The disposal of spent-chemical cleaning solutions and chemicals has recently become more difficult and expensive, because of new environmental regulatory guidelines. Increasing public awareness makes it clear that new and more effective treatment methods are needed which completely eliminate or detoxify hazardous substances.

The use of thiourea in combination with inhibited acid is well-established technology for the chemical removal of iron and copper scales from industrial equipment. However, thiourea is a suspected carcinogen that has caused cancer (skin, thyroid and liver) in laboratory rodents.1 Because of thiourea's link to cancer and its toxicity, it is defined by the Resource Conservation and Recovery Act and California Proposition 65 Controlled Substance Act as a hazardous substance. Laboratory results are presented using a patented chemical treatment process that is capable of removing greater than 99% of the thiourea in the spent-acid cleaning solvents.2

Subject
Acids, Water, Hydrogen peroxide, Sulfates, Alkaline solutions, Peroxide, Acidity, Metals, Urea, Chemical reactions, Wastes, Cleaning, Samples
© 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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