Removal of Chromate from Cooling Tower Blowdown by Reaction with Electrochemically Generated Ferrous Hydroxide E . I . Onstott' and William S. Gregory University of California, Los Alamos Scientific Laboratory, Los Alamos, N.M. 87544
Edward F. Thode New Mexico State University, Las Cruces, N.M. 88001
Treatment of cooling tower blowdown with electrochemically generated Fe(0H)z quantitatively reduced Cr(V1) to Cr(II1) and concurrently precipitated it without pH adjustment. Concentrations of Cr(V1) of 200 mg/l., then mix with unreacted blowdown to give the final product. 3. Electrolyze blowdown to give a concentration of Fe >200 mg/l.; electrolyze a second batch to give a concentration of Fe of 20-25 mg/l.; mix the two batches to give the final product. Procedure 2 or 3 would ordinarily be preferred to minimize both iron consumption and electricity consumption, since 85 mg/l. of Fe would suffice. However, as will be seen later, for this stage of development, neither procedure 2 or 3 was effective for reducing total Cr to a very low level of 99.96 >99.96
