STATE OF MINNESOTA MINNESOTA POLLUTION CONTROL AGENCY FINDINGS OF FACT

Transcription

1 STATE OF MINNESOTA MINNESOTA POLLUTION CONTROL AGENCY IN THE MATTER OF THE DECISION ON THE NEED FOR AN ENVIRONMENTAL IMPACT STATEMENT FOR THE PROPOSED LESTER PRAIRIE WASTEWATER TREATMENT FACILITY EXPANSION MCLEOD COUNTY LESTER PRAIRIE, MINNESOTA FINDINGS OF FACT CONCLUSIONS OF LAW AND ORDER FINDINGS OF FACT Pursuant to Minn. R (2003), 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,, and Order: FACILITY HISTORY Overview The city of Lester Prairie s (City s) existing mechanical activated sludge wastewater treatment facility (WWTF) was built in 1982 and consists of an influent lift station, a screening basket located within the lift station, a static screen and two parallel grit channels in the preliminary treatment building, an oxidation ditch, two final clarifiers, and chlorine disinfection. After disinfection, chlorine is neutralized by the addition of sulfur dioxide. Treated effluent is continuously discharged through 280 feet of 12-inch outfall pipe to the South Fork of the Crow River. This existing WWTF has an average wet weather (AWW) design flow capacity of 182,000 gallons per day (gpd). A back-up generator ensures operation of the lift station pump in times of power outages. The WWTF also has a bypass at the lift station that would allow untreated wastewater to flow directly to the outfall line and to the South Fork of the Crow River. The bypass is manually controlled and locked at all times. The MPCA files for this WWTF, and conversations with City staff, indicate that the bypass has never been used. Sludge wasted from the clarifiers is treated in an aerobic digester where it is stabilized and prepared for final disposal. The City also currently treats sludge from the Mayer WWTF. Over the past year, the Lester Prairie WWTF has accepted and treated 110,000 gallons of sludge from the city of Mayer. Stabilized biosolids are land applied to MPCA-approved land application sites. Permitting History The National Pollutant Discharge Elimination System/State Disposal System (NPDES/SDS) Permit has been reissued several times, most recently on September 24, TDD (for hearing and speech impaired only): (651) Printed on recycled paper containing at least 30% fibers from paper recycled by consumers

2 Previous Environmental Review This WWTF has never previously undergone environmental review. Compliance/Enforcement History In 2003, the WWTF violated its fecal coliform effluent limitation on two occasions. Operationally, it was difficult to pinpoint the root problem, but it may have been a combination of sampling technique mistakes, lab error, and poor operations. There were no effluent violations in 2004 and compliance staff believes that the WWTF is generally well run. PROPOSED PROJECT DESCRIPTION Proposed Project The City is proposing to add to their wastewater treatment capacity by upgrading and expanding the existing Lester Prairie WWTF. The proposed project will increase the AWW design flow capacity from 182,000 gpd to 364,000 gpd. The proposed WWTF expansion will consist of modifying the influent pumps, replacing the existing fine screen with a static fine screen, replacing chlorine disinfection with ultraviolet disinfection and adding biological phosphorus removal, an additional oxidation ditch, a new final clarifier and two effluent filters. Treated effluent will continue to be discharged to the South Fork of the Crow River. Sludge generated in the treatment process will be transferred to the existing aerobic digester where air and mixing will provide biosolids stabilization. From the aerobic digester, the stabilized biosolids will be land applied on MPCA-approved land application sites. It is anticipated that a second aerobic digester will be necessary in five to ten years, depending on the community s growth, and so the consideration of potential impacts from the construction of the second digester was included in the EAW. The city of Mayer is constructing a sludge management system and once this system is operational, the Lester Prairie WWTF will no longer accept sludge from the city of Mayer. 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 proposed project will be constructed approximately 40 feet from a wetland that is adjacent to the South Fork of the Crow River. The U.S. Army Corps of Engineers finds that a wetland delineation may be advisable to ensure that there will be no wetland impacts. A copy of their letter and the MPCA s response can be found in Appendix A of the Findings. Permitting Requirements Required permits are listed in Findings 22 below. Construction for the proposed project will not start until all permits are issued. These permits will mandate that the WWTF operate in compliance with all applicable regulatory requirements. 2

