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STATE OF MINNESOTA MINNESOTA POLLUTION CONTROL AGENCY IN THE MATTER OF THE DECISION ON THE NEED FOR AN ENVIRONMENTAL IMPACT STATEMENT FOR THE PROPOSED LONG PRAIRIE MUNICIPAL WASTEWATER TREATMENT FACILITY IMPROVEMENTS CITY OF LONG PRAIRIE TODD COUNTY, MINNESOTA FINDINGS OF FACT CONCLUSIONS OF LAW AND ORDER FINDINGS OF FACT Pursuant to Minn. R. 4410.1000-4410.1600, the Minnesota Pollution Control Agency (MPCA) staff has prepared an Environmental Assessment Worksheet (EAW) for the proposed Long Prairie Municipal Wastewater Treatment Facility (WWTF) Improvements project (Project). Based on the MPCA staff environmental review, the EAW, comments and information received during the comment period, and other information in the record of the MPCA, the MPCA hereby makes the following,, and Order. Project Description 1. The city of Long Prairie (or City) currently holds two National Pollutant Discharge Elimination System/State Disposal System (NPDES/SDS) Permits to treat domestic and industrial wastewater at three separate facilities located in the same vicinity in. 2. The City owns and operates a mechanical WWTF regulated under NPDES/SDS Permit MN0066079. The mechanical facility was constructed in 2003. The facility is designed to treat a 30-day average wet weather (AWW) flow of 0.923 mgd (million gallons/day) and discharge continuously to the Long Prairie River. The mechanical WWTF replaced a City-owned three-cell stabilization pond system that was constructed in 1989 to treat primarily domestic wastewater. One of the pond cells was kept for flow equalization when the new mechanical WWTF was built. In 2003, two of the pond cells were sold to a local rendering facility, Central Bi-Products (CBP), to provide operational flexibility to the industry s wastewater system. 3. The existing mechanical WWTF consists of one 12.67-acre flow equalization pond; a mechanical fine screen used to remove sticks, rags, and other large items from the influent waste stream; vortex grit removal where flow is slowed down to allow sand, grit, and other materials to settle out; an anaerobic basin and an anoxic (oxygen deficient) basin used for biological phosphorus removal; four extended aeration basins used to reduce organic wastes, nitrify ammonia in the wastewater, and remove additional phosphorus; two final clarifiers used to remove solids from the water; disinfection with the use of a chlorine contact basin; dechlorination using sulfur dioxide; and three biosolids storage tanks for 180 days of storage. The existing mechanical WWTF discharges continuously through a 3,800-foot outfall to the Long Prairie River. 4. The second NPDES/SDS Permit (MN0020303) covers several pond systems that receive wastewater from industrial sources. The first of these facilities was constructed in 1956 to treat wastewater primarily from the Long Prairie Packing (LPP) Company. It consists of one anaerobic pond, two p-ear2-20b TDD (for hearing and speech impaired only): 651-282-5332 Printed on recycled paper containing at least 30% fibers from paper recycled by consumers
aerated ponds, and a three-cell stabilization pond system. This system treats 0.400 mgd and currently discharges on a controlled basis (spring and fall) to the Long Prairie River. A second pond system was constructed in 1975 to treat wastewater from CBP. The system was designed to treat 0.313 mgd and consists of one anaerobic pond, four aerated ponds, three holding ponds, and the two ponds purchased from the City in 2003. Originally, the CBP pond system discharged directly to the Long Prairie River; however, the controlled discharge to the river was eliminated in September 2010 and rerouted for connection to the City s mechanical WWTF. The current pond system for CBP is used as a pretreatment system prior to discharge to the City s mechanical WWTF. 5. The LPP Company currently treats its wastewater in a pond system owned and operated by the City. New, more stringent ammonia limits are being required to meet the waste load allocations needed to improve the water quality of the Long Prairie River (see Findings 33 to 36). To meet these requirements, the City proposes to expand and upgrade its existing mechanical WWTF to treat the wastewater from the LPP Company and eliminate its controlled discharge to the Long Prairie River. After completion of the upgraded and expanded mechanical WWTF and elimination of the LPP Company discharge, all waste streams will be regulated under one permit (MN0067099). The MPCA will then terminate NPDES/SDS Permit MN0020303. 6. The existing LPP Company pond system will be used as a pretreatment facility and will be owned by the LPP Company. Its stabilization pond will be used for storage and wastewater will be discharged to the upgraded mechanical WWTF for phosphorus and ammonia removal. The storage component of the treatment system will allow 210 days of storage. The stabilization pond will discharge to the upgraded mechanical WWTF during the months of April through October. Therefore, the Project includes the construction of 2,100 lineal feet of new 10-inch forcemain and a new lift station located east of the existing LPP Company pond system. 