Specialty chemicals company Evonik is using its membrane technology to support the wastewater treatment industry by doping microorganisms that take over important material conversion reactions in the biological treatment of wastewater with oxygen.

Set to present its findings at environmental technologies trade fair IFAT in Munich (May 30th – June 3rd), Evonik plans to generate oxygen-enriched air using its SEPURAN N2 hollow-fibre membranes. 

Originally designed for efficient gas separation, the Austrian membrane specialist aims to harness its technology to support sustainable wastewater treatment, especially as population growth rates in urban areas continue to increase. 

Its approach involves accelerating the natural biological process undertaken by microorganisms such as bacteria and fungi through various purification stages. 

“We can accelerate these processes by specifically optimising the living conditions of the microorganisms. This enables them to grow faster and work more efficiently,” said Dr. Jörg Balster, Head of SEPURAN Process Gases, Evonik. 

“We dope bacteria with oxygen, so to speak, which we obtain locally using our membrane technology and feed selectively.” 

To enable the organisms to absorb extra nutrients during the process, Evonik has used nitrogen to add to the upstream solids separation, slowing down the growth of the microorganisms. 

Evonik headquarters

Evonik headquarters

“With our membranes, we are able to precisely determine the biochemical boundary conditions per wastewater treatment stage.” 

“In this way, plant operators can run their processes much more efficiently and expand plant capacities without requiring large-scale construction,” added Balster. 

When used for industrial gas purposes, Evonik’s membrane-based separation technologies act as a filter that allows certain gases to pass through while others remain behind. 

An advantage of its SEPURAN range is that it features no moving parts and is considered less complex than techniques such as pressure swing adsorption (PSA). 

Speaking to gasworld earlier this year, Balster commented on the technology, saying, “You don’t need auxiliaries, chemicals, or anything.” 

“If you have a pressurised airstream and you have a membrane, you automatically can produce nitrogen or oxygen enriched air. This simple process makes it so you can use it for a lot of decentralised production.” 

Wastewater treatment plant

Technologies to increase the efficiency of wastewater treatment could also prove invaluable when it comes to supplementing the availability of clean drinking water in underprivileged countries such as Lebanon and certain regions of West Africa. 

Water shortages

In an article published last November, gasworld explored the water nexus and examined how the industrial gas sector could help mitigate shortages in water-scarce regions. 

A warning issued by UNICEF Executive Director Henrietta Fore last August stated that ‘urgent action’ must be taken. 

“More than four million people across Lebanon – predominantly vulnerable children and families – face the prospect of critical water shortages or being completely cut off from safe water supply in the coming days.” 

 

“Last month, UNICEF warned that more than 71% of the population of Lebanon could run out of water this summer,” she added. 

With water and sanitation services under ‘huge strain’, millions of people could be forced to resort to unsafe water sources, risking an increase in waterborne diseases and a surge in Covid-19 cases. 

In addition to efforts increase water safety such as those undertaken by Evonik, companies involved in the water-intensive realm of carbon capture and storage (CCS) could mitigate water usage by implementing state-of-the-art CCS technologies that separate carbon dioxide (CO2) from flue gas by adsorption onto solid materials or pass the exhaust gas through membranes. 

Furthering the concept of a circular economy, Evonik uses its SEPURAN Green range to purify biogas that accumulates during wastewater treatment processes. The CO2-neutral gas can then either be injected into the natural gas grid or utilised as a green fuel for municipal vehicles. 

Stating that the company’s membrane technology solves ‘key challenges’ faced by cities today, Volker Wehber, Head of SEPURAN Green, Evonik, added, “We believe our products can play an important role in smart wastewater systems and in the energy and mobility transition.”