Download Zinc Reduction Program for Gas Cleaner Effluent Saves

Case Study
Zinc Reduction Program for Gas Cleaner
Effluent Saves US$216,000
Challenge
Results
Zinc effluent from the gas cleaner at this steel mill in
the eastern U.S. was regularly exceeding limitations
established under an environmental initiative to
clean up a nearby river. The steel producer's choices were to build a new thickener for the gas cleaner
at a cost of US$1.5 million, install permanent pressure filters to process thickener effluent prior to discharge, implement a treatment optimization
program, or pay fines of US$27,500 per day under
the terms of a federal court consent decree.
No zinc effluent violations from the gas cleaner
have occurred since the treatment program was
changed, less sludge is being generated, and the
mill is saving US$120,000 per year from lower
chemical costs and US$96,000 annually from the
elimination of analytical and on-site services, for
total savings of US$216,000. The company is also
realizing substantial cost avoidance savings by being in compliance with the consent decree.
Solution
GE Water & Process Technologies and the customer
worked together to avoid a major capital investment by modifying the thickener and vacuum filter
operation. A CO2 injection system was installed for
pH control and calcium precipitation softening optimization, and centrifuge solids handling equipment was replaced by plate and frame filters. In
addition the thickener treatment program was optimized using GE clarification aids. The products
used included a GE KlarAid* coagulant and
PolyFloc* flocculant.
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ch424.doc Mar-13