Please note that comment letters submitted to the MPCA do become public documents and will be part of the official public record for this project.

Transcription

1 February 27, 2004 TO: INTERESTED PARTIES RE: Enclosed is the Worksheet (EAW) for the proposed Byron Wastewater Treatment Plant Improvements, Olmsted County. The EAW was prepared by the Minnesota Pollution Control Agency (MPCA) and is being distributed for a 30-day review and comment period pursuant to the Environmental Quality Board (EQB) rules. The comment period will begin the day the EAW availability notice is published in the EQB Monitor, which will likely occur in the March 1, 2004, issue. Comments received on the EAW will be used by the MPCA in evaluating the potential for significant environmental effects from this project and deciding on the need for an Environmental Impact Statement (EIS). A final decision on the need for an EIS will be made by the MPCA Commissioner after the end of the comment period. If a request for an EIS is received during the comment period, or if the Commissioner recommends the preparation of an EIS, the MPCA Citizens Board (Board) will make the final decision. The final EIS need decision will also be made by the Board if so requested by the project proposer, other interested parties or MPCA staff and if this request is agreed to by one or more members of the Board or the MPCA Commissioner. The Board meets once a month, usually the fourth Tuesday of each month, at the MPCA office in St. Paul. Meetings are open to the public and interested persons may offer testimony on Board agenda items. A listing of Board members is available on request by calling (651) Please note that comment letters submitted to the MPCA do become public documents and will be part of the official public record for this project. If you have any questions on the EAW, please contact Denise Leezer of my staff at (651) Sincerely, Beth G. Lockwood Supervisor, Environmental Review Unit Operations and Environmental Review Section Regional Environmental Management Division BGL:gs Enclosure

2 ENVIRONMENTAL ASSESSMENT WORKSHEET Note to reviewers: The Worksheet (EAW) provides information about a project that may have the potential for significant environmental effects. This EAW was prepared by the Minnesota Pollution Control Agency (MPCA), acting as the Responsible Governmental Unit (RGU), to determine whether an Environmental Impact Statement (EIS) should be prepared. The project proposer supplied reasonably accessible data for, but did not complete the final worksheet. Comments on the EAW must be submitted to the MPCA during the 30-day comment period which begins with notice of the availability of the EAW in the Minnesota Environmental Quality Board (EQB) Monitor. Comments on the EAW should address the accuracy and completeness of information, potential impacts that are reasonably expected to occur that warrant further investigation, and the need for an EIS. A copy of the EAW may be obtained from the MPCA by calling (651) An electronic version of the completed EAW is available at the MPCA Web site 1. Project Title: 2. Proposer: City of Byron 3. RGU: Minnesota Pollution Control Agency Contact Person Gerald Henricks Contact Person Denise M. Leezer and Title City Administrator and Title Project Manager Address 11 4th Street Northwest Address 520 Lafayette Road North P.O. Box 1137 St. Paul, MN Byron, MN Phone 507/ Phone 651/ Fax 507/ Fax 651/ Reason for EAW Preparation: EIS Scoping Mandatory EAW X Citizen Petition RGU Discretion Proposer Volunteered If EAW or EIS is mandatory give EQB rule category subpart number and name: Minn. R , subp.18b 5. Project Location: County Olmsted City/Twp Byron/Kalmar SW 1/4 SW 1/4 Section 20 Township T107N Range R15W Figures attached to the EAW: Figure 1. State and county map showing the general location of the project; Figure 2. Site plan showing all significant project features; Figure 3. U. S. Geological Survey Quad Map; Figure 4. Soils Survey Map; Figure 5. Wetland Classification Map; TDD (for hearing and speech impaired only): (651) Printed on recycled paper containing 30% fibers from paper recycled by consumers