7. The proposed expansion of the existing mechanical WWTF will require the construction of a new 50- foot diameter final clarifier, an additional 5,500-gallon chlorine contact basin, three additional aerated sludge storage tanks, a lime storage silo, the installation of two additional aeration blowers and two additional sludge aeration blowers, a return activated sludge pump, and another building to house equipment. The expansion will take approximately one acre of land on property currently owned by the City north and adjacent to the existing facility. The expanded facility will have an AWW design capacity of 1.836 mgd. The existing mechanical facility s outfall pipe will be used to discharge to the Long Prairie River. Procedural History 8. Prior environmental review was conducted during the summer of 2001 for construction of the mechanical WWTF in 2002 through 2003. The MPCA was the responsible governmental unit for the Project and issued a negative declaration on the need for an Environmental Impact Statement (EIS) on July 27, 2001. 9. The City s NPDES/SDS Permit Application for the proposed Project was submitted on January 31, 2011. The Project was determined to exceed the threshold for a mandatory EAW in accordance with Minn. R. 4410.4300, subp. 18.B. 2
10. Pursuant to Minn. R. 4410.1400, an EAW was prepared by MPCA on the proposed Project. Pursuant to Minn. R. 4410.1500, the EAW was distributed to the Environmental Quality Board (EQB) mailing list and other interested parties on April 15, 2011. 11. The MPCA provided a notice of the availability of the EAW for comment. A news release was provided to media in Todd, Wadena, Morrison, Stearns, Pope, Douglas, and Otter Tail Counties, as well as other interested parties, on April 18, 2011. The notice of the availability of the EAW was published in the EQB Monitor on April 18, 2011, and the EAW was made available for review on the MPCA website at http://www.pca.state.mn.us/news/eaw/index.html. 12. The comment period for the EAW began on April 18, 2011, and ended on May 18, 2011. During the 30-day comment period, the MPCA received one comment letter from the Minnesota Department of Natural Resources and no comment letters from citizens. The one comment letter received is included as Appendix A to these findings. Criteria for Determining the Potential for Significant Environmental Effects 13. Under Minn. R. 4410.1700, the MPCA must order an Environmental Impact Statement for projects that have the potential for significant environmental effects. 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. These criteria are: A. the type, extent, and reversibility of environmental effects B. cumulative potential effects C. the extent to which the environmental effects are subject to mitigation by ongoing public regulatory authority 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 14. The first criterion that the MPCA must consider when determining if a project has the potential for significant environmental effects is the type, extent, and reversibility of environmental effects (Minn. R. 4410.1700, subp. 7. A). The MPCA findings with respect to this criterion are set forth below. 3
15. The types of impacts that may reasonably be expected to occur from the Project include the following. Air quality impacts related to construction activities Water quality impacts related to stormwater runoff Water quality impacts related to wastewater discharge 16. There were no additional issues raised during the comment period for this Project. Air quality impacts related to construction activities 17. With respect to the extent and reversibility of impacts that are reasonably expected to occur from the Project, the MPCA makes the following findings. 18. Dust emissions will temporarily increase due to excavation, earth moving, and vehicle traffic during construction. The contractor for the Project will be required to employ appropriate measures to control the amount of dust produced during construction. Operation of the expanded WWTF will not create dust. 19. Construction equipment will generate noise. These impacts will be mitigated by the use of proper muffling equipment and limiting construction activities to daylight hours. Noise is not expected to cause a significant impact due to the distances of receptors from the construction site. The expanded WWTF is not expected to increase the current noise level generated by operation of the existing facility. 20. The air quality impacts related to the generation of dust emissions and equipment noise during construction will be short-term and temporary in nature; therefore, the impacts on air quality that are reasonably expected to occur from the Project are reversible. 