Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-22 - REGULATION NO. 22 - SITE LOCATION AND DESIGN REGULATIONS FOR DOMESTIC WASTEWATER TREATMENT WORKS
Section 5 CCR 1002-22.23 - STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE (JULY 13, 2009 RULEMAKING, EFFECTIVE SEPTEMBER 30, 2009)

Current through Register Vol. 47, No. 5, March 10, 2024

The provisions of sections 25-8-202 and 25-8-401, C.R.S., provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted, in compliance with section 24-4-103(4) C.R.S., the following statement of basis and purpose.

Basis and Purpose

Definitions, (22.2): Significant changes to the definitions include:

"Construction" - The Commission modified the definition of construction to address the situation where the owner uses in-house work forces, instead of contracted work forces, to construct a domestic wastewater treatment works. In this situation, the Commission found it appropriate to establish the time that construction begins as the point where any activity described in the previous definition of construction is initiated. This is appropriate in order to ensure that the regulation is applied under both circumstances. The Commission recognizes that this would allow an entity to purchase equipment without having obtained site application approval which the owner would be doing at its own risk with the possibility that the Division would not approve the site application and/or design based on the use of such equipment. The Commission also broadened the last sentence to include the many forms of alternative construction delivery approaches that are frequently all lumped into the term "design-build."

"Design Capacity" - The Commission clarified the definition of design capacity to indicate that the proposed treatment process must be capable of reducing the concentrations of pollutants in the wastewater to a level that will meet the preliminary effluent limits developed in accordance with subsection 22.4 , rather than "effluent limits." This is necessary to avoid confusion as to which effluent limits the proposed facility must be able to meet, particularly where there is an existing permit with limits based on different circumstances than those on which the preliminary effluent limits for the proposed facility are based. The Commission also deleted the provision that design capacity could be based on the capability of the proposed facility to treat another pollutant such as ammonia. The Commission found that this provision could have applied to organic and inorganic pollutants other than ammonia and that the depth of analysis required to ensure that the capacity is based on the most limiting pollutant would be overwhelming. The Commission understands that the Division will ensure that the proposed facility is able to treat the expected loading of pollutants such as ammonia during the design review process.

"Expansion" - The Commission simplified the definition of expansion and modified the provision regarding in-kind replacement given that a definition of "in-kind replacement" has been added to the regulation. The Commission clarified the definition of expansion to specify that an expansion must be addressed in a discharge permit amendment in order to revise existing discharge permit effluent limitations.

"In-Kind Replacement" - The Commission added a definition of "in-kind replacement" based on recommendations by stakeholders who were concerned that replacement of a piece of equipment (e.g., an aerator) with a similar piece of equipment with a slightly higher rating was being required to obtain site approval by the Division. The Commission recognizes that replacement of equipment or a structure is not an exact science due to the fact that exact models may no longer be available or that construction methods may have changed such that use of current common practice would result in a slightly different structure being built. The Commission intends the use of the term "similar" in the definition to provide flexibility for the owner of a domestic wastewater treatment works to replace older equipment with modern versions that may be more efficient or to have one of several units at a higher rated capacity to provide a "factor of safety." The Commission intends to allow replacement or technology upgrades to qualify as in-kind replacement as long as the original intent of the unit process being renovated is not changed (e.g., replacing a bar screen with a fine screen). The Commission expects that in-kind replacement will generally be limited to situations where equipment/structure failure occurs or where the expected design life has been reached and removing the equipment /structure is prudent to ensure continued compliance. The Commission does not intend for replacement "in-kind" of several critical pieces of equipment or structures to be used as a means of achieving a significant increase in the DWWTW capacity that could then be realized through the amendment process under section 22.8 . Under these circumstances, the entity should be required to seek such increase(s) through the facility expansion process at section 22.5 . The Commission understands that interpretation of these situations will require judgment and expects the Division and facility owners to work together to find common sense solutions under these circumstances.

"Preliminary Effluent Limitations (PELs)" - The Commission revised the definition of preliminary effluent limitations (PELs) to clarify that they are to be used to guide the treatment needs for the alternatives to be considered for evaluation as well as for the selected alternative that is proposed in the site application. The Commission also deleted the reference to PELs being developed in support of a permit application to clarify that PELs are used in the site application process.

