According to Ms. Dang Thi Thanh Hien (a resident of Vinh Tan Ecological Urban Area), continuously for about 15 days before Tet 2023, the water in Vinh Tan Ecological Lake suddenly turned black like used engine oil, giving off an extremely unpleasant smell.
Ms. Hien's house is located on Van Tue Street, close to the area with sewers, wastewater separation wells and Vinh Tan ecological lake. This location is very beautiful, because there are roads, lakes and lots of trees. Therefore, when she heard the project owner explain that Vinh Tan lake is an ecological lake, she decided to buy land to build a house. However, in reality, the lake not only has no ecological function, but is also heavily polluted, threatening the health of residents living in the area. "I go to work all day and it's fine. But the elderly and children have to breathe polluted air day after day. The smell is so bad that even though my mother is indoors, she has to wear a mask all day. Because I couldn't stand it, I had to move her to my brother's house a long way away, but there is still a phenomenon of odor pollution..." - Ms. Hien said.
Regarding the cause of pollution, according to Ms. Hien, at this stage, the wastewater drainage system overflowed freely into the ecological lake. “Some evenings, we discovered water overflowing from the sewer into the lake; some late nights, even inside the house, we could clearly hear the sound of water flowing. During those days, the lake surface was pitch black, bubbling, and covered with thick layers of scum. This situation was very worrying. If it was like this in winter, what would we do in summer…”.
Also living on Van Tue Street and having to endure the "terrible" stench from Vinh Tan Ecological Lake, Ms. Nguyen Thi Thuong said, "Coming here, we thought we would live in an ecological urban area, but we were wrong. This place does not live up to its ecological name..." According to Ms. Thuong, about a month before Tet 2023, the lake water was normal, and people were very comfortable walking and exercising. However, after that, the lake water suddenly turned black and emitted an unbearable stench. Because it was so stench, Ms. Thuong had to take her child to temporarily live elsewhere for a while. "As a resident, I cannot assess the cause, nor do I know which unit will be responsible for handling it. But that is the reality, so we have given our opinion to the investor. Since Tet until now, the smell is no longer terrible, but it still stinks. We hope the press will inform the authorities so that they can clarify the cause and find a solution to ensure the environment..." - Ms. Thuong suggested.
On January 13, 2023, in response to the polluted lake water and public outrage, Handico - Vinh Tan Urban Investment and Development Joint Stock Company (the management unit of Vinh Tan Ecological Urban Area Project) issued Official Dispatch No. 05/CV-CT to Vinh Urban Infrastructure Management and Development Joint Stock Company. Here, the pollution situation is reflected: “Based on the actual pollution situation at Vinh Tan Lake and the petition and appeal for help from households living in Vinh Tan Eco-Urban Area Project. Through inspection and survey of the current situation, the cause of pollution of the regulating lake at Vinh Tan Eco-Urban Area is due to dirty domestic water flowing from the Hong Bang canal system and the canal along Nguyen Son Street through the discharge gate, overflowing into the regulating lake of Vinh Tan Eco-Urban Area Project, causing the lake water to turn black and cloudy, emitting a strong stench, polluting the environment, affecting the lives and health of households around the area, especially directly affecting children and the elderly”.
And Handico - Vinh Tan Urban Investment and Development Joint Stock Company commented: "To minimize pollution for people to celebrate the traditional New Year and avoid frustration for residents living in Vinh Tan Eco-Urban Area Project and households around the area, Vinh Tan Eco-Urban Investment and Development Joint Stock Company respectfully requests Vinh Urban Infrastructure Management and Development Joint Stock Company to consider a plan to operate the transfer pump system in Trung Do ward regularly to avoid water overflowing the partition into Vinh Tan Eco-Lake and have a plan to reduce the amount of stagnant dirty water in Vinh Tan Eco-Lake, and at the same time open the bar to let river water flow in to dilute the dirty water in the lake".
