Water for the Worlds: Cutting-edge research provides rapid water quality analysis
The earthquake that devastated Haiti in 2010 not only killed 200,000 people but also left more than two million homeless. As a result of drinking polluted water, many of those have since contracted cholera – resulting in a further 10,000 deaths.
Lack of sanitation and safe drinking water are the reality of life for billions of people in developing countries – 2.5 billion don’t have access to a flushing toilet, 768 million don’t have access to a running tap – and natural disasters and civil wars exacerbate the problem.
Cutting-edge research carried out by Birmingham’s Professor John Bridgeman could make a significant difference: he and his team have been working on a quick, novel and robust way of determining water quality, and have developed an optical water-testing device that has the potential to save millions of lives.
‘Water is essential to life – the vital, natural resource – and we face significant challenges in water and energy security in both the developed and developing worlds,’ explains John, Professor of Environmental Engineering, whose recent Inaugural Lecture was entitled Water for the Worlds. ‘We all need water to exist, but we also need it for manufacturing processes, food production, trade, energy, sanitation and the environment – it’s implicit in everything we do.’
First and foremost, we need water to drink, so when people get displaced after an event such as the Haiti earthquake, they set up camp near a water source. At present, however, there is no rapid test for determining whether that water is safe.
'A charity or aid organisation will come along and test the water, but it may take three days to find out if the quality is okay. Meanwhile, people become thirsty and start drinking it anyway.'
To address this problem, John and his research team have adapted a known optical technique called fluorescence spectroscopy – where you irradiate a water sample with light of a certain wavelength and fluorophores (pollutants) within it absorb the light and then re-emit it at a longer wavelength – to develop a quick-and-easy testing device.
‘We know that if we identify high fluorescence at specific wavelengths, then this is indicative of certain pollutants in the water,’ explains John. ‘We have correlated certain wavelengths with microbial presence, which allows us to conclude that there may be, say, e-coli or other bacteria in the water. Our technique can’t numerate bacteria, but what it does is give you an indication of water quality.’
The dual wavelength-LED portable instrument John and his team have built can detect these pollutants instantly. It is also capable of continuous sampling – allowing people who live in permanent settlements where water security is an issue to monitor the supply.
We have proved the concept and are now talking to aid agencies and charities about their precise needs and budgets,’ says John. ‘We’re looking to deploy these devices in disaster situations, as well as in areas of poor sanitation, such as informal settlements.
In the developed world, the issue of water security is different – but also of grave importance.
‘The challenge here is that we use huge amounts of energy and water, and the two are linked,’ says John, who spent 15 years in industry as a water engineer before joining the University in 2005.
He concurs with the ‘perfect storm’ scenario postulated two years ago by the Government’s then-chief scientific adviser Professor Sir John Beddington, that by 2030 the world will need to produce 50 per cent more food and energy, along with 30 per cent more fresh water, while also mitigating and adapting to climate change.
So without enhanced knowledge of water security, our adaptation measures will have limited success, and so will our ability to survive.
John has carried out extensive research into water and wastewater treatment through mathematical modelling of processes aimed at reducing energy and chemical consumption yet maintaining quality.
One way he has done this is by refining the process of coagulation and flocculation – where a chemical salt, known as a coagulant, is added to water taken from a river and full of potentially harmful but tiny particles. The effect of the coagulant is to reduce the surface charge on the particles, making them ‘chemically sticky’. This means that when the water is mixed slowly, the particles clump together into a ‘floc’. Bigger and heavier as a result, the flocs then sink to the bottom of the tank as sediment.
Using computational fluid dynamics (CFD) – a way of mathematically modelling processes that involve fluid mechanics and heat transfer – John modelled the flocculation processes in order to minimise the amount of mixing that was needed while at the same time maximising the size of the floc. The process is so efficient it can reduce the energy bill of a water treatment works by two-thirds.
‘This is something I’ve been working on for ten years,’ says John, who is also the College’s Director of Research and Knowledge Transfer. ‘We now model a lot of water and wastewater treatment processes using CFD, such as chlorination and hydraulics of service reservoirs. We are also working on optimising the mixing of sewage sludge in anaerobic digestion processes, where we produce methane that can then be sold back to the grid as an energy-neutral product.’
In fact, John has spent his whole career working to meet the growing challenges of water security facing the world. However, it is his work on helping to improve water hygiene and sanitation in developing countries that gives him the most satisfaction.
‘That’s the bit I’m most proud of – the fact we are on the verge of really making a tangible difference to people’s lives.’