"Vault" - The Commission revised the definition of "vault" to make it more consistent with the definition in the Individual Sewage Disposal System Guidelines.

The Commission revised the provisions of subsection 22.3 to delete the reference to a discharge permit as it is the preliminary effluent limits developed in accordance with subsection 22.4 that set the appropriate effluent quality requirements for the site application planning process.

The Commission revised the provisions of subsection 22.3 to allow consolidation to be determined infeasible based on any one of the identified criteria. Given that the statute requires the Division to "encourage" consolidation, the Commission found it appropriate to make this change since a consolidated project should arguably have advantages over separate projects in all of these areas. This change is not intended to diminish the consideration the Division must give to a 208 plan that specifies a consolidated facility.

The Commission revised the provisions of subsection 22.3 to add a goal for the Division to complete review of site applications in a total of sixty days. The Commission finds it is appropriate to state a general expectation for the review of site applications given that the facilities for which approval is being requested are critical to the protection of public health and environment as well as to the financial well-being of the applicant. The Commission recognizes that not all applications are complete upon initial submittal to the Division and that the sixty day goal does not include time during which the applicant is developing responses to Division comments.

The Commission increased the default period before an approved site application expires in subsection 22.3 to eighteen months based on the Division's experience that completing the design , Division review of the design and obtaining other approvals/easements can take up to eighteen months.

The Commission revised the provisions of section 22.4 to clarify that the applicant can indicate that it intends to meet preliminary effluent limits for metals, organic parameters, and inorganic parameters, other than for total residual chlorine, by controlling sources to the collection system through a pretreatment program rather than through planned domestic wastewater treatment. The Commission found this to be appropriate since, where concentrations of these parameters would exceed the preliminary effluent limit, domestic wastewater treatment entities usually meet such limits through control of sources rather than installing treatment to remove them. The Commission also provided the option for the applicant to indicate that limits for these parameters can be met with no specific controls on sources to the collection system.

The Commission included in subsection 22.4 a provision to clarify, where a temporary modification for a parameter has been adopted pursuant to subsection 31.7 of the Basic Standards and Methodologies for Surface Waters (Basic Standards) for metals, organic parameters and/or inorganic parameters, other than for total residual chlorine, that preliminary effluent limits for existing or proposed discharges will be set based on the provisions of subsection 31.14 of the Basic Standards. The Commission required PELs for new facilities proposing to discharge to segments where a temporary modification has been adopted pursuant to subsection 31.7 of the Basic Standards to be based on the underlying standard.

The Commission also modified subsection 22.5 to reference the provisions at subsection 22.4 with an exception, where a temporary modification has been adopted pursuant to subsection 31.7 , that the Division may defer the requirement to treat for the parameter to a compliance schedule to be included in the permit. The Commission adopted this provision with the understanding that the Division will use this option in limited circumstances such as where the treatment necessary meet a PEL based on the underlying standard would require technology such as reverse osmosis.

The Commission revised the provisions of subsection 22.4 to delete the requirement for a site specific geotechnical investigation and report for the site of the alternative and proposed treatment works during the site location approval application phase of the project. In making a determination as to the suitability of the proposed site to support the proposed facility, the applicant may use existing geotechnical data and information that is considered to be representative of anticipated site conditions in lieu of a site-specific geotechnical investigation and report. At the applicant's option, a site-specific geotechnical investigation and report may be accomplished and submitted in support of the site location approval application.

The Commission found the requirement for a site-specific subsurface soil and/or geological and geotechnical investigation to be overly burdensome to applicants at the planning phase. Some communities do not have the financial resources at the site location application stage of the project to support what may be a design phase level of evaluation and investigation. Funding from sources such as the Revolving Loan Fund and/or Department of Local Affairs has not necessarily been completed at the site location application phase of the project.

The Division may require a site-specific geotechnical investigation in the design phase of the project to be submitted at the time of review of the process design report. If the applicant submits a site-specific geotechnical investigation report with the site location approval application, such a site-specific geotechnical report will not be required with the process design report. Similar changes were made to subsection 22.5(3).

