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HomeMy WebLinkAboutNC0023736_Environmental Assessment_19940802NPDES DOCUWENT !I CANNING COVER SHEET NPDES Permit: NC0023736 Gunpowder Creek WWTP Document Type: Permit Issuance Wasteload Allocation Authorization to Construct (AtC) Permit Modification Complete File - Historical Engineering Alternatives (EAA) Correspondence Instream Assessment (67b) Speculative Limits (Environmenta1Assessmen.t (EA) Document Date: August 2, 1994 This document is printed on reuse paper - ignore any content on the reYerse aide ENVIRONMENTAL ASSESSMENT FOR GUNPOWDER CREEK WASTEWATER TREATMENT PLANT IMPROVEMENTS CITY OF LENOIR CALDWELL COUNTY, NORTH CAROLINA PREPARED BY: MICHAEL J. WARESAK, P.E. t McGILL ASSOCIATES, P.A. CONSULTING ENGINEERS ASHEVILLE, NORTH CAROLINA FOR THE CITY OF LENOIR, NORTH CAROLINA JUNE, 1994 94158.00 ,`..11117 , ill ,.off.\N CAROL • =; 19950 = • Z s, ,.� ; MIS fugl TABLE OF CONTENTS SECTION 1 - EXISTING ENVIRONMENT 1.1 Background Information 1.2 Land Features of Area SECTION 2 - NEED 2.1 Existing Wastewater Flows and Speculative Effluent Limits 2.2 Flow Projection SECTION 3 - ALTERNATIVE ANALYSIS 3.1 List of Alternatives 3.2 Discussion of Alternative Analysis • SECTION 4 - ENVIRONMENTAL CONSEQUENCES 4.1 General 4.2 Discussion of Environmental Consequences SECTION 5 - MITIGATIVE MEASURES 5.1 List of Mitigative Measures SECTION 6 - RESULTS 6.1 Results APPENDIX A APPENDIX B LIST OF FIGURES AND TABLES Figure 1.1 - Location Map Figure 1.'2 - Surrounding Area USGS Map Figure 1.3 - Existing WWTP Site Plan Figure 1.4 - 'Proposed WWTP Improvements Figure 2.1 - Gunpowder Creek WWTP Service Areas Table 4-1 - Effluent Monitoring Records Table 4-2 - Monitoring Records 100 feetUpstream of WWTP Discharge Table 4-3 Monitoring Records Upstream from Start of Old Millpond fool Table 4-4 Monitoring Records of Pooled Area of Old Millpond r EXECUTIVE SUMMARY The existing Gunpowder Creek WWTP is currently permitted for an average daily discharge to Gunpowder Creek of 1.2 MGD. The plant's current influent flow exceeds 80% of the permitted flow, creating the need for a plant expansion. Population projections and an alternative analysis indicate that the City of Lenoir should expand the plant to a capacity of 2.0 MGD. The proposed plant expansion includes the following improvements: 1. Convert the existing contact stabilization treatment process to a four (4) basin sequencing batch reactor (SBR) process with ammonia removal. I al 2. Install a new chlorination and dechlorination facility to reduce All • nig chlorine residual in the effluent to the creek. 3. install a step aeration facility to • increase dissolved oxygen concentration prior to discharge. This environmental assessment indicates that the proposed improvements shall cause no significant adverse affects to the creek, the downstream water bodies, or the surrounding wildlife in the area. In fact, the SBR treatment process and other improvements will decrease B0D and will likely decrease instream toxicity through improved ammonia and chlorine residual removal. The proposed improvements are designed to comply with the speculative NPDES permit limits issued by the Division of Environmental Management. In addition, the regional office of the North Carolina Wildlife Resources Commission has determined that it is unlikely that the project will adversely affect the fish and wildlife in the area. ISM enel fan SECTION 1 EXISTING ENVIRONMENT 1.1 BACKGROUND INFORMATION The Gunpowder Creek Wastewater Treatment Plant is owned and operated by �► the City of Lenoir. The facility is located east of US 321 and south of SR 1127, near the Town of Hudson (See Figure 1.1 for location map). The facility 'a"' is currently permitted to discharge an average daily flow of 1.2 million gallons per day (MGD) to Gunpowder Creek. According to monthly operating reports, the average daily flow to the plant between March, 1993 and February, 1994 was 0.99 million gallons per day (MGD). Since this flow exceeds 80% of the permitted plant capacity, the City is proposing to expand the facility to provide additional treatment capacity. The Gunpower Creek WWTP was originally constructed in the mid 1970's at a permitted average discharge of 1.0 MGD to Gunpowder Creek. In September, 1992 the Department of Environment, Health and Natural Resources increased the permitted capacity to 1.2 MGD at the request of the City. This permit expires June 30, 1995. A copy of the current NPDES permit is included in Appendix A. The area surrounding the wastewater treatment plant site is undeveloped and heavily wooded. The plant site property includes approximately 10 acres on 0.16 north side of Gunpowder Creek, approximately one half mile south of SR 1127. Of ,this property, only approximately 1.7 acres is utilized for the wastewater treatment plant. Figures 1.2 and 1.3 show the location of the wastewater treatment plant with respect to the surrounding area. It should be Pegs 2 OM fan Mei noted that most of the proposed improvements to the plant will be made within the existing fence line boundaries. The only exceptions will be the expansion of the influent structure, and the step aeration facility. Both of these proposed improvements will be located just south of the existing fence line. The proposed treatment plant improvements are shown in Figure 1.4. TOPOGRAPHY At the time the plant was originally constructed, the final grade elevation for the plant site was raised from an average grade elevation of approximately 1117 feet to an elevation of approximately 1127 feet. The maximum flood elevation shown on the original plant drawings is 1125.0 feet. LAND USE Approximately 1.7 acres of the 10 acre parcel owned by the City of Lenoir is - being utilized for the wastewater treatment plant. The remainder of the land has been left in its undeveloped condition. '°'" SOILS . The existing plant was apparently constructed on approximately 10 feet of structural fill that was brought in from off site. The existing soils in the area faM reportedly contain large amounts of soft rock and are high in iron. fffA SURFACE WATERS rem Pape 3 At the point that the treated effluent is discharged to Gunpowder Creek, the creek is classified by the State of North Carolina as a Class 'C water. Class C AIM SIM Rol AlMt earn waters are protected for secondary recreation, fishing, wildlife, fish and aquatic life propagation and survival, and agriculture. According to the Division of Environmental Management, the average flow of the creek is 17.4 cfs, the summer 7Q10 flow is 2.9 cfs, and the winter 7Q10 flow is 4 cfs. Gunpowder Creek is in the Catawba River Basin. r Page 4 FIGURE 1.2 SURROUNDING AREA USGS MAP SOURCES = USGS - GRANITE FALLS QUADRANT SCALE - 1" = 2000' fan Pal Owl RIR SECTION 2 NEED 2.1 EXISTING WASTEWATER FLOWS AND SPECULATIVE EFFLUENT LIMITS As stated in Section 1.1, the current wastewater flow to the plant exceeds 80% of the permitted plant capacity. In addition, the speculative effluent limits for the proposed plant expansion to 2.0 MGD indicate that the new NPDES permit will require a new summer ammonia limit of 2.0 milligrams per liter,.and a reduced chlorine limit of 28 micrograms per liter. The plant currently has no limit for ammonia or chlorine residual. A copy of the speculative NPDES effluent limits received from the Division of Environmental Management is included in Appendix A. For the reasons stated above, it is clear that there is an immediate need to increase the capacity of the plant, and, at the same time, provide high level treatment to remove ammonia and reduce the chlorine residual concentration in the effluent. 