Technology used to check for diluted beer in kegs returned to breweries could soon be used to monitor water quality in water treatment plants.
The AquaPod is kept clear of the water
A new technique developed by an Irish firm determines how "dirty" water is by analysing the colours in the light reflected from it.
The AquaPod could save money by cutting the chemicals needed to clean up water.
A similar device used in breweries is important because returned beer kegs can result in refunds for publicans.
Breweries do not want to pay out for tap water that some unscrupulous landlord might have added to a barrel just to make its contents look greater than they really are.
In and out
Previously, examining if the beer inside was diluted or not would have required a painstaking chemical analysis of each sample.
But the Spectral Signatures instrument provided a quicker alternative that simply involved shining light on the dregs and measuring its spectral profile to decipher the contents.
Recently, the firm applied for a patent for a device it calls AquaPod, which is designed specifically to monitor water quality.
Its uses range from checking the incoming water quality at drinking water plants to examining the content of sewerage inflows or outflows.
The main advantage of having a remote instrument is that, regardless of how dirty the water is, the instrument will not be fouled up - a problem that can befall analytical instruments that need to be immersed in fluids.
The AquaPod is mounted above the water. It determines what is in the water by measuring the colour spectrum of light reflected.
Water molecules, H2O, show a peak in the spectrum in the infrared, just past where the eye can see.
This never changes, so the instrument is calibrated by the water molecules themselves. The change in the light due to other
dissolved materials is seen by comparison with the water.
These materials include organic molecules, such as phosphates, nitrates and proteins.
They all produce the same colour, which is why many liquids look brown. It is these dissolved materials that give, for example, beer and urine their brownish colour.
Aquapod also looks for suspended matter in the water, which can be anything from sand and dirt to faeces. This material scatters the light and makes the water appear cloudy.
Measuring just how much dissolved and suspended material there is determines how dirty the water is and how much processing is required.
In water treatment plants, dirty water clogs up filters if there is too much suspended matter. Excess dissolved matter means the colour of the water will be brown and this colour needs to be removed to make it palatable.
This is done by adding chemicals such as aluminium or iron salts. Minimising the use of chemicals is better for the water drinkers and also for company costs. And knowing the colour of the incoming water and therefore the amount of dissolved material should cut these costs.
"AquaPod is essentially a laboratory spectrometer brought out into the open and made robust enough to keep working in all weathers," said Spectral Signatures director Dr Eon O'Mongáin.
"It is put in a box, acts like a web server and can be controlled from an operator's desk."
The company previously developed and patented a product called ChlorFlow which is used by the UK's Environment Agency for monitoring chlorophyll levels in English coastal waters.
A build-up of chlorophyll in the water, which is caused by too much nitrogen coming off the land, can kill off fish by depleting the oxygen in the water they need to breathe.
It can also lead to large, smelly algal blooms being deposited on beaches. It has been known for bulldozers to be called in to remove large piles of horrible gunge from a beach.
The accuracy of the AquaPod is now being tested against traditional sampling methods at a water treatment plant in Dublin.