3 Figure 6. Sanitary Sewer Service Area Map; Figure 7. Minnesota Department of Natural Resources (DNR) Natural Heritage and Nongame Research; and Figure 8. Minnesota Historical Society correspondence 6. Description: a. Provide a project summary of 50 words or less to be published in the EQB Monitor. The city of Byron (City) is proposing to expand the existing wastewater treatment facility s (WWTF) mechanical plant system, located in Section 20 of Olmsted County. The proposed expansion will increase the current capacity by 0.88 million gallons per day (MGD), for a total design flow of 1.40 MGD. The effluent will continue to follow the existing route; discharging to an unnamed creek which flows approximately 2.0 miles into South Branch Middle Fork Zumbro River and then to Shady Lake and Zumbro Lake. The WWTF will limit the discharge concentration of phosphorus to one milligram per liter (mg/l). b. Give a complete description of the proposed project and related new construction. Attach additional sheets as necessary. Emphasize construction, operation methods and features that will cause physical manipulation of the environment or will produce wastes. Include modifications to existing equipment or industrial processes and significant demolition, removal or remodeling of existing structures. Indicate the timing and duration of construction activities. Background: The existing Byron WWTF was constructed in 1983 and It is designed to treat an average flow of 0.52 MGD and a peak flow of 1.28 MGD. Wastewater was originally conveyed to the treatment facility by two interceptor sewers. A third interceptor sewer was constructed the summer of The facility plans indicate that the existing treatment system consists of a bar screen, aerated grit chamber, preaeration basin, two primary settling tanks, two roughing trickling filters, two intermediate settling tanks, two aeration basins, two secondary settling tanks, chlorination facilities, anaerobic digester, and approximately 1,150 feet of outfall sewer. The WWTF has a continuous discharge (SD001, formerly Discharge 010) to an unnamed creek (class 7 water) and is designed to treat an average flow of up to 520,000 gallons per day with 5-day biochemical oxygen demand (CBOD 5 ) strength of 182 mg/l. Proposed WWTF Expansion: Modifications to the existing WWTF will be necessary to meet the new effluent requirements and the future hydraulic and organic loading projections. The proposed modifications include replacing: the existing preliminary treatment equipment (including the flow measurement equipment), the mechanical bar screen, the grit collection system, and the filter media in the existing trickling filter. The project also includes replacing the two existing primary clarifiers with two new clarifiers. The additional new equipment will include: one additional trickling filter, two intermediate clarifiers, two aeration basins, two final clarifiers, phosphorus removal equipment, a biosolids storage tank, and a second outfall line parallel to the existing outfall. The proposed WWTF will be a class A facility. Byron, Minnesota 2 Worksheet

4 c. Explain the project purpose; if the project will be carried out by a governmental unit, explain the need for the project and identify its beneficiaries. The purpose of this project is to provide wastewater treatment service to existing and new development in the City and surrounding areas, and to protect water quality in the Zumbro River and local tributaries. The current treatment system is not designed to treat projected flows and loads. The beneficiaries of the project are the current and future residents of the City, as well as current and future commercial and industrial users located in the City. The expansion will enable the construction of residential, commercial, and light industrial developments. d. Are future stages of this development including development on any outlots planned or likely to happen? Yes No If yes, briefly describe future stages, relationship to present project, timeline and plans for environmental review. A site map (Figure 7) is attached designating the anticipated growth regions with interceptor sewers and lift stations required for providing service. The expansion area will not be fully developed by the end of the 20-year planning period. It is estimated that it will take approximately 30 to 35 years for an area of this size to be developed at current population growth rates. (See Section 29, Cumulative Impacts, for further discussion of future development.) e. Is this project a subsequent stage of an earlier project? Yes No If yes, briefly describe the past development, timeline and any past environmental review. The existing WWTF was constructed in 1983 and 1984, along with two sewer interceptors. Waste water was delivered to the WWTF by the two interceptors until the summer of 2002, when one additional interceptor sewer line was constructed. A fourth interceptor sewer line has been proposed. 7. Project Magnitude Data Total Project Area (acres) 4 (WWTF Site) or Length (miles) 0.20 (1040 ft.) (outfall sewer) Number of Residential Units: Unattached 0 Attached 0 maximum units per building 0 Commercial/Industrial/Institutional Building Area (gross floor space): total square feet 25,000 Indicate area of specific uses (in square feet): Office 1325 Manufacturing 0 Retail 0 Other Industrial 5175 Warehouse 0 Institutional 0 Light Industrial 0 Agricultural 0 Other Commercial (WWTF process tanks) 18,500 Building height ~18 max If over 2 stories, compare to heights of nearby buildings NA Note: The WWTF site is located on a portion of a City owned 33 acre parcel. Byron, Minnesota 3 Worksheet

5 8. Permits and approvals required. List all known local, state and federal permits, approvals and financial assistance for the project. Include modifications of any existing permits, governmental review of plans, and all direct and indirect forms of public financial assistance including bond guarantees, Tax Increment Financing and infrastructure. Unit of Government Type of Application Status MPCA Plans and Specifications Submitted MPCA National Pollutant Discharge Elimination System Submitted (NPDES) Permit for a discharge to receiving waters MPCA NPDES General Stormwater Construction Permit To be submitted MPCA NPDES Phase II Permit Requirements To be submitted City of Byron Building Permit To be submitted 9. Land use. Describe current and recent past land use and development on the site and on adjacent lands. Discuss project compatibility with adjacent and nearby land uses. Indicate whether any potential conflicts involve environmental matters. Identify any potential environmental hazards due to past site uses, such as soil contamination or abandoned storage tanks, or proximity to nearby hazardous liquid or gas pipelines. The existing site has been used as a WWTF since Land to the north and west of the site is agricultural. Land to the south and east is a newly developed golf course, with residential units included on the land to the east. Future plans include construction of soccer fields on City property immediately east of the WWTF site. There are no known environmental concerns regarding past land use, such as underground or above ground storage tanks and unauthorized filling or dumping. There are currently no known environmental contamination issues in the area of the proposed construction. 10. Cover Types. Estimate the acreage of the site with each of the following cover types before and after development: Before After Before After Types 1-8 wetlands 0 0 Lawn/landscaping Wooded/forest Impervious Surfaces Brush/grassland Other (describe) Cropland 0 0 TOTAL 4 4 Note: Other includes Process Tanks and Equipment. 11. Fish, Wildlife, and Ecologically Sensitive Resources. a. Identify fish and wildlife resources and habitats on or near the site and describe how they would be affected by the project. Describe any measures to be taken to minimize or avoid impacts. No significant or long-term impacts are expected as a result of the project. There are no fish habitat areas within the project limits. Small grass/brush land areas near the site provide cover and nesting for small birds and game and are not anticipated to be affected by construction. The WWTF site is, and would continue to be, fenced. NPDES Permit guidelines and regulations will be strictly followed to prevent excess runoff from leaving the site. Byron, Minnesota 4 Worksheet

