Water, water, everywhere...
Industry buys a vast amount of high quality drinking water, much of a far higher quality than is required for industrial applications. IEM reports on a recent Scottish project to cut costs and stem the flow.
Under the project, NEL has brought together the Grangemouth Water Users Group (GWUG), comprising East of Scotland Water, British Waterways, BP, Avecia, EniChem UK, Nalco, CalGavin annd the Scottish Environmental Protection Agency. The vast Grangemouth industrial complex, situated on the Firth of Forth at its junction with the Grange Burn, River Carron and the eastern end of the 35-mile (56 km) long Forth and Clyde Canal, is a major port facility handling oil, forest products, coal, clay, sand, soda ash, bauxite and other bulk loads. BP's Grangemouth oil refinery pipes oil directly from the North Sea Oil Field. In total, Grangemeouth consumes around 75 per cent of the local demand for water; in cooling processes, steam generation, as a transport medium, and for cleaning or diluting.
BP Grangemouth uses around 12 million gallons of water per day and, according to Dr Ray Mountford, speaking at the Sustainable Industrial Water Use conference in Edinburgh in April, it is keen to play its part in reducing consumption: "We're committed to treating water as a valuable resource which must be managed correctly in order to reduce the pressure on drinking water supplies. We've created the role of Water Focus Engineer at Grangemouth and have undertaken a water study across the complex in conjunction with water treatment company Nalco to look at ways of reducing water consumption through improved management of water resources."
The BP Grangemouth site is the largest user of potable water in the UK with over 20 million cubic metres flowing through the site in a typical year. Historically this potable water has been supplied direct from the East of Scotland Water network and this practice continues today. This quality of water is not always required but to date no other alternatives have proven economically viable. Almost half of this water is used to produce steam as a heating medium in the site process plants. This extremely high pressure steam requires high quality boiler feed water and as such the drinking water supply undergoes further treatment before use in the boilers. The remainder of the potable water is used as a top-up to the site's numerous circulated cooling water systems. Since all of the current plant has been built based on potable water quality for both steam raising and water cooling needs, then a step change in quality for any alternative water supply represents a risk to operation that requires careful consideration. Therefore an alternative water supply must be of an acceptable standard in terms of suspended solids, chlorine levels, hardness etc.
The Industrial Waters Project will complement existing initiatives already undertaken by the partners involved. One possible planned alternative source of water for use at Grangemouth is the water from the Forth and Clyde and Union Canals, which are being reinstated as navigable waterways under the auspices of the British Waterways- managed £78.3m Millennium Link project. And East of Scotland Water has already begun a major capital investment programme of £1.7bn industry-wide over three years to March 2002 aimed at improving or renewing treatment works and underground infrastructure.
Dr Frank Kinghorn, director of NEL, sums up: "The outcome of this project will permit better decisions on investment in infrastructure to meet both demand and water quality standards. Closer and more open interaction between water suppliers and major waterr users should enable decisions on how finite water resources can sustain growing demand, particularly in the context of climate change. Development and adoption of recycling technologies and of monitoring and controlling instrumentation should provide UK industry with know-how which can be exported and exploited worldwide to provide commercial advantage."