3 PROCEDURAL HISTORY 1. Pursuant to Minn. R , subp.18b, an EAW was prepared by MPCA staff on the proposed project. Pursuant to Minn. R (2003), the EAW was distributed to the Environmental Quality Board (EQB) mailing list and other interested parties on January 17, The MPCA notified the public of the availability of the EAW for public comment. A news release was provided to interested parties on January 14, In addition, the EAW was published in the EQB Monitor on January 17, 2005, and available for review on the MPCA Web site at on January 17, The public comment period for the EAW began on January 17, 2005, and ended on February 17, During the 30-day comment period, the MPCA received one comment letter from a government agency. 4. The MPCA prepared responses to all comments received during the 30-day public comment period. Comment letters and the MPCA responses to comments received have been hereby incorporated by reference as Appendix A to these findings. CRITERIA FOR DETERMINING THE POTENTIAL FOR SIGNIFICANT ENVIRONMENTAL EFFECTS 5. Under Minn. R (2003), 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 , subp. 7 (2003). 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. 3

4 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 , subp. 7.A (2003). 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: A. Odors; B. Noise; and C. Dust. 8. The extent of any potential air quality effects that are reasonably expected to occur: A. Odors The property is currently used for the treatment of wastewater and there have been no odor complaints regarding its operation. Odors can sometimes arise with the operation of wastewater treatment ponds; however, mechanical activated sludge treatment processes (such as the proposed WWTF) are aerated systems and normally do not cause odors. Since the proposed WWTF will be aerated and most of the equipment will be covered or located within an enclosed building, conflicts between residents and the City regarding the proposed WWTF are not anticipated. B. Noise There would be a temporary increase in noise generated by heavy machinery during the construction of the proposed WWTF. The contractors would have to comply with City noise ordinances. Construction would be allowed only during daylight hours. Operation of the expanded WWTF will not create noise disturbances. C. Dust During construction, dust emissions will increase temporarily. The contractor will be required to employ appropriate measures to minimize the amount of dust produced during construction, such as watering the site, planting temporary grass cover, and the use of crushed rock in travel areas. Operation of the expanded WWTF will not create dust. 9. The reversibility of any potential air quality effects that are reasonably expected to occur: The MPCA finds that any potential effect that is reasonably likely to occur from this project would be reversible. Any air emissions or noise released to the atmosphere would not be recovered, but further emissions or noise could be stopped, if necessary. However, as discussed above, there is no record evidence indicating that this project is reasonably expected to cause a significant negative effect on air quality. 10. The MPCA finds that the environmental review is adequate to address the concerns because: 4

5 All potential impacts to air quality that are reasonably expected to occur from the proposed project have been considered during the review process and methods to prevent these impacts have been developed. 11. The MPCA finds that the project, as it is proposed, does not have the potential for significant environmental effects based on the type, extent, and reversibility of environmental effects reasonably expected to occur as a result of its air emissions. 12. Reasonably expected environmental effects of this project to water quality: A. Surface-water runoff; B. Water quality impacts; and C. Erosion and sedimentation. 13. The extent of any potential water quality effects that are reasonably expected to occur: A. Surface-water runoff The quality and quantity of runoff produced by this site will not be noticeably altered by the proposed project, which will only increase the amount of impervious surface by 0.1 acre. The NPDES General Stormwater Permit for Construction Activity from the MPCA will have specific requirements for the treatment and overall management of stormwater prior to discharge from the site. The Permit will also require that a Stormwater Pollution Prevention Plan (SWPPP) be developed to manage pollutants in stormwater runoff from the site that will occur during construction and after construction is complete. Temporary erosion control measures, such as silt fencing, will be utilized to prevent runoff and sedimentation. After construction is completed, turf will be established immediately. SWPPP and Best Management Practices (BMPs) implementation strategies must be prepared prior to submitting a permit application. B. Water quality impacts Effluent will be discharged through the existing outfall structure to the South Fork of the Crow River. The MPCA has proposed effluent limits for the expanded WWTF s discharge which will be incorporated into the WWTF s modified NPDES/SDS Permit and are intended to protect the uses of and minimize the impact on the receiving water. Effluent limits set in the NPDES/SDS Permit will be met at the point where treated effluent leaves the WWTF. The reach of the South Fork of the Crow River to which the WWTF discharges is listed on Minnesota s 303(d) list of impaired waters for mercury. Approximately 4.65 miles downstream, another reach of the South Fork Crow River is on the 303(d) list of impaired waters for biota, mercury, and turbidity. The information contained in Item 18b of the EAW describes how a combination of stringent limits and additional technology will ensure protection of the river s water quality standards. No significant impacts to the receiving waters from the proposed project are anticipated. 5

