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Regulatory Alert - RA 03-08 - DATA NEEDED FOR PATHOGEN STUDY

Member Pipeline - Regulatory - Alert (RA 03-08)

To: Members & Affiliates, Wet Weather Issues Committee
From: National Office
Date: September 12, 2003
Subject: COLLECTION SYSTEM CAPACITY-SETTING MATRIX AND NARRATIVE
Reference: RA 03-08

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The Association of Metropolitan Sewerage Agencies (AMSA) is pleased to provide the membership with its recently completed Collection System Capacity-Setting Matrix and Narrative (Matrix). The Matrix supports AMSA’s 2002 Wet Weather Survey (Survey) and related efforts to increase the Environmental Protection Agency’s (EPA or Agency) understanding of the methodologies used by collection system operators to make system capacity assessments. AMSA’s Sanitary Sewer Overflow (SSO) Workgroup used Survey information to identify the factors considered and the processes used by utilities to make capacity-related decisions in the construction and rehabilitation of their collection systems. The Workgroup then developed a matrix of this information to illustrate the decision-making process. The intent of the Matrix and accompanying narrative is to provide information to the Agency on capacity-setting methodologies, both to support an eventual SSO Rule and to serve as a tool for AMSA members to use when discussing capacity issues with permitting authorities or when responding to enforcement actions.

It is critical to note that the Matrix is not a set of concrete, step-by-step instructions for the capacity-setting process. Instead, it provides to those outside the wastewater design community a guide to the numerous issues examined and the engineering practices used throughout the decision-making process.

Background
EPA first made public a draft SSO regulation and preamble in 2001 during the Clinton administration. AMSA and its membership had serious concerns with both the regulatory text and the preamble, which it aggressively communicated to EPA. The 2001 proposal was withdrawn by the Bush administration, and EPA has indicated that it intends to propose an SSO Rule after it concludes work on a national blending guidance. The Agency has indicated that the proposed regulatory text will remain the same, including an untenable prohibition of SSOs, but the preamble of the rule is expected to be broadened to include the views and concerns of the publicly owned treatment work (POTW) community and other stakeholders and to allow for public comment on alternatives to the regulatory structure established in the proposed rule.

The preamble of the 2001 draft SSO Rule included language that illustrated the Agency’s lack of sound information regarding of industry procedures for sizing sanitary sewer systems and the technological incapability of sewers to avoid SSOs under all conditions. The regulatory text of the draft rule states that “sanitary sewer system discharges to waters of the United States that occur prior to a publicly owned treatment works treatment facility are prohibited.” The only exceptions to the prohibition are for severe natural conditions (hurricanes, tornados, widespread flooding, earthquakes, etc.), or discharges caused by other factors not within the reasonable control of the operator. This latter exception is significantly limited by the potential for an after-the-fact, subjective determination by a regulator that a system did not have adequate capacity, and that the operator could have prevented an overflow by increasing the capacity of the system. Furthermore, the draft regulatory text did not directly link a POTW’s implementation of a robust Capacity, Management, Operation and Maintenance (CMOM) Program with a solid affirmative defense to overflows. Because of the subjectivity of the above exceptions and the absence of a performance-based standard against which to measure POTW operators’ capacity setting decisions, this rule could result in numerous costly enforcement actions for many AMSA members.

While AMSA supports the principles underlying the CMOM concept, it continues to assert that capacity and management, operation, and maintenance (MOM) are separate issues that must be evaluated and addressed independently. While MOM activities can be implemented in the short-term, the capacity-setting process requires long-term approaches and solutions. AMSA generally believes that EPA does not fully recognize the intense effort POTWs routinely give to the capacity-setting process. Accordingly, AMSA’s SSO Workgroup met over the course of several months to develop a framework to capture all of the various factors that could be considered and actions that could be taken to establish appropriate system capacity. When applied as appropriate for each specific system, the tasks and evaluations included in the framework would result in system capacity decisions that protect human health and designated waterbody uses, while also establishing the technological baseline for determining if a given event was beyond the capabilities of the system as designed and any resulting overflow was thus unavoidable.

Summary of Matrix and Narrative
The matrix narrative first identifies five fundamental principles:

  1. There can be no “one size fits all” capacity standard or planning process.
  2. Grossly oversized sewers allow for the settling of solids, which can reduce the overall capacity of the sewer, result in formation of malodorous and/or explosive gases, and generally prevent implementation of an effective Management, Operation and Maintenance (MOM) program.
  3. All collection systems will overflow under certain conditions, as recognized by EPA in the draft SSO Rule preamble. It is impossible and environmentally unnecessary to make all existing sewers water tight from a wet weather perspective.
  4. Collection systems that have MOM programs in place will overflow less frequently.
  5. Significant wet weather flow infiltration is a legacy issue. Utilities are finding that collection systems constructed in the last thirty years are not showing the same degree of overflow occurrences. Overflows will still occur as infrastructure is repaired or replaced, but at a much reduced level. Thus, as investments are made over time, the problem that we face now in many cases will be self-correcting.

The matrix narrative next describes the most common components of a capacity evaluation, which encompass:

A. Data Gathering, including:
• Assessments of overflows and their impacts on public health and the environment
• Assessments of treatment facilities and collection systems, including wet weather modeling

B. Preliminary Planning and Alternatives Identification:
• If data supports, alternatives to reduce overflows
• Public participation in alternatives analysis to gain support

C. Alternatives Refinement, which might include:
• Relief sewer or interceptor construction
• Inflow and infiltration (I/I) rehabilitation
• Storage facilities and/or equalization tanks

D. Implementation:
• Detailed capacity-related capital improvement program (CIP)
• Post-CIP performance measurement
• Routine, ongoing MOM program and annual capacity reviews

Next Steps
As AMSA continues to have discussions with the Agency on the direction the eventual SSO Rule will take, it is imperative that the Association provide EPA with information on the capacity-setting processes that POTWs routinely perform. AMSA plans to meet with key EPA Headquarters staff this fall to present the Matrix and to further educate the Agency on the capacity-setting process.

AMSA hopes that its members will share the Matrix with their regulators, both at the state and EPA Regional levels. By providing this insight into the capacity-setting process, AMSA members can enable their regulatory authorities to assess the reasonableness of a utility’s capacity determinations, and thereby define when a wet weather-induced overflow is unavoidable for regulatory purposes.

AMSA is also working to develop a white paper on legal arguments for a more appropriate and reasonable standard for SSOs and collections systems. AMSA anticipates releasing this document in November. The Matrix is available online at http://www.amsa-cleanwater.org/private/legreg/outreach/2003-09-12FinalMatrix.pdf.

While AMSA is not seeking formal comments on the Matrix, we welcome any feedback members may have. Please contact Chris Hornback, AMSA’s Director of Regulatory Affairs at 202/833-9106 or chornback@amsa-cleanwater.org with any comments or questions.