clear lake/clearwater wwt expansion environmental ...wastewater treatment expansion environmental...

p-ear1-04 TDD (for hearing and speech impaired only): 651-282-5332

Printed on recycled paper containing 30% fibers from paper recycled by consumers

ENVIRONMENTAL ASSESSMENT WORKSHEET

Note to reviewers: The Environmental Assessment 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 651-297-8510. An electronic version of the completed EAW is available at the MPCA Web site http://www.pca.state.mn.us/news/eaw/index.html#open-eaw. 1. Project Title: Clear Lake/Clearwater Wastewater Treatment Expansion 2.

Proposer:

Clear Lake/Clearwater Sewer Authority

3.

RGU:

Minnesota Pollution Control Agency

Contact Person William Kiffmeyer Contact Person Nancy Drach and Title Chair and Title Project Manager Address 7684 1st Avenue West Address 520 Lafayette Road North P.O. Box 307 St. Paul, Minnesota 55155 Clear Lake, Minnesota 55319 Phone 320-743-3111 (City of Clear Lake) Phone 651-297-8236 Fax 320-743-4307 (City of Clear Lake) Fax 651-297-2343 4. 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. 4410.4300, subp. 18B

5. Project Location: County Sherburne City/Twp Clear Lake Township NW 1/4 NW 1/4 Section 25 Township T34N Range R30W

Facility Discharge Location: Section 26 Township T34N Range R30W

Clear Lake/Clearwater Phase I Wastewater Treatment Expansion Environmental Assessment Clearwater, Minnesota 2 Worksheet

Tables, Figures, and Appendices attached to the EAW: • Attachment 1 – Project Location Map • Attachment 2 – U.S. Geologic Survey Quad Map showing wastewater treatment facility (WWTF)

site • Attachment 3 – Facility Schematic • Appendix 1 – Minnesota Department of Natural Resources (DNR) Natural Heritage and

Nongame Research Program Response Letter, dated April 28, 2008. • Appendix 2 – Minnesota Historical Society e-mail dated July 19, 2005, Clear Lake Clearwater

Sewer Authority cultural resource database search 6. Description:

a. Provide a project summary of 50 words or less to be published in the EQB Monitor. The Clear Lake/Clearwater Sewer Authority is proposing to expand and upgrade its existing WWTF in two phases. Construction of Phase I, proposed for 2008, would expand the WWTF’s existing average wet weather (AWWF) design flow of 240,000 gallons per day (gpd), to 484,000 gpd. The Phase II expansion, which would not begin until 2015 or later, is proposed to have a design AWWF of 1,345,000 gpd. Both phases would be constructed at the existing WWTF site, and would discharge out of the existing outfall to the Mississippi River.

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.

The Clear Lake/Clearwater Sewer Authority is proposing to expand and upgrade its existing WWTF to provide additional wastewater treatment capacity to serve growth of the member communities. The existing WWTF, and proposed expansions, are all located at the same location, on approximately ten area acres of city-owned property (see Attachment 1). The design capacity of the existing WWTF is 240,000 gpd of AWWF. The treated effluent discharges to the Mississippi River in a portion of the river that was designated as an Outstanding Resource Value Water (ORVW) on November 5, 1984. The design capacity of the proposed facility after completion of Phase I would be 484,000 gpd AWWF. The design capacity of the proposed facility after completion of Phase II is to be 1,345,000 gpd. Construction of Phase II is not expected to occur until at least 2015 or later, and is dependent on the rate of growth in the member communities. The design schematic, shown as Attachment 3, includes the footprint of the existing facility as well as both proposed expansions.


Existing Facility Description All flow entering the existing WWTF passes through a coarse bar screen and is then split into two treatment trains that operate in parallel. The design AWWF is 120,000 gpd for each treatment train. The first treatment train consists of the following: • A single-cell aerated pond system; and • two effluent gravity sand filters.

The second wastewater treatment train consists of the following: • a pre-treatment room that houses one rotary fine drum screen, one static screen, and one

screenings compactor; • one aeration tank with two submersible pumps and aeration diffusers; • a membrane biological reactor plant housing two membrane reactors, four blowers, two

chemical feed systems (citric acid and sodium hypochlorite), two air compressors and an electrical room; and

• One aerated sludge holding tank with aeration diffusers.

The treated effluent from the gravity sand filters mixes with the treated effluent from the membrane reactors. This combined flow then flows through a pipe for chlorination/ dechlorination prior to discharge.

