Pollution Prevention and Control Technologies
for Plating Operations
Section 2 - General Waste Reduction Practices
2.3 GOOD OPERATING PRACTICES
2.3.5 Leak/Spill Prevention and Control
Chemical losses from leaks and spills can equal or outweigh the
losses due to routine production operations. If small leaks from
pumps, filters or tanks go unnoticed or ignored over a long time
period, the overall loss can be very significant. Catastrophic
losses, such as a tank failure caused by corrosion, will cause
more immediate results. Several methods for reducing the potential
of chemical losses from these sources were identified from the
literature and Users Survey. These include:
- Conduct preventive maintenance of pumps, filters, tanks, etc.,
as discussed in Section 2.3.4.
- Employ a controlled method of adding make-up water to process
tanks (do not permit use of unattended hoses).
- Install overflow alarms on all process tanks and especially
on tanks that are heated and require regular evaporative replacement.
- Install double-walled tanks and for added protection install
a sight tube that will indicate if a leak of the inner wall has
occurred. Two shops indicated use of this method for cyanide baths
(PS 124, PS 133) (see note).
- Implement company rules for tank additions and other chemical
- Construct secondary containment with segregation that would
permit reuse of spilled material. For example, install berms around
process tanks, external filter systems (PS 149) and pumps (PS
- Install pH, ORP, moisture sensors, and/or conductivity sensors
with an associated alarm system in bermed areas (PS 146, PS 155),
sumps (PS 089, PS 165, PS 172), drain lines, or around treatment
tanks (PS 036). Example: shops PS 089 and PS 165 installed moisture
sensing alarms in sumps that under normal operation are dry. Of
the 318 plating shops responding to the Users Survey, 50 (or 15.7%)
indicated that they have installed overflow alarms on process
tanks and 47 (or 14.8%) have installed other spill or leak detection
systems (see questions 13 and 14 in Exhibit 2-6).
Note: One of these shops fabricated double
walled tanks themselves and installed sight glasses (PS 133).
During a follow-up conversation, this shop warned that brass sight
glasses, which are most commonly used, are not applicable to cyanide-containing
tanks. They suggest using either stainless steel or PVC (PVC sight
glass available from U.S. Plastic Corp., Lima, Ohio). PS 133 also
suggests placing the sight glass in a protected, front corner
of the tank (i.e., should be readily visible but protected from
Next Section|Main Table of Contents|Section 2