Bacteria-growing water toxicity monitor wins innovation award

A device that grows light-emitting bacteria to continuously detect for water impurities has won a university innovation award.

The Continuous Toxicity Monitor (CTM), which allows authorities to monitor water supplies in real time for suspicious biological or chemical contaminants, received the prize from Cardiff University last week.

The technology was developed by a team from the university’s School of Biosciences, led by Prof David Lloyd, and spin-out Cymtox, now a subsidiary of Guildford-based technology firm Modern Water.

Bio-luminescent (light-emitting) bacteria from deep in the ocean are grown inside the CMT and any changes in the water being tested can be detected because they affect the amount of light produced.

‘The light emission is a complicated system that is sensitive in a non-specific way to many different toxicants — thousands, maybe tens of thousands of chemicals. So almost anything will affect the light output,’ Lloyd told The Engineer.

Water samples inside the CMT are mixed with a small amount of bacteria and sensors known as photomultiplier tubes are used to measure any change in the light produced.

The 60kg device can be monitored remotely and in real time using the internet, and can check individual samples or automatically collect water from open bodies such as rivers or from domestic or industrial supplies or outflows.

The CMT is able to continuously monitor a water source because it uses the same stock of bacteria for up to one month. Then a new culture of organisms can be installed and monitoring can begin again.

‘If you mimic their natural environment you can get them growing continuously simply by renewing their nutrients,’ said Lloyd. ‘If you do that you have organisms with the same properties over an extended time, so any sample you take is identical.

‘Most competitors in the field uses freeze-dried bacteria that have to be reconstituted, but no two batches are the same so you have to have internal standards.’

He added: ‘The major challenge was to have the engineering expertise on pumps that don’t break down and flow systems.’

The company is now in the process of miniaturising the technology so that it can be used as a more portable device or as a personal protection system.

The Cardiff University Innovation Awards are awarded for successful collaborations forged between the university and industry.