Whitewater Pollution Control Facility Expansion Findings of Fact
Total Page:16
File Type:pdf, Size:1020Kb
STATE OF MINNESOTA MINNESOTA POLLUTION CONTROL AGENCY IN THE MATTER OF THE DECISION ON THE NEED FOR AN ENVIRONMENTAL IMPACT STATEMENT FOR THE PROPOSED WHITEWATER POLLUTION CONTROL FACILITY EXPANSION - DOVER-EYOTA-ST. CHARLES AREA SANITARY DISTRICT FINDINGS OF FACT WINONA COUNTY CONCLUSIONS OF LAW ST. CHARLES TOWNSHIP, MINNESOTA AND ORDER FINDINGS OF FACT Pursuant to Minn. R. 4410.1000 - 4410.1600 (2005), the Minnesota Pollution Control Agency (MPCA) staff has prepared an Environmental Assessment Worksheet (EAW) for the proposed project. Based on the MPCA staff environmental review, comments, and information received during the comment period, and other information in the record of the MPCA, the MPCA hereby makes the following Findings of Fact, Conclusions of Law, and Order. FACILITY HISTORY Overview The Dover-Eyota-St. Charles Area Sanitary District (DESCASD) operates an interceptor and wastewater treatment facility (WWTF), known as the Whitewater Pollution Control Facility (WPCF), that provides service to the cities of Dover, Eyota and St. Charles in Winona County, Minnesota. The interceptor consists of 53,489 feet of 15-inch, 18-inch, and 21-inch sanitary sewer. The WPCF has an average wet weather (AWW) design flow of 1.12 million gallons per day (mgd) and consists of a fine screen, mechanical bar screen, vortex grit chamber and classifier, two oxidation ditches, two final clarifiers, three dual-media tertiary effluent filters, a chlorine contact tank, “cascade” effluent aeration manholes for dechlorination, and a biosolids storage basin. Treated effluent is continuously discharged to the South Fork of the Whitewater River. Permitting History A permit from the MPCA’s Division of Water Quality was issued in 1975. Since then, a permit authorizing the discharge has been reissued many times. The existing WPCF operates under National Pollutant Discharge Elimination System/State Disposal System (NPDES/SDS) Permit No. MN0046868, which was most recently reissued in 2001. Previous Environmental Review The MPCA staff is unaware of previous environmental review for the WPCF through the MPCA, though the proposer does have information in its archived files regarding an Environmental Assessment Statement, Environmental Evaluation Factors for Municipal Wastewater Treatment Projects and Minutes for Public Hearing and Printer's Affidavits for Notice of the Public Hearing. The Public Hearing on the Environmental Assessment Statement was held March 19, 1974, at the city of St. Charles City Hall. The Environmental Assessment was prepared by McGhie & Betts, Inc., of Rochester, Minnesota. The WPCF began operation on January 1, 1978. TDD (for hearing and speech impaired only): (651) 282-5332 Printed on recycled paper containing at least 30% fibers from paper recycled by consumers Whitewater Pollution Control Facility Expansion – Findings of Fact Dover-Eyota-St. Charles Area Sanitary District Conclusions of Law On the Need for an Environmental Impact Statement And Order St. Charles Township, Minnesota PROPOSED PROJECT DESCRIPTION Proposed Project DESCASD proposes to expand and upgrade its existing WPCF to treat an AWW design flow of 2.184 mgd (Project). The expansion will occur on the site of the existing WPCF and continue to discharge to the South Fork of the Whitewater River. Proposed construction is scheduled to start in the summer of 2006 and will consist of the following items: • Alter existing oxidation ditch splitter box; • Raise walls on two existing oxidation ditches to increase the depth and capacity; • Construct one new oxidation ditch; • Raise walls on two existing final clarifiers and replace existing clarifier mechanisms; • Construct one new final clarifier; • Construct a final clarifier splitter structure; • Construct a chemical phosphorus removal system to assist biological removal; • Replace the Return Activated Sludge (RAS) pumps and Waste Activated Sludge (WAS) pumps; • Construct new gas chlorine disinfection facilities; • Construct new effluent cascade aeration facilities; • Construct a new site drainage/supernatant return/subnatant return lift station; • Construct a new effluent water system for wastewater plant use; • Construct a new 750,000-gallon sludge storage tank; • Provide a new effluent sampler and flow meter; • Construct associated yard piping; • Construct associated site work; • Construct associated mechanical systems; • Construct associated electrical and instrumentation and control systems; • Decommission existing effluent flow meter; • Decommission existing chlorine disinfection facilities and leave the chlorine tank in place; • Decommission existing effluent sampler; • Decommission and salvage existing RAS and WAS pumps; • Demolition of existing