6 C. Erosion and sedimentation The project proposer will be required to obtain a NPDES General Stormwater Permit for Construction Activity from the MPCA to control erosion and runoff. This permit must be obtained prior to commencing any land disturbing activities (i.e., clearing, grading, filling and excavating) at the site. The Permit specifically requires implementation of BMPs. Construction plans will include BMPs, such as scarifying only those portions of the site actively under construction, placing silt fencing down slope of any land that is graded, and seeding and re-vegetating disturbed areas as soon as possible after construction is complete. Potential impacts from stormwater runoff are not anticipated to be significant. 14. The reversibility of any potential water quality effects that are reasonably expected to occur: The MPCA finds that any potential effect that is reasonably likely to occur from this project would be reversible. As discussed above, the expected effects on water quality are minimal. There is no reason to believe that this project is reasonably expected to cause a significant negative effect on water quality. 15. The MPCA finds that the environmental review is adequate to address the concerns because: All potential impacts to water quality that are reasonably expected to occur from the proposed expansion of this facility have been considered during the review process and a method to prevent these impacts has been developed. 16. The MPCA finds that the project as it is proposed does not have the potential for significant environmental effects on water quality based on the type, extent, and reversibility of environmental effects reasonably expected to occur. Cumulative Potential Effects of Related or Anticipated Future Projects 17. The second 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 "cumulative potential effects of related or anticipated future projects," Minn. R , subp. 7.B (2003). The MPCA findings with respect to this criterion are set forth below. 18. The EAW, public comments, and MPCA follow-up evaluation did not disclose any related or anticipated future projects that may interact with this project in such a way as to identify any potential cumulative environmental impacts that are reasonably expected to occur. 19. In considering the cumulative potential effects of related or anticipated future projects, the MPCA finds that the reasonably expected effects from this project will not be significant. 6

7 The Extent to Which the Environmental Effects Are Subject To Mitigation by Ongoing Public Regulatory Authority 20. The third 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 extent to which the environmental effects are subject to mitigation by ongoing public regulatory authority," Minn. R , subp. 7.C (2003). The MPCA findings with respect to this criterion are set forth below. 21. The following permits or approvals will be required for the project: Unit of Government Permit or Approval Required Status A. MPCA Plans and Specifications To be approved MPCA NPDES/SDS Permit Submitted; to be issued MPCA NPDES General Stormwater Permit To be submitted for Construction Activity B. Minnesota Department of Temporary Water Appropriations To be submitted Natural Resources (DNR) Permit C. City of Lester Prairie Building Permit To be submitted 22. A. MPCA Plans and Specifications Approval Construction plans and specifications for the project are submitted to the MPCA for technical review and approval. This review is performed to ensure that the facility design is consistent with good engineering practice and state and federal criteria. NPDES/SDS Permit An NPDES/SDS Permit will be prepared and issued by the MPCA following a 30-day public comment period. The NPDES/SDS Permit authorizes a maximum discharge flow and pollutant loading allowed from the WWTF to a surface water. Effluent limitations established within the NPDES/SDS Permit ensure that water quality in the receiving water is protected. NPDES General Stormwater Permit for Construction Activity A NPDES General Stormwater Permit for Construction Activity is required when a project disturbs one or more acres. It provides for the use of BMPs, such as silt fences, bale checks, and prompt re-vegetation, to prevent eroded sediment from leaving the construction site. The project proposer must have an erosion and sediment control plan that will provide more detail as to the specific measures to be implemented and will also address: phased construction; vehicle tracking of sediment; inspection of erosion control measures implemented; and timeframes in which erosion control measures will be implemented. The NPDES General Stormwater Permit also require adequate stormwater treatment capacity be provided to assure that water quality will not be impacted by runoff once the project is constructed. 7