21. The MPCA finds that information presented in the EAW and other information in the environmental review record is adequate to address the concerns related to air quality impacts from construction activities. The impacts on air quality that are reasonably expected to occur from the proposed Project have been considered during the review process and methods to prevent significant adverse impacts have been developed. 22. 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 impacts on air quality that are reasonably expected to occur as a result of construction-related air emissions from the Project. Water quality impacts related to stormwater runoff 23. With respect to the extent and reversibility of potential water quality impacts from stormwater runoff that are reasonably expected to occur from the Project, the MPCA examined the potential for environmental effects associated with stormwater runoff and erosion during and after the construction of the expanded WWTF. Construction of the Project will affect four acres north and immediately adjacent to the existing WWTF. Three of the four acres will be returned to grassland, one-half acre will consist of lawn and landscaping, and one-half acre will be turned into impervious surfaces consisting of the new treatment units. 4
24. The City must obtain an NPDES/SDS General Stormwater Permit for Construction Activities (NPDES/SDS General Stormwater Permit) from the MPCA for this Project. This permit has specific requirements for the treatment and overall management of stormwater, including the preparation of a Stormwater Pollution Prevention Plan (SWPPP) and the development of best management practices (BMPs) to minimize impacts of stormwater runoff during construction. Soil erosion control measures must be implemented prior to the start of any construction activities. Since the Project is located within one mile of an impaired water, it must incorporate additional BMPs, as instructed in Appendix A of the general permit. 25. Stormwater runoff from the site will be routed to two stormwater infiltration basins located on the site. The stormwater infiltration basins will serve as a permanent stormwater management system for the expanded WWTF. There will be no stormwater discharged directly to any surface water. 26. The mitigation measures imposed by the NPDES/SDS General Stormwater Permit will mitigate the potential for sediment entering surface waters during construction at the WWTF site. Ongoing maintenance at WWTF and the permanent stormwater ponds will prevent significant impacts from stormwater runoff during operation of the expanded WWTF. 27. If any stormwater-related impacts during construction were to occur, they would be temporary in nature and addressed through appropriate construction stormwater BMPs; therefore, the impacts would be reversible. 28. The MPCA finds that information presented in the EAW and other information in the environmental review record is adequate to address the concerns related to water quality impacts from stormwater. The impacts on water quality from stormwater that are reasonably expected to occur from the proposed Project have been considered during the review process and methods to prevent significant adverse impacts have been developed. 29. 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 stormwater impacts on water quality that are reasonably expected to occur as a result of stormwater runoff from the Project. Water quality impacts related to wastewater discharge 30. With respect to the extent and reversibility of water quality impacts related to the discharge of wastewater that are reasonably expected to occur from the Project, the MPCA makes the following findings. 31. The expanded mechanical facility will discharge to the Long Prairie River through an existing outfall located within a reach of the Long Prairie River that has the designated use classifications 2B, 3C, 4A, 4B, 5, and 6. These classifications are established to protect the use of the river for aquatic life, recreation, industrial consumption, agriculture, wildlife, aesthetic enjoyment, navigation, and other uses. 5
