Corrosive process wastes safely contained
Corrosive process wastes safely contained
Keywords Agilent Technologies, Effluent, Hazardous materials,Corrosion, Waste disposal
When a routine environmental review identified that trade effluents had a potential to cause harm, optical fibre producers Agilent Technologies responded quickly. Expert advice was sought, as a result of which sewer refurbishment specialist Insituform Technologies is reported to have provided an effective and permanent solution to a potentially expensive and troublesome problem.
Agilent is described as an international company that adopts the highest environmental standards. At its Ipswich site it operates its own effluent treatment works to preprocess liquid waste to make it suitable for downstream treatment at the sewage treatment works. Hot and acidic process effluent was conveyed in a 160-metre vitrified clay pipe beneath the factory. Replacement of this network using normal trenching techniques would have been costly and very disruptive.
A method of lining the pipes was called for but this was complicated by three factors. The optical fibre production process is continuous, so pipe lining could only take place during the Christmas shutdown. The aggressive nature of the effluent meant that a system needed to be adopted with suitable chemical resistance. Finally, limited headroom required the use of compact installation plant.
Adviser to the company Nigel Wakefield, a chartered surveyor, sought tenders from three specialist pipe lining companies. The specification called for a heat cured liner to resist the acidity of the effluent and the use of compact plant. Insituform Technologies, the company that pioneered trenchless pipe lining technology 30 years ago, was reportedly the only company able to meet all requirements.
The Insituform process uses a prefabricated tube, made from polyester needlefelt tailored precisely to fit the pipe. The company is thought to be the only installer to make its own liners and take responsibility for the entire manufacturing and installation process. The felt serves as both reinforcement and carrier for the thermosetting styrene resin that is impregnated in a carefully controlled vacuum process at the Insituform factory.
The company explains the installation process thus. Liners are transported to site in refrigerated vehicles. The liner is inverted into the pipe using water,so that the liner conforms to the shape of the pipe to create a fully structural pipe within a pipe. A rapid, stable and chemically resistant cure is achieved by introducing hot water into the pipe and sustaining this condition for several hours. Once cured, the end of the pipe is opened to release the water and robot cutters are sent in to open feeder pipes.
Insituform also informs us that it can adapt the system to meet different site needs. Liners, for example, are supplied in a thickness according to the structural properties required. Similarly, the resin system can be selected for resistance to different effluents. In addition to use in effluent pipes the Insituform process is also frequently employed to refurbish cooling pipe work on process plants, fire mains and similar hard to access services.
The Agilent installation was complicated by being within the building. A special pressurised tank was needed to create the head normally produced by gravity installation by a high tower. Despite the problems the crews finished all works within the allocated time between 27 December and New Year's Day.
The completed Agilent installation claims a minimum design life of 50 years. In Insituform's opinion the system will resist chemicals in use and is totally seam free. The company believes that any potential environmental or structural hazard from leakage of process waste has been eliminated.
Further details are available from: Insituform Technologies Ltd. Tel: +44(0)1924 277076; Fax: +44 (0) 1924 265107; E-mail: jbowes@insituform.com; Web site: www.insituform.com/sites/site_uk.html