2.2 FLOW PROJECTIONS The Gunpowder Creek Wastewater Treatment Plant receives about 45% of its flow from the Town of Hudson; and the remainder from the City of Lenoir. The 0.+ incoming flow is approximately 75% domestic wastewater and 25% industrial wastewater. Based on population and flow estimates from both the City of Lenoir and the Town of Hudson and estimated future flows from the Page 5 Mn tan Min fan ezul Mei Fin f fain surrounding Towns of Cajahs Mountain and Saw Mills, the projected flow for the Gunpowder Creek WWTP future service area was calculated as shown in the Table below. Figure 2.1 shows the existing and future service areas of the Gunpowder Creek WWTP GUNPOWDER CREEK WWTP FLOW PROJECTIONS YEAR PROJECTED AVERAGE DAILY FLOWS (MGD) 1995 1,000,000 2000 1,326,000 2005 1,689,000 2010 2,052,000 r Page 6 -„OMI 0 earl SIM PEI SECTION 3 ALTERNATIVE ANALYSIS 3.1 LIST OF ALTERNATIVES During the preliminary planning and design phases, the following alternatives were evaluated. a. Abandon Gunpowder Creek WWTP and pump wastewater flow from the service area to the City of Lenoir Lower Creek WWTP. b. Upgrade the Gunpowder Creek WWTP for a capacity to receive the projected flow through at least the year 2005, and begin planning to construct a regional wastewater facility near Granite Falls to serve the . entire region. c. Do not provide additional capacity or treatment improvements for the Gunpowder Creek WWTP service area. �► 3.2 DISCUSSION OF ALTERNATIVE ANALYSIS Alternative (c) was immediately eliminated as a possible alternative due to the current and projected wastewater flows. Alternative (a) included nearly $7,000,000 in estimated capital costs to include construction of over 6 miles l• of 24-inch wastewater force main, a 7.25 MGD regional pump station, and expansion of the City's Lower Creek WWTP to receive the additional flow. Due to the locations of the drainage areas in the region, alternative (a) would also MEI require the other towns in the region to pump long distances to transmit flow Page 7 to the regional pump station. Considering the region's drainage areas, alternative (b) was selected as the preferred alternative to meet the region's immediate and long term needs. The alternative makes the best use of the existing facilities and provides for an overall more efficient collection, transmission and treatment system for the region. The City of Lenoir is taking the lead on initiating the effort to construct a regional wastewater treatment plant in the next 10 years near Granite Falls to serve the entire region. r- Page 8 n SECTION 4 ENVIRONMENTAL CONSEQUENCES 4.1 GENERAL Since there is already an existing treatment facility on the site, the primary environmental consequence to be considered is the affect the increased discharge will have on wildlife in the area. The expected environmental consequences as a result of this project are discussed in this section. 4.2 DISCUSSION OF ENVIRONMENTAL CONSEQUENCES a. Changes in Land Use: The land use for the property will remain as a publicly owned wastewater treatment facility. b. Wetlands: It does not appear that the increased discharge to Gunpowder Creek will affect any wetlands in the area. c. Prime or Unique Agricultural Lands: It does not appear that this project will impact any agricultural lands in the area. d. Public Lands Such as Parks: It does not appear that this project will impact any public park lands in the area. e. Scenic and Recreational Areas: It does not appear that this project will affect any scenic or recreational areas. f. Areas of Archeological or Historical Value: Since this is an existing plant Pap. 9 MR MI MR fall fill g site with very little construction outside the existing fence line, it does not appear that there are any areas of archeological or historical value in the vicinity of the project. Air Quality: The proposed improvements to the plant include a sludge holding tank to store approximately 120,000 gallons of sludge for several days of retention time. This tank will be mixed and aerated sufficiently to minimize odors. There will be approximately 200 feet between the sludge holding tank and nearest property line. Since the surrounding area is undeveloped wooded land, there should not be any odor complaints. The sludge will be emptied from the sludge holding tank on a regular basis and hauled to the Lower Creek WWTP for treatment. h. Groundwater Quality: This project will not affect the groundwater '=s' quality in the area. MR MR i. Noise Levels: This project will not significantly affect the current noise levels at the existing plant. j. Water Supplies: According to the Division of Environmental Management there are no known water supply intakes on Gunpowder Creek. The nearest downstream water supply intake is the City of rim Hickory's facility on the Catawba River. Therefore, it does not appear that this project will affect any water supplies in the area. r run has reviewed the project scope and stated that the project should F , improve water quality for fish and other aquatic organisms in the stream. r k. Shellfish or Fish and their Habitats: The Wildlife Resources Commission rya Page 10 Or, rag rusi The North Carolina Natural Heritage Program has provided a listing of rare shellfish and fish and plant species for Caldwell County that could be present if the habitat is suitable. The listing shows that there are no State or Federal protected natural communities in the County. Three (3) plants are listed as threatened species, the Mountain Bittercress, Bent Arens and Heller's Blazing Star. Please refer to Appendix B for a complete listing of rare vertebrates, invertebrates and plants present in Caldwell County according to the Natural Heritage Program. The speculative effluent limits received from the Division of Environmental Management (See Appendix A) limit the ammonia (NH3-N) level to 2 milligrams per liter during the summer and 4 milligrams per liter during the winter. It is explained that these limits are based on protecting Gunpowder Creek against instream toxicity. DEM has determined that these limits will protect the creek for an instream ammonia criteria of 1 mg/I in the summer and 1.8 mg/I in the winter' under 7Q10 flow conditions to follow the guidelines of the Environmental Protection Agency (EPA). The speculative effluent limits also reduce the maximum chlorine level to 28 micrograms per liter to "ensure protection against acute toxicity." To meet these criteria, the proposed plant improvements include a sequencing batch reactor treatment process with nitrification to reduce ammonia (NH3-N) to 1 mg/I, and a dechlorination chamber with automatic monitoring and controls to maintain the chlorine residual level below 28micrograms per liter through the injection and mixing of sulfur dioxide. In addition, a step aeration facility will be constructed downstream of the dechlorination chamber to raise the dissolved oxygen (D.0.) concentration in the effluent to 5 mg/I or more. Due to these improvements to the treatment process, it is expected that this Peg. 11 project will not adversely affect shell fish or fish and their habitats. Wildlife and their Habitats: The North Carolina Wildlife Resources Commission regional