Engineering in the water industry conjures up images of large-scale projects such as reservoirs and irrigation – the exclusive domain of civil engineers. But in the past decade, stringent regulations and better knowledge of the chemicals, microbes and viruses water contains have demanded more complex purification plants.
Over the next five years, the UK water industry will spend £8bn on projects to expand business and meet regulatory standards. Just over a decade ago, the only enforced standard was that drinking water should be `wholesome’. Now it must be `fit for human consumption’, and a plethora of regulations cover permitted levels of chemicals, including nitrites and bromates, and micro-organisms, such as cryptosporidium. The water industry has turned to process engineers for the answers.
That, at least, has been the approach at water specialist Binnie, Black & Veatch. When Don Ratnayaka, technical director for process engineering at the firm’s water treatment unit started working in the water industry 25 years ago, civil engineers did everything. `I was the first chemical engineer Binnie employed,’ he says. `But my boss had foresight – he saw the process engineering challenges that were coming along. Since then my unit hasn’t employed anyone but chemical engineers,’
The technologies used in the water industry have grown from the two basic operations carried out by civil engineers: clarification – which involves particles settling out under gravity – and filtration. Clarification technology may not have advanced much, but filtration, driven by other process industries, has.
Filtration is the key weapon in dealing with one of the biggest issues facing the industry: how to prevent levels of the micro-organism cryptosporidium rising to dangerous levels. In healthy adults the micro-organism can cause stomach cramps and diarrhoea. For the very old and very young it can be fatal. Outbreaks in the UK have been rare, but an occurrence in Sydney in 1998 forced residents to boil their water for around a month.
UK cryptosporidium regulations to be introduced in March 2000 will compel water companies to monitor cryptosporidium levels in rivers and reservoirs – at an estimated annual cost of around £500,000.
Microfiltration can remove impurities down to 0.2 microns, while ultrafiltration is applicable for contaminants – including cryptosporidium – down to 0.01 microns. Filters with finer porosities for removing salts are used in nanofiltration and reverse osmosis – techniques commonly used in other process industries.
`In the chemical industry, feedstock for the same type of plant anywhere in the world is the same. But water from every river or reservoir has a different bacteria, virus and mineral content. That is the challenge,’ Ratnayaka says.
Sophisticated monitoring and measurement technology developed in the process industries is also improving drinking water standards.
One example is in the ozonation process, in which ozone is used as an alternative to chlorine to disinfect the water. New measurement techniques have picked up low concentrations of bromate – a carcinogen. It has been found that the bromate forms when ozone reacts with trace levels of bromine in water. Studies have been commissioned by the Drinking Water Inspectorate to define a safe level of bromine in water to overcome the problem.
UK water engineers are also facing new challenges abroad. The export of water engineering expertise is a large contributor to the UK’s invisible earnings. Ratnayaka has worked on projects as far afield as Botswana and Uzbekistan. Training and technology transfer now form an integral part of many projects abroad.
However, there are fears that these activities could be under threat from a review of the Export Credit Guarantees Department, the agency through which the Government underwrites risky projects. Water UK, the industry trade body, has made clear to the Government the importance of the agency to its members.
The UK’s falling overseas aid budget is another cause for concern. `The French and the Danes both use overseas aid to fund projects abroad,’ explains Richard Coackley, Binnie Black & Veatch’s director of sales and business development. `But they attach strings so that contractors have to buy plant and equipment produced by their own manufacturers. By contrast, we’ve been reducing overseas aid.’