This corrosion control study was based on, and closely followed, the AWWA Guidance Manual and AWWARF1  pipe loop protocol2 . The primary objective of this study was to provide a corrosion control recommendation for the site to satisfy State of Maryland and EPA requirements to define and maintain optimal corrosion control treatment. A second objective was to identify technical and cost constraints that may affect the application of specific corrosion control treatments in finished water. Blended zinc potassium polyphosphate /Zinc orthophosphate showed lower corrosion rates and reduced lead concentrations in finished water for the majority of days studied in plant pipe loop models and remote location (barracks) pipe loop models. Blended potassium monophosphate/potassium tripolyphosphate followed a close second in overall efficacy. The pH adjusted and control strategies exhibited little demonstrated corrosion control benefit. Recommendations based on this study included: (1) addition of blended zinc potassium polyphosphate/zinc orthophosphate with a residual concentration between 2.0 and 4.5 mg/L, (2) installation of a chemical feed to buffer well water with sodium bicarbonate to stabilize alkalinity when 100% well water is used, and (3) investigation of lime addition to raw well water to control buffer capacity in the combined raw well water/surface water.

Subject
Costs, Water, Piping, Corrosion loops, Potassium, Probability, Lead, Acidity, Phosphates, Corrosion modeling, Corrosion protection, Copper, Zinc
Keywords:
Lead, Copper, Phosphate, Pipe Loop
© 1995 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1995
Association for Materials Protection and Performance (AMPP)
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