Taking water from West Lake to supplement To Lich River
To Lich River is more than 14km long, originating from Nghia Do Ward (Cau Giay District), flowing into Nhue River - Huu Hoa Commune (Thanh Tri District).
According to the Hanoi Department of Natural Resources and Environment, on average, the To Lich River receives about 160,000m3 of domestic wastewater per day. Most of this wastewater has not been treated or has not been treated to standards and has been discharged directly into the river.
According to Lao Dong, in recent days, hundreds of workers have been dredging the entire To Lich River. Speaking with Lao Dong, Mr. Bui Ngoc Uyen - Deputy Head of External Affairs and Communications Department, Hanoi Drainage One Member Co., Ltd. - said that the company is using 4 mechanical dredging lines with about 17 closed-cast vehicles transporting sludge in the To Lich River area.
"Currently, we are deploying 2 dredging shifts per day - 1 day shift and 1 night shift with a number of about 40 people/shift (including commanders and technicians)" - Mr. Uyen said.
On average, a day shift will dredge about 180 tons of sludge. Up to now, workers have constructed 300m from the upper reaches of the To Lich River. The dredging of To Lich River is considered a stepping stone for the process of "reviving" To Lich River with the plan to add water to To Lich River that the Hanoi People's Committee had proposed earlier.
Accordingly, the Chairman of the Hanoi People's Committee assigned the Department of Construction to preside over and coordinate with Hanoi Drainage One Member Co., Ltd. to immediately carry out the overall dredging of To Lich River, basically to be completed in August 2025.
Assign the Department of Construction to preside over research and propose a plan to collect water from West Lake to supplement the To Lich River if necessary to keep the water level of To Lich River through the regulating gate of West A Lake - Cong Do - Muong Thuy Khue to be completed in August 2025.
Multiple pilots
To "revive" To Lich River, in 2000, Hanoi City implemented a project to dredge and embank the two banks of To Lich River.
In 2008, Hanoi City had a project to pump water from the Red River into West Lake, then flow into the To Lich River to circulate the flow. However, this option is at risk of changing the ecosystem of West Lake, and silt gradually filling the lake bed. Therefore, this option is not agreed by economic and environmental experts.
In 2019, Hanoi City tested the cleaning of To Lich River with Redoxy-3C product. At that time, according to the report of Hanoi Drainage Company, the river section was tested with positive results, in which the amount of oxygen had increased significantly and the stench had decreased. However, this option was not replicated afterwards.
Also in 2019, Nhat Viet Environmental Improvement Joint Stock Company (JVE) piloted the cleaning of To Lich River (near Hoang Quoc Viet and Cau Giay streets) using Nano-Biorector technology. This technology is expected to completely decompose the mud layer at the bottom without dredging.
Evaluating the pilot process, Japanese experts said that the thickness of the mud layer in the iron enclosure area decreased by 38cm - 48cm. The domestic domestic domestic domestic domestic domestic dissolved oxygen (DO) content increased sharply and reached 6.67mg/l, meeting column A1 standards - Vietnam's technical standards on surface water quality.
After turning off the nano rain spraying system for 3 hours, the water in the surrounding area subsided, and the bottom of the mud and white ice layer could be seen as close as possible. However, this technology was not widely replicated after that.