The Commission added new section 22.4 to include the requirement to develop an emergency operations plan to demonstrate that a new domestic wastewater treatment works owner has a level of emergency operations capability. Policy 96-1, Design Criteria Considered in the Review of Wastewater Treatment Facilities, provides expectations for facilities such as emergency power or emergency wastewater storage where an equipment or power failure could cause discharge of partially treated or raw wastewater.

The Commission added new subsection 22.4 to clarify the minimum information necessary to ensure shared capacity in a treatment facility. This information was previously included in guidance only. This requirement is not intended to limit the expansion of a facility service area in the future.

The Commission added new subsection 22.4 to clarify that service areas must be consistent with those described in the water quality management plan. The Commission made mandatory this aspect of consideration of the water quality management plan in the Division's decision making process as it is critical, for planning and facility sizing purposes, to have confidence in the service area designation and that information is best taken from the water quality management plan.

The Commission revised section 22.5 to address requests for decreases in design capacity for instances where construction has taken place or will take place. Prior to this revision, the language in section 22.5 was specific to expansions (increases in the approved design capacity) although section 22.5 was the only means for the Division to evaluate and process requests for a reduction in the approved design capacity for a wastewater treatment works where construction was or would be involved. The revisions to the language remedy this issue and will help to clarify the requirements associated with a request for a reduction in the design capacity of a wastewater treatment works,

The Commission added new subsection 22.7 to section 22.7 to include the requirement to develop an emergency operations plan to demonstrate that a new domestic wastewater treatment works owner has a level of emergency operations capability. Policy 96-1, Design Criteria Considered in the Review of Wastewater Treatment Facilities, provides expectations for facilities such as emergency power, portable pumping, or emergency wastewater storage where an equipment or power failure could cause discharge of partially treated or raw wastewater.

The Commission revised the provisions of section 22.8 to provide the Division authority to require an application for treatment plant expansion in cases where a significant increase in capacity is being requested based on one or more in-kind replacements. The Commission, in the new definition of in-kind replacement, has provided significant flexibility to treatment plant owners to replace structures and equipment with larger units. Where a significant increase in capacity has resulted from such replacement(s), the Commission finds it appropriate that the site application go through the full local review process consistent with the requirements for a facility expansion. However, since this request for capacity increase would be based on already-constructed facilities, the Commission exempted the applicant from submitting the implementation plan and schedule and geotechnical information otherwise required under subsections 22.5(2)(f) and 22.5(3), respectively.

The Commission revised the provisions of newly designated subsection 22.8 to include pilot projects and full scale demonstration projects (e.g., odor control at a lift station). This is appropriate in order to allow testing to confirm the expected performance of technology to be conducted under the amendment process that has a quicker agency coordination and review process. The Commission limited the period of authorization for pilot/demonstration projects to one year or as determined by the Division after which time continuing use of the facilities will require approval of a site application and design documents.

The Commission added a new section 22.10 in conjunction with the new definition of in-kind replacement to require Division notification of certain in-kind replacements and to clarify that these replacements must be limited to the previously approved site unless the Division waives the requirement for a new site application. The Commission finds this to be appropriate in order give the Division the opportunity to confirm the replacement meets the requirements of in-kind and to keep the Division appraised of changes to the DWWTW. This will allow the Division to respond to inquiries from third parties and to be familiar with the current configuration of the treatment works in the event that an amendment is sought. The Commission emphasizes the intent of this provision is to allow replacement of equipment in an emergency or as part of normal operation and maintenance. If there is any doubt on the part of the owner that the replacement may not meet the definition of "in-kind", the Commission strongly encourages the owner to contact the Division in advance to confirm that the replacement will not be determined to be outside of the definition requiring an after the fact site application approval. The Commission exempted several types of replacement from the requirement to notify the Division, including replacement with the same piece of equipment or structure as well as other types of replacement that would not necessarily affect the operational capability or capacity of the treatment works. This will limit the types of notification to those that have the potential to affect the capacity of the treatment works or its capability to operate in a manner necessary to meet its intended performance requirements. The Commission clarified that revisions to the regulation are intended to apply prospectively only; therefore, in-kind replacements occurring before the effective date of the revised regulation are not subject to the notification requirements in section 22.10.

The Commission revised the provisions of subsection 22.11(1) to