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Waste Treatment - Neutralizers: Method
Neutralization Background:
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 *Neutralization is the pH adjustment of waste streams to
within acceptable limits set by regulatory agencies (local, state and
federal). While it is certainly not a complete treatment of industrial or
commercial wastes, it is required in many instances as a final step before
discharging into the public sewers. Many municipalities allow
discharges of pH's within 6-9, but always check with your own regulatory
agency for complete guidelines.
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- The neutralization process may also be
used to precipitate and settle out heavy metals such as iron, zinc,
copper, cadmium, and chromium. The first step in this process is
adjustment of the pH of the waste stream. Insoluble metal hydroxides are
formed by the reaction of the basic chemical with the metal at a pH range
of 6.0 - 9.0. Not all metals become insoluble at the same pH. For this
reason, the pH is usually adjusted to remove the metals that are the most
toxic or the highest concentrations. In many cases flocculants are
used to precipitate out other heavy metals.
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Neutralization Method:
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 For waste treatment neutralization.
Add small quantities with agitation to treatment tank or process stream at
ambient temperatures. Care should be taken when adding to systems with
pH’s greater than 12 or less than 3. Addition of Neutralizer 1 or 14 can
cause violent exothermic reactions (creating heat) and “boil-out” or
explosions in non-vented systems.
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- Note: For safety reasons Neutralizer 1 is
a partially neutralized with water to prevent extremely violent exothermic
reactions with water and alkaline solutions as would be the case with
concentrated sulfuric acid.
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- After the
stream is neutralized it should be determined if there are any materials
that render it still hazardous, such as heavy metals, otherwise it can be
poured down the drain.
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Neutralization Process Set-up:
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 pH Neutralization Systems from
Panner:
- The old method of passing effluent through a
neutralizing basin loaded with limestone chips is no longer adequate.
Equally unacceptable is the method of neutralization by dilution. Today,
a typical neutralization process requires a system capable of handling
both acid and caustic wastes at different concentrations and varying
flow rates. Such a system must be able to accurately measure and control
the pH by using state-of-the-art pH monitoring and control instruments,
in conjunction with correctly sized chemical injection pumps.
- To meet the ever tightening regulations and to
prevent accidental non-compliant discharge, the system must also offer a
selection of safety features such as Alarms, safety shut off valves,
diversion valves, level controls, etc.
- Panner offers a wide range of skid-mounted
self-contained neutralization systems in various configurations such as
single and dual stage systems, in either standard or dual containment
construction. All systems are offered in either gravity flow or complete
with installed pumps, when required.
- Common to all systems is a minimum field work
requirement. All components within the system are pre-installed and
wired. The only field requirement is to bring power to the control panel
and to hook-up the inlet and outlet piping.
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