What is the NXO Engineering NXSTEP Project?
NXO engineering, a deeptech startup in the Water and Sanitation industry, presents the new generation of wastewater treatment plants: NxSTEP. After 5 years of R&D, NXO engineering designed a new wastewater treatment plant that uses algae bioremediation – a major turning point in sanitation. Microalgae are at the heart of the NxSTEP treatment plant, where wastewater, rich in macro and micronutrients, acts as a tremendous growth vector for these algae. This advanced process demonstrates that a Negative Carbon and Positive Energy treatment plant is indeed possible… It is an innovative approach which not only purifies wastewater but also transforms it into a valuable resource.
Main Benefits
- CO2 consumption (photosynthesis): 26 tonnes of CO2 remedied/year/100EH
- Energy efficiency: 255 tonnes of CO2 avoided/year/100EH
- No release of N2O (nitrous oxide): NEGATIVE GHG IMPACT
- Energy consumption: Only 0.12 kWh/m³ in comparison to the French average of 0.8 kWh/m³
- Autonomous station operation through renewable methane production and sludge energy surplus
Innovative Approach in Wastewater Treatment
NXO engineering has reimagined wastewater management by making microalgae the central element of purification. Wastewater is not just treated but transformed – with the use of algae that thrive on the nutrients present and capture CO2 via photosynthesis. The process is a profound shift from conventional techniques that are energy intensive and rely on chemical treatments. By adopting this bioremediation strategy, the NxSTEP process creates opportunities to exploit the hidden value in wastewater, generating income streams from what was traditionally seen as a financial burden.
Enhanced Energy and Environmental Transition
Current technologies in wastewater treatment are structurally very energy intensive, leading to higher water prices for communities and contributing to significant GHG emissions (CO2, N2O, and CH4) – around 1% of overall greenhouse gas emissions in France. In contrast, the NxSTEP process requires only 0.12 kWh/m³, dramatically reducing energy consumption. The station’s autonomous operation is made possible by generating renewable energy (methane) from wastewater, while the sludge produces an energy surplus that can be marketed or used in cogeneration. This technology embodies the continuous improvement of purification performances and is a true ally in the energy and environmental transition.
Breakthrough in Research and Innovation
In partnership with renowned institutions like CNRS, IFREMER, and INRAE, NXO engineering has further developed two microalgal bioremediation technologies designed both to purify wastewater and treat atmospheric CO2. These technologies are energy positive and carbon negative, presenting a sustainable solution where nature’s own devices are put to work. Moreover, NXO engineering has developed a biocoagulant based on cacti slime, which effectively eliminates the need for metal salts. Algal digestates, much like vegetable waste, are valued as biofertilizers, thus turning by-products into assets. This approach taps into the natural processes, emphasizing that sanitation need not be a burden but rather an opportunity for resource valorization.
Redefining Sanitation for a Sustainable Future
NXSTEP calls for a profound paradigm shift; it is no longer just about treating wastewater but about capturing and converting its resources into energy and secondary products. The emerging model is economically innovative and environmentally sound. By reducing energy needs and lowering carbon emissions while leveraging renewable energy, the technology offers significant cost advantages compared to conventional treatment methods. These productions not only reduce processing costs but also deliver clear environmental benefits, establishing a new benchmark in the water and decarbonation sectors.
Project Impact on Sustainable Development Goals
- SDG 6: Clean Water and Sanitation – Innovating water treatment processes to secure sustainable sanitation solutions
- SDG 7: Affordable and Clean Energy – Achieving energy-positive operations through renewable methane production
- SDG 9: Industry, Innovation and Infrastructure – Developing breakthrough technologies with the support of leading research institutions
- SDG 12: Responsible Consumption and Production – Transforming waste into resource, ensuring efficient use of materials
- SDG 13: Climate Action – Reducing greenhouse gas emissions and mitigating the impact of climate change
Looking Ahead: Future Prospects and Community Impact
The VOLTA project (Valorization of wastewater via light energy and micro-algal technologies) exemplifies the forward-thinking vision of NXO engineering by aiming to build the first pre-industrial demonstrator wastewater treatment plant with 500 pe capacity. This plant will be not only positive energy but also display a negative carbon footprint and operate without chemical products. In the upcoming world, simple signage will not be enough to meet environmental challenges – a full, integrated approach to sanitation is vital. NXO engineering’s work on both technical and commercial development of innovative, automated processes showcases that, in the light of this new century, sanitation should be viewed not as a cost but as an opportunity. Microalgae are poised to drive a change in the status and image of sanitation, offering hope that resource recovery becomes an essential part of the transition towards a sustainable future… The NXSTEP project stands as a testament to innovation, combining nature’s own methods with modern engineering to redefine how wastewater is treated and transformed.
