5 Colo. Code Regs. § 1002-62.13
The provisions of 24-4-103; 25-8-202(1)(c) and (2); and 25-8-205, C.R.S. provide the specific statutory authority for consideration of the regulatory amendments proposed by this Notice. The Commission also adopted in compliance with 24-4-103(4), C.R.S., the following statement of basis and purpose.
BASIS AND PURPOSE:
In considering whether to adopt the changes proposed in this proceeding, the Commission considered the applicability of section 25-8-202(8)(a) of the Colorado Water Quality Control Act. This section, adopted in 1989, establishes requirements that must be met when the Commission adopts "rules more stringent than corresponding enforceable federal requirements." Although the existing Regulations for Effluent Limitations are more restrictive than federal secondary treatment requirements, these regulations were initially adopted in 1975. Section 25-8-206, C.R.S. explicitly validates all Commission regulations adopted prior to July 1, 1981.
Because the changes adopted in this proceeding operate only to make the existing effluent limitations requirements more lenient, the Commission does not believe that the requirements of section 25-8-202(8)(a) apply to the current actions. However, the Commission also believes that there is sound scientific and technical evidence in the record that the revised statewide effluent limitations are necessary to protect the public health, beneficial use of water, and the environment of the state. These provisions establish technology-based requirements to establish a minimum level of wastewater quality to be met by dischargers throughout the state. The existing requirements, which are being marginally relaxed in this proceeding have been in place for nearly twenty years. During this time, compliance with these requirements has not proved to be a major technological or economic problem for dischargers.
The applicability of the residual chlorine limitation has been modified so that it does not apply to discharges to irrigation ditches. This change has been made in response to a concern, raised by a permittee, that the 0.5 mg/l limit may require additional expenditures to dechlorinate the effluent in order to meet the limit. They also expressed a concern that compliance with the limit could potentially cause higher levels of fecal coliform in irrigation ditches.
Footnote 5 to the oil and grease effluent limitation has been revised. The previous "no visible sheen" provision in this footnote has been eliminated. Clarifying language has been added to provide that monitoring for a "visible sheen" generally will be required as a screening test, to determine when it may be necessary to analysis a grab sample for oil and grease.
The format of the regulation has been modified to be consistent with that of other Commission regulations. The word "average" has been deleted from the last sentence of section 10.1.3 , subsection 2, in recognition of the fact that the limits for total residual chlorine and oil and grease are instantaneous maximum limits. One outdated provision has been deleted from section 10.1.4 . Also, the citations in section 10.1.5 , subsection 1, have been updated to reflect current documents and/or agency addresses.
The Commission incorporated by reference in these rules documents that describe analytical and sampling methods to be used by the discharger. The documents are published by nationally recognized associations or organizations. A third document, prepared by the EPA, and proposed for incorporation by reference, was excluded in the final rule upon advice by the Attorney General's Office, because of potential conflicts with the Administrative Procedure Act.
The Commission added a new paragraph 10.1.1 to indicate that the documents incorporated by reference in these rules are not to include later amendments to those documents, and that copies of incorporated documents may be obtained from the Commission. This paragraph was added to comply with the requirements of ' 24-4-103 (12.5).
5 CCR 1002-62.13