32. Historical monitoring of the Long Prairie River has shown that dissolved oxygen (DO) concentrations in portions of the river intermittently fall below the minimum DO level considered necessary to support aquatic life. Periodic fish kills have been reported in the river. The MPCA conducted a Total Maximum Daily Load (TMDL) study on the Long Prairie River Watershed to assess the causes of the impairment, the contributing sources of the pollutant, and the pollutant load reductions to the river that are needed to meet the applicable water quality standards. 33. The TMDL study for the Long Prairie River Watershed was approved by the U.S. Environmental Protection Agency (EPA) on August 5, 2005. The results indicated that the water quality standard for DO could be attained by reducing ammonia levels in the Long Prairie River. The TMDL study also concluded that the loadings of oxygen demanding pollutants from the spring season controlled discharges from the industrial sources would need to be reduced. The Project will allow the City to comply with the TMDL waste load allocation by upgrading the municipal mechanical WWTF to accommodate the industrial source loadings and eliminate their controlled discharges to the Long Prairie River. 34. The proposed Project will be covered under an NPDES/SDS Permit issued by the MPCA. The NPDES/SDS Permit regulates maximum discharge flow and pollutant loadings allowed from the Long Prairie municipal WWTF. The NPDES/SDS Permit establishes effluent limitations to ensure that water quality standards and designated uses of the receiving water are protected. Load restrictions on the City s WWTF needed to meet the DO standard are also implemented through the NPDES/SDS Permit. 35. Because the Project would increase the existing AWW design flow from 0.923 mgd to 1.836 mgd, the expansion required additional review by MPCA staff under Minn. R. 7050.0185 Nondegradation requirements for all waters of the state. The nondegradation rule allows the MPCA to require additional control measures beyond the minimum needed to maintain water quality standards, and to protect receiving waters from further degradation. MPCA staff determined that the upgraded WWTF should be designed to meet effluent limits that would not cause significant increases in the mass loads of pollutants to the receiving waters. The summer concentration ammonia limit for the existing mechanical facility will be reduced from 16 milligrams per Liter (mg/l) to 5 mg/l. The direct discharge from the LPP Company to the Long Prairie River will be eliminated and the waste stream re-routed to the expanded mechanical WWTF for further treatment to remove ammonia and phosphorus. 36. The expanded mechanical WWTF will be required to meet a summer ammonia-nitrogen limit derived from the DO TMDL studies for the Long Prairie River. The assessment included the municipal sanitary waste stream plus the industrial waste streams from CBP and the LPP Company. The ammonia limit will also protect aquatic life in the Long Prairie River from ammonia toxicity. 37. The MPCA reviewed the proposed expansion to assess the need for a total phosphorus water quality based effluent limitation (WQBEL). The Project was reviewed to determine the impacts to the immediate receiving waters and downstream waters, including Lake Pepin. The MPCA determined that the expanded discharge has the reasonable potential to contribute to the impairment in Lake Pepin by excess nutrients and is, therefore, required to have a WQBEL. The expanded facility will be required to meet a 1.0 mg/l limit for total phosphorus. Since the Project will eliminate the industrial discharges that essentially received no treatment for phosphorus, there will be an overall annual load reduction of 11,966 kilograms of total phosphorus per year. 6
38. The Project was evaluated for mercury based on a reasonable potential analysis and the nondegradation requirements. Since the expanded WWTF is required to remove phosphorus to 1.0 mg/l, MPCA staff expects that the facility will also remove any mercury that is bound in the suspended solids to a significant degree. To ensure that the expanded WWTF is complying with the statewide mercury TMDL, the NPDES/SDS Permit will require influent and effluent monitoring. The permit will also require development of a Mercury Minimization Plan to determine possible sources of mercury in the collection and treatment systems with options for reducing mercury in the waste stream should it be present. 39. The NPDES/SDS Permit contains additional requirements to ensure the water quality standards of the receiving water will be met. A stringent carbonaceous biochemical oxygen demand limit will protect the receiving water during low flow conditions the expanded facility will also be required to meet a minimum effluent DO limit of 6.0 mg/l. The permit also requires the City to conduct whole effluent toxicity testing and priority pollutant scans to ensure that there is no toxicity present in the effluent. The permit will require periodic monitoring for total Kjeldahl nitrogen, nitrite + nitrate nitrogen, total dissolved solids, and a number of parameters indicating a potential salty discharge. This monitoring will be used by the MPCA to determine if the discharge has the reasonable potential to exceed a water quality standard in the receiving waters for any of these pollutants. 