A section of Tô Lịch applied with the nano-Bioreactors technology. — Photo baodatviet.vn

HÀ NỘI — The flooding of the Japan-Vietnam Environmental Improvement JSC’s (JVE) testing area was caused by heavy rain on July 15, claimed Võ Tiến Hùng, general director of the Hà Nội Sewage and Drainage Company.

Following reports that an intentional discharge water from West lake into the Tô Lịch River affected the clean up, Hùng said the JVE had been notified before they started the cleanup that the Tô Lịch had a constant flow and was the main drainage for the city whenever it was rainy and when West Lake was at risk of flooding.

Speaking at a press conference on Tuesday, he said running the cleanup trial in the rainy season was inappropriate, he added.

According to a report from the drainage company, following a weather forecast on July 9 that there would be heavy rain over the next five days and the water level of the West Lake was 5.96m (above the permitted level of 5.6m) the company discharged water on July 12 to ensure the safety.

Earlier on July 16, Dr Tadashi Yamamura, president of the Japan Environment and Trade Promotion Organisation (JETRO), the group cleaning the polluted river, sent a letter to the Prime Minister, Ministry of Natural Resources and Environment and Hà Nội’s People’s Committee to delay the termination of the trial cleaning project until September 17.

In the letter, Yamamura noted initial positive results after two months of using the Japanese nano-bioreactor.

According to JETRO, discharging water from the West Lake into the Tô Lịch River swept away good micro-bacteria created by nano-bioreactor panels which were put into the Tô Lịch River two months ago.

He said the organisation needed time to re-activate the micro-bacteria system.

The discharge of water from the West Lake into Tô Lịch of the Hà Nội Sewerage and Drainage Company was a regular operation to prevent flooding, said Lê Tự Lực, deputy chief of office of Hà Nội People’s Committee.

Lực said the discharge was carried out in line with regulations.

Thanks to proactiveness in regulating West Lake’s water level, its basin didn't flood, he said.

Japanese experts and JVE proposed a trial cleanup of a section of Tô Lich River using nano-bioreactor technology, beginning in May and scheduled to finish on July 17.

Nguyễn Tuấn Anh, chairman of the Board of Directors of the Japan-Vietnam Environment Investment JSC, said Hà Nội Sewerage and Drainage Company has provided timely support for the company in the pilot.

The discharge of water in the rainy season to prevent flood was in accordance with the city’s direction. However, he said, because the trial was on a 300m section of the river, the company proposed Hà Nội Sewage and Drainage Company adjust West Lake’s water discharge plans until the project was completed. — VNS