Update on Water Quality-Related Initiatives Which May Impact Wastewater Treatment Plant Operations

This article was originally published in the Maine Wastewater Control Association Newsletter.


By Bill Taylor 

In 2009, I wrote a short article highlighting new water quality initiatives that had the potential to impact wastewater treatment plant operations.  At that time, I focused on the recently proposed Atlantic salmon listing and Maine DEP’s new DeTox Program.  Those two regulatory initiatives are still important permitting factors and worthy of update.  Since 2009, there have been many other water quality-related initiatives undertaken, two of which warrant discussion: the proposed nutrient rule for fresh waters and the arsenic and toxics rulemaking.  A brief summary of each of these regulatory initiatives is provided below.

Endangered Species Listings

As I noted in my 2009 article, the U.S. Fish and Wildlife Service and National Marine Fishery Service (“federal fisheries agencies”) proposed, and ultimately listed Atlantic salmon as an endangered species on the upper Penobscot, Kennebec and Androscoggin Rivers.  The July 2009 listing affected approximately 85 MPDES permittees in those watersheds.  While the federal fisheries agencies’ focus has been on hydropower and connectivity impacts, several meetings have been held to discuss whether Maine’s water quality/MPDES permitting programs are sufficiently protective of Atlantic salmon. 

Of particular concern may be discharges which are not regularly tested, including CSOs and other stormwater-related dischargers.  The National Marine Fishery Service is also apparently conducting toxicity tests on Atlantic salmon to determine whether Maine’s Brook Trout testing protocols are sufficiently protective.  Gulf of Maine Atlantic sturgeon were listed as threatened in early 2012.  Alewives and Blueback Herring are proposed for listing.  It is expected that because of these listings and proposed listings, dischargers will face additional scrutiny and it is likely that the federal fisheries agencies will focus on select MPDES permits in the future. 

DEP DeTox Program and Metals Limits

In 2009, Maine DEP had begun to implement new procedures for calculating toxic pollutant limits in MPDES permit.  The DEP’s “DeTox” program has resulted in new toxics limits either based on reasonable potential to exceed a criterion or actual exceedances of a criterion.  New DeTox assumptions and calculations include: use of 10% of the ambient water quality criteria as background and a 15% reserve for non-point source contributions and future growth.  In addition, the remaining 75% of the water quality criteria is now allocated among all dischargers in the watershed. 

As a result of feedback on the new program from several dischargers and their associations, including Maine Wastewater Control Association, DEP has agreed that the 15% reserve may be used where that use would eliminate a reasonable potential or exceedance.  DEP is also about to begin a stakeholder process to look at options for developing site-specific criteria, primarily for metals.  A key goal of this process is to allow dischargers having trouble meeting new toxics limits to develop new criteria based on local water chemistry.  It will be important for municipal dischargers to be engaged in this stakeholder process. 

Arsenic and other Water Quality Rulemakings

Many municipalities were concerned about the imposition of arsenic limitations either as a result of the application of the existing water quality criteria or sludge utilization standards.  There is no EPA approved test method for inorganic arsenic, the portion of arsenic that is regulated under state of Maine rules.  DEP assumed one half of total arsenic was inorganic and required testing of total arsenic.  Again, a group of dischargers, including Maine Wastewater Control Association, developed draft legislation to revise the inorganic arsenic criteria.  After several meetings, the group gained the support of the Maine DEP and the state toxicologist. The legislature approved the changes in May of 2011 and Maine DEP began Chapter 584 rulemaking shortly thereafter.  The proposed rule has gone through several iterations and is currently being finalized with EPA Region 1 which must approve the rule change.  The prior inorganic arsenic criteria was 0.014 ppb.  The new inorganic arsenic criteria is likely to be 1.2 ppb, an 80 fold increase despite a significant increase in the fish consumption rate for high consumers. 

DEP is also proposing to amend Chapter 530 to eliminate concentration-based limits unless required by an effluent limitation guideline.  This change should help several dischargers maintain compliance.

DEP’s Proposed Nutrient Rule

As many of you will recall, DEP held a series of stakeholder meetings and two public hearings on proposed freshwater nutrient criteria (Chapter 583).  The rulemaking process was stopped in its tracks when EPA Region 1 objected to the use of instream response variables for determining attainment status.  Almost two years later, EPA has apparently reversed that decision and has indicated that DEP’s rule does pass muster under the Clean Water Act.  EPA has suggested a few changes to the rule.  DEP has indicated that it will reconvene stakeholder discussions within the next few months.  Marine nutrient criteria are also being developed and a schedule for the stakeholder process was recently circulated by Maine DEP.

The Maine Wastewater Control Association and its members will be monitoring these initiatives closely and will be active participants in any stakeholder meetings.  There will always be new water quality regulations affecting municipal dischargers, and I will provide updates as they become available.