Llyn Alaw
Dwr Cymru Welsh Water upgrades Anglesey to Kalic.
THE PLANT that supplies most of the drinking water to the island of Anglesey has undergone a dramatic upgrade. Kalic Liquid Lime from Buxton Lime Industries is playing a central role.
The plant, Llyn Alaw Water Treatment Works, is set to raise its capacity by 40% to 35 megalitres/day. It needed a pH control system capable of meeting that increase.
United Utilities Operational Services, which operates water and wastewater assets throughout Wales on behalf of Dwr Cymru Welsh Water, decided in favour of Kalic and cites the product's operational and cost efficiencies. There are also fewer health and safety concerns compared to alternative treatment chemicals. Kalic is non-toxic, non-corrosive and easy to handle.
"It's a major improvement," says Alan Jones, capital projects engineer for United Utilities Operational Services.
"We wanted to steer away from a conventional lime system because of problems with gumming, blocking-up and dust extraction. With Kalic all these issues have been eliminated."
Lime dosing is needed to ensure that pH is correct before water enters supply pipelines. It can also be used to speed the removal of solids from raw incoming water.
United Utilities has adopted Kalic at a number of other water treatment works that it operates on behalf of Dwr Cymru Welsh Water in Wales such as Bryn Cowlyd, Carno and Cefn Llan. Warwickshire-based Aquatreat Environmental Engineering won the contract to design, install and commission the Kalic set-up at Llyn Alaw.
"We set out to maximise the use of existing plant and equipment to provide the best possible capital efficiencies," says Aquatreat's Liam Coyle. "It was a challenge but it went in completely trouble-free and has attained better standards of operational reliability and efficiency."
Llyn Alaw's existing hydrated lime silo was converted to a Kalic bulk storage tank for the new dosing system. It incorporates a re-circulation system supplying Kalic to the Bredel peristaltic dosing pumps.
The dosing control and monitoring system was installed in an unused storage room in Llyn Alaw's main building. Dosing is controlled by a signal from the existing pH controller in the process line.
"It's a failsafe system with a fully automated back-up on the pumps," adds Liam Coyle. "With all these advantages we believe that Kalic will continue to be widely adopted throughout the water industry."
The capital cost of the switch to Kalic was far less than the price of upgrading a conventional lime system says Alan Jones. He is predicting further savings in the long term and also plans to upgrade Anglesey's smaller water treatment plant at Cefni to Kalic.
Handling is safe and easy. The system needs minimal attention, which has freed up staff at Llyn Alaw to work elsewhere in the plant.
Editors' notes
Kalic Liquid Lime represents a major advance in lime-based treatment for drinking water, waste water and acidic effluent. It is used by industries such as water and sewage treatment, food processing, pharmaceuticals, steel production, oil and agri-chemicals.
Kalic's key selling points are its technical superiority and cost-effectiveness.
Made from natural material, Kalic is a non-toxic, non-corrosive calcium hydroxide suspension of exceptional purity. Its fine particles provide a stable suspension and large surface area that make it highly reactive and extremely efficient for acid neutralisation and pH control.
It is safer than caustic soda, an aggressive chemical classed as corrosive that needs careful handling and storage. Its costs are lower, for handling, protection, plant maintenance and environmental protection. Kalic complies with current and predicted safety and anti-pollution legislation. It also does not suffer from caustic soda's fluctuating price.
Kalic can help protect tanks, vessels, valves and pipework from corrosion. Its low freezing point (0ºC) reduces the need for lagging and trace heating of pipework, pumps and tanks. It is also easy to pump, handle and transport.
Kalic was introduced in 1997. It is made by Buxton Lime Industries, the largest producer of lime products in the UK and is part of the Tarmac Group. Buxton Lime's base in Buxton, Derbyshire, is situated on extensive deposits of limestone of an exceptional purity.