40. With respect to reversibility of water quality impacts, the NPDES/SDS Permit contains monitoring requirements to assure that water quality standards will be met. The MPCA finds that if monitoring indicates a reasonable potential to exceed a water quality standard, the permit can be modified and more stringent effluent limits will be imposed on the discharge. Therefore, any potential environmental effects on water quality from the discharge are expected to be reversible. 41. The MPCA finds that information presented in the EAW and other information in the environmental review record is adequate to address the concerns related to water quality impacts related to the discharge. The impacts on water quality that are reasonably expected to occur from the proposed Project have been considered during the review process and methods to prevent significant adverse impacts have been developed. 42. 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 impacts related to water quality that are reasonably expected to occur as a result of the discharge from the Project. Cumulative Potential Effects 43. The second criterion that the MPCA must consider when determining if a project has the potential for significant environmental effects is the cumulative potential effects. In making this determination, the MPCA must consider whether the cumulative potential effect is significant; whether the contribution from the project is significant when viewed in connection with other contributions to the cumulative potential effect; the degree to which the project complies with approved mitigation measures specifically designed to address the cumulative potential effects; and the efforts of the proposer to minimize the contributions from the project (Minn. R. 4410.1700 subp.7.b). The MPCA findings with respect to this criterion are set forth below. 7
44. When developing effluent limits for the NPDES/SDS Permit, the MPCA assessed the cumulative water quality effects of all sources of pollutants known to cause or contribute to a violation of water quality standards in the Long Prairie River. The proposed expansion of the Long Prairie municipal WWTF has been evaluated by MPCA staff in conjunction with the approved DO (2005) and mercury in fish tissue (2007) TMDLs, and the TMDL implementation plans that were subsequently approved by the MPCA. The effluent limitations for the proposed Project will be subject to future review and revision pending the results of the Long Prairie Major Watershed Project and intensive watershed monitoring that will address impairments, scheduled for completion in 2015. Also, more restrictive total phosphorus effluent limits may be necessary following completion of the Lake Pepin excess nutrient TMDL study and the adoption of numeric river nutrient criteria during the next triennial rulemaking session. 45. The Project proposes to expand the existing AWW design flow from 0.923 mgd to 1.836 mgd. Most of the additional flow to the mechanical WWTF results from the elimination of the direct discharge of the industrial sources, Central Bi-Products (0.313 mgd), and the Long Prairie Packing Company (0.400 mgd) to the Long Prairie River. As a result of the Project, the expanded WWTF will have 0.200 mgd of reserve capacity that will be regulated under the proposed NPDES/SDS Permit. The 0.200 mgd of new flow represents the amount allotted for future growth for residential and commercial users of the City s WWTF. The effluent limitations assigned to the expanded facility are more stringent that those now in place for the currently permitted discharges. The proposed changes in treatment and discharge of the three major waste streams will improve the quality of the receiving water. 46. The availability of expanded wastewater service will allow additional development in the Project area. An increase in development would be accompanied by increases in traffic, stormwater runoff, and solid waste generation. Potential impacts from future development can be mitigated through the implementation of local, state, and federal ordinances and regulations. 47. 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 result in significant cumulative potential environmental effects. 48. Based on information obtained from the TMDL study, operational experience, the effluent limit setting process, the permit development process, engineering plans submitted by the City s consultant, and a site visit by MPCA staff, and other information presented in the EAW, the MPCA does not expect significant cumulative effects from this Project. 49. The MPCA finds that the Project does not have the potential for significant environmental effects due to related potential cumulative effects. 8
