A floating module that purifies water with sunlight
CLEAR is a floating photocatalytic module that purifies water with sunlight. It is a new and original solution, and potentially patentable.
How it works
The structure and surface chemistry of the pore network give the material high photocatalytic activity, including in the visible region of the spectrum.
Natural convection remixes the water around the spheres. Pollutants are broken down by photocatalytic degradation, and organic micropollutants are degraded completely.
A treatment uses 250 to 500 spheres per cubic metre of water, each between 3 and 7 cm in diameter.
Measured degradation
Half-lives measured in the laboratory for 4-nitrophenol, a persistent organic pollutant, set against the natural processes that would otherwise break it down.
| Process | Matrix or condition | Half-life |
|---|---|---|
| CLEAR BlueTech | Ultrapure water | 23 min |
| CLEAR BlueTech | Tap water | 70 min |
| CLEAR BlueTech | Simulated river water | 15 min |
| CLEAR BlueTech | Simulated seawater | 42 min |
| Natural photolysis | pH 5 | approx. 8,200 min (approx. 6 days) |
| Natural photolysis | pH 7 | approx. 9,650 min (approx. 7 days) |
| Natural photolysis | pH 9 | approx. 19,700 min (approx. 14 days) |
| Biodegradation | River water | 1,440-11,520 min (1-8 days) |
| Biodegradation | Seawater | 18,720-200,160 min (13-139 days) |
| Hydrolysis | Natural water | far above 1,000,000 min |
| Natural redox | Oxic conditions | Highly variable |
| Natural redox | Reducing environments (Fe3+) | Hours to days |
Compared with commercial technologies
| Criterion | CLEAR BlueTech | Advanced oxidation (ozone) | Conventional processes (activated carbon) |
|---|---|---|---|
| Operating energy | None | High | Low |
| PFAS and pharmaceutical removal | Advanced photocatalytic degradation, complete mineralisation | Partial removal or transformation | Adsorption, regeneration required |
| Infrastructure | None | Reagents | Complex plant |
| Cost | 0.05-0.15 EUR/m3 | 0.80-1.50 EUR/m3 | 0.15-0.35 EUR/m3 |
| Environmental impact | Zero energy, therefore zero operating emissions | Formation of toxic by-products | Produces secondary waste requiring disposal |
| Weaknesses | Requires sunlight | High OPEX | Energy-intensive and costly regeneration, material degradation, waste requiring disposal |
The CLEAR figure is an estimate under optimal conditions: strong sunlight, low turbidity, and low concentrations of PFAS and pharmaceuticals. Advanced oxidation costs depend on energy and reagents and vary with pollutant load. Activated carbon costs depend on saturation frequency and waste management.