LNAPL Skimming

LNAPL Skimming

The process for groundwater remediation is an innovative and unique solution for contaminated wastewater: it relates to a LNAPL Skimming technique developed by ODS International SA. This technology is exclusive and based on the pumping-skimming of hydrocarbons in the free phase. In other words, it is a groundwater treatment system. Pollutants are recovered as fast as allowed by soil permeability thanks to a maximized dynamic technology.

It is typically composed of:

  • 1 DS 500 or DS 100 vacuum pumping unit
  • 1 set of SKIM 2 or 4 skimmers immerged in wells and connected to the pumping unit using a flexible hose.
  • 1 ST 2500 L or higher capacity storage unit

It is also possible to opt for the purification of pumped effluent, the purification of fumes produced during pumping/storage and the ATEX (Explosion Proof) electrical compliance of the installation.

The principle is simple, fast and effective

Skimming is carried out using pump cycles. During each cycle, the supernatant liquid is pumped sequentially and independently in each well while monitoring is carried out by a PLC. The frequency of pumping between two cycles depends on 2 factors:

  • The time required to recharge the well with the pollutant.
  • The time of suction per well, linked to the quantity of free phase present in the well.

Pumping into the wells is achieved using a SKIM 2 or 4 float connected to the pumping unit with a flexible hose.
The pumped mixture is then transferred automatically to a settling tank. The product is stored in a tank, awaiting removal by a specialised com-pany. The small quantities of effluent are then sent to a coalescence separator.

Following the request from the client, the effluent can then be treated by a small unit of activated carbon before discharge. Similarly, vapours produced during pumping and storage can be purified before discharge by an activated carbon treatment unit. The installation is under continuous monitoring via modem.

The benefits of this solution

  • Complete disposal of the pollutant free phrase

    Disposal of any type of free phrase in the aquifer. Guaranteed pumping of the free phase, even in the event of variations in the aquifer level.

  • Reduced cost of effluent treatment

    Minimum volume of water pumped with the pollutant, requiring only a very small effluent reprocessing installation.

  • Low energy consumption

  • Reduced maintenance costs

    Reduced maintenance fees. On site visit every 4 to 6 weeks.

  • Easily adjustable installation

  • Proven reliability

    Extremely low breakdown rate.

  • Accidents protection

    Complete protection against accidents due to the presence of an integrated holding tank and implementation of vacuum hoses.

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