Seven Trent
Kalic in record Severn Trent Water Lime dosing installation.
The largest ever Kalic lime dosing system to be installed at any water treatment works to date will form part of Severn Trent Water's major upgrading programme at its Church Wilne works near Nottingham. A new Kalic dosing system forms the core element of an upgrade which will secure compliance with current and anticipated water supply standards and attain the best standards of operational reliability and efficiency.
Located alongside the M1 motorway and not far from the town of Long Eaton, Church Wilne has a daily output of 135 megalitres per day and is the key supply works feeding the city of Nottingham. Part of Severn Trent Water's Strategic Grid System, the plant's ability to maintain a continuous 24 hours a day, seven days a week operating capacity is crucial. Scheduled for upgrading within the current AMP3 capital programme, the new works are a manifestation of Severn Trent's continuous improvement programme.
Lime dosing is primarily needed to ensure that pH is correct before it enters supply pipelines. But it can also be used to hasten the removal of solids from raw incoming water which, during the summer, may contain high levels of organic matter. Lime is subsequently dosed to optimise pH prior to filtration through rapid gravity filters, which is in addition to the usual lime dosing required for pH adjustment.
Severn Trent Water's decision to use Kalic Liquid Lime is based on a number of factors. Firstly, with several years experience using smaller Kalic systems, Severn Trent has concluded that compared to conventional lime systems, Kalic systems have significantly higher reliability and require minimal attention. These benefits have already been reaped at one of Severn Trent's largest treatment works at Bamford in Derbyshire, where three new tanks have been commissioned to help store the weekly deliveries of Kalic.
Secondly, Kalic Liquid Lime is a safe liquid. Delivered by bulk tanker, it is potentially less hazardous and more straightforward than bulk powder deliveries, even though it necessitates a higher delivery frequency. In the event of it being spilt or otherwise discharged, liquid Kalic will not become airborne, which means minimal exposure of personnel to the product. If contact does by chance occur, Kalic will be considerably less hazardous than other liquids such as caustic soda solution.
Thirdly, where capital costs are concerned, Kalic is priced significantly lower than competitor products. This applies both to conventional lime systems and to other liquid products such as caustic soda, which because of its high freezing point often necessitates the installation of costly heating precautions.
Severn Trent Water has already reaped the many benefits of Kalic and will soon see the same benefits flowing through at the upgraded Church Wilne works. As such, the use of a Kalic dosing system will play a major role in achieving optimal operational efficiency standards as well as compliance with current and anticipated water supply standards.
Editors' notes
Signifying a major advance in lime-based treatments for drinking water, waste water and acidic effluent, Kalic Liquid Lime from Buxton Lime is a non toxic, non-corrosive and cost effective calcium hydroxide suspension of exceptional purity. Its very fine particles provide a stable suspension and large surface area which make it highly reactive and extremely efficient for acid neutralisation and pH control.
Manufactured from natural material, Kalic is a safer and more economic alternative to caustic soda - an aggressive chemical which is classed as a corrosive and demands careful handling and storage. Kalic also satisfies the requirements of all current and predicted safety and anti-pollution legislation requirements. Furthermore, Kalic does not suffer from caustic soda's wildly fluctuating price variations. And because Kalic requires fewer precautions for safe and easy use, the result is lower costs all round, whether for handling, protection, plant maintenance or environmental protection.
Because Kalic can help protect tanks, vessels, valves and pipework from corrosion, it is less likely to damage plant and machinery. Furthermore, its low freezing point (0°C) significantly reduces the need for lagging and trace heating of pipework, pumps and tanks. It is also easy to pump, easy to handle and easy to transport.
Kalic is manufactured by Buxton Lime Industries, the largest producer of lime products in the UK is part of the Tarmac Group. Buxton Lime's base in Buxton, Derbyshire, is sited on an abundant supply of pure limestone which is highly regarded by the water and effluent sectors, as well as by other key processing and manufacturing industries.
Since its introduction in 1997, Kalic has enjoyed widespread use in a wide variety of industrial processes which include food processing, pharmaceuticals, steel production, oil and agri-chemicals. And in water and sewage treatment, processors have started to reap the superior technical performance and cost benefits of what has become a tried and trusted formulation.
It also has a shorter 'maturing time' and better permeability than conventional limewash. It is consistent in physical and chemical characteristics due to stringent quality assurance. It contains no toxic compounds or solvents.
