Rivanna Water & Sewer Authority
Moores Creek VPDES Permit Renewal
July 22, 2005
The Rivanna Water & Sewer Authority (RWSA) operates five wastewater treatment plants for the City of Charlottesville and Albemarle County. The largest of these plants is the Moores Creek WWTP, with a design capacity of 15 million gallons per day (MGD), presently operating within a range of 9.5 MGD to 11.0 MGD on an annual average basis. Each wastewater plant in Virginia operates under what is called a VPDES Permit issued by the Department of Environmental Quality (DEQ), which establishes enforceable limits for the quality of treatment of the wastewater. The Moores Creek WWTP consistently meets all permit conditions, and this facility has been certified by DEQ for Environmental Excellence (E2 Program). During an informational meeting sponsored by the League of Women Voters in Charlottesville on July 20, 2005, Mr. Keith Fowler of DEQ described RWSA’s operation of the Moores Creek WWTP as “exemplary”.
VPDES Permits are renewed every five years by DEQ. The Moores Creek WWTP permit is presently up for renewal, and a draft permit was prepared by DEQ and advertised for public comment. The comment period ends July 30, 2005.
The Rivanna Water & Sewer Authority is strongly committed to compliance with all provisions of VPDES Permits. Toward this objective, the Authority’s staff also thoroughly reviews proposed changes in new permits to be sure that the conditions drafted by DEQ are achievable, and includes legal consultation in these reviews as appropriate. The Authority’s staff reviewed a draft last fall prepared by DEQ and requested several issues be clarified, most of them minor. All of these issues were quickly resolved with the DEQ regional staff in Harrisonburg, with the exception of a draft condition to establish interim limits for total nitrogen and total phosphorus at the Moores Creek WWTP. The remainder of this fact sheet addresses the nutrient issues.
Nutrient Issues in Virginia
The Commonwealth of Virginia is part of an effort by six states and the District of Columbia set up to provide for clean-up of the Chesapeake Bay sufficient to remove the Bay from the U S Environmental Protection Agency’s list of impaired waters by 2010.
DEQ has also identified a section of the James River, approximately between Hopewell and Williamsburg (called the “lower tidal fresh”), as nutrient enriched. RWSA is not aware that DEQ has identified any adverse effects from nutrients in the waters of the Rivanna River, or the sections of the James River above the “fall line” (west of Richmond).
The Moores Creek WWTP discharges treated water to Moores Creek near the confluence with the Rivanna River. This water then flows down the Rivanna River to the James River at Columbia. Once in the James River, this water eventually reaches the “lower tidal fresh” section of the James River, at which, according to DEQ, total nitrogen has been naturally attenuated to 61% of its strength at Moores Creek. Several much larger WWTP dischargers in the Richmond area, including the City of Richmond, Henrico County, Chesterfield County, City of Hopewell, the South Central Wastewater Authority (Petersburg), and several industrial facilities discharge much larger volumes of nutrients (compared with Moores Creek WWTP) in the “tidal fresh” sections of the James River with little or no attenuation.
Treated water from the Moores Creek WWTP has ZERO affect on the quality of the main stem of the Chesapeake Bay. That is because this water flows down the James River to the Chesapeake Bay at Newport News and the Norfolk area, a very short distance from where the Bay enters the Atlantic Ocean.
The Moores Creek WWTP, like many wastewater plants in the Commonwealth and in the nation, is designed to convert ammonia (from human wastes) to nitrates and nitrites (called “nitrification”), but is not designed to convert nitrates and nitrites to nitrogen gas. The Moores Creek WWTP VPDES Permit includes ammonia limits, and the facility is in continuous compliance with these limits. To meet a “total nitrogen” limit, facilities have to be modified and expanded to complete the conversion to nitrogen gas (called “denitrification”). These advanced nutrient removal facilities are complex and require an expensive construction project of many months to complete. Likewise, Moores Creek WWTP is not designed to biologically or chemically remove phosphorus and would require a similar construction project to economically meet a “total phosphorus” limit. Once these limits are clearly known, a specific budget, financial plan, and a schedule can be established to design and construct the needed improvements, but it is very important to have a clear target. Design decisions are very sensitive to changes in the target; therefore, trying to start design when the target is still moving (as is presently happening) will likely result in wasted engineering costs and numerous starts and stops. The “target” for Moores Creek WWTP will hopefully be defined through decisions made by the State Water Control Board (SWCB) later this year and by DEQ’s development of General Permits in 2006 based on the SWCB’s decision.