Proposed Phase I Expansion

The proposed Phase I expansion is an expansion to the second treatment train. No changes will be made to the existing pond or existing effluent gravity sand filters. Attachment 3 shows a site plan of the treatment process. The proposed Phase I expansion would increase the facility treatment capacity to a design AWWF of 484,000 gpd. The upgrade of the existing facility includes the following:

• New pretreatment building that will provide fine screening and grit removal for entire flow

entering the facility. The existing rotary fine drum screen, static screen, and screenings compactor shall be relocated to the new pretreatment building. A second static screen, screenings conveyor, grit tank, grit pump, and grit classifier will be added as part of Phase 1. The building also includes a small laboratory, toilet, electrical room, and mechanical room.

• The existing aerated sludge holding tank will be converted to an aeration tank. • One additional submersible pump will be added to the existing aeration tank. • Two new membrane reactors and two new blowers will be installed in the existing membrane

biological reactor building. • Conversion of the existing pre-treatment room into an office. • One, two-cell aerobic digester. • One 180-day biosolids holding tank. • A biosolids handling building housing two sludge transfer pumps, one sludge loading pump,

and one sludge storage mix pump in the lower level. The main level houses three blowers and an alum-feed system for chemical phosphorus removal.

• One chlorine contact tank for chlorination/dechlorination of the combined effluent flow from the membrane biological reactors and effluent gravity sand filters.


The process tanks and structures are to be constructed of reinforced concrete and/or concrete masonry block. Many of the structures will be built below-grade, requiring several site excavations. Average excavation depth will be 10 to 15 feet. The need for temporary or permanent ground-water dewatering is not expected. Construction will last approximately 18 months. The WWTF, after construction of Phase I, would produce the following waste streams: (1) effluent wastewater, meeting National Pollutant Discharge Elimination System (NPDES)/State

Disposal System (SDS) Permit requirements of 36.4 pounds per day Carbonaceous Biochemical Oxygen Demand, 65.5 pounds per day Total Suspended Solids (TSS), 1 mg/l phosphorus, and 200/100 ml fecal coliform limit, as well as the daily pH limits of 6-9 standard units.

(2) Waste biosolids, to be treated aerobically and land-applied on approved land application sites, in compliance with State and Federal 503 Regulations for Class B biosolids, including requirements for pathogen reduction and vector attraction reduction.

(3) Grit and screenings, to be washed, dried, and hauled to an approved sanitary landfill. Proposed Phase II Expansion

Should the need for the Phase II expansion of the existing facility occur, which would be designed to treat an AWWF of 1,345,000 gpd, the pre-treatment building would be expanded for additional screening and grit removal capacity. New aeration tanks and a new membrane reactor building to house additional membrane reactors, blowers, and electrical equipment would be constructed. An additional aerobic digester would also be added. Dependent on when Phase II occurs, it is likely the biosolids handling and disinfection would be re-evaluated. Due to changes in regulations, the construction of additional on-site biosolids storage versus alternatives to biosolids handling would be evaluated at that time. In addition, transmittance through the wastewater for both the existing and proposed Phase I flow is too low to be effective for ultra-violet disinfection. If transmittance remains low, then an expansion of the existing disinfection system would be provided.

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 the proposed project is to provide wastewater treatment service to existing and potential new development in the cities of Clear Lake and Clearwater.

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 Phase II expansion of the existing facility, described above, is dependent on the future growth and development in the cities of Clear Lake and Clearwater, and would occur in the year 2015 at the earliest.


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.

A three-cell pond wastewater treatment system was constructed on the site in 1978. Several years later, around 1997, two of the cells were abandoned and the third cell was provided with an aeration system, effluent gravity sand filters, and chlorine disinfection was added.

Recent interim improvements done to the existing facility, done in late 2007 for the purpose of

improving winter wastewater treatment capabilities for the existing design flow, included the addition of fine screens for the influent flow, an aeration tank, an aerated sludge holding tank, as well as an interim membrane bioreactor system.

