Dwr Cymru Welsh Water supplies over three million people with drinking water throughout most of Wales (UK). Ortho-phosphate has increasingly been dosed at around 1 mg/L (P) to further reduce the corrosivity of supplies to the lead pipes which connect approximately 30% of houses to water mains in the company's area, additional to long-establish pH adjustment measures. The installation of new ortho-phosphate dosing schemes and the optimisation of these and existing dosing schemes, 29 schemes in total, were subject to a regulatory programme of work, agreed with the Drinking Water Inspectorate (DWI). Optimisation comprised (i) selection of appropriate ortho-phosphate doses by a procedure involving laboratory based plumbosolvency testing linked to zonal lead emission (compliance) modelling, (ii) tight dose control and (iii) extensive monitoring of lead in supply by random daytime (RDT) sampling and by the use of lead pipe test rigs. The successful outcome was confirmed by 99% of over 5,000 RDT samples complying with the future standard of 10 μg/L for lead in drinking water.
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Research Article|
January 01 2008
Experience in Wales (UK) of the optimisation of ortho-phosphate dosing for controlling lead in drinking water
C. R. Hayes;
1Swansea University, School of Engineering, Singleton Park, Swansea, Wales SA2 8PP, UK
Tel.: ++44 (0)1792 602257 Fax: ++44 (0)1792 295676; E-mail: [email protected]
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S. Incledion;
S. Incledion
2Asset Strategy and Regulation, Dwr Cymru Welsh Water, Pentwyn Road, Nelson, Mid-Glamorgan, Wales CF46 6LY, UK
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M. Balch
M. Balch
3United Utilities Operational Services Ltd., Pentwyn Road, Nelson, Mid-Glamorgan, Wales CF46 6LY, UK
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J Water Health (2008) 6 (2): 177–185.
Article history
Received:
January 04 2007
Accepted:
April 19 2007
Citation
C. R. Hayes, S. Incledion, M. Balch; Experience in Wales (UK) of the optimisation of ortho-phosphate dosing for controlling lead in drinking water. J Water Health 1 June 2008; 6 (2): 177–185. doi: https://doi.org/10.2166/wh.2008.044
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