Ask the Expert Question-and-Answer Archive (Wastewater Treatment)
by Mike McGinness, EcoShield Environmental Systems, Inc.
Finding Source of Cyanide in Pretreat Line
CN has become a problem from a pretreat line that does not use cyanide nor does any plant process use CN. Some parts come from outside. Pretreat is a wash/rinse/phosphate/rinse/sealer/rinse system. None of the chemicals have any listed CN based chemicals. Problem has been growing since 2001. Help!
First begin by sampling all the chemicals used in the pretreatment line. Send the samples to the lab for cyanide analysis to see if any of them contain traces of cyanide. Osha reporting limit on the MSDS is 1,000 mg/l for ingredients! Also start taking samples of outside parts as received. Rinse them in DI water and send
the DI water sample to the lab for analysis. If you do not find the source email me back for more help.
Also send in a raw DI sample and or tap water sample ( call it an unknown sample on the COC ) as a control test of the labs cyanide tests with each sample batch to see if the lab is the problem.