The response of attached bacteria on internal surfaces of steel pipes to various biocide treatments was assessed using a custom designed field test facility equipped with five separate flow lines. Successful biocide formulations induced a rapid decrease in viable bacterial counts; however, survivors often persisted after prolonged treatment in low level steady state biofilm populations (approximately 104 cells per cm2). Direct epifluoresence counts of total biofilm populations (viable and non-viable cells) showed no change before and after biocide treatment. This suggests the biocides killed, but did not remove, attached bacteria. Disinfection of input water by ultra-violet irradiation did not significantly enhance biocide performance. The implication is sustained growth of adherent bacteria is more important than attachment of planktonic cells in the formation of steady state biofilm communities in this system. Biocide treatment maintained general corrosion and pitting tendency rates at reduced levels compared to the untreated control. A slight trend towards higher corrosion rates with increasing numbers of sulfate-reducing bacteria was observed, but there was no apparent relationship between SRB activity levels as measured in the laboratory and the corrosion rates.

Subject
Water, Correlation, Bacterial growth, Corrosion rate, Biocide treatment, Tubes, General corrosion rate, Biofilms, Scatter, Bacteria, Water injection, Pitting, Biocides
© 1990 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).
1990
Association for Materials Protection and Performance (AMPP)
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