Introduction
Water is a vital resource, but treating it — whether to make it drinkable or to clean up wastewater — consumes enormous amounts of energy and materials. In a context of climate change and carbon neutrality targets, the question is no longer whether to act, but how to reduce the carbon footprint of water treatment.
Local authorities, industrial operators and utilities must now reconcile two imperatives: guaranteeing irreproachable water quality while reducing their environmental impact.
Understanding the carbon footprint of water treatment
What does carbon footprint mean in the water sector?
The carbon footprint of water treatment includes:
- Direct emissions (Scope 1): on-site combustion (generators, boilers, thermal sludge drying).
- Indirect energy-related emissions (Scope 2): electricity consumption, very energy-intensive in treatment plants.
- Other indirect emissions (Scope 3): manufacture and transport of chemicals, infrastructure construction, sludge management.
In a conventional wastewater treatment plant, the largest share of emissions comes from Scope 2 — the energy needed to aerate basins, pump water and keep the process running continuously.
The main sources of emissions
1. Energy consumption
Pumps, aerators and filtration systems account for up to 60 to 70% of the carbon footprint of a treatment plant.
2. Use of chemicals
Coagulants, flocculants, disinfectants: their production and transport generate significant emissions.
3. Construction and maintenance of infrastructure
Concrete, steel and construction materials have a high carbon footprint.
4. Sludge from treatment
Transport, drying, incineration or recovery: each option has a different carbon impact.
Sector-wide impact
According to the UN, the water and sanitation sector accounts for approximately 5% of global greenhouse gas emissions — more than civil aviation.
Levers for reducing the carbon footprint
Energy efficiency as the first step
- Optimising pumps and motors: sizing them to actual needs can reduce consumption by 10 to 20%.
- Automation and smart control: SCADA, digital twins, real-time adjustment.
- Variable-speed drives: adjusting consumption to actual demand.
Concrete example: a plant equipped with variable-speed drives and automated control reduced its electricity consumption by 30% over two years.
Renewable energy
- Solar: photovoltaic panels on rooftops and available land.
- Biomethane from sludge: anaerobic digestion generates recoverable biogas.
- Micro-hydroelectricity: using gravity to generate electricity in distribution networks.
Some pilot plants in Europe already cover 100% of their energy needs from biogas and solar power.
Optimising treatment processes
- New generation low-pressure membranes, less energy-intensive.
- Low-energy biological processes (fluidised beds, biofilters).
- Reuse of treated wastewater to reduce volumes to be treated.
Sludge management and recovery
- Solar drying: avoids heavy use of fossil fuels.
- Anaerobic digestion: biogas production from sludge.
- Agricultural use: treated sludge used as a soil amendment.
Example: a plant serving 500,000 population equivalents produces enough biogas to cover 50% of its annual energy consumption.
The role of digital technology and innovation
Digital twins and real-time optimisation
A digital twin allows simulation of different scenarios, anticipation of energy needs and real-time settings adjustment. A plant in Spain reduced its electricity consumption by 20% without any loss of performance.
Smart sensors and AI
In the Netherlands, a sensor system coupled with AI reduced aeration energy by 40% across several pilot plants.
Regulation and stakeholder pressure
The EU targets carbon neutrality by 2050. The European Green Deal and Fit for 55 plan aim for a 55% emissions reduction by 2030. Operators who anticipate this regulatory transition access green funding more easily and gain market share.
Nomado's approach: low-carbon plants
Modular prefabrication to reduce the construction footprint
Cement production accounts for approximately 8% of global CO₂ emissions. Nomado's approach:
- Workshop prefabrication with rigorous quality control.
- Installation in weeks rather than months.
- Less concrete and civil engineering.
Result: a prefabricated Nomado plant can reduce CO₂ emissions from construction by up to 30% compared with a conventional plant.
Optimised processes that consume less
Every Nomado plant incorporates high-efficiency equipment, intelligent energy management systems, renewable energy readiness and innovative low-footprint treatment processes.
A circular economy approach
Reuse of treated water, reduction of chemical inputs through automation. Example: a Nomado plant in Africa reduced its chemical use by 40% while maintaining drinking water quality compliant with international standards.
Conclusion
Reducing the carbon footprint of water treatment is no longer optional — it is an obligation. The solutions already exist: optimise energy efficiency, switch to renewable energy, choose low-carbon circular processes, leverage digitalisation, and embed sustainability from the design stage as Nomado does with its prefabricated solutions.
Tomorrow's water treatment plants will need to be conceived as smart, modular and low-carbon infrastructure.
FAQ
1. What are the main sources of carbon emissions from a treatment plant?
Energy consumption (pumps, aerators), chemical production, concrete/steel construction and sludge management.
2. How do renewable energies reduce the carbon footprint?
Solar, wind power and especially biogas from sludge can cover part or all of energy consumption.
3. What role does digitalisation play?
Smart sensors, AI and digital twins optimise processes in real time and reduce energy consumption by 20 to 40%.
4. Are prefabricated plants really more eco-friendly?
Yes. They require less concrete and civil engineering, and their modular design facilitates integration of the best energy technologies.
5. Can a water treatment plant achieve zero carbon?
It is possible with a combination of levers: energy efficiency, renewable energy, sludge recovery and digitalisation. Several pilot plants in Europe are already moving towards energy autonomy.
