Successful sump sealing in the Chinese city of Wenzhou

Tank sumps are actually critical elements in storage facilities, due to the potential contaminating liquids they link with. It is essential to consider the liquid transfer process, as this can contact the walls of the sumps or, in some cases, small volumes of products may fall into the environment, polluting the soil or the groundwater if the sump walls are not liquid proof. Moreover, surrounding water can seep through sumps, in case they have not appropriate conditions. 

In order to avoid any kind of contamination or leaks, Wolftank Adisa provides its high-quality sump sealing system, which is highly sustainable and offers an innovative, economic and excellent solution for sump refurbishments.

Several markets demands these works, such as the Chinese one, where our Shanghai team (Wolftank Adisa Shanghai Environmental Technology) recently restored a sump achieving the complete customer satisfaction.

The scope of the project

The Jinxiang gas station is located in the Cangnan county of WenZhou city, specifically at Jinxiang Avenue; just 3 km away from the coastline. The weather in this area is very rainy and the surrounding water system is really abundant. Actually, the average groundwater level in the zone is about 30/40 cm.

Wolftank Adisa had already installed DOPA® (Wolftank’s double wall transformation) in this gas station in July 2019. It has 3 oil tanks (gasoline 92, 95 and a diesel tank) and every tank has 2 sumps. The sump sealing works required in this case referred specifically to the gasoline tanks. In summary, the task was to provide 4 sump refurbishments in total, where all these sumps had seeps and needed a restoration.

A deep field investigation developed by our technicians showed that filtrations in the sumps were mainly happening between the steel wall and the top cement model joints. After removing the waterproof surface layer, there were different degrees of seepages in the whole circle, exactly at the junction of the cement and the steel plate. Even though the filtered water had no pressure and little flowed, at the same time, there was not binding force between the steel 4 walls and the external cement protective layer.

The dimensions of the manhole were:

  • Inner cuboid size: 120x135x110 cm
  • Ground wellhead size: 89 cm
  • Tank manhole size: 60 cm
  • Every sump had an internal surface area of approximately 6 m2

The solution

The sump sealing period lasted from the 8th of January 2021 to the 12th of the same month. The weather conditions (wintertime) during the installation were extremely challenging, from -3 to 8°C, with an average of 3°C of temperature.

The process entailed:

  1. First step: water stop.
  2. Second step: surface treatment. It is important to mention that, as usual, surface preparation was mandatory. The surface was cleaned, dried, and freed of any hydrocarbon residuals.
  3. Third step: special primer and Epoflex® adhesive mortar reinforcement application.
    In the primer phase, in order to achieve proper adhesion, it was directly applied on the cleaned surface with a roller. The Epoflex® adhesive mortar was applied with a spatula.
  4. Forth step: conductive and pipeline recovery developed.

We can confirm that the complete site maintenance operation just took a few days!

The watter stopped by quick-drying concrete and with Epoflex® adhesive mortar. This covered a small amount of water leakage after heating it up and applying at a very high temperature.

The outcome

Within a few days it was possible to apply Wolftank’s sealing technologies in 4 sumps. The gas station owner praised the quick works as well as the preparation and the refurbishment. Despite the surrounding wet environment, the sumps and the tanks are completely isolated and the gas station can go on with its business in total safety.  

No doubt that Wolftank’s sump sealing technologies bring an easy and quick solution to customer’s necessities. Sumps can be perfectly restored, no matter how wet the conditions are they are surrounded by!

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