Juneau Douglas Wastewater Treatment Plant Energy Audit

Transcription

1 Juneau Douglas Wastewater Treatment Plant Energy Audit Final Report August 14, 2009 Juneau Douglas Wastewater Treatment Plant City and Borough of Juneau Prepared for: City and Borough of Juneau Contract No. RFP E Prepared by: Alaska Energy Engineering LLC Amalga Harbor Road Tel/Fax: Juneau, Alaska

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3 Table of Contents Table of Contents 1 Project Team 2 Abbreviations 2 Section 1: Executive Summary 3 Background 3 Energy Conservation Opportunities 5 Facility Guidelines 8 Summary 11 Section 2: Introduction 13 Background 13 Methodology 16 Section 3: Buildings 19 Control Building 19 Aeration Buildings 23 Clarifier Building 23 UV Building 24 Digester Building 26 Incinerator Building 27 Section 4: Wastewater Treatment Process 33 Headworks 33 Aeration Basins 33 Clarifiers 34 UV Treatment 34 Digester 34 Incineration 34 Section 5: Energy Conservation Opportunities 37 Appendix A: Appendix B: Appendix C: Energy Use Data Energy Analysis Calculations Life Cycle Cost Analysis Calculations City and Borough of Juneau 1 JDWWTP Energy Audit

4 Project Team Energy Engineering Jim Rehfeldt, P.E., Mechanical Engineer Alaska Energy Engineering LLC Amalga Harbor Road Juneau, Alaska Civil Engineering Jim Dorn, P.E., Civil Engineer Carson Dorn Inc. 712 West 12th Street Juneau, Alaska Abbreviations AEL&P Alaska Electric Light & Power Co. AHU Air handling unit AV Automatic valve BTUH BTU per hour CBJ City and Borough of Juneau CFL Compact Fluorescent Lamp DX Direct expansion EF Exhaust fan HP Horsepower ECO Energy Conservation Opportunity GPM Gallons per minute Inc. Incandescent HPS High pressure sodium JDWWTP Juneau Douglas Wastewater Treatment Plant kw Kilowatt kwh Kilowatt-hour LCC Life cycle cost MH Metal halide MWWTP Mendenhall Wastewater Treatment Plant NEMA National Electrical Manufacturers Assoc NPW Non-potable water OH Overhead P.E. Professional Engineer RAS Return activated sludge UV Ultraviolet VFD Variable frequency drive W Watt WAS Waste activated sludge City and Borough of Juneau 2 JDWWTP Energy Audit

5 Section 1 Executive Summary This report presents the findings of an energy audit of the Juneau Douglas Wastewater Treatment Plant (JDWWTP). The purpose of the energy audit is to identify energy conservation opportunities (ECOs) and determine if investments in energy efficiency will provide a life cycle savings. The findings were gathered through on-site observations, review of construction documents, and interviews with operations and maintenance personnel. The energy audit was performed by Jim Rehfeldt, P.E. of Alaska Energy Engineering LLC with technical assistance by Jim Dorn, P.E. of Carson Dorn, Inc. BACKGROUND Plant Description The Juneau Douglas Wastewater Treatment Facility processed 508M gallons of influent and incinerated 1,020 metric tons of sludge in The plant wastewater flows through the following process facilities: Headworks: Consists of a receiving basin that removes sand and grit with a grit ladder, a bar screen that is manually raked to remove rags, a comminutor that grinds plastics, and a distribution box that divides the flow to the aerators. Aeration Basins: There are two aeration basins, each with two