office has reviewed the scope of the proposed project and has stated that it is unlikely that the project will adversely affect fish and wildlife resources in the area. Please refer to Appendix B for this correspondence. The North Carolina Division of Wildlife Management has identified one threatened animal species that could be present in the project area that is classified by the State as "threatened", the Bog Turtle. In addition, six (6) species which are of "special concern" status and two (2) species which are of "significantly rare" status are identified by the Division. Please reference Appendix B for the complete listing. Paragraph (m) of this section addresses affects to water quality as a - result of this project. It is likely that the concentrations of toxic substances which affect wildlife will actually decrease due to improvements in the treatment process. Therefore, it is not expected that this project will adversely affect wildlife or their habitats in the project area. m. Introduction of Toxic Substances: DEM has determined that the instream waste concentration (IWC) will increase from 38% to 52% as a result ofthe expansion to 2.0 MGD. The speculative limits received , from DEM state that "test results for toxicity have been inconsistent and a toxicity evaluation may be required". However, the regional DEM office has further investigated this matter and determined that a toxicity evaluation will not be necessary. According to the regional DEM office, Pegs 12 the Gunpowder Creek WWTP effluent has failed its toxicity test only three times in the last 30 months, and a toxicity evaluation will not be required to obtain an NPDES permit for the increased flow of 2.0 MGD. Table 4-1 shows the concentrations of toxic substances in the plant effluent for the period March, 1993 through February, 1994. For reference, Table 4-2 shows monitoring records for samples taken 100 feet upstream of the discharge point. It is noted that the average concentrations of ammonia and chlorine residual averaged 2.6 mg/I and 0.39 mg/I, respectively, for this twelve month period. At 1.2 mgd, these concentrations equate to approximately 26 pounds per day (ppd) of ammonia and 3.9 ppd of chlorine. While the IWC will increase 14% from 38% to 52%, the proposed plant improvements will reduce the concentrations of ammonia and chlorine to 1.0 mg/I and 0.028 mg/I, respectively. At 2.0 mgd, these concentrations equate to approximately 17 ppd of ammonia, and 0.5 ppd of chlorine for a 35% reduction in" ammonia concentration, and an 87% reduction in chlorine residual. These reductions should be sufficient to overcome the increased IWC and should actually reduce the instream toxicity. The plant has consistently met its effluent requirements for metals, and this success is expected to continue. n. Eutrophication of Receiving Waters: The Division of Environmental Management has apparently determined that the Old Millpond in Granite Falls is the downstream waterbody with the most critical potential for r eutrophication. The City of Lenoir has been required to monitor total phosphorous, total nitrogen, chlorophyll a, and pheophytin a upstream of and in the pooled area of the Old Millpond to assist in determining whether the Gunpowder Creek discharge is creating the potential for Papa 13 rim fir Mr CM fall Parl fowl eutrophication. Tables 4-3 and 4-4 show the results of this testing. The monitoring results at the Old Millpond thus far have been favorable, but the speculative limits indicate that this monitoring will continue as a requirement of the new NPDES permit. SECTION 5 MITIGATIVE MEASURES 5.1 MITIGATIVE MEASURES To improve the quality of the effluent water discharged to Gunpowder Creek, the City of Lenoir has elected to convert the existing treatment process to a sequencing batch reactor (SBR) process. Some of the mitigative features of the SBR process are listed below: MITIGATIVE FEATURES OF THE SBR PROCESS 1. Process is very flexible for achieving BOD and nitrogen removal at peak organic and hydraulic loadings. 2. Mixed -liquor solids cannot be washed out by hydraulic surges. 3. Process is simple to operate. Additionally, the proposed improvements include a dechlorination chamber to reduce chlorine residual in the effluent, and a step aeration facility to increase the dissolved oxygen concentration. The proposed improvements should actually decrease BOD and instream toxicity in Gunpowder Creek due to ammonia and chlorine residual. The City will continue to monitor the condition of the Old Millpond to determine if the r• WWTP discharge is creating a potential for eutrophication in that water body. • Pepe 20 sea SECTION 6 RESULTS 6.1 RESULTS The results of this Environmental Assessment indicate that the proposed wastewater treatment plant expansion will cause no significant adverse effects to Gunpowder Creek or downstream waters. Other ordinary potential 1.9 environmental consequences are minimized because most of the plant improvements will be constructed within the existing wastewater treatment plant fenced boundaries. The North Carolina Wildlife Resources Commission has indicated that it is unlikely that the project will adversely effect the fish and wildlife in the area. foal r Page 21 4 s •t ENVIRONMENTAL ASSESSMENT FOR LOWER CREEK WASTEWATER TREATMENT FACILITY EXPANSION TO 6.0 MGD CITY OF LENOIR CALDWELL COUNTY, NORTH CAROLINA PREPARED BY: M ICHAEL J. WARESAK, P. E McGffl ASSOCIATES Engineering • Planning • Finance SS Broad Street Asheville, North Carolina 28801 DECEMBER, 1996 96318.00 ._`\N CARp j ", • 19950 �., /2 -//_ J RIR mrf c cal rta 143 r: *• + • 9. TABLE OF CONTENTS SECTION 1 — SECTION 2 — SECTION 3 — SECTION 4 — SECTION 5 — APPENDIX A — • APPENDIX B — APPENDIX C — APPENDIX D— APPENDIX E — EXISTING ENVIRONMENT NEED ALTERNATIVE ANALYSIS ENVIRONMENTAL CONSEQUENCES RECOMMENDATIONS LETTER TO NCDEHNR SPECULATIVE NPDES PERMIT LIMITS AND CURRENT NPDES PERMIT LISTING OF ENDANGERED AND THREATENED SPECIES IN CALDWELL COUNTY SCOPING COMMENTS FROM STATE REGULATORY AGENCIES CATAWBA RIVER BASINWIDE MANAGEMENT PLANT EXCERPTS z SECTION 1 EXISTING ENVIRONMENT The Lower Creek Wastewater Treatment Facility is located in the southwest portion of the City of Lenoir as shown in Figure 1. The facility is currently permitted to discharge an average flow of 4.08 million gallons per day (MGD) to Lower Creek and is cu 7ently treating an average daily flow of approximately 2.2 MGD. The approximate service area of the plant is shown in Figure 2. The existing plant is an activated sludge wastewater treatment plant with an aeration basin capacity of approximately 1.86 million gallons, and six (6) floating aerators. The existing site plan is provided in Figure 3. The proposed improvements include the conversion of digested sludge basin to a 4.15 mullion gallon aeration basin with submerged air diffusers, and the conversion of the existing aeration basin to one anaerobic basin and one anoxic basin. These basins are necessary to achieve nutrient removal. The proposed improvements are shown in Figure 4. The plant entrance road is located on the north side of the plant, which is approximately 25 feet below the highest portion of the plant. The wastewater treatment facility covers an area of approximately 11 acres, including approximately 4.4 acres of concrete lined aeration and fir sludge holding basins which cover the south half of the plant site. Fat Mgt: PEI The plant