As mentioned in my previous blog, this blog entry will explain pretreatment standards  and their corresponding regulations. Also in this blog I will talk little about the Industrial Users and corresponding designations.

EPA promulgated the General Pretreatment Regulations at 40 CFR Part 403 in 1978.  This regulation establishes responsibilities for federal, state and local government entities, industry and the public.  The various responsibilities have to do with implementing the pretreatment standards that control pollutants that pass through or interfere with POTW. The most recent revision of the regulation is called the pretreatment Streamlining Rule and became effective in November 2005. The Streamlining Rule increased a POTW’s flexibility in its program implementation by allowing for a reduction in minimum program requirements. However, it is always recommended that the POTWs should discuss with their approval authority regarding any program modifications and the implementation of the Streamlining Rule.

As mentioned above, industry has specific responsibilities under the pretreat rules.  The pretreatment regulations apply to all non-domestic sources that introduce pollutants into POTW; these sources are commonly referred to as Industrial Users (IUs). EPA has developed criteria that would define a significant IU (referred to as SIU) and the distinction is based on the presumption that control of SIUs will in most cases provide adequate protection of the POTW. If a smaller IU has the potential to adversely affect the POTW, the POTW would be expected to designate the facility as an SIU. Hence many of the pretreatment regulations apply to SIUs as opposed to IUs.

In my blog next month I will talk about the criteria for defining SIU and different Industrial User categories.

If you have any questions, please contact me at

Source: U.S. EPA Introduction to the National Pretreatment Program, 2011.