| |
ASSURED
COMPLIANCE
and
RECOVERY Most metal finishing operations, and printed
circuit board shops in particular, are the focus of water
pollution control enforcement actions because of the threat
posed by discharges of toxic heavy metals (Copper, Nickel,
Chromium, Lead) into the environment.
Manchester Corporation has a long and successful history
of designing, building, installing and commissioning wastewater
treatment facilities to remove heavy metal contamination down
to the very low limits required by many communities.
Efficient designs always incorporate a range of technologies,
tailored to the particular
situation in the plant, and suited to the regulatory environment.
The first step in all Manchester wastewater treatment projects
is to seek out ways to reduce water usage and recover contaminants
at the source.
During the site survey, Manchester engineers will make recommendations
which may include the installation of counter-current rinses,
flow restrictors, point-source ion exchange recovery systems,
and segregation of waste to make treatment less costly. Ease,
convenience, reliability and economy of operation are hallmarks
of Manchester Corporation designs. Detailed manuals and operator
training are included in every Manchester project to insure
that the performance of the waste treatment system will not
be compromised by human error, and that full compliance with
environmental regulations is achieved. |
so that treating a stream of mixed metals
involves a compromise, and closer -- and more difficult --
control of pH values. It is almost always advisable, therefore,
to segregate the wastewater discharge from different plating
or metal finishing operations, and to combine only compatible
streams for common treatment.
2. Point-Source Recovery:
Where possible, the heavy metal content of the final waste
stream should be minimized by removing the contaminant at
the source. For this purpose, selective ion exchange has the
advantage in that the metals can often be recovered as saleable
product. Manchester-designed point-source recovery systems
also include electrolytic plate-out cells the especially for
copper-bearing streams.
3. Sludge
Disposal:
When toxic heavy metals are precipitated as hydroxides or
sulfides, a filter press is usually installed to minimize
the volume for disposal. Recent advances in drying technology,
combined with higher hauling cost of regulated toxic waste,
make sludge driers, which remove up to 95% of the water, an
economical proposition in many locations.
|
| |
Toxic Metal Treatment and
Recovery Considerations:
1. Segregation:
Generally, mixed streams of toxic heavy metal are more difficult
(and more costly) to treat. If chemical, precipitation treatment
is used, minimum solubility of different metals occurs at
different pH values,
|