6 Since the project will enable the development of portions of the City, there will be an alteration of previously undeveloped areas. This conversion will result in a reduction in the species diversity, a reduction in the populations of individual species, and a conversion of types of resident species to those that are more tolerant of humans. Some species will be extirpated from the area if their habitat is eliminated. b. Are any state (endangered or threatened) species, rare plant communities or other sensitive ecological resources such as native prairie habitat, colonial waterbird nesting colonies or regionally rare plant communities on or near the site? Yes No If yes, describe the resource and how it would be affected by the project. Indicate if a site survey of the resources has been conducted and describe the results. If the DNR Natural Heritage and Nongame Research program has been contacted give the correspondence reference number. ERDB Describe measures to minimize or avoid adverse impacts. Based on the DNR Natural Heritage database review, there are 12 known occurrences of rare species or natural communities within a one-mile radius of the project area. Several of the rare feature occurrences represent fresh water mussels. Freshwater mussels are declining nation-wide and have been described as one of North America s most imperiled groups of animals. The primary reason behind the decline is the degradation of lakes and rivers as a result of runoff and physical changes. The proposed WWTF will operate under required new NPDES discharge limits which were developed to protect the water use classification listed in Minnesota Rules. 12. Physical Impacts on Water Resources. Will the project involve the physical or hydrologic alteration (dredging, filling, stream diversion, outfall structure, diking, and impoundment) of any surface waters such as a lake, pond, wetland, stream or drainage ditch? Yes No If yes, identify water resource affected. Describe alternatives considered and proposed mitigation measures to minimize impacts. Give the DNR Protected Waters Inventory (PWI) number(s) if the water resources affected are on the PWI. The existing outfall to an unnamed creek will not be changed 13. Water Use. Will the project involve installation or abandonment of any water wells, connection to or changes in any public water supply or appropriation of any ground or surface water (including dewatering)? Yes No If yes, as applicable, give location and purpose of any new wells; public supply affected, changes to be made, and water quantities to be used; the source, duration, quantity and purpose of any appropriations; and unique well numbers and DNR appropriation permit numbers, if known. Identify any existing and new wells on the site map. If there are no wells known on site, explain methodology used to determine. The City owns one existing well on the site, which is used to provide potable water at the WWTF. Capacity of the existing well is approximately 45 gallons per minute. Byron, Minnesota 5 Worksheet

7 14. Water-related land use management districts. Does any part of the project involve a shoreland zoning district, a delineated 100-year flood plain, or a state or federally designated wild or scenic river land use district? Yes No If yes, identify the district and discuss project compatibility with district land use restrictions. Portions of the existing WWTF lie within the 100-year flood plain. All structures are, and all new structures will be, built above the 100-year flood elevation. The outfall sewer also crosses the 100-year flood plain. Since the outfall pipe is installed underground, and existing surface elevations will be restored, no alteration of the flood plain is anticipated. Erosion control methods will be implemented throughout construction. Upon completion, vegetative cover will be reestablished in all disturbed areas. 15. Water Surface Use. Will the project change the number or type of watercraft on any water body? Yes No If yes, indicate the current and projected watercraft usage and discuss any potential overcrowding or conflicts with other uses. 16. Erosion and Sedimentation. Give the acreage to be graded or excavated and the cubic yards of soil to be moved: 1 acres; 100,000 cubic yards. Describe any steep slopes or highly erodible soils and identify them on the site map. Describe any erosion and sedimentation control measures to be used during and after project construction. This project will require a NPDES General Stormwater Permit for construction activity. Erosion control will be maintained throughout construction at the WWTF site and along the outfall sewer. This includes permanent and temporary sediment and erosion control measures to reduce and eliminate erosion and keep sediment on site during and after construction. This can be achieved by implementing best management practices on the project as a part of the temporary and permanent erosion control measures. These practices include removing accumulated sediment and repairing or replacing damaged and deteriorated erosion control devices. Temporary erosion control devices may include silt fence, straw bales, and storm sewer inlet protection. Additional erosion controls methods for steep slopes or highly erodible soils are not expected to be necessary during the construction process. 17. Water Quality - Surface Water Runoff. a. Compare the quantity and quality of site runoff before and after the project. Describe permanent controls to manage or treat runoff. Describe any stormwater pollution prevention plans. All areas disturbed by construction will be returned to pre-construction condition. Construction site best management practices will be employed for managing and treating site runoff during construction. No significant long or short-term impacts are expected. There will not be a significant increase in impermeable surfaces at the site following construction. b. Identify routes and receiving water bodies for runoff from the site; include major downstream water bodies as well as the immediate receiving waters. Estimate impact runoff on the quality of receiving waters. The majority of the stormwater generated at the WWTF will be directed into a drainage ditch and infiltrated through the soil into the ground water at the site. Any remaining stormwater runoff will be routed to wetlands or grassy areas adjacent to the plant or into an unnamed creek that flows approximately two miles into the south branch of the middle fork of the Zumbro River. No adverse effects are anticipated as a result of surface-water runoff. Extreme precipitation events may cause Byron, Minnesota 6 Worksheet

