Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/957171
www.wwtonline.co.uk | WWT | XXXX 20XX | 21 Precast concrete panels get flexible for sludge storage The Works F or municipal wastewater treatment plant operators, the management of sludge cake presents numerous challenges, especially because its properties and volumes can be inconsistent. On one level, biosolids can be seen as a potential threat to the environment, yet they are also now increasingly viewed as a resource with value – so much so that the government and regulators have backed the use of biosolids as a resource, rather than as a waste. Comprising phosphate, nitrogen, sulphur, potash and magnesium, around 3.6 million tonnes per annum of biosolids (mainly cake at 20-25 per cent dry solids) is recycled to agricultural land. However, End-to-end service While no supplier can build in guarantees against the impact made by large loading machines, a tailor-made, one-stop pack- age can now provide a water company and its contractors with a 50-year life span solution. In addition to the precast concrete elements, the end-to-end service of design, concept, structural calcula- tions, CAD, groundworks, civils and drainage provides a very cost-effective and fast-track package, which for one leading water company has proved far more effective than other methods of construction. Anglian Water, the first company to achieve 100 per cent compliance under the Biosolids Assurance Scheme, recently worked with JP Concrete on six new ro- bust cake pads for the short-term storage of treated sludge. Totalling 580m in length of highly resilient CL Agri 214 (2,140mm high) pre- cast concrete wall panels, the new cake pads prevent liquids from escaping into local watercourses. They have replaced walls that had reached the end of their www.wwtonline.co.uk | WWT | APRIL 2018 | 21 it has o"en been the case that insufficient attention has been given to the storage of this material. The use of straw bales was not uncommon in some places, nor the sight of highly corroded steel posts and rotted wood that was somehow still standing upright. Little wonder that the environmental authorities were concerned about its escape into watercourses; more stringent fines and penalties for pollution have gone some way to focusing minds on the issue. However, innovations in precast concrete mean that storing this resource – which has an annual nutrient value to UK agriculture of approximately £25 million – has become more secure, flexible and cost-efficient than ever before. Ofwat's reforms to create a new market for bioresources will mean a greater focus on the way sludge cake is stored. Precast concrete recently proved the answer in a project for Anglian Water by Chris French JP Concrete has completed six new cake pads for Anglian Water