Redoxy-3C, a substance used to cut pollution in lakes and researched by Hanoi and a German company, has shown positive results when being tested, according to the Hanoi Sewerage and Drainage Company (HSD).

The company announced that after being tested in polluted lakes in the capital such as Giap Bat, Ho Me, and Ba Mau, odor levels have fallen and the water is clearer, much to the pleasure of those who live nearby.

The substance also cuts alkaline levels and total suspended solids (TSS) in the water. Chemicals indicators are also at safe levels. Aquatic organisms in the lakes and plants on the water surface grow better, and the concentration of oxygen in the water is higher.

Mr. Tran Trong Van, Deputy Director of HSD, said that the initial results bring hope that the city can use the substance in its other polluted lakes. Adding Redoxy-3C to the lake water, however, is just one step in cutting pollution, he said, as trash still needs to collected regularly.

Initial results also show that spreading the substance takes little time and so is a relatively low-cost solution, Mr. Van said. The pilot projects were funded by the city’s budget and while exact figures haven’t been tabulated he believes it is cheaper than when the city has used other substances.

The management of Hanoi’s lakes exhibits many shortcomings. Some are managed by HSD while others are managed by local authorities at the ward or district level. HSD monitors water levels in some lakes, but other companies are responsible for dredging.

Hanoi has about 120 lakes, 76 per cent of which cover 1,000 sq m or more, 6 per cent cover between 500 and 1,000 sq m, and 17.5 per cent cover less than 500 sq m.

Recent research on the capital’s lakes have concluded that most are polluted, with 50 being severely polluted. After not being dredged for many years, sedimentation has seen some of the smaller lakes turn into fields.

Domestic wastewater is said to be the main cause of the pollution. Because many households discharge their wastewater without much thought, the concentration of organic and inorganic matter in lakes increases dramatically and exceeds the ability of the lakes to self-clean. Nearby ecosystems have also been affected.

Though the city pays great attention to curbing pollution in its lakes it remains a major challenge that requires the participation of the whole community. 

VN Economic Times