8 the discharge of greater volumes of plant runoff; however, these discharges will be infrequent and will be under the requirements of the NPDES General Stormwater Permit. 18. Water Quality Wastewater. a. Describe sources, composition and quantities of all sanitary, municipal and industrial wastewater produced or treated at the site. The proposed WWTF will receive domestic and limited industrial wastewater from the City. The WWTF would be designed to treat an average flow of 0.96 MGD with incoming loads as follows: CBOD 5, of 1, 632 pound per day and total suspended solids (TSS) of 1,920 pounds per day. b. Describe waste treatment methods or pollution prevention efforts and give estimates of composition after treatment. Identify receiving waters, including major downstream water bodies, and estimate the discharge impact on the quality of receiving waters. If the project involves on-site sewage systems, discuss the suitability of site conditions for such systems. The treatment process begins with preliminary treatment. Raw wastewater enters the preliminary treatment building from the interceptor sewers. Preliminary treatment consists of screening and grit removal to remove material from the raw wastewater which could clog, damage, or cause unusual wear to pumps or other equipment located downstream. Typical materials removed in this process include: rags, sticks, pieces of metal, glass, sand, and stones. After preliminary treatment, the wastewater flows by gravity to the primary clarifier distribution box. The flow is then equally distributed to each primary clarifier to remove floatable material and settleable solids. Primary clarifiers typically remove 40 percent to 70 percent of the suspended solids. The clarified wastewater then flows upward and into the influent stilling well where it flows radially outward and flows upward and out over the perimeter effluent weir. The clarified wastewater is then collected in the circular trough and is carried, via pipe, to the trickling filter. The solids that settle to the bottom of each primary clarifier are continuously scraped to a sludge hopper in the bottom of the clarifier. The sludge is then pumped to the anaerobic digester for further treatment. Floatable solids, such as grease and scum, are collected by surface skimmers. The surface skimmers deposit the floatable solids into the scum box. The clarified wastewater then enters the trickling filter distribution system where it is split at the head of the filter into two headers. Each header is comprised of 12 flow distributors that distribute the wastewater evenly over the filters plastic media. The wastewater then trickles downward through the plastic media covered by biological growths (algae, bacteria and slimes). The biological growth absorbs and utilizes suspended colloidal and dissolved organic matter from the wastewater. Oxygen is supplied from the dissolved oxygen in the wastewater and from circulation of air through the interspaces between the media. The wastewater is collected, along with fine sludge particles that are washed of the media, in the filter underdrains. The wastewater then flows into an effluent pipe to the intermediate clarifier distribution box. Wastewater entering the intermediate clarifier distribution box is equally divided to each intermediate clarifier. The wastewater then flows upward through a center column and into a stilling well. The stilling well provides equal distribution of the incoming wastewater outward from the Byron, Minnesota 7 Worksheet