The Extent to Which the Environmental Effects Are Subject to Mitigation by Ongoing Public Regulatory Authority 50. The third criterion that the MPCA must consider when determining if a project has the potential for significant environmental effects is "the extent to which the environmental effects are subject to mitigation by ongoing public regulatory authority" (Minn. R. 4410.1700, subp. 7.C). The MPCA findings with respect to this criterion are set forth below. 51. The following permits or approvals will be required for the Project: Unit of Government Minnesota Public Facilities Authority MPCA MPCA MPCA MPCA Todd County Permit or Approval Required Application for State Revolving Fund Program NPDES/SDS Surface Water Discharge Permit WWTF Plans and Specifications Approval NPDES/SDS General Stormwater Permit Industrial Stormwater Multi-Sector General Permit Building Permit 52. Here follows numbered paragraphs describing each permit listed above, including special conditions. 53. Minnesota Public Facilities Authority (PFA) Approval for State Revolving Loan Fund Program for Construction. In order to receive funding assistance for construction of the two additional ponds, the City must receive approval of specific submittals and technical information by both the PFA and the MPCA. 54. NPDES/SDS Surface Water Discharge 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. Effluent limitations established within the permit ensure that water quality standards and uses of the receiving water are protected. 55. WWTF Plans and Specifications Submittal. 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. 56. NPDES/SDS General Stormwater Permit for Construction Activities. A General NPDES/SDS Construction Stormwater Permit 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 proposer must have a sediment and erosion control plan that will provide more detail as to the specific measures to be implemented. The plan will also address phased construction, vehicle tracking of sediment, inspection of erosion control measures implemented, and time frames in which erosion control measures will be implemented. The general permit also requires that adequate stormwater treatment capacity be provided to assure that water quality will not be impacted by runoff once the Project is constructed. 9
57. Industrial Stormwater Multi-Sector General Permit. The Industrial Stormwater Multi-Sector General Permit covers public and private facilities with industrial activities if they fit into one of 11 categories or specific Standard Industrial Classification (SIC) Codes. The Industrial Stormwater General Permit can require the elimination or reduction of stormwater contact with potentially polluting materials, treatment of stormwater, creation of an SWPPP incorporating BMPs for managing industrial materials and activities, and monitoring of stormwater discharges to pass specific benchmarks. Some facilities may apply for a conditional exclusion from the permit if they can maintain a condition of No Exposure. 58. County Building Permit. Building permits and inspections assure that the Project will be constructed or installed in accordance with county ordinances and codes. 59. The above-listed permits include general and specific requirements for mitigation of environmental effects of the Project. The MPCA finds that the environmental effects of the Project are subject to mitigation by ongoing public regulatory authority. 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 60. 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. 4410.1700, subp. 7. D). The MPCA findings with respect to this criterion are set forth below. 61. The following documents were reviewed by MPCA staff as part of the environmental impact analysis for the proposed Project. Data presented in the EAW NPDES/SDS Surface Water Discharge Permit Application and supporting documents Effluent Limitations Summary form and attachments Long Prairie WWTF Expansion 2011 Nondegradation Review Long Prairie Watershed TMDL study and implementation plan approved August 5, 2005 Facility Plan for the city of Long Prairie Wastewater Treatment dated February 2010 Minnesota Department of Natural Resources Long Prairie River 2002 Stream Population Assessment Permits and environmental review of similar projects 62. This list is not intended to be exhaustive. The MPCA also relies on information provided by the Project proposer, persons commenting on the EAW, staff experience, and other available information obtained by staff. 63. 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. 10
APPENDIX A Minnesota Pollution Control Agency Environmental Assessment Worksheet COMMENT LETTER RECEIVED 1. Melissa Doperalski, Regional Environmental Assessment Ecologist, Minnesota Department of Natural Resources. E-mail received May 16, 2011. RESPONSES TO COMMENTS ON THE EAW 1. Comments by Melissa Doperalski, Regional Environmental Assessment Ecologist, Minnesota Department of Natural Resources. E-mail received May 16, 2011. Comment 1-1: From a natural resource perspective, the document appears to be complete and accurate and does not require the preparation of an Environmental Impact Statement. Response: No response required.
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