site in the area of these basins and to the west of these basins is relatively level, but is elevated above the entrance road to the plant at El 1081. Between the basins and the final clarifier located to the north, the grade drops off at slopes ranging from approximately 1:1 to 1.5:1 before sloping more moderately toward Lower Creek. The area to the south of the large basins drops off at approximately 2:1 slope. The 100 year flood elevation at the plant is El 1064. Drainage swales on the east and west sides route stonnwater from the south to the north side of the plant. During recent construction, groundwater was not encountered approximately 10 feet below the 100 year flood elevation, or El. 1054. The soils at the plant site are sandy loam, with some clays present at the higher elevations. Lower Creek is a Class C water. An aerial photograph of the plant site and surrounding property is provided as Figure 5, and a topographical map is provided as Figure 6. As shown in Figure 4, the proposed construction will not directly impact any surrounding property or woodlands. The proposed construction will be limited to the existing plant site. f • Roo 1•. 1•-1 1tA4•!1S11 11..,. .j L • r.1 ..ti 1.. 1 1 1 PROJECT LOCATION DISCHARGE LOCATION LOWER CREEK WASTEWATER TREATMENT PLANT SR 1404 • SR 1387 • 41" i • %g0 /' ./ r • sa i sa t149 CITY LIMITS sR Citt LENOIR Ik•Ift A jSr PIx WAY 1150 tit • J tgi � I , Iy / 1 • tra SECTION 2 NEED AMMONIA REMOVAL PROBLEMS The Lower Creek Wastewater Treatment Facility's NPDES permit previously permitted a discharge of 6.0 MGD to Lower Creek. In 1987 plant modifications were made to down rate the plant and the NPDES permit to a 4.08 mgd discharge in order to better treat the relatively low flow the plant was receiving at the time, and to reduce the operating requirements. The facility has experienced numerous problems over the past several years in meeting its summer effluent ammonia permit limit of 7.0 milligrams per liter (mg/1). (See letter to the North Carolina Division of Water Quality dated September 6, 1996 in Appendix A). The City has recently submitted an application to the State of North Carolina to obtain a Special Order by Consent (SOC) to allow time to correct the ammonia removal problem. Based on preliminary engineering design, it is anticipated that one of the existing sludge holding basins will be converted to an aeration basin to provide additional detention time. FLOW PROJECTIONS Currently the plant is treating an average daily flow of approximately 2.2 mgd. When the plant influent reaches 3.26 mgd, the City will be required to submit a plan of action to the State. The Town has recently signed agreements with the nearby towns of Gamewell and Cajah's mountain for allocations to treat 450,000 gpd, with an estimated 300,000 gpd of this flow going to the Lower Creek facility. The engineering firm McKim and Creed is currently preparing a 201 Facility Plan for Caldwell County and, based on population and flow projections to be included in this plan for a 20-year planning period, the projected flow for the Lower Creek drainage basin is 5.2 MGD. As mentioned previously, the plant was originally constructed as a 6.0 mgd plant, and the clarifiers and chlorine contact basin are already sized for 6.0 mgd. Since the City will be performing plant modifications to correct the ammonia removal problem, they would like to -4 • f�l a Y Je, incorporate into the project the necessary improvements to increase the plant capacity back to 6.0 mgd. This will provide cost savings to the City by constructing a large capital improvements project now instead of several smaller projects in the future. Savings should be experienced in engineering, bidding, permitting and construction. In addition, in light of the statewide trend toward nutrient reductions in the waters of North Carolina, the City will be incorporating removal of both nitrogen and phosphorous into this project through a biological nutrient removal process. SECTION 3 ALTERNATIVE ANALYSIS In order for an alternative to be considered acceptable, it must be capable of correcting the ammonia problem and must include a treatment process with nutrient removal capability. The following alternatives were evaluated: 1. Convert the existing aeration basin and sludge holding basin to a biological nutrient removal treatment system, upgrade the influent pumps and return sludge pumps, and modify piping as required to expand the plant to a 6.0 mgd capacity. Continue to discharge improved quality effluent to Lower Creek. The biological nutrient removal equipment will include multiple aeration blowers, air diffusers in the bottom - of the aeration basin, and mixers in the anaerobic and anoxic basins (see Figure 4 in Section 1). .j 2. Expand and modify the plant as described in Alternative No. 1 and pump 2.0 mgd of the effluent to a spray irrigation disposal field. In addition to the treatment equipment included in Alternative No. 1, this alternative also includes an effluent pump station at the WWTP to transmit the effluent to the spray irrigation site, and a spray irrigation „4. pump station. 6 14, 3. Do not perform improvements to the plant Alternative No. 3 is not an environmentally feasible alternative in light of the anunonia removal problems which the facility is currently experiencing. Since improvements to the plant must be performed, the City of Lenoir would like this project to be the final major capital improvements project at the facility and include the expansion to 6.0 mgd with the improvements. Therefore, Alternative No. 3 is rejected. Alternatives No. 1 and No. 2 are identical in improvements to the WWTP, but differ in their method of effluent discharge. Alternative No. 1 continues to discharge to Lower Creek. Alternative No. 2 requires a total of 1125 acres for a spray irrigation field sized for 2.0 MGD • • at forl Enq (size of expansion) including 150' property line setbacks required by the State. The City of Lenoir does not own land of magnitude, so this alternative includes the purchase of this land at an estimated cost of $5,000 per acre. In addition, the State requires storage lagoons with a minimum 5 days of storage capacity to be used during wet or freezing weather. For this region, we recommend a minimum of 15 days of storage, or 30,000,000 gallons.. The cost of . this spray irrigation facility is enormous when compared to the cost of treatment plant improvements. Total project costs for Alternatives No. 1 and No. 2 are provided in Tables 3- 1 and 3-2, respectively. Table 3-3 provides operating costs and a calculated present value cost for each alternative. Based on these cost estimates, Alternative No. 2 is not economically feasible, although it is certainly environmentally feasible. Therefore, Alternative No. 1 is the preferred alternative. The environmental consequences of Alternatives No. 1 and No. 2 will be evaluated in Section 4 of this report, to determine if it is environmentally feasible. f�1 Gli SECTION 4 ENVIRONMENTAL CONSEQUENCES GENERAL The state agencies listed below were contacted for scoping comments belated to the proposed expansion. Comments received to date are included in Appendix D. • North Carolina Division of Land Resources • North Carolina Division of Forest Resources • North Carolina Wildlife Resources Commission • North Carolina Division of Parks and Recreation • North Carolina Department of Cultural Resources • North