On-site nitrogen generation in wastewater treatment

According to United Nations figures, more than half of the world's population now lives in cities. By 2050, more than two-thirds of people are expected to spend time in urban living spaces. The unstoppable urban growth raises questions about sustainability, quality of life and scarcity of resources and space. Considering this, intact water management is of vital importance. Evonik's innovative technology for efficient gas separation using membranes shows how this can be optimized for wastewater treatment. 

Modern wastewater treatment plants rely on biology. Microorganisms take on important tasks across various purification stages: Bacteria, fungi and single-celled organisms absorb the components of wastewater into their metabolism and thus purify the wastewater. Evonik can accelerate these processes by specifically optimizing the living conditions of the microorganisms by doping bacteria with oxygen, so to speak, which can be obtain locally using SEPURAN® N₂ membrane technology and feed selectively. This enables them to grow faster and work more efficiently.

Based on the same SEPURAN® membrane technology, another gas from the air - nitrogen - can be added to the upstream solids separation to again slow down the growth of the microorganisms. This allows more nutrients from the pretreatment to enter the biology. With Evonik membranes, wastewater treatment plant operators are able to precisely determine the biochemical boundary conditions per wastewater treatment stage. In this way, they can run their processes much more efficiently and expand plant capacities without requiring large-scale construction.

Another gas separation membrane from Evonik-SEPURAN® Green-also makes it possible to purify the biogas that accumulates during wastewater treatment processes into high-purity biomethane and return it to the circular economy. The CO₂-neutral gas can be fed directly into the municipal natural gas grid or used as a green fuel (Bio-CNG) to power municipal vehicles.

Evonik's SEPURAN® N₂ membrane has been especially developed for nitrogen generation combining low air consumption at all temperature levels with high nitrogen capacity. Efficient air separation and nitrogen generation with SEPURAN® N₂ is especially suitable when spaces are being blanketed to achieve an inert atmosphere. They combine low air consumption with high nitrogen capacity. The benefits for you: you need a small compressor, only a few modules, and operational costs are low.