basically have been dealt with (approximately 90%). Working environment for workers at his copper casting workshop has indeed improved dramatically.

As estimated, the initial investment for an exhaust gas treatment system is about VND400 million.

By Tran Quy