Contact Vinh Tan Ecological Urban Development Investment Joint Stock Company to ask what is the basis for affirming that the cause of pollution is from "dirty domestic water" overflowing into the lake? The representative of this company presented a series of clips and images of wastewater from the canal system overflowing the discharge gate into Vinh Tan ecological lake. According to him, the clips and images were sent by residents, taken directly by company employees, and taken from cameras installed by the company near Tet. "The clips and images were all recorded late at night. Residents were very upset so they stayed up all night to record them as evidence. Upon receiving the feedback, we also organized inspections and recorded them. Although we sent images and clips and sent a document requesting handling, it was not until we installed surveillance cameras that the situation of wastewater overflowing into the lake was stopped. It was not until December 29 of the lunar calendar that things stabilized again...".
Present at Vinh Tan ecological lake on the afternoon of January 30, 2023, Vinh city officials introduced the system of sewers and separation wells of the Hong Bang canal and the canal along Nguyen Son street. Observed, the canal and the lake are separated by a concrete partition. It was explained that when the weather is dry, wastewater will pass through the separation well into the self-flowing canal to the transfer pumping station No. 2 in Trung Do ward (nearly 1km away). This pumping station operates continuously to carry out the task of transferring wastewater to the main pumping station's holding tank (located in Hung Hoa commune), from there transferring wastewater to the centralized wastewater treatment plant for treatment. Only when there is heavy rain, pumping station No. 2 does not operate, allowing surface water to flow through the canal through the self-flowing partition into the lake, then through the diversion channel to the Tay Nam pumping station's holding tank to the river to prevent flooding for the city.
At this time, it was noticed that the wastewater from the two canals flowed into the separation well, down the canal, and did not overflow the partition into Vinh Tan ecological lake. The water in the lake was not too black, but still had a slight foul smell. One thing that was easy to see was that there was a lot of sludge in the lake; in some places, the sludge formed quite large mounds.
Suggested to visit some transfer pumping stations, at pumping station No. 2 the machine was operating, but at Dong Nam pumping station (Ben Thuy drainage pumping station) it was not operating. Here, we accidentally discovered that the wastewater with a strong foul smell was freely flowing into the reservoir. Suggested to clarify the cause, according to the Vinh city official, the whole city has 4 pumping stations that carry out the task of transferring wastewater to the main pumping station's holding tank, from there it is transferred to the centralized wastewater treatment plant for treatment. However, there are still problems during the operation. For example, when the tank at the main pumping station is overloaded, there is a backlog of waste... "The capacity of the main station's water tank is limited, while people still dump waste into the canal system. When the tank is overloaded or backlog of waste, if 4 transfer pumping stations are still operating at the same time, it may lead to the release of wastewater into the fields. At that time, the operating unit may temporarily stop a transfer pumping station, leading to wastewater overflowing the baffle and freely overflowing into the lake and tank as we have seen..." - the officer discussed.
This fact shows that the reflection of Vinh Tan ecological lake pollution due to wastewater overflow is well-founded. We ask: Is there a situation where, because of the strong reflection from residents of Vinh Tan ecological urban area, people are forced to operate pumping station No. 2 but stop Dong Nam pumping station to let wastewater into this reservoir to avoid overload? The Vinh City official replied: “In December 2022, the issue of pollution in some lakes and canals was raised for questioning at the 7th session of the City People's Council. In the explanatory report, the City People's Committee clearly stated the current situation, causes, shortcomings, problems as well as solutions. Regarding the causes of pollution, there are from wastewater and sludge. As for the shortcomings and problems, there are from the operation work that allows wastewater to overflow into lakes and reservoirs... After the meeting, the City People's Committee assigned specific tasks to each department, office, and functional unit to focus on handling. Regarding the wastewater overflowing freely into the reservoir of the Dong Nam pumping station, I can only point out some situations that can lead to this, but cannot conclude the cause...".