Process intensification with ZeeLung and zeeDENSE I Veolia

with ZeeLung* Membrane Aerated Biofilm Reactor with zeeDENSE*

Because of growing populations and stricter environmental rules (like EU Directive 2024/3019), facilities need to treat more wastewater and remove more nutrients than ever before.

Expanding plant capacity traditionally means building expensive new bioreactor tanks, which requires major capital investment, takes up valuable land, and increases energy demands. The ZeeLung Membrane-Aerated Biofilm Reactor (MABR) and the zeeDENSE technology offer a smarter, simpler way to upgrade your existing assets without new civil construction.

How it works

This technology combination couples the synergies of intensified biological nutrient removal with continuous flow densification:

In the bioreactor: ZeeLung cassettes are simply immersed in the mixed liquor. They support the growth of a biofilm that increases the inventory of nutrient-removing biomass in the system. The ZeeLung media “breathes” – transferring oxygen to the biofilm without the use of bubbles, which reduces aeration energy by up to 75% and mitigates N₂O emissions. With ZeeLung, facilities can achieve up to 50% more biological treatment capacity within the same tank volume.

In the sludge stream: zeeDENSE racks process the waste-activated sludge or mixed liquor using hydrocyclones to create continuous gravimetric selection pressure. The system actively separates biomass:

✅ the dense highly active fraction is returned to the bioreactor

✅ The lighter, slower-settling fraction is wasted from the process

The result is improved settling characteristics of the mixed liquor, which enables up to 50% intensification of secondary clarification.

What this means for your plant

🔷 Increased capacity in current tanks: You can increase both biological and hydraulic capacity by up to 50% within your existing footprint, avoiding the need for new civil works.

🔷Significantly reduced energy consumption: The system's bubble-less oxygen transfer reduces the energy required for biological treatment by up to 75% (a 4-fold reduction) compared to conventional methods.

🔷Support your environmental targets: High process efficiency directly supports carbon-neutrality goals by mitigating overall greenhouse gas (GHG) and nitrous oxide (N₂O) emissions.

🔷 Improved process resilience: Selectively retaining dense biomass improves sludge settleability and ensures stable removal of nitrogen and phosphorus, even during variable load conditions.

🔷 Modular implementation: Both technologies are modular and can be installed rapidly without interrupting existing plant operations.

Curious to see how it works in practice?

Watch this 45-second video for a firsthand look at exactly how the modular ZeeLung cassettes are lifted and deployed directly into an active treatment tank in Yorkville-Bristol.

Read about the results from the world's largest MABR installation. Download the case study to see how these technologies helped United Utilities at Bolton Wastewater Treatment Works in the UK meet strict new ammonia limits for 446,000 people within their existing footprint.