9 center of the clarifiers. The solids in the wastewater settle to the bottom and the clarified wastewater passes over a weir located near the perimeter of the clarifier. Clarified wastewater is collected in the circular effluent trough and enters the aeration basin distribution box from the intermediate clarifiers. At this distribution box, the flow is again divided equally to each aeration basin. In the activated sludge process, wastewater is mixed in the aeration tank with biologically active sludge and air. The tank provides an environment where microorganisms in the sludge can grow in population and feed on the organic material in the wastewater, converting it into insoluble settleable solids called activated sludge. Air is introduced into the mixed liquor through air-jet type diffusers to dissolve the air in the mixed liquor. The mixed liquor is a combination of wastewater and activated liquid sludge. The activated sludge, influent wastewater, and air are all thoroughly mixed in the aeration basin for a sufficient time to treat the wastewater. The activated sludge mixture then flows into the final clarifiers through a center pipe. Ports in the center pier discharge the wastewater into a center well which distributes it at a low velocity in the final clarifier. The wastewater flows downward and out into the final clarifier from the center well and moves upward and out from the center to the perimeter of the final clarifier. The clarified water flows out through the effluent trough and into an outlet box. The settleable material falls to the floor, which slopes toward the center of the clarifier to a sludge sump. A sludge collector scrapes the settled sludge to the center sludge collection sump. The activated sludge collected in the sludge sump can be pumped to three different locations. The sludge can also be recirculated to the primary clarifier influent line for settling and disposal to the primary digester and can be used to bring any microorganism still in the activated sludge back in contact with waste. The sludge can also be recirculated back into the aeration basins. The third place the activated sludge can be pumped is the primary digester. The wastewater leaving the final clarifier outlet box flows to the chlorination manhole for final treatment. At the chlorination manhole, a chlorine solution is added to the effluent by a submerged diffuser. The purpose of disinfection is to kill any harmful bacteria which may be present in the effluent before it is discharged. The anaerobic digester receives sludge from the primary and final clarifiers for further treatment. It also receives scum collected by the primary, intermediate, and final clarifiers. Anaerobic sludge digestion is a process used to decompose complex organic materials into more stable end products, such as methane gas, a relatively inert solids mass, and water. The secondary digester is used for storage of digested sludge and methane gas produced in the primary digester. The biosolids are then land applied. The WWTF is being designed to comply with the effluent limits to be contained in its NPDES Permit. Effluent limits, according to the preliminary effluent limits determination, are as follows: Design Average Wet Weather Flow: Design Average Dry Weather Flow: Carbonaceous Biochemical Oxygen Demand (CBOD 5 ): TSS: 1.40 MGD 0.74 MGD 15 mg/l 30 mg/l Byron, Minnesota 8 Worksheet

10 Ammonia (N): June 1 September 30 October 1 November 30 December 1 March 31 April 1 May mg/l 21.0 mg/l N/A mg/l N/A mg/l ph (Standard Unit): Total Phosphorous: 1.0 mg/l The WWTF discharges to an unnamed creek, flows approximately 2.0 miles into South Branch Middle Fork Zumbro River, and then to Shady Lake and Zumbro Lake. The unnamed creek has been assigned water use classifications of 7, 3C, 4A, 4B, 5, and 6 under MPCA rules. The South Branch Middle Fork has been assigned water use classifications of 2B, 3B, 4A, 4B, 5, and 6. These multiple classifications include consideration for aquatic life and recreation, industrial consumption, agriculture and wildlife, aesthetic enjoyment and navigation, and other beneficial uses not listed. c. If wastes will be discharged into a publicly owned treatment facility, identify the facility, describe any pretreatment provisions and discuss the facility s ability to handle the volume and composition of wastes, identifying any improvements necessary. The project is a publicly owned WWTF. d. If the project requires disposal of liquid animal manure, describe disposal technique and location and discuss capacity to handle the volume and composition of manure. Identify any improvements necessary. Describe any required setbacks for land disposal systems. NA 19. Geologic hazards and soil conditions. a. Approximate depth (in feet) to Ground water: 8 minimum; 12 average. Bedrock: >26 minimum; average. Describe any of the following geologic site hazards to ground water and also identify them on the site map: sinkholes, shallow limestone formations or karst conditions. Describe measures to avoid or minimize environmental problems due to any of these hazards. None identified. b. Describe the soils on the site, giving SCS classifications, if known. Discuss soil granularity and potential for groundwater contamination from wastes or chemicals spread or spilled onto the soils. Discuss any mitigation measures to prevent such contamination. The general site profile consists of topsoil overlying various interbedded alluvial and glacial tills. Dark brown clayey silt topsoil is present at depths up to two feet. Beneath the topsoil, soils consist of silt, clayey silt fine alluvium, silty sand, sand coarse alluvium, sandy silt, clayey sand, sandy clay mixed alluvium, lean clay, and sandy clay glacial till soils. These soils are very loose to very dense for the noncohesive soils and soft to stiff for the cohesive soils. Generally, the stiff and very dense soils are found at greater depth. Byron, Minnesota 9 Worksheet

