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The National Pretreatment Program was established to regulate the introduction
of pollutants from non-domestic sources into Publicly-Owned Treatment Works
(POTW). Discharges targeted for regulation include those which will interfere
with the operation of a (POTW), including interference with its sludge digestion
processes, sludge use or disposal; which will pass through the treatment works;
or which are otherwise incompatible with such works.
In addition, the program is intended to improve opportunities to reclaim municipal
and industrial wastewaters and sludges (see 40 CFR §§403.1 and 403.2). To accomplish
these objectives, the National Pretreatment Program relies on a pollution control
strategy with three elements:
- National Categorical Standards: National technology-based standards developed
by EPA Headquarters which set industry-specific effluent limits
- Prohibited Discharge Standards:
- General Prohibitions (403.5(a)) - National prohibitions against
pollutant discharges from any non-domestic user which cause pass-through
or interference.
- Specific Prohibitions (403.5(b)) - National prohibitions against
pollutant discharges from any non-domestic user causing: (1) fire or
explosion hazard; (2) corrosive structural damage; (3) interference due
to flow obstruction; (4) interference due to flow rate or concentration;
and (5) interference due to heat.
- Local Limits:
- Enforceable local requirements developed by POTWs to address federal
standards as well as state and local regulations.
The rationale behind this three-part strategy is, first, that categorical
standards provide nationally uniform effluent limits affording a technology-based
degree of environmental protection for discharges from particular categories of
industry. Second, the prohibited discharge standards recognize the site-specific
nature of the problems they are intended to address at sewage treatment works and
provide a broader baseline level of control that applies to all industrial users
discharging to any POTW, whether or not the industrial users fall within particular
industrial categories. Third, local limits are specific requirements developed and
enforced by individual POTWs implementing the general and specific prohibitions,
and also going beyond them as necessary to meet state and local regulations.
This approach ensures that site-specific protections necessary to meet pretreatment
objectives are developed by those agencies best placed to understand local concerns,
namely POTWs. In this scheme, POTW development and implementation of local limits
is the critical link in ensuring that pretreatment standards protecting both the
local treatment works and local receiving environment are applied.
The following are summaries of the most recent Local Limits Evaluations performed
by the Johnson County Environmental Department.
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