Hoan Kiem Lake, a symbol of Ha Noi, will be restored in the next two weeks by low-impact environmental German technology which has already successfully removed 600cu.m of sludge from the lake over the last 10 days.
Le Xuan Rao, director of Ha Noi’s Science and Technology Department yesterday said that the geological, hydrological, biological and chemical balance of the lake had remained unchanged following the extraction, left only cleaner water behind.
The device, a Serditurtle, used buoyancy to dip and rise like a submarine. Minimum turbulence and release of toxic compounds is ensured, leaving the surrounding water and eco-system unaffected.
The device used two corkscrew-like spirals that dig and funnel the mud into a pipe while also propelling the device forwards.
The liquid mud was pressed into solid blocks and transported outside the capital without any harm to the environment.
The processed water was discharged into the city’s waste water system due to the high proportion of ammonia and toxic algae in the water.
Rao said that the depth of the lake’s part being removed sludge has increased from a previous one metre to 1.60.
Associate Professor Dr Ha Dinh Duc from the Viet Nam Nature and Environment Protectors’ Association said that if the sludge of Hoan Kiem Lake had not been removed, it would have become a swamp in 50 years.
Duc said that removing sludge will be carried out in every small part of the lake to avoid the disrupting the eco-system. If the capacity of the devices is raised, it will take only 100 days to accomplish the task.
Professor Duong Duc Tien of the Biological Technology Centre said that all the activities would be carried out carefully to ensure the lives of the underwater species residing in the lake.
The US$2.4 million project to remove sludge from Hoan Kiem Lake is among a dozen initiatives which are the result of a co-operation agreement signed in June 2006 between the Ministry of Science and Technology and the German Federal Ministry of Education and Research.