11 Soil Classifications: 322C Timula Silt Loam 369B, C Waubeek Silt Loam 401C2 Mt. Carroll Silt Loam 468 Otter Silt Loam 477B Littleton Silt Loam 516C Dowagiac Sandy Loam 1846 Kato Silt Clay Loam The ground-water table at the site varies and was measured at 8 feet to 16 feet below the surface. Ground-water level variations can be expected as seasonal and annual fluctuations occur. Any accidental spills of controlled substances due to construction activities will be cleaned up quickly and thoroughly by the contractor to protect soil and ground water from contamination. 20. Solid Wastes, Hazardous Wastes, Storage Tanks. a. Describe types, amounts and compositions of solid or hazardous wastes, including solid animal manure, sludge and ash, produced during construction and operation. Identify method and location of disposal. For projects generating municipal solid waste, indicate if there is a source separation plan; describe how the project will be modified for recycling. If hazardous waste is generated, indicate if there is a hazardous waste minimization plan and routine hazardous waste reduction assessments. During the expansion of the WWTF certain portions of the existing plant may be demolished. If so, all such demolition debris will be managed in accordance with the appropriate Minnesota solid waste regulations. The Byron WWTF will generate biosolids as a byproduct of the wastewater treatment process. All biosolids will be stored and treated on site until they can be disposed of by land application. Sludge is stabilized in one primary anaerobic digester and one secondary anaerobic digester. Grit and screenings from the pretreatment of influent will be washed, dried, and hauled to an approved sanitary landfill. Operations at the WWTF generate small volumes of hazardous waste (e.g. waste oils and lubricants) as part of routine maintenance and operation of the treatment equipment. All such wastes will be stored and contained in accordance with state and local Hazardous Waste Rules and Ordinances and the WWTF s existing County Hazardous Waste License. b. Identify any toxic or hazardous materials to be used or present at the site and identify measures to be used to prevent them from contaminating groundwater. If the use of toxic or hazardous materials will lead to a regulated waste, discharge or emission, discuss any alternatives considered to minimize or eliminate the waste, discharge or emission. The current Byron WWTF uses chlorine gas for disinfection and will continue its use following expansion. The WWTF will also begin the use of ferric chloride for phosphorous removal. These chemicals will be stored in a heated chemical building with a cement floor and secondary containment structures according to all state rules and regulations. Byron, Minnesota 10 Worksheet

12 c. Indicate the number, location, size and use of any above or below ground tanks to store petroleum products or other materials, except water. Describe any emergency response containment plans. An existing underground fuel oil storage tank is to be removed as part of this project. One additional above ground LP storage tank will be constructed at the site. Any below ground storage tank with a volume greater than 110 gallons will be subject to the requirements of Minn. R. ch Any above-ground storage tank with a capacity greater than 500 gallons within 500 feet of Class 2 water (or any above ground tank with a capacity greater than 1,100 gallons) will be subject to the requirements of Minn. R. ch Traffic. Parking spaces added: 0 Existing spaces (if project involves expansion): Estimated total average daily traffic generated: NA Estimated maximum peak hour traffic generated (if known) and its timing: NA Provide an estimate of the impact on traffic congestion affected roads and describe any traffic improvements necessary. If the project is within the Twin Cities metropolitan area, discuss its impact on the regional transportation system. No significant increases in traffic volumes or congestion are anticipated. The access to the WWTF is sufficient and will be restored to its original state upon project completion. 22. Vehicle-related Air Emissions. Estimate the effect of the project s traffic generation on air quality, including carbon monoxide levels. Discuss the effect of traffic improvements or other mitigation measures on air quality impacts. Note: If the project involves 500 or more parking spaces, consult EAW Guidelines about whether a detailed air quality analysis is needed. Vehicle emissions in the vicinity of the project would not measurably increase. However, residential development enabled by the completion of this project may result in measurable, but not significant impacts. If traffic increases result in future deterioration in levels of service or air quality violations, there are mitigative measures, such as roadway improvements and signal installation to bring the community into compliance. 23. Stationary Source Air Emissions. Describe the type, sources, quantities and compositions of any emissions from stationary sources of air emissions such as boilers, exhaust stacks or fugitive dust sources. Include any hazardous air pollutants (consult EAW Guidelines for a listing), any greenhouse gases (such as carbon dioxide, methane, and nitrous oxides), and ozone-depleting chemicals (chlorofluorocarbons, hydrofluorocarbons, perfluorocarbons or sulfur hexafluoride). Also describe any proposed pollution prevention techniques and proposed air pollution control devices. Describe the impacts on air quality. The WWTF will have a building heating system or systems. Heat will be provided by unit heaters and/or small boiler systems that will use natural gas. Digester (methane) gas generated during the wastewater treatment process will be burned off using open flame at the site. These systems do not generate significantly different emissions relative to each other and are not expected to require an air permit. Diesel fuel generators will be used for emergency power as well as peak usage control/saving. The City has an agreement with the local power utility to reduce power cost for the WWTF. Air emissions from the use of the emergency standby generator are not considered to be significant. Byron, Minnesota 11 Worksheet

