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[ Biological Oxydation (High Salinity) ]

Unidro has consolidated experience in the design, supply, commissioning and start-up of biological treatment units treating high salinity wastewater streams.

Typical application includes treatment of:

  • Produced Water
  • Wastewater containing Spent Caustic
  • Wastewater containing Wet Air Oxidation (WAO) effluent

The salinity of wastewater has an important effect on biological treatment units performance.

Biological sludge can operate with extremely high salinity but it is heavily sensitive to rapid variations of TDS (Total Dissolved Salt) concentration because osmotic pressure inside cell changes and this could inflate or squeeze the cell.

When high salinity waste waters are fed to a biological treatment unit and TDS can significantly change during plant start-up or operations, a controlled and slow variation is required to reach an equilibrium between internal and external osmotic pressure without cell damages.

Shock variation of salinity could irreversibly damage the bacteria community, leading to dramatic decrease of biological sludge activity and consequently of contaminant removal efficiency. Recovery of treatment efficiency could require some months and in worst cases may require scheduling a new plant start up.

Unidro brings its know-how for the design and supply of technological solutions to monitor and control wastewater salinity including:

  • Continuous monitoring of wastewater conductivity
  • Storage, equalization and feeding of high / low salinity streams
  • “Synthetic” brine solutions preparation and injection facilities to prevent salinity shocks

Unidro commissioning and start-up team is also fully committed to support client through the development of seeding and bio-sludge acclimatization schedules advising on acceptable salinity ramp-up / ramp-down.