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September 12, 2025

When wastewater gets salty:
a microbial breakthrough in extreme conditions

Treating wastewater is already a complex affair. But what happens when that water is not just dirty but salty, oily, and biologically hostile?
Keywords: Bioaugmentation, Bioremediation, Consortium, Mud treatment, Sludge reduction, Wastewater treatment
When wastewater gets salty:
a microbial breakthrough in extreme conditions

For years, industries discharging high-salinity effluents such as refineries, coastal installations, or municipal systems facing brine overload have struggled with the limitations of traditional biological treatments. High salt concentrations can halt microbial activity, slow down degradation, and generate persistent, toxic sludge.

So how do you engineer life to thrive where few microbes dare?

At Proventus, we took on the challenge with a simple question: Can a microbial consortium be optimized to remain functional and even highly performant in saline wastewater conditions?

The salinity barrier

Salinity has long been a bottleneck in biological treatment systems. Sodium chloride concentrations above 5% begin to stress most conventional microbial communities. At 10–15%, degradation of hydrocarbons and organic matter drops sharply.

Yet industrial activities, from offshore drilling to chemical processing, regularly generate saline waste streams containing hydrocarbons, ammonia, phosphorus, and suspended solids. Treating them efficiently remains one of the industry’s most pressing unsolved puzzles.

Instead of fighting salinity, we chose to partner with it.

Testing grounds: from municipal sludge to oil-based mud

To push the boundaries of what’s possible, we partnered with two research institutions:

  • Université de Sherbrooke, to test sludge reduction in municipal lagoon slurry.
  • Cranfield University (UK), to evaluate crude oil biodegradation in oil-based mud (OBM) collected from a refinery in Tunisia.

The conditions? Harsh.
The salinity? Up to 15%.
The stakes? High.

How we engineered the consortium

Our formulation referred to here as Optimize, is a tailored microbial blend designed for extreme environments. Each strain was selected for its salt tolerance, metabolic versatility, and ability to operate effectively within complex matrices.

But formulation is only the first step.

Results from the lab: promising, persistent, powerful

Cranfield University (OBM trials):

  • >95% COD reduction after 42 days, even at 15% NaCl
  • 60–70% hydrocarbon biodegradation, including long-chain alkanes and aromatic compounds
  • Performance improved at higher temperatures (35°C), suggesting robust thermotolerance
  • Visual biosurfactant production confirmed in multiple setups, enhancing bioavailability of hydrophobic pollutants

Université de Sherbrooke (municipal sludge):

  • Up to 18% reduction in sludge volume
  • 94% removal of ammonia (NH₃-N) and 89% COD reduction in only 14 days
  • Optimal results when Optimize was combined with alum or silica formulations
  • Notably, bioaugmented systems also reduced trace organic contaminants (TrOCs) such as caffeine and carbamazepine

Why It Matters

These results are more than numbers. They suggest a new frontier in microbial wastewater treatment where biology is engineered not just to survive, but to perform under pressure.

  • Effective in high-salinity environments
  • Scalable across industries with complex waste profiles
  • Compatible with both aerobic treatment systems and field applications

As global water stress and industrial pollution rise, especially in coastal and arid zones, such resilient solutions are not just “nice to have” they’re necessary.

What’s next?

Proventus is now exploring field deployment strategies to bring this formulation into full-scale operations. Pilot programs are being designed for:

  • Sludge reduction in overburdened municipal lagoons
  • Pre-treatment of saline wastewater in oil and gas installations
  • Hybrid treatment models integrating microbial and physico-chemical approaches

Because when it comes to microbial innovation, salinity shouldn’t be a stop sign.

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Proventus Bioscience Inc.
4455 Rue Griffith, Saint-Laurent
QC H4T 2A2 Canada