Ammonia Standards and Implementation Work Group

Meeting Summary
September 6, 2005

Purpose of the Workgroup:

To assist the Water Quality Control Division in implementing the ammonia criteria adopted at the June 2005 Basic Standards Rulemaking Hearing.

Implementation Issues and Concerns:

How best to move from the Basic Standards for ammonia to basin-specific and site-specific criteria. The schedule for the upcoming Basin Hearings is as follows:

2006 – San Juan and Gunnison
2007 – Arkansas and Rio Grande
2008 – Upper and Lower Colorado
2009 – South Platte

Note: once basin standards are adopted, they would become effective at the beginning of the following year, as EPA needs to review and approve them first.

• To date, no one has requested any site-specific modifications; however, there have been several requests for changes to ammonia permit limits, specifically Paonia and Clifton Sanitation District. This raised the issue of whether there is a way to avoid having cold water dischargers requesting changes to permit limits without first changing the standards.

• The ammonia criteria are a function of both pH and temperature. Another important consideration for warm water dischargers is the presence/absence of early life stages. It was noted that early life stage determination is a Water Quality Control Commission determination, not a permitting issue.

• The Commission recognizes that temporary modifications may be an appropriate mechanism for site-specific ammonia criteria implementation, especially on warm water segments.

• There are possible implications to Division workloads if revised standards are adopted for the entire state at one time, instead of utilizing the normal basin-by-basin approach. Speaking on behalf of the Division, Sarah Johnson indicated that it would be preferable to have one hearing. One possibility would be March 2007, which would provide plenty of time for data collection and outreach activities by the Division. The San Juan and Gunnison hearing would go forward as normal.

• The timing of permit renewals would be an issue if one statewide hearing was held, which could possibly be addressed through lengthy compliance schedules (> 5 years) and/or the use of temporary modifications.

• The Division does not feel that they have the authority to use a compliance schedule to delay implementation of total ammonia limits based on the current criteria, until the new criteria are adopted for a segment.

• There was some discussion regarding training on the use of the AMMTOX model as well as a peer review of the model.

Determinations for the Workgroup to Make:

• Should cold water and/or warm water standards be adopted for the entire state at one time?

• Could there be associated accommodation through the permitting process?

• Are compliance schedules appropriate for warm water dischargers? How long?

• Could compliance schedules for cold water dischargers be used to cover the gap until the standards are adopted?

• Should PELs be based on the newly adopted standards for near-term basin hearings only, e.g., not for the South Platte?

• Will there be a workgroup recommendation to the Commission or will the Commission choose from several different options? It was noted that a number of site-specific requests to adopt criteria “out of sequence” would likely influence the Commission’s perspective on the question. But, as noted above, so far there have been no such requests.

• Are there antidegradation and/or anti-backsliding issues that need to be considered?

• What kind of data requirements would be needed for early life stages present/absent?

• What are the data requirements for modeling?

• Is AMMTOX the appropriate means of determining effluent limits?

Follow Up

It was decided that more feedback was needed before a decision can be made regarding whether to adopt the criteria in a single hearing. Paul Frohardt stated that he would discuss this with the Commission during the retreat. It was agreed that it would also be discussed at the South Platte Forum.

The next meeting is scheduled for September 28 at 9 am in the CDPHE Board Room.