8 B. DNR General Permit for Temporary Dewatering Approval of dewatering through a DNR Water Appropriation Permit is required when the amount of appropriation exceeds 10,000 gpd, or one million gallons per year. C. City of Leister Prairie Building Permit Building permits and inspections assure that the project will be constructed or installed in accordance with City ordinances and codes. 23. The MPCA finds that ongoing public regulatory authority will address any significant potential environmental effects that were identified as reasonably expected to occur. 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. 24. The fourth criterion that the MPCA must consider is "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." Minn. R , subp. 7.D (2003). The MPCA findings with respect to this criterion are set forth below. 25. The following documents were reviewed by MPCA staff as part of the potential environmental impact analysis for the proposed expansion of the WWTF. This list is not intended to be exhaustive. The MPCA also relies on information provided by the project proposer, commenters, staff experience, and other available information. EAW data; NPDES/SDS Permit file; Facility plan; Proposed effluent limitation sheet; and NPDES/SDS Permit modification application and related application submittals. 26. There are no elements of the project that pose the potential for significant environmental effects that cannot be addressed in the project design and permit development processes, or by regional and local plans. 27. Based on the environmental review, previous environmental studies, and MPCA staff expertise on similar projects, the MPCA finds that the environmental effects of the project that are reasonably expected to occur can be anticipated and controlled. 8

9 CONCLUSIONS OF LAW 28. The MPCA has jurisdiction in determining the need for an EIS for this project. The EAW, the permit development process, the facility planning process, responses prepared by MPCA staff in response to comments on the Lester Prairie Wastewater Treatment Facility Expansion EAW, and the evidence in the record are adequate to support a reasoned decision regarding the potential significant environmental effects that are reasonably expected to occur from this project. 29. Areas where the potential for significant environmental effects may have existed have been identified and appropriate mitigation measures have been incorporated into the project design and permits. The project is expected to comply with all MPCA standards. 30. Based on the criteria established in Minn. R (2003), there are no potential significant environmental effects reasonably expected to occur from the project. 31. An EIS is not required. 32. Any findings that might properly be termed conclusions and any conclusions that might properly be termed findings are hereby adopted as such. ORDER The Minnesota Pollution Control Agency determines that there are no potential significant environmental effects reasonably expected to occur from the Lester Prairie Wastewater Treatment Facility Expansion project and that there is no need for an Environmental Impact Statement. IT IS SO ORDERED Sheryl A. Corrigan, Commissioner Minnesota Pollution Control Agency Date 9

10 APPENDIX A Minnesota Pollution Control Agency (MPCA) Lester Prairie Wastewater Treatment Facility Expansion (Facility) Environmental Assessment Worksheet (EAW) LIST OF COMMENT LETTERS RECEIVED 1. Timothy J. Fell, U.S. Army Corps of Engineers. Letter received February 3, RESPONSES TO COMMENTS ON THE EAW 1. Comments by Timothy J Fell, U.S. Army Corps of Engineers. Letter received February 3, Comment 1-1: The commenter concurs with MPCA that, as currently planned, the proposed project will not discharge fill material into a wetland and therefore will not require a Department of the Army permit. Response: The comment is noted. Comment 1-2: The commenter notes that, should the project necessitate construction within the 40 foot buffer that currently separates the Facility s fence and a nearby wetland, that a wetland delineation would be advisable to ensure that there will be no wetland impacts. Response: The Plans and Specifications for construction have not yet been completed; however, the plan is to entirely avoid moving the fence and constructing closer to the wetland. If this plan is impossible and construction closer to the wetland is necessary, the city of Lester Prairie will rely on the advice and experience of their City Engineer to determine if a wetland delineation is needed. Whether the fence remains in place or is moved, construction documents will require mitigation measures such as silt fencing, as mentioned in Items 16 and 17 of the EAW. Comment 1-3: If a wetland delineation is completed and shows that the proposed project will result in wetland impacts, the proposer must submit a completed permit application to the U.S. Army Corps of Engineers. Response: The MPCA appreciates the comment and has passed it along to the proposer.