13 24. Odors, noise and dust. Will the project generate odors, noise or dust during construction or during operation? Yes No If yes, describe sources, characteristics, duration, quantities or intensity and any proposed measures to mitigate adverse impacts. Also identify locations of nearby sensitive receptors and estimate impacts on them. Discuss potential impacts on human health or quality of life. (Note: fugitive dust generated by operations may be discussed at item 23 instead of here.) Dust and noise will be generated during construction. Both dust and noise will be controlled to every extent possible. Water trucks will be used during dry or windy conditions and construction noise will be limited to daylight hours. Permanent vegetation will be established both as an erosion control measure and to minimize dust generation after construction is complete. Odors from the existing WWTF have not been an issue and are not expected to be generated as a result of construction or the expansion. 25. Nearby resources. Are any of the following resources on or in proximity to the site? a. Archaeological, historical, or architectural resources? Yes No b. Prime or unique farmlands or land within an agricultural preserve? Yes No c. Designated parks, recreation areas, or trails? Yes No d. Scenic views and vistas? Yes No e. Other unique resources? Yes No If yes, describe the resource and identify any project-related impacts on the resources. Describe any measures to minimize or avoid adverse impacts. According to the State Historic Preservation Office databases, there are no recorded archaeological sites in this area. One documented structure, Bridge No. L-6286 on Township Road 247, exists in Section T107 R15 S20, but is not located within the project area. 26. Visual impacts. Will the project create adverse visual impacts during construction or operation? Such as glare from intense lights, lights visible in wilderness areas and large visible plumes from cooling towers or exhaust stacks? Yes No If yes, explain. The expanded WWTF will be at the same site as the existing plant, and despite its increased size, is anticipated to have a similar impact on the visual quality of the area. 27. Compatibility with plans and land use regulations. Is the project subject to an adopted local comprehensive plan, land use plan or regulation, or other applicable land use, water, or resource management plan of a local, regional, state or federal agency? Yes No If yes, describe the plan, discuss its compatibility with the project and explain how any conflicts will be resolved. If no, explain. The plan is consistent with both the City s land use plan and comprehensive plan. There are no known conflicts. Byron, Minnesota 12 Worksheet

14 The project also follows the City s Stormwater Management Plan, developed in March This project will not have a significant impact on the amount of stormwater runoff generated at the site. Any new secondary development would be required to be in accordance with the City s Stormwater Management Plan. The City s Stormwater Management Plan was developed in March 1997 and is currently under revision. All necessary erosion control measures, including retention/detention ponds would be implemented as part of any new development. 28. Impact on infrastructure and public services. Will new or expanded utilities, roads, other infrastructure or public services be required to serve the project? Yes No If yes, describe the new or additional infrastructure or services needed. (Note: any infrastructure that is a connected action with respect to the project must be assessed in the EAW; see EAW Guidelines for details.) 29. Cumulative impacts. Minn. R , subp. 7, item B requires that the RGU consider the cumulative potential effects of related or anticipated future projects when determining the need for an environmental impact statement. Identify any past, present or reasonably foreseeable future projects that may interact with the project described in this EAW in such a way as to cause cumulative impacts. Describe the nature of the cumulative impacts and summarize any other available information relevant to determining whether there is potential for significant environmental effects due to cumulative impacts (or discuss each cumulative impact under appropriate item(s) elsewhere on this form). Increased Demands on and for Infrastructure The expanded WWTF is intended to support new development within the service area. As a result of increased development, there will be increased pressures on infrastructure such as streets and roads, municipal water and sewer lines, natural gas, electricity, and telephone and cable services, schools, fire and police protection, emergency medical services and stormwater collection and treatment. Increased commuting has already resulted in demands for major highway construction. Stormwater Runoff Storm-water runoff volume and velocity will increase as a result of increases in impervious surfaces (roadways, parking lots, rooftops, driveways, sidewalks, etc.) as a result of development. This can in turn result in flooding. Stormwater runoff will entrain pollutants as it makes contact with pavement, and natural surfaces (especially in the first half-inch of rainfall). If runoff velocity is high or prolonged, it can cause erosion, entrain sediment, and rainfall on parking lots can be raised in temperature. The adverse impacts of stormwater runoff include increased pollutant loading of lakes and streams, erosion and sedimentation, and even thermal pollution. Adequate stormwater controls must be implemented by cities. The facilities constructed in this project are to serve existing and new development and to protect water quality in the local watershed. New construction would be in accordance with current zoning and land use requirements. It is anticipated that a new West Interceptor Sewer will be constructed sometime following completion of this project to facilitate new development to the west of the City. A sewer extension permit will be required in conjunction with this project. The East Interceptor Sewer and Sanitary Lift Station have already been constructed in conjunction with the Somerby Golf Course development. The development is consistent with the City s land use plan. Water Quality The WWTF discharges to an unnamed creek, flows approximately 2.0 miles into South Branch Middle Fork Zumbro River, and then to Shady Lake and Zumbro Lake. Consideration of a phosphorous effluent limit was made based on eutrophocation impacts on Zumbro Lake. Lake Zumbro is managed as a centrarchid lake by the Minnesota Department of Natural Resources and is used for recreational purposes. It is one of the few multi-purpose recreational lakes in the Rochester area. Efforts are currently underway to reduce nutrient loadings and improve the trophic status of Lake Zumbro. Recent lake water quality Byron, Minnesota 13 Worksheet