effluent filters; • Demolition of existing effluent water system; • Demolition of existing blower building and foundation; • Decommission and salvage existing blowers; • Construct four new aerated sludge holding tanks with a sludge mixing and transfer station and associated blowers; • Construct four new reed drying beds (7,500 square feet each) and associated sludge distribution structure; • Construct associated yard piping; • Construct associated site work; 2 Whitewater Pollution Control Facility Expansion – Findings of Fact Dover-Eyota-St. Charles Area Sanitary District Conclusions of Law On the Need for an Environmental Impact Statement And Order St. Charles Township, Minnesota • Construct associated mechanical systems; • Construct associated electrical and instrumentation and controls systems; and • Construct new standby power facilities. Environmental Concerns Typical environmental concerns from WWTFs include the potential for noise and dust during the construction phase; odors; erosion and sedimentation; and water quality impacts to surface water. Additional Concerns Described in Comment Letters The MPCA received one comment letter from a citizen, one from the Minnesota Department of Natural Resources (DNR) and one from Winona County, all of whom raised concerns about the expanded discharge’s potential to thermally impact downstream trout habitat and to increase river bed and bank erosion. These concerns are addressed in Findings 16 and 17 below and in Appendix B, Responses to Comments document. The citizen also raised a wide variety of additional concerns. Responses to these additional concerns raised can be found in Appendix B, Responses to Comments. PROCEDURAL HISTORY 1. Pursuant to Minn. R. 4410.4300, subp. 18B, an EAW was prepared by MPCA staff on the proposed Project. Pursuant to Minn. R. 4410.1500 (2005), the EAW was distributed to the Environmental Quality Board (EQB) mailing list and other interested parties on June 2, 2006 2. The MPCA notified the public of the availability of the EAW for public comment. A news release was provided to interested parties on June 8, 2006. In addition, the EAW was published in the EQB Monitor on June 5, 2006, and available for review on the MPCA Web site at http://www.pca.state.mn.us/news/eaw/index.html on June 5, 2006. 3. The public comment period for the EAW began on June 5, 2006, and ended on July 5, 2006. During the 30-day comment period, the MPCA received three comment letters from government agencies and received one comment letter from a citizen. 4. The MPCA prepared responses to all comments received during the 30-day public comment period. Comment letters received have been hereby incorporated by reference as Appendix A to these findings. The MPCA responses to comments received are hereby incorporated by reference as Appendix B to these findings. 3 Whitewater Pollution Control Facility Expansion – Findings of Fact Dover-Eyota-St. Charles Area Sanitary District Conclusions of Law On the Need for an Environmental Impact Statement And Order St. Charles Township, Minnesota CRITERIA FOR DETERMINING THE POTENTIAL FOR SIGNIFICANT ENVIRONMENTAL EFFECTS 5. Under Minn. R. 4410.1700 (2005), the MPCA must order an Environmental Impact Statement (EIS) for projects that have the potential for significant environmental effects that are reasonably expected to occur. In deciding whether a project has the potential for significant environmental effects, the MPCA must compare the impacts that may be reasonably expected to occur from the project with the criteria set forth in Minn. R. 4410.1700, subp. 7 (2005). These criteria are: A. the type, extent, and reversibility of environmental effects; B. cumulative potential effects of related or anticipated future projects; C. the extent to which the environmental effects are subject to mitigation by ongoing public regulatory authority; and D. the extent to which environmental effects can be anticipated and controlled as a result of other available environmental studies undertaken by public agencies or the project proposer, including other EISs. THE MPCA FINDINGS WITH RESPECT TO EACH OF THESE CRITERIA ARE SET FORTH BELOW Type, Extent, and Reversibility of Environmental Effects 6. The first criterion that the MPCA must consider, when determining if a project has the potential for significant environmental effects that are reasonably expected to occur, is the "type, extent, and reversibility of environmental effects" Minn. R. 4410.1700, subp. 7.A (2005). The MPCA findings with respect to each of these factors are set forth below. 7. Reasonably expected environmental effects of this Project to air quality: Dust and noise will be generated by construction equipment during construction. Odors may also be generated from construction equipment exhaust. Equipment used during construction will