Dr. Peter Werner and Prof. Ha Dinh Duc at the Sword Lake.

Dr. Werner is the chair of the ongoing $2.4 million project, which uses low-impact environmental German technology to remove sludge from the Sword Lake to help ensure Hanoi’s legendary old tortoise is at less risk from environmental pollution. This project commenced experimentally last November on 1000sq.m and results have been good. The project will continue this March to clean up the whole lake. 

TTCT: How did you become involved in this project and when did the project begin?

Dr. Peter Werner: This is a long story. We had the idea to improve the water environment of the Sword Lake around seven years ago. At that time everybody worried that this was a difficult and sensitive job because the Sword Lake is a holy site to Vietnamese people where this giant tortoise was living. We contacted Prof. Ha Dinh Duc, an expert on the giant tortoise in the Sword Lake, to discuss the project. Prof. Duc agreed with our project and took action to help promote it.

Our measures are very gentle and friendly to the environment. It can help improve the living environment of the old tortoise and doesn’t make any big changes to the lake’s ecological system. We conducted the project step by step, in a natural way. We dug and funneled the mud into a pipe, layer by layer. This method is different from others that kill the existing ecological system.

TTCT: Could you explain further about this method?

Dr. Peter Werner: First of all, we have to talk a little about Sword Lake. This is a closed lake and that type of lake will get eroded sometimes. Moreover, the lake can collect rubbish. Trees growing on its bank develop and create a new layer of mud. The lake will be filled up in the near future if it is not dredged. The current water level is only 40cm and there is no living environment for creatures in the lake. Fish, aquatic animals and the old tortoise are facing danger. There is only one way to save the lake and that is by dredging mud.

Our project splits and sucks each layer of mud, from top to bottom. However, we only remove the newly-formed mud layer and maintain the mud layer that was created 40-50 years ago. In the past, many craft guilds around the lake discharged polluted wastes to the lake for years, making a sediment mud layer in the lake’s bottom. That is why we don’t touch that mud. In addition, this mud layer prevents the water soaking into the soil. If we dig and dredge the bottom mud layer, the water will be completely absorbed by the ground.

For these reasons, we very carefully implemented the project. We only removed around 1-1.5m of mud layer within each pieces of 1000sq.m to prevent impact on the lake’s environment.

TTCT: Before cleaning up the Sword Lake, did you test this method at the fish pond in the President Ho Chi Minh Presidency Palace?

The old turtoise.

Dr. Peter Werner: Yes. That was requested by the Hanoi authorities. They wanted to see whether our method is effective or not and what are its impacts on aquatic animals and plants. The experiment took place in March 2009. We released a tortoise to the pond and it was still healthy. So our method was approved.

I clearly understand our technology and I’ve never worried about its effectiveness. To be sure, we cordoned off the area where we would remove mud with a net to ensure that the old tortoise was outside the net. When I went to Vietnam on January 19, I was accompanied by reporters from the MRD channel. After that, ARD, MDR and 3Sat channels also reported about this project. (ARD – the German national TV channel, MDR – a sub-channel of ARD covering Germany’s Sachsen state, 3Sat – the channel for Germany, Austria and Switzerland).

TTCT: Have you ever seen the old tortoise in the Sword Lake?

Dr. Peter Werner: Oh, yes, three times, all in the morning between 6 and 7am.

Wonderful! The old tortoise is around 3m length, with an extremely big head. I took some picture of him. When we conducted our project, students in my group saw him very near. He often crawls to the small island amid the lake and lies there so our students could see him from every direction while Prof. Ha Dinh Duc had to stand on the bank and he was very jealous (smile).

TTCT: How is the pace of this project?

Dr. Peter Werner: I think that if we implement the project quickly, the lake’s ecological system will be harmed. It is better to carry out the project over one and a half years. This technology can clean up other lakes in Hanoi like West Lake and the other 40 lakes. The mud taken from lakes can be used as fertilizer.

TTCT: Can Vietnam use this technology to clean up the other lakes itself?

Dr. Peter Werner: This is our goal. Scientific cooperation between Vietnam and Germany has been established closely.

TTCT: How many years more that the Sword Lake will need to be cleaned up again after this project is finished?

Dr. Peter Werner: It is a thorny question (smile). After this project, we need to analyze all the procedures to know when will the water environment worsen again. However, I think the lake doesn’t need to be dredged for around 30 to 50 years.

We want to use biological methodologies to self clean the lake. But it is important that people do not throw rubbish into the lake anymore. The situation is so bad because the lake has to contain rubbish and waste from surrounding streets for many years.

We also like the idea of the expansion of the area for trees around the lake because then the more natural conditions for the lake are enhanced, the less bad impacts to the lake are created and a self-cleaning mechanism will be set up for the lake. Of course, it is difficult to do it.

TTCT: Apart from this project, do you implement other projects in cooperation with Vietnamese colleagues?

Dr. Peter Werner: We are working on a project to treat rubbish and waste water discharged from food processing enterprises in Ha Tay and Bac Ninh into biogas and a project to treat waste water in Long Bien district, Hanoi.

In South Vietnam, we are involved in projects to generate wind and solar power and some waste treatment projects in the Tra Noc Industrial Zone (Can Tho City). We also have projects on education and student exchange and combine with the Hanoi University of Natural Sciences to train masters of environment.

Thank you very much!