15 data suggest that the lake is improving, largely as a result of point source effluent phosphorous limitations that have been applied to the watershed. Proposed Sewer Extensions A site map (Figure 7) is attached showing the anticipated growth regions with interceptor sewers and lift stations required for providing service. The site map identifies an approximate 50-acre region, northeast of the City, designated as a non-serviceable area. Approximately 40-acres, of this 50-acre area, have been designated for Somerby Golf Course. This rest of the area is a low lying wetland, designated nonserviceable because the existing Interceptor Sewer is too shallow to accept flows from this region. The area is also outside the drainage area of the proposed interceptor sewers, eliminating the possibility of sending wastewater from this area to a proposed interceptor sewer without the use of a lift station. The expansion area will not be fully developed by the end of the 20-year planning period. It is estimated that it will take approximately 30 to 35 years for an area of this size to be developed at current population growth rates. Service Area A The Proposed West Interceptor Sewer serving Service Area A will collect wastewater from the northwest anticipated growth area and carry it to the existing WWTF. According to the April 2000 Land Use Plan, this service area consists of approximately 660 acres of land with 480 acres planned for low density residential growth, 10 acres planned for medium density residential growth, 160 acres planned for light industrial growth and 10 acres planned for public land. Based on the criteria for estimating flow, this area would generate approximately 2,840 gallons per minute (gpm) of wastewater when the area is fully developed. Service Area B The existing Northeast Interceptor Sewer serving Service Area B collects wastewater from the northeast anticipated growth area and sends it to the existing East Interceptor Sewer. According to the April 2000 Land Use Plan, Service Area B consists of approximately 450 acres of land with 400 acres planned for low density residential growth and 50 acres designated for Somerby Golf Course. Based on the criteria for estimating flow, this area would produce a peak wastewater flow of 1,200 gpm when the area is fully developed. Service Area C The existing East Interceptor sewer in Service Area C collects wastewater and sends it to the WWTF. According to the April 2000 Land Use Plan, this service area consists of approximately 480 acres of land with 400 acres planned for low density residential growth, 10 acres planned for medium density residential growth, 10 acres planned for high density residential growth, 10 acres planned for commercial growth, 10 acres planned for public land, and 40 acres designated for Somerby Golf Course. Based on the criteria for estimating flow, this area would produce a peak wastewater flow of 1,390 gpm when the area is fully developed. Byron, Minnesota 14 Worksheet

16 Service Area D Service Area D has an area of approximately 135 acres. Development of Area D is part of the Byron Town Square project. According to the April 2000 Land Use Plan, Service Area D consists of approximately 70 acres planned for commercial growth, 50 acres planned for low density residential growth, 10 acres planned for high density residential growth, and 5 acres of public land. Based on the criteria for estimating flow, this area will produce a peak wastewater flow of approximately 790 gpm. Service Area D is located outside the gravity service area in which the WWTF is located. Therefore, a lift station is required to pump wastewater across the drainage divide to the existing East Interceptor Sewer. Existing Lift Station No. 4 The wastewater from the East and West Interceptor Sewers will be entering the WWTF at an elevation lower than the existing influent line. Existing Lift Station No. 4 is required to pump the wastewater to the existing WWTF headworks. The lift station must be sized to handle the peak flows from all three proposed interceptor sewers. The sum of the peak hydraulic loads from all interceptor sewers is approximately 6,220 gpm. Wastewater flows from Regions A, B, C, and D will increase as development occurs. The full capacity of Lift Station No. 4 will not be needed until all four regions are fully developed. It is recommended the City increase the capacity of the lift station as the hydraulic load increases. The initial structure was sized for the ultimate development; the pumps and piping can be sized and constructed in phases to match the increasing flows. Lift Station No. 4 is intended to last for the life of the existing WWTF. The expansion of the existing WWTF will determine the hydraulic capacity of Lift Station No. 4. When the hydraulic capacity of the expanded WWTF is reached, a new WWTF will need to be constructed. At that time, Lift Station No. 4 will be removed, and a new interceptor sewer constructed from the existing site to the new site. 30. Other Potential Environmental Impacts. If the project may cause any adverse environmental impacts not addressed by items 1 to 28, identify and discuss them here, along with any proposed mitigation. No adverse environmental impacts are anticipated. 31. Summary of issues. List any impacts and issues identified above that may require further investigation before the project is begun. Discuss any alternatives or mitigative measures that have been or may be considered for these impacts and issues, including those that have been or may be ordered as permit conditions. All known environmental impacts have been discussed previously in this document. Byron, Minnesota 15 Worksheet

17 RGU CERTIFICATION. I hereby certify that: The information contained in this document is accurate and complete to the best of my knowledge. The EAW describes the complete project; there are no other projects, stages or components other than those described in this document, which are related to the project as connected actions or phased actions, as defined at Minn. R , subps. 9b and 60, respectively. Copies of this EAW are being sent to the entire EQB distribution list. Name and Title of Signer: Beth G. Lockwood, Supervisor, Environmental Review Unit Operations and Environmental Review Section Regional Environmental Management Division Date: The format of the Worksheet was prepared by the staff of the Environmental Quality Board at Minnesota Planning. For additional information, worksheets or for EAW Guidelines, contact: Environmental Quality Board, 658 Cedar St., St. Paul, MN 55155, , or at their Web site Byron, Minnesota 16 Worksheet