7. Project Magnitude Data Total Project Area (acres) 10.0 or Length (miles)

Number of Residential Units:

Unattached

Attached

Maximum Units Per Building:

Commercial/Industrial/Institutional Building Area (gross floor space):

total square feet

Indicate area of specific uses (in square feet):

Office N/A Manufacturing N/A Retail N/A Other Industrial N/A Warehouse N/A Institutional N/A Light Industrial N/A Agricultural N/A Other Commercial (WWTF) N/A Building height 20 feet If over 2 stories, compare to heights of nearby buildings 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 Facility Plan Approval Submitted MPCA Nondegradation to an ORVW Review Submitted MPCA NPDES/SDS Surface Water Discharge

Permit Submitted

MPCA Plans and Specification Approval To be submitted MPCA NPDES/SDS General Stormwater

Permit for Construction Activity To be submitted

Public Facilities Authority Funding Application Submitted Sherburne County Conditional Use 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 project site is currently used for wastewater treatment with aerated ponds, filters, and membrane bioreactors. All expansion work will occur within the limits of the existing site.

There are no known environmental concerns regarding past land use such as underground or above-ground petroleum storage tanks and unpermitted fill or dumping. There are no currently known environmental contamination issues along the proposed construction. None are anticipated to be discovered. The treatment facility is to be constructed on land that is neither wetland or of other environmental concern. Land use will not be impacted. The area located to the west of the treatment facility site is wooded and zoned low density residential. The closest residential buildings in this area are located approximately 460 feet west of the existing aerated pond and 900 feet to the west of where the new structures will be placed. The area to the north and east of the site is zoned agricultural and currently utilized for growing soy beans and corn. The Mississippi River is located approximately 2,000 feet to the south of the site. The land between the plant site and the river is a combination of woodland and near the river wetlands. The odors associated with this WWTF would not increase as a result of the expansion. The current area, to the north and east of the plant site, which is currently zoned for agricultural use, could change to residential in the future as the city grows. Due to the layout of the site and property owned by the utility, new homes would not be closer than 600 feet to the existing pond to the north or 450 feet to the existing treatment facility structures to the east. The zoning of the land to the west is projected to remain low density residential and is near build-out.

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 0 3.8 Wooded/forest 0 0 Impervious Surfaces 0 0.2 Brush/grassland 10 6 Other (describe) Cropland 0 0 TOTAL 10 10 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. Wildlife in the area primarily consists of species native to rural Minnesota. There are a variety of inspects, birds, reptiles, and mammals in the area. The existing WWTF at the project site has operated as a WWTF since 1978 and has minimal value with respect to wildlife habitat. In


addition, the WWTF property is and will continue to be fenced. Any wildlife inhabiting the remaining open area on the ten-acre, city-owned WWTF site would leave the area and find new homes elsewhere. No significant or long-term impacts to fish and wildlife resources are expected as a result of the project.

b. Are any state (endangered or threatened) species, rare plant communities or other sensitive ecological resources such as native prairie habitat, colonial water bird 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 20040601-0002

Describe measures to minimize or avoid adverse impacts. The DNR Natural Heritage and Nongame Research Program was contacted, and its Information System queried, to determine if any rare plant or animal species or other significant natural features are known to occur within an approximate one-mile radius of the project. Two known occurrences of rare species were identified; however, based on the nature and location of the proposed project, the DNR does not believe the project will affect any known occurrences of these rare species (Appendix 1). The DNR’s letter to the proposer, Correspondence #ERDB 20040601-0002 (shown as Appendix 1), indicated that: a) the Minnesota County Biological Survey identified an Oak Woodland-Brushland native plant community adjacent to the proposed expansion; and b) reports were found that Blanding’s Turtles (Emydoidea blandingi) - a state-listed threatened species, have been found in the area. Oak Woodland-Brushland native plant community The DNR has indicated that the project should not directly impact the Oak Woodland-Brushland native plant community, but recommend that indirect impacts from runoff and the introduction/spread of invasive species be considered during the project design and implementation stages. Blanding’s Turtles requirements Because of the reported sightings of the Blanding’s Turtles in the area, the DNR’s letter to the proposer (Appendix 1) included the reminder that the destruction of threatened or endangered species is prohibited by state law and rules, except under certain prescribed conditions. The DNR also enclosed a fact sheet with recommendations for working in or near Blanding’s Turtle habitat.

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 outfall structure for the existing WWTF will not be altered for the Phase I or Phase II proposed expansions.