Carolina Division of Water Resources • North Carolina Division of Environmental Health • North Carolina Division of Soil and Water Conservation Since there is already an existing treatment facility on the site, the primary environmental consequence to be considered is the affect the increased discharge will have on wildlife. -- The proposed nutrient removal capability of the project for nitrogen and phosphorous removal will also be considered. CHANGES IN LAND USE 6 Alternative No. 1 is limited to the existing WWTP site and will not directlyaffect any Y TT other properties. The land use of the site will remain as a publicly owned wastewater treatment facility. The potential cumulative and indirect effect of expanding the plant capacity is that it could accelerate residential, commercial, and industrial growth in the surrounding area. Based on an average flow of 300 gallons per day (gpd) per equivalent residential unit (ERU), an additional 2 mgd of capacity could result in an additional 6,667 .4 1 PIO Pen ERU's. If it is assumed that 40 percent of the growth will be industrial or commercial in nature, this would result in approximately 4,000 residential connections, and a combination of commercial and industrial establishments, which generate approximately 800,000 gpd. Since one large wet industry could exceed this. flow, it is difficult to estimate the number of commercial and industrial establishments. However, in general, the cumulative and indirect effects could be some changes in land use in the surrounding area to accommodate the future growth. Alternative No. 2 would have the same direct, cumulative and indirect effects as Alternative No. 1, and would have one additional direct effect. The City would need to acquire approximately 1,125 acres to use as spray irrigation fields and wet/cold weather storage lagoons. This would result in a change in land use for those 1,125 acres. Additional cumulative and indirect affects would include changes in land use around the spray irrigation fields due to negative public opinions. Residents or commercial establishments may relocate as a result of the installation of spray irrigation fields. Alternative No. 3 would have no direct, cumulative or indirect effects on land use, except that it could limit future growth. WETLANDS Alternative No. 1 is limited to the existing plant site. There are no wetlands that will be 5a, : directly impacted during construction of the proposed improvements. Alternative No. 2 1 - includes 1,125 acres of spray irrigation fields. It is assumed that the spray irrigation P Y fields will not be located in existing wetlands and, therefore, would have no direct effect to wetlands. sig 4,' Indirect and cumulative effects of Alternative No. 1 and No. 2 is that increased development as a result of the reserve treatment capacity could impact wetlands in the area. Maps provided by the Division of Soil and Water Conservation, which delineate wetlands in the service area are provided at the end of this section. Again, it is assumed that the state regulatory offices and the Army Corps of Engineers will not allow construction in wetlands. However, if this is not enforced, the wetlands areas shown on • gig fiC the maps could be affected. In addition, the increased sedimentation as a result of the future construction could have adverse effects on wetlands in the area. Sedimentation and control devices should be required by the local land resources offices in areas of concern to minimize adverse effects to wetlands: PRIME OR UNIQUE AGRICULTURAL LANDS Alternative No. 1 will not directly affect any agricultural lands because it is limited to the existing site. The cumulative and indirect effect is that the additional reserve capacity could spur growth in the area and agricultural lands could potentially be converted to residential, commercial, or industrial establishments. The Caldwell County soils survey prepared by the U.S. Department of Agriculture -Natural Resources lists the following soils as being prime farmland: Prime Farmland Soils ApB . Applying sandy loam, 2 to 8 percent slopes CeB2 Cecil sandy loam, 2 to 8 percent slopes, eroded DnB . Davidson clay loam, 2 to 8 percent slopes DoB Dougue fine sandy loam, 2 to 8 percent slopes MaB Masada loam, 2 to 8 percent slopes SeB State loam, 2 to 8 percent slopes TaB Tate fine sandy loam 2 to 8 percent slopes In addition, the soils survey lists the following soils as being important to state and local ,.� agriculture: Important Farmland Soils ApD Applying sandy loam, 8 to 15 percent slopes CeD2 Cecil sandy loam, 8 to 15 percent slopes, eroded/ Cm Chewacla loam, occasionally flooded Co Congaree fme sandy loam, occasionally flooded DnD • • Davidson clay loam, 8 to 15 percent slopes MaD Masada loam, 8 to 15 percent slopes TaE Tate fine sandy loam 8 to 25 percent slopes The general soils map for Caldwell County, and a map showing soils in the Lower Creek WWTP service area is provided at the end of this section. According to the soils survey, approximately 7%, or 20,686 acres of the county is prune farmland, and the largest areas are in general areas No. 1 and No. 2. Approximately 20%, or 58,822 acres of the county is classified as important to state and local agriculture, and the largest areas are in general areas No. 1, 2 and 4. The Lower Creek WWTP service area includes general soils areas No. 1 and No. 4, but not No. 2. Therefore, prime and important agricultural lands could potentially be impacted by future development. However, the total potential amount of land to be developed as indirect effects is 4,184 acres (see paragraphs .regarding forest land later in this section). Most likely only a portion of this land would be classified as prime or important farmland. Therefore, considering the total amount of land that could potentially be impacted, the effects are considered insignificant. NUL � f .41 PUBLIC LANDS SUCH AS PARKS According to the Caldwell County map prepared by Champion Map Corporation, there are no known local, state, or national parks in the vicinity of the Lower Creek WWTP. The Pisgah National Forest does not extend into the WWTP service area. Therefore, Alternative No. 1 will have no direct, cumulative, or indirect impacts to public lands. Alternative No. 2 will require that additional land be purchased by the city for spray irrigation fields that would have restrictions on public access. Therefore, the direct effect of Alternative No. 2 would be less land with full public access. The cumulative and indirect effect of Alternative No. 2 could be less land available for public parks. This is n ot considered a significant impact. SCENIC AND RECREATIONAL AREAS 1 Based on scoping comments received from the North Carolina Division of Parks and Ph i Recreation, there are no known high quality natural communities or significant natural II areas within a one (1) mile radius of the proposed Lower Creek WWTP (see Appendix D). Therefore, all alternatives will have no direct effects on scenic and recreational areas, since none currently exist. Alternative No. 1 will also have no indirect or cumulative effects. Alternative No. 2, however, may have the cumulative and indirect effect of limiting potential scenic and recreational areas due to the 1,125 acres required = q for the spray irrigation fields. However, based on the large amount of uninhabited land z= available in Caldwell County, the impact should be insignificant. Alternative No. 3 �"• obviouslywill have no direr indirect,cumulative t, or cumulative effects. tio Tr. I. AREAS OF ARCHEOLOGICAL OR HISTORICAL VALUE Scoping comments from the North Carolina Department of Cultural Resources indicate that there are no known properties of architectural, historic or archaeological significance which will be impacted by Alternative No. 1. Since Alternative No. 1 is limited to the existing plant site, no direct, cumulative or indirect effects will result. Alternative No. 2 includes 1,125 acres of off -site spray irrigation fields, and the locations for these fields would need to be examined to ensure that they do not affect properties of architectural, rcEli 4 -.... 