NDN+MBR

Wastewater treatment with high nitrogen loading can be optimized with continuous operation with nitrification/denitrification (N/DN) using membrane bioreactor (MBR) at the final stage to ensure effluent quality. This technology takes up less space than a conventional settling treatment plant and has various applications in industrial sectors such as food and beverage or pharmaceutical where intensive and efficient wastewater treatment is required. It is also an optimal technology for landfill leachate treatment or urban wastewater treatment in small towns or dense urban areas where space is limited. Treatment efficiency is key especially in sensitive or protected areas with strict regulations on nitrogen and phosphorus in the effluent. This treatment allows the reuse of treated wastewater for applications such as process water or irrigation water.

The process of treating wastewater with high contaminant load in a continuous Nitrification/Denitrification (N/DN) system with a Membrane Bioreactor (MBR) combines advanced biological processes with physical separation by means of membranes.
After an adequate pretreatment the wastewater enters the reactors. In an anaerobic tank the heterotrophic bacteria use organic carbon as an energy source to convert nitrates (NO₃⁻) into nitrogen gas (N₂), which is released into the atmosphere. This process is known as denitrification.

In an aerobic tank, through intense aeration to supply sufficient oxygen (by air diffusers), nitrifying bacteria (autotrophic) oxidize ammonia (NH₄⁺) to nitrites (NO₂⁻) and then to nitrates (NO₃⁻), which will be recirculated to the denitrification stage.

The key to the process is the internal recirculation of the nitrate generated in nitrification towards denitrification to maintain the efficiency of the process. Finally, the water flows to the MBR module, which consists of ultrafiltration or microfiltration membranes. These membranes physically separate the treated water (clean effluent) from suspended solids, along with biomass and other contaminants.