The Rivanna Water & Sewer Authority is committed to doing what is fair and equitable for its facility to meet the goals of the Commonwealth with respect to the James River. RWSA has already included in an adopted capital budget over $3 million for upgrading the facility to biological nutrient removal (BNR) and will likely be faced with considering additional funding for this project once the SWCB takes final action later this year. Within the past year DEQ has floated at least three different possible standards for our area, and we have shown in parentheses the current order of magnitude cost to the Moores Creek WWTP for each option based on quick estimates obtained from a wastewater consultant. These possible standards for nitrogen include (1) 8 mg/l or parts per million ($8,000,000); (2) 6.34 mg/l ($15,000,000); and (3) 4 mg/l ($30,000,000). We are still obtaining data on the potential annual operation and maintenance costs for these options and intend as soon as we can to provide a “ballpark” estimate of the impact on households receiving public sewer service in the urban area; the cost impact will be significant. DEQ’s most recent proposal (released to the public in late June 2005) favors the 4 mg/l (highest cost) option. RWSA is currently attempting to understand the justification (does it add measurable benefit to the environment?) as well as the equity of this latest proposal that would greatly increase Rivanna’s costs that would have to be passed on by the City and ACSA in the form of higher retail sewer rates. With respect to equity, we understand that DEQ is proposing that most wastewater plants west of Williamsburg go to this stringent 4 mg/l limit, but they are recommending exemptions with higher limits for the City of Richmond and City of Lynchburg (based on being combined sewer cities) and the City of Hopewell (based on high industrial demand).
The Rivanna Water & Sewer Authority has taken the following additional short-term measures to maximize its treatment within the capabilities of its current facilities:
Ø All four aeration basins are being operated even though present flows indicate only three are necessary to meet the current permit limits. This has been done to take advantage of even slight gains that may result from operating the facilities as if they were at capacity.
Ø RWSA has applied for and obtained a State grant to review and look for ways to better optimize its treatment facility operations. RWSA is currently soliciting engineering proposals to perform the optimization, expected to be performed in the next three months.
Interim Limits for the VPDES Permit
Recognizing that treatment facilities are designed to meet specific criteria and in many cases cannot immediately adjust to new criteria without time-intensive capital improvements, the U S Environmental Protection Agency has long endorsed a permitting process that allows that when water quality standards need to be amended, a permittee is given the new standard in a clear numerical description, and is given a reasonable amount of time to undertake the financing, design, and construction process to upgrade its facility, before the effective date for enforcement of the new standard. This process is called a compliance schedule. DEQ has used this process frequently over many years in VPDES permit conditions across the Commonwealth.
In the summer of 2004 DEQ was under intense public pressure to complete the development of nutrient standards and published a guidance document on “stop gap” interim limits for WWTPs. At a Senate Committee of the Environment meeting in Westmoreland County in August, where Mr. Bob Burnley, DEQ Director, was an invited speaker, Mr. Burnley stated that DEQ would apply this guidance such that it “is flexible to address situations with facilities that cannot comply with the interim limits without an upgrade.”
In October 2004, RWSA had an opportunity to review a draft of DEQ’s proposed renewal of a VPDES Permit for Moores Creek WWTP. DEQ had proposed interim limits from the guidance document. RWSA performed a statistical analysis to determine if the present facility could achieve these interim limits and concluded, based on available past data (no growth factor added) that there would be a 33% probability (within one standard deviation) of a violation of these interim standards in any given year if they were imposed as legal requirements before allowing time to upgrade the treatment facility. As a result, RWSA offered three options to DEQ as a counterproposal, each of these options adhering to Mr. Burnley’s August 2004 offer to show appropriate flexibility, as follows: (1) express interim limits in the permit as voluntary goals as used by the State of Maryland in a similar situation; (2) set no nutrient limits until the SWCB adopts new water quality standards, after which a compliance schedule would be allowed to achieve compliance with new standards; or (3) modify the interim limits as a permit requirement to a level RWSA’s analysis showed could be consistently achieved with existing facilities.
In the 2005 session of the General Assembly, new legislation (HB 2862 and SB 1275) passed called the Nutrient Trading and General Permit Act of 2005. The bill includes many provisions, but with respect to the issue in this summary, the act eliminated the use of interim limits by DEQ in exchange for a firm schedule by which DEQ would complete the development of water quality standards and reopen VPDES permits (including Moores Creek WWTP) through what is called a General Permit for nutrient limits.
In March 2005, RWSA learned through its attorney that Mr. Burnley was considering dropping the issue of establishing interim limits in the Moores Creek VPDES permit. In June 2005, RWSA was notified by the DEQ Harrisonburg office that interim limits had been deleted from the proposed permit and that the draft permit was ready for the public comment period.
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