4 4 o. fmn historic, or archaeological significance. Obviously, Alternative No. 3 will have no direct, cumulative or indirect effects. AIR QUALITY Based on the other plants that utilize biological nutrient removal processes, no odor problems are expected to result from these plant improvements. Thereforp, Alternative No. 1 will have no direct impacts to air quality. As flow to the plant increases, more sludge will be removed to be treated, which will result in three indirect and cumulative — effects. The first is that more dry lime will be used to treat the sludge, potentially creating the potential for additional release of lime particulates into the air. The City has an air quality permit to operate the existing lime silo and the silo includes a dust collector to capture lime dust that may be released during loading of the silo. This therefore, should keep any degradation of air quality to a m niznum. The second indirect effect is that the odors in the immediate area may increase as additional sludge is generated. As part of this project, the City is considering covering the basin, which holds - and thickens the liquid sludge to minimize nuisance odors to operators and nearby property owners. Alternative No. 2 includes spray irrigation fields, which may have some odor in the immediate areas of the sprayed effluent. These odors, however, are not considered to be a significant nuisance. The third indirect effect is that the reserve plant capacity could potentially encourage industrial growth in the area. Depending on the type of industries that develop, the industries could generate byproducts that would be a detriment to the quality of the air. The North Carolina Division of Air Quality has strict requirements that industries must follow in order to preserve the quality of the air. The indirect effects will be directly dependent on the types of industries that develop and the degree of enforcement of the North Carolina air quality regulations. With propoer enforcement of regulations, the effects should be insignificant. 4 GROUNDWATER QUALITY During construction of the proposed expansion, care will be taken to prevent the accidental discharge of wastewater to the ground. Any direct impacts to groundwater is a result of Alternative No. 1 will be minimal and will be limited to the plant site. Alternative No. 2 includes a spray irrigation fields that will discharge effluent to the land surfaces. This water will have been treated and will receive further treatment as it percolates through the soil. The required 150 foot setback from adjacent property lines, and 100 foot setback from wells will help minimize the direct impacts of Alternative No. 2 to groundwater. However, Alternative No. 2 would clearly have a greater potential for adversely affecting groundwater than Alternative No. 1. Indirect and cumulative effects to groundwater as a result of increased development in the area will be dependent on the enforcement of setbacks from wells. Local health officials are required to locate septic tanks such that they will not impact drinking wells. If proper enforcement of regulations is practiced the indirect and cumulative effects should be insignificant. NOISE LEVELS The direct effects to noise levels for Alternatives No. 1 and No. 2 are that the new aeration blowers will produce additional noise. The blowers will include silencers of minimize the noise. If the noise generates complaints from local residents, the blowers may have to be enclosed in a building. There will also be a temporary increase in noise due to the construction of the project. This will be limited primarily to daylight hours, except in emergencies or when work must be done during the low flow periods (i.e., during the night). These direct effects are considered to be insignificant because steps will be taken if nearby property owners complain about excessive noise. The indirect and cumulative effects are that this increased development would most likely result in increased noise due to normal urban and rural development, traffic, factories, or other industries. These indirect and cumulative effects would be basically the same for rams • "k• •. both Alternatives No. 1 and No. 2. This noise level will be no more than normal for a • typical community of this size, and are considered insignificant. FOREST LAND Alternative No. 1 is limited to the existing plant site and will not require the removal of any trees. Indirect and cumulative effects of Alternative No. 1 woul . include the potential for removal of surrounding forest land to accommodate future development that may result from the reserve wastewater treatment capacity. The following criteria will be used to estimate the amount of forest land that could potentially be impacted by future development: • Commercial and industrial - 0.1 gpd/SF • Residential - 300 gpd/acre • Residential land use - 70 percent of total available • Commercial/Industrial land use - 40 percent of total available Based fir on the above criteria and assuming 60 percent of future development (1.2 mgd) will be residential, it is estimated that approximately 4,000 acres of land could be required for future residential development. Further, it is estimated that approximately 184 acres of land could be required for future commercial and industrial development. If it is assumed that 80 percent of this land is forest land, and using the land use criteria listed above, it is estimated that approximately 2,240 acres of forest land could be removed due to future residential development, and approximately 59 acres of forest land could be removed due to future commercial and residential development, for a total of Tr' 2,299 acres of forest land to be impacted due to indirect and cumulative effects. It is noted that these are merely projections based on average assumptions, and these figures could change dramatically if at least one large wet industry were to be constructed. i Another indirect impact would be construction of sewer lines to accommodate future development, and the removal of trees to install the sewer lines. Normally, for ease of construction, unwooded routes are selected for sewer lines. However, it can reasonably rim r ij melt 41 MAE rat be expected that some trees would need to be removed. For this project, it is estimated that approximately 5 acres of forest land could be cleared for installation of future sewer lines. Alternative No. 2 includes approximately 1,125 acres of spray irrigation fields that would directly impact surrounding forest lands. If it is assumed that 80 percent of the land used will be forest land, it is estimated that Alternative No. 2 would impact approximately 900 acres of forest land. Based on scoping comments provided by the