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

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

15. Water Surface Use. Will the project change the number or type of watercraft on any water body? Yes No

16. Erosion and Sedimentation. Give the acreage to be graded or excavated and the cubic yards of soil to be moved: 4 acres; 9,000 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. For the proposed Phase I expansion, there will be four acres that are graded or excavated, and 9,000 cubic yards of soil to be moved. The Clear Lake/Clearwater Sewer Authority is required to obtain an NPDES/SDS General Construction Stormwater Permit prior to commencing any land disturbing activities (i.e., clearing, grading, filling, and excavating) at the site, and permit requirements will be followed. Erosion control will be maintained during project construction. Silt fences and a vegetated buffer will be employed. After construction is complete, final grading will be controlled to minimize scouring and erosion from runoff. The WWTF site will be either seeded or sodded. There are no steep slopes or highly erodible soils on the construction site. Best management practices (BMPs) to control erosion and sedimentation will be employed. Erosion of soils subject to wind erosion will be minimized by watering practices intended to minimize dust during construction. Silt fences and seeding will minimize water erosion. Re-establishment of disturbed areas will occur upon completion of construction in each segment. Wood fiber blankets will be used on any localized steep slopes to provide a stable substrate for vegetation re-establishment. A buffer area will be maintained downhill from the construction area. The WWTF site will be sodded and/or seeded, and graded to promote controlled site runoff.

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 storm-water pollution prevention plans. There will be little change in the quantity and quality of runoff from the site due to the expansion.


The NPDES/SDS General Stormwater Pond for Construction Activity requires the development of BMPs and preparation of a Stormwater Pollution Prevention Plan to manage pollutants that may be in stormwater runoff both during and after construction. All areas disturbed by construction will be returned to pre-construction conditions. No short-term or long-term impacts are expected.

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. At the existing WWTF site, both before and after expansion, stormwater runoff would drain overland in the same direction, towards the adjacent Mississippi River. There would be little increase in the amount of runoff after expansion.

18. Water Quality – Wastewater. a. Describe sources, composition and quantities of all sanitary, municipal and industrial

wastewater produced or treated at the site.

After the proposed Phase I expansion, the WWTF would discharge an AWWF of 484,000 gpd when operating at full capacity. The majority of the wastewater discharged to the WWTF will be from primarily residential sources (more than 75 percent of the total flow). Because there are no significant industrial high-strength dischargers, the wastewater could be categorized as normal domestic sewage. Under NPDES/SDS Permit No. MN004749, the treated effluent discharge would be required to meet effluent limits and water quality standards required for that reach of the Mississippi River, as well as downstream water bodies. Proposed average monthly concentration discharge limits established by the MPCA are: • 25 mg/L of 5-day Carbonaceous Biochemical Oxygen Demand (CBOD5); • 30 mg/L of TSS • 1 mg/L phosphorus; and • 200 organisms/100 mL fecal coliform April through October. The treated effluent discharge would also be required to meet daily minimum and maximum for pH range of 6.0 – 9.0 standard units, and a daily maximum chlorine residual limit of .038 mg/L, when chlorine is used.

The particular reach of the Mississippi River where the existing effluent discharge is located, is listed as a Class 1C, 2Bd, 3B, 3C, 4A, 4B, 5, and 6 water, and designated as an ORVW on November 5, 1984. Since the existing outfall structure would be used for the proposed expansion, the effluent discharge from the expanded WWTF would continue to discharge to the same ORVW-designated reach of the Mississippi River. The Clear Lake/Clearwater Sewer Authority has accepted a “freeze” for the mass limits based on the originally constructed facility’s design AWWF of 174,000 gpd in effect for the WWTF on that date. The average monthly mass limit for CBOD5 is set at, or “frozen,” at 16.5 kilograms/day (kg/day). To meet this mass limit, the Phase I expansion of the WWTF would need to treat the wastewater down to 9.0 mg/L.


The average monthly mass limit for TSS is set at, or “frozen,” at 29.7 kg/day. To meet this mass limit, the Phase I expansion of the WWTF would need to treat the wastewater down to 16.2 mg/l.

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 WWTF would employ an expansion of the biological treatment process utilizing membrane bioreactors (MBRs). This membrane separation process provides a high level of removal for additional treatment efficiency and effectiveness. The process treats the wastewater to meet effluent limits and water quality standards that are protective of the Mississippi River and for complying with treatment standards established by the MPCA. The process includes a membrane separation process that removes organic and inert solids, which are then processed and hauled to agricultural land for disposal. A portion of the wastewater will continue to be treated in an aerated pond. The on-land disposal will meet quality limits for pathogens and vector attraction. A Class B biosolids will be produced, which complies with Federal (40 CFR 503) and State (Minn. R. ch.7041) regulations. The WWTF will use an aerobic digestion process to meet these quality limits. Also, the WWTF will include a biosolids storage basin so that on-land biosolids disposal can be limited to periods of the year when incorporation of the biosolids into the soil is possible. The downstream water bodies, including Lake Pepin, into which the Mississippi River drains, currently require protection from phosphorus loadings. The WWTF will remove phosphorus down to a level of 1.0 mg/l (annual average). The phosphorus-reduction process is with chemical additions to guarantee that the 1.0 mg/l limit will be met. The WWTF will first disinfect the effluent with chlorination in a contact tank to meet the fecal coliform limit required April through October of each year, and will follow with dechlorination.

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. Wastewater treated by the expanded WWTF would come from sources located within city limits. The treated effluent discharge would meet NPDES/SDS Permit limits. There is no existing or planned high-strength industrial users, therefore pretreatment would not be necessary. All influent wastewater generated is expected to be typical of residential strength wastewater.

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. Not Applicable.


19. Geologic hazards and soil conditions. a. Approximate depth (in feet) to Ground water: >34 feet minimum; >34 feet average. Bedrock: >34 feet minimum; >34 feet 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 Natural Resources Conservation Service classifications, if known. Discuss soil granularity and potential for ground-water contamination from wastes or chemicals spread or spilled onto the soils. Discuss any mitigation measures to prevent such contamination. The following soil types will be encountered in the project area. SP Poorly graded sand SM Silty sand 7A Hubbard sandy loam 7B Hubbard sandy loam 7C Hubbard sandy loam 258B Sandberg Loamy Coarse Sand 258E Sandberg Loamy Coarse Sand 768 Mosford Sandy Loam The potential for ground-water contamination is extremely low. Pipes will be pressure tested during construction to assure there are no leaking joints or cracked pipe. Conveyance lines are to be placed on granular bases to prevent movement or undue pressures on the lines. Gravity lines are to be constructed of approved materials that are appropriate for sanitary sewer construction. Pipe joints will be gasketed. Connections to manholes will be made using flexible cast-in-place gasket connectors, or boots, to provide positive seals. Manholes will be pre-cast concrete with water-tight gasketed joints. All tanks are to be tested with clean water prior to being placed into service. The clean water levels are monitored over a length of time to insure there are no leaks. Tanks will be reinforced concrete with internal coatings or above-ground coated steel.

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.


No solid wastes, other than the wastes from construction, piping, and demolitions common to WWTF construction, will be generated. The construction wastes will be disposed of by the contractor in accordance with applicable rules and regulations. No hazardous wastes are anticipated from the construction or operation of the proposed project. Wastewater biosolids generated at the WWTF will be treated with aerobic digestion on site to meet Federal 503 Regulations and State (Minn. R. ch.7041) regulatory requirements for quality and handling. Treated biosolids will be hauled and land applied to MPCA-approved land application sites in accordance with permitted conditions issued by the MPCA. The grit and screenings removed at the head of the treatment plant during preliminary treatment will be hauled to a sanitary landfill.

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 ground water. 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. Fuel oils, generally associated with construction equipment, will be present on site. Routine inspections of the construction equipment and of any storage areas will verify that petroleum product leakage does not occur.

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. The aerobic digester will have a 260,000-gallon capacity. The digester will be a partially-buried reinforced concrete tank. The sludge storage tank will be 435,000 gallons. No emergency response containment plan is required for these types of tanks.

21. Traffic. Parking spaces added: 3 Existing spaces (if project involves expansion): 2 Estimated total average daily traffic generated: 10 Estimated maximum peak hour traffic generated (if known) and its timing: 4

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 impacts on traffic congestion are expected.

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. This project does not involve vehicle-related emissions, other than temporary emissions during construction.


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.

24. Odors, noise and dust. Will the project generate odors, noise or dust during construction or during operation? Yes No Dust Dust would generally be generated during construction from earthwork activities. The contractor would need to control dust to the extent possible. Water would be used as a dust suppressant on road, dirt piles, and open cut areas as needed. To minimize dust during operation, the site would receive sod, driveways would be paved, and walkways would be made of concrete. Noise Noise would generally be generated during construction, and includes noise of vehicles (backhoes, dump trucks, cement trucks, delivery vehicles, construction employee vehicles), construction equipment (saws, drills, hammers), and noises generated from general construction activities. Noise would be limited to working hours. Weekend and holiday work would be discouraged. Noises related to the operation of the WWTF would be limited to that of employee and chemical delivery vehicles, and that of WWTF outside equipment operating. To limit noise, whenever possible, WWTF equipment would be housed within buildings. Equipment creating noise during operation would include existing aerators in the ponds, motors/fans for the ventilation systems on buildings, and operation of the on-site generator. All sounds would be minimal. Odor Odor would not be expected to occur from construction activities. Sewage odors, after completion and construction and operation of the expanded WWTF, would not be expected to change from odors generated from the existing WWTF operation. New equipment would, whenever possible, be housed in enclosed buildings. Sludge would be aerobically digested in covered digesters to decrease odors.

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. The project’s construction activities will be conducted on the existing site. A Minnesota Historical Society database search conducted for the same site in July 2005 (Appendix 2) indicated that there were no archaeological sites identified.

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. Minimal exterior lighting will be provided at the site near building entrances and near the aeration tank, digester, and sludge storage tank. There will be no visible plumes coming from the site. The WWTF is remotely located and no adverse visual impacts to nearest residents are projected.

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 Clear Lake/Clearwater Sewer Authority owns the site where the existing WWTF and both proposed phases of the expansion exist. The project site is located in an agricultural zone, as zoned by Sherburne County, and its use is consistent with the Sherburne County Comprehensive Plan. A Conditional Use Permit will be sought from Sherburne County prior to expansion of the Clear Lake/Clearwater WWTF. The Mississippi River from St. Cloud to Anoka was added to the Minnesota Wild and Scenic Rivers Program in 1976. The specific reach between Clearwater and Anoka was classified by the DNR as an outstanding recreational river, deemed to provide excellent fishing, canoeing, and boating opportunities. In addition, the Mississippi River is a designated state canoe and boating route. Proposed land use zoning and planning activities for this river corridor are contained in a draft Mississippi Scenic Riverway Management Plan, prepared by the DNR’s Division of Waters, dated January 2003. Since the proposed project is an expansion of an existing WWTF, and the Clear Lake/Clearwater Sewer Authority will design the expanded facility to maintain recommended permitted mass limitations for discharged pollutants, the project is compatible with the draft Mississippi Scenic Riverway Management Plan.


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.) No major public infrastructure project would be related to construction of the proposed Phase I expansion. However, the purpose of the proposed Phase I expansion of the WWTF is to allow for development in the cities of Clear Lake and Clearwater. Future new development would require new and separate infrastructure and services, such as roads, new municipal sewer and water lines, as well as other utilities.

29. Cumulative impacts. Minn. R. 4410.1700, 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). Enable Development The proposed project is part of the overall development plan for the cities of Clear Lake and Clearwater. The proposed project would increase the capacity of the WWTF and, therefore, allow for new development in the service area. Increased development would also result in increased traffic, air pollution, stormwater runoff, and the generation of solid waste. As residential and commercial areas expand, the amount of farmland, open space, and wildlife habitat in the area decrease. However, the expansion of the residential and commercial areas are dependent on local economics and, as such, the timing of this is uncertain. Potential cumulative effects from future development will be mitigated through enforcement of local, state, and federal ordinances and regulations. Individual development projects located within the project area that would be subject to project-specific environmental review and permitting. Water Quality The existing WWTF and the proposed project would have a continuous discharge to restricted ORVW, to a reach of the Mississippi River located between Clearwater and the confluence of the Elk River. The mass limitations CBOD5 and TSS for the proposed project are frozen at the same mass limitations as the existing WWTF. The existing WWTF proposed project discharge is upstream of Lake Pepin. Lake Pepin was placed on the 2002 MPCA Clean Water Act Section 303(d) Total Maximum Daily Load (TMDL) list of impaired waters due to excess nutrients which impede swimming in the lake. Phosphorus is the primary nutrient responsible for excess algal growth in Lake Pepin. Federal regulation [40 CFR 122.44(d)(1)(i)] restricts mass increases from new and expanding NPDES permitted facilities upstream of impaired waters. The proposed project will have a 1 mg/L average monthly phosphorus in their NPDES/SDS Permit and, with that limit, there will be a mass reduction of 1,452 pounds per year phosphorus to the Mississippi River. Once a TMDL is established for Lake Pepin, additional controls or limits may be required.


Because the project’s discharge is subject to the requirements of the approved mercury TMDL that includes this reach of the Mississippi River, this discharge will be included in the development of a TMDL implementation plan for mercury. Pre and post-initiation of operation permit requirements will include quarterly influent mercury monitoring, and quarterly effluent total and dissolved mercury monitoring with a concurrent TSS grab. A mercury minimization plan will also be required. The proposed project will operate under an NPDES/SDS Permit with effluent limits set at levels that ensure that the project does not cause or contribute to water quality impairments, either individually or cumulatively with other sources in the watershed. The potential for significant cumulative effects to water quality or to aquatic organisms from this proposed project is not expected.

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. None known at this time.

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.

Treatment Options The known environmental impacts and mitigation measures have been previously discussed in this document. The project proposer did consider several other wastewater treatment alternatives prior to selecting a final proposal. The alternatives considered were the MBRs, activated sludge treatment, aerated pond treatment system, MBRs in combination with a pond system, and activated sludge in combination with a pond treatment system. These alternatives, with the discharge to the Mississippi River, were evaluated with both frozen and nonfrozen mass limits. The alternatives were also evaluated with additional land application treatment options, such as spray irrigation or rapid infiltration basins. The project proposer also evaluated the option of connecting to the city of St. Cloud’s WWTF. The Clear Lake/Clearwater Sewer Authority determined that all treatment options with continued discharge to the Mississippi River would need to meet “frozen” mass limitations because of the ORVW designation. Therefore, all discharging treatment options, with the exception of the MBRs, were not considered viable options. Land Application Spray irrigation was determined not cost-effective, because large application sites are necessary for the wastewater. Both the amount of acreage and management would be costly. Also, because spray irrigation cannot be done in winter months, over-winter storage of the wastewater would be required. Rapid infiltration basins were also determined not cost effective because of the need to treat the wastewater to meet nitrate limits for the ground water. Connection to St. Cloud WWTF The Clear Lake/Clearwater Sewer Authority also evaluated the option of connecting their wastewater collection system to the St. Cloud WWTF. The earliest they could connect to the St. Cloud WWTF is 2012. They need additional capacity in 2008. In addition, St. Cloud would need to accept the waste with the remaining capacity of their WWTF, as St. Cloud is not planning to expand their WWTF until 2017.

EXHIBIT 1 - PROJECT LOCATION MAP

CLEAR LAKE - CLEARWATER SEWER AUTHORITY

ATTACHMENT 1

CLEAR LAKE - CLEARWATER SEWER AUTHORITY

EXHIBIT 2 - TOPOGRAPHIC MAP

PROJECT LOCATION

ATTACHMENT 2

PROPERTY LINE

MBR BUILDINGAERATION

TANK

PHASE I ACCESSROAD TO BE REMOVEDIN PHASE II

PRETREATMENT BUILDING ADDITION

AEROBICDIGESTERS

EXISTING FILTER/DISINFECTION BUILDING

CHLORINATION/DECHLORINATION CONTACT TANK

SLUDGE BUILDING

SLUDGE LOADSTAND

SLUDGE TANKCONVERTED TO

AERATION TANK

MBR BUILDINGADDITION

AEROBICDIGESTERS

PRETREATMENTBUILDING

EXPAND OR CONVERT CHLORINE CONTACTTANK TO UV DISNFECTION

SLUDGESTORAGE

TANK

SLUDGESTORAGE

TANK

ACCESS ROAD

AERATIONTANK

AERATIONTANK

PHASE I ACCESSROAD TO REMAININ PHASE II

PHASE I ACCESSROAD TO REMAININ PHASE II

INTERIM IMPROVEMENTS

PHASE I IMPROVEMENTS

PHASE II IMPROVEMENTS

COMM:

ATTACHMENT 3

mosborn1

Text Box

DNR Information: 651-296-6157 ● 1-888-646-6367 ● TTY: 651-296-5484 ● 1-800-657-3929

An Equal Opportunity Employer Who Values Diversity

Phone: (651) 259-5109 Fax: (651) 296-1811 E-mail: [email protected] April 28, 2008 Mr. Karen Cavett Bonestroo 54205 - 211 Lane Mankato, MN 56001 Re: Request for Natural Heritage information in the vicinity of the proposed Clear Lake Clearwater WWTF Expansion, T34N R30W Section 25, Sherburne County Correspondence # : ERDB 20040601-0002 Dear Ms. Cavett, As requested, the Minnesota Natural Heritage Information System has been queried to determine if any rare species or other significant natural features are known to occur within an approximate one-mile radius of the proposed project. Based on this query, several rare features have been documented within the search area (for details, see the enclosed database reports). Please be aware that the following rare features may be impacted by the proposed project:

• The Minnesota County Biological Survey (MCBS) has identified an Oak Woodland-Brushland native plant community adjacent to the proposed expansion (A GIS shapefile of MCBS native plant communities can be downloaded from the DNR’s Data Deli website at http://deli.dnr.state.mn.us). While the project should not directly impact this community, indirect impacts from runoff and the introduction/spread of invasive species should be considered during project design and implementation.

