A Water Lab Inside a Smartphone

Sending a water sample to the lab tells you what happened, not what is happening. A way around it is to use paper strips and portable monitoring devices, but they don’t cover everything.

For example, in my last few months as Trade Effluent Manager at Wessex Water, PFAS in wastewater was starting to become a really hot topic. PFAS are a family of toxic, highly persistent contaminants, the ones you hear called “forever chemicals”. Lots of ongoing discussion around how to regulate them in industrial wastewater discharges and what safe, reasonable limits could be. More data is needed. The problem is that very few labs are capable of doing PFAS analysis. Everyone sends samples there. It gets expensive and slow.

That gap is what David Sarphie is going after.

David is CEO of AquAffirm™, a London startup that developed a portable water testing sensor that plugs into your smartphone and runs through an app.

The tech is based on aptamers, single strands of DNA that bind to one specific target and ignore everything else. An aptamer binds a PFAS molecule, and that produces a tiny, repeatable change in current. This gives you a concentration value.

In practice it is a small reader on the bottom of a phone. You place a drop of water and get a result in seconds. Faster and cheaper than sending the sample to a lab.

AquAffirm started with arsenic. In Bangladesh, roughly 30% of the population drinks water contaminated with it, a poison that works slowly and undetected.

The problem was never that arsenic couldn't be measured. It was that testing a country's water sources, one sample at a time, was far too slow to be useful.

As lead partner in the Arsenic 4M project, AquAffirm put the first rapid, cloud-connected arsenic test into the field. Every result carried GPS coordinates and a timestamp, so the map filled in as the testing happened, revealing the hotspots.

Tests have now been developed for other parameters as well, such as salinity (useful for monitoring desalination plants) and chlorine, with other tests in the pipeline.

From a regulatory perspective, this technology doesn’t replace laboratory testing, but in terms of managing wastewater treatment operations on site, it can be a game changer.

For a site operator with twelve other jobs and a discharge permit to meet, that is the difference between hoping you are compliant and making calibrated decisions in real time.

If you are wondering what PFAS are and why they matter, check out the film Dark Waters. I probably watched it over five times and recommended it more times than I can count.