North Carolina Division of Forest Resource s(see Appendix D), the Division would prefer that effluent not be sprayed directly on wooded areas. The estimated 900 acres of forest land would need to be removed to satisfy this request. It is unlikely that enough cleared land could be found to accommodate the required acreage based on density of forest land surrounding the project area. The indirect and cumulative effects of Alternative No. 2 would be the same as Alternative No. 1. It is clear that Alternative No. 1 would have less direct impact to forest land and would be preferred over Alternative No. 2. Alternative No. 1 will have no direct effects to forest land. Because of the vast amounts of forest land available in Caldwell County, the indirect and cumulative effects for both altematives are considered insignificant. SURFACE WATERS This project is located in the Catawba River drainage basin. The Catawba River Basinwide Water Quality Management Plan prepared by the North Carolina Division of Environmental Management in July 1995, indicates that Lower Creek is experiencing problems with sedimentation and elevated fecal coliform levels due to non -point and point source discharges (see Appendix E). Lower Creek received a Fair beathos rating and a Fair -Good fish rating. The basinwide management plant also lists Lower Creek as -17 being "partially supporting", meaning that the stream has experienced some degradation due to the excessive sedimentation and fecal coliform levels. Lower Creek has been listed as a high priorityfor g a sediment control program. 4. s rse x fal The basinwide management plan indicates that the sediment and fecal coliform levels being experienced by Lower Creek are attributed to both wastewater discharges and urban stormwater. Fecal coliforms are currently reduced at the Lower Creek WWTP by chlorination and are limited by the NPDES permit. Alternative No. 1 would increase the discharge to Lower Creek by 2 mgd and would increase the level of fecal coliforms in Lower Creek, since the requirements of the NPDES speculative permit for fecal coliform removal is identical to the current requirement. During construction of the fxpansion, the contractor will be required to install sedimentation and erosion control devices to prevent sediment from entering the stream. This will minimize the temporary direct effect of additional sediment entering the stream during construction. It is the North Carolina Division of Water Quality's responsibility to set permit limits that will not be harmful to the surface waters. Assuming this is accomplished, the direct effect of the expansion should not be harmful to the creek. The direct effects of Alternative No. 2 would be identical to Alternative No. 1 with respect to temporary sediment impacts to Lower Creek during construction of the expansion. Regarding fecal coliform levels, since Alternative No. 2 is a non -discharge alternative, there would be no effect to fecal coliform levels. - Indirect and cumulative effects of both Alternatives No. 1 and No. 2 would be the potential for sediment entering the creek during the construction of future development. The North Carolina Division of Land Resources requires that erosion and sedimentation control be practiced during construction. If the regulations are properly followed and enforced, additional sediment to the creek should be minimized. Additionally, potential future development will increase the amount if impervious areas and could result in additional sediment entering Lower Creek as run off from roofs and paved areas. This situation should be monitored closely by the Division of Land Resources to minimize adverse impacts. This monitoring should make the effects insignificant. c OEM ran A t.x "tll WATER SUPPLIES There are no known water supply intakes on Lower Creek. The point of discharge is approximately nine (9) miles upstream of the point where Lower Creek flows into the Catawba River. • The nearest downstream water supply intake is the City of Lenoir's Lake Rhodhiss Water Treatment Plant on the Catawba River, approximately 10 miles downstream of the point that Lower Creek enters the Catawba River. Therefor, it does I1ot appear that , Alternative No. 1 will directly affect any existing water supplies in the area. It is noted, however, that, according to the regional North Carolina Department of Environment, Health and Natural Resources (NCDEHNR) office, Lower Creek itself is classified as a WS-4 water supply. Alternative No. 2 is a non -discharge alternative and therefore, will not directly affect any surface water supplies. Additionally, the state required setback of 100 feet from wells for the spray irrigation field should minimize any impacts to wells. Indirect and cumulative effects of Alternatives No. 1 and No. 2 would be similar to those discussed in the Surface Water Section related to increased sedimentation. Increased sedimentation could make treatment of the water more difficult. In addition, if fecal colifonm levels continue to increase as follow increases due to future development, the quality of the water as a water source could degrade. The State Division of Water Quality's monitoring should make these effects insignificant. SHELLFISH OR FISH AND THEIR HABITATS The basinwide management plan gives Lower Creek a Fair -Good fish rating. Excessive sedimentation and fecal coliform levels have prevented the creek from achieving a higher rating. A listing of rare species that may be located in Caldwell County as provided by the North Carolina Natural Heritage Program is included in Appendix C. Four (4) invertebrates are listed as rare in North Carolina, but no fish or shellfish are listed as endangered or threatened on a national level. Ammonia -nitrogen (NH3), total nitrogen and phosphorous are nutrients present in most effluent discharges from wastewater treatment plants. Ammonia -nitrogen and phosphorous can be assimilated by algae and aquatic plants and could cause excessive growths (euthophication) that create water quality problems. Additionally, biological nitrification of the ammonia can occur which, if excessive, could deplete the dissolved oxygen (D.O.) concentration in the stream and have an adverse affect on. fish. Nitrates can be used by algae and other plants to make protein, and if excessive, could contribute to eutrophiication. Total nitrogen removal by denitrification removes nitrates before they are discharged to the stream. Since the plant has been experiencing difficulty in removing ammonia, the main objective of this project is to reduce the ammonia concentration in the effluent to less than 2.0 mg/I. This would comply with the speculative limits issued by NCDEHNR (See Appendix A). Between September, 1995 and August, 1996, the plant was only able to achieve an average effluent ammonia concentration of 11.3 mg/1. At the current flow of 2.2 mgd, the amount of ammonia discharged to Lower Creek will be reduced from 207 pounds per day to approximately 37 pounds per day. For Alternative No. 1, at 6.0 mgd, approximately 100 gpd will be discharged, which will directly decrease the amount of ammonia discharged to the stream. Since Alternative No. 2 is a non -discharge alternative for the 2 mgd expansion, 4 mgd will continue to be discharged to Lower Creek. At 4.0 mgd, approximately 67 gpd of ammonia would be discharged to the stream. The Plant does not currently have effluent limit for phosphorous, but