• Blanding’s turtles (Emydoidea blandingii), a state-listed threatened species, have been reported

from the area and may be encountered on site. If Blanding’s turtles are found on the site, please remember that destruction of threatened or endangered species is prohibited by state law and rules, except under certain prescribed conditions. Please see the enclosed fact sheet for recommendations on working in or near Blanding’s turtle habitat. The attached flyer should be given to all contractors working in the area.

The Natural Heritage Information System (NHIS), a collection of databases that contain information about Minnesota’s rare natural features, is maintained by the Division of Ecological Resources, Department of Natural Resources. The NHIS is continually updated as new information becomes available, and is the most complete source of data on Minnesota's rare or otherwise significant species, native plant communities, and other natural features. However, the NHIS is not an exhaustive inventory and thus does not represent all of the occurrences of rare features within the state. Therefore, ecologically significant features for which we have no records may exist on the project area. The enclosed results include an Index Report and a Detailed Report of records in the Rare Features Database, the main database of the NHIS. To control the release of specific location information, which might result in the destruction of a rare feature, both reports are copyrighted. The Index Report provides rare feature locations only to the nearest section, and may be reprinted, unaltered, in an environmental review document (e.g., EAW or EIS), municipal natural resource plan, or

Minnesota Department of Natural Resources

500 Lafayette Road

St. Paul, Minnesota 55155-4025

Division of Ecological Resources, Box 25

APPENDIX 1

report compiled by your company for the project listed above. If you wish to reproduce the index report for any other purpose, please contact me to request written permission. The Detailed Report may include specific location information, and is for your personal use only. If you wish to reprint or publish the detail report for any purpose, please contact me to request written permission. Please be aware that this letter focuses only on potential effects to rare natural features; there may be other natural resource concerns associated with the proposed project. This letter does not constitute review or approval by the Department of Natural Resources as a whole. If you would like further information on the environmental review process, please contact your Regional Environmental Assessment Ecologist, Mike North, at (320) 255-4279 ext. 235. An invoice in the amount of $130.35 will be mailed to you under separate cover within two weeks of the date of this letter. You are being billed for the database search and printouts, and staff scientist review. Thank you for consulting us on this matter, and for your interest in preserving Minnesota's rare natural resources. Sincerely,

Lisa Joyal Endangered Species Environmental Review Coordinator encl: Rare Features Database: Index Report Rare Features Database: Detail Report Rare Features Database Reports: An Explanation of Fields Blanding’s Turtle Fact Sheet and Flyer

CLCW WWTFCalcuations from the 2006 IPCC Guidelines for National Greenhouse Inventories Vol. 5 Wastewater

Given: 6 kg CH4/kg BOD157 MMTCO2e in Minnesota949 lbs BOD influent/day

Emmissions of CH4

= (6 kg CH4/kg BOD) x (949 lbs BOD/day) / (2.2 lbs/kg) = 6 kg CH4/kg BOD

949 lbs BOD/day2.2 lbs/kg

2,588 kg/d CH4 produced at the facility944,686 kg/year CH4 produced at the facility

1 CH4 equals 24 Equiv. CO2emetric ton = 1000 kg

22,672,473 kgCO2e22672.47273 metric tons of CO2e0.022672473 MMTCO2e

157 MMTCO2e in Minnesota (from the Center for Climate Strategies CCS, page iii)0.0144% percent of CO2e in the State

N2O Emissions from Wastewater Effluent

N2O Emissions = N effluent x EF effluent x 44/28

N effluent = nitrogen in effluent discharged to riverN effluent = 30 mg/l x 0.484 MG x 8.34 = 121.0968 lbs N/dayN effluent = 55.044 kg N/dayEF effluent = a factor between -.0005 - 0.25 kg N2O/kgN (use 0.005) 0.005 kg N2O/kgNConversion factor 1.571429 conversion kg N2O-N to kg N2O

N2O Emissions = 0.43 kg N2O /day157.86 kg N2O /year

1 N2Oequals 298 CO2e47041.78191 kgCO2e47.04178191 metric tons CO2e4.70418E-05 MMTCO2e

157 MMTCO2e in Minnesota0.000030% percent of CO2e

APPENDIX 3

clear lake/clearwater wwt expansion environmental ...wastewater treatment expansion environmental...

Documents