the goal of this project is to reduce phosphorous to a concentration of 2 mg/I in the effluent. This should also help to minimize the potential for eutrophication. Indirect and cumulative effects for Alternatives No. 1 and No. 2 would be similar to those discussed in the Surface Water Section. Increased sedimentation and fecal coliform levels could eventually be a detriment to fish and their habitats. The sediment and fecal coliform levels should be monitored carefully by the State to ensure that the fish rating for Lower Creek does not drop below Fair -Good. lint • 118 • mg• Li mat WILDLIFE AND THEIR HABITATS A listing of rare species that may be located in Caldwell County as provided by the North Carolina Natural Heritage Program is included in Appendix C. The spruce fir moss spider is the only listed species that is endangered. • Alternative No. 1 is limited to the plant site and should not directly impact any wildlife or their habitats. Alternative No. 2 includes 1,125 acres of spray irrigation fields and most likely, would have a direct impact on wildlife present at the spray irrigation sites. The treated effluent that is sprayed on the ground is not expected to be harmful to wildlife, but wildlife in the area may relocate to another habitat. Indirect and cumulative effects of both Alternatives No. 1 and No. 2 are that as new development occurs, construction of homes and buildings will push any wildlife present to other habitats. Based on the large amounts of uninhabited land in Caldwell County, wildlife should not have difficulties establishing new acceptable habitats. Therefore, the indirect and cumulative effects should be insignificant. INTRODUCTION OF TOXIC SUBSTANCES Because this project will significantly reduce ammonia nitrogen the amount of ammonia discharged to the stream and the design flow of 6..0 mgd will actually be significantly less than that currently being discharged at 2.2 mgd. At the design effluent concentration of 2.0 mg/I., 100 ppd of ammonia nitrogen will be discharged at 6.0 mgd, compared to 207 ppd currently being discharged. The facility currently does not have an effluent limit for chlorine residual, and, according to the City, an average of approximately 200 micrograms per liter is currently discharged. The City recently installed a dechlorination facility designed to reduce chlorine residual in the effluent by adding sulfur dioxide. Based on the speculativepermit limits, it is anticipated that sP P a chlorine residual limit of 28 micrograms per liter will be included with the new NPDES permit. At the current flow of 2.2 mgd, approximately 3.7 pounds per day of chlorine is discharged at a concentration of 200 micrograms per liter. And the project design flow of 6.0 mgd, and at the expected limit of 28 micrograms per liter, the amount of chlorine discharged to Lower Creek will be reduced to 1.4 ppd, for Alternative No. 1. For Alternative No. 2, the amount of chlorine discharge at 4.0 mgd is about 0.9 ppd. XCI The facility is currently monitoring copper, zinc, cadmium and cyanide. According to the City, copper averages approximately 10 micrograms per liter, and zinc averages approximately 50 micrograms per liter. The current NPDES permit limits cadmium to 4.9 micrograms per liter, and cyanide to 12 micrograms per liter. At the project, jiesign flow of 6.0 mgd, 0.5 ppd of copper, 2.5 ppd of zinc, 0.25 ppd of cadmium, and 0.6 ppd of cyanide would be discharged to the stream. NCDEHNR has indicated that a chronic toxicity testing requirement with quarterly monitoring will remain a condition of the NPDES permit. During 1996, the plant has reportedly failed the toxicity testing on one occasion (February, 1996). NCDEHNR indicated that a complete evaluation of limits and monitoring requirements for metals and other toxicants will be addressed at the time of formal NPDES permit application. In addition, Alternative No. 2 would directly introduce ammonia and chlorine to the land that the effluent is sprayed on. The low levels are not expected to be harmful to the land. Treated effluent is often used to irrigate golf courses and even some cropland in other states. The direct effects of the project for both Alternatives No. 1 and No. 2 would be a reduction in ammonia and chlorine to the creek. There should not be any indirect or cumulative effects for - either alternative. RESULTS Table 4-1 compares the direct, indirect, and cumulative environmental effects of Alternatives No. 1 and No. 2. Since Alternative No. 3 is not considered a viable option, it is not included in the table. Alternative No. 3 is the "do nothing" alternative and would have no effects. riki. rik 3 • $ a ICI aim PPM ex, st !mt. , '1 mid al El The results of the environmental consequences analysis is that neither Alternative No. 1 or No. 2 will have any significant impacts on the environment except related to land use changes and fish and their habitats. Land use changes are expected as indirect and cumulative effects of Alternative No. 1, and as direct, indirect and cumulative effects of Alternative No. 2. However, these land use changes in and of themselves are not considered to be harmful to the environment. The effects of the project on fish and their habitats will actually directly improve as the ammonia and chlorine levels of the effluent discharged to Lgwer Creek are lowered through advanced treatment methods (i.e., ammonia removal and dechlorination). Other subjects, most notably air quality, forest land and surface waters rely on mitigative measures by contractors, developers and state regulators to result in no significant impacts as a result of the proposed expansion. TABLE 4-1 ENVIRONMENTAL CONSEQUENCES SUBJECT ALTERNATIVE NO. 1 ALTERNATIVE NO. 2 DIRECT INDIRECT & CUMULATIVE DIRECT INDIRECT & CUMULATIVE Land Use Changes Wetlands Prime Agricultural Lands Public Lands Scenic & Recreational Areas Archeological or Historical Areas Air Quality Groundwater Quality Noise Levels Forest Land Surface Waters Water Supplies Fish & their Habitats Wildlife & their Habitats A Tl1TT _ • None None None None None None Insignificant Insignificant Insignificant None Insignificant None Improved None • Significant Insignificant Insignificant None None None Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant _ Significant None Insignificant Insignificant None Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Improved Insignificant — Significant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Insignificant Significant = Project will have a significant impact on subject None = No impact Insignificant = No significant impact Improved = Alternative will improve conditions for subject. • rya Pal 1I r' SECTION 5 RECOMMENDATIONS Alternative No. 3 was dismissed previously as an unacceptable alternative because it would not correct the ammonia removal problem. In addition, Alternative No. 3 does not expand the plant, and based on population projections, the plant capacity is inadequate for a 20-year planning period. The environmental consequences analysis indicates that mitigative measures would result in no significant hannfiul impacts to the environment by either Alternative No. 1 or Alternative No. 2. Alternative No. 2 is not financially feasible, so, Alternative No. 1 is the recommended alternative. It is recommended that the City proceed with the construction of a biological nutrient removal facility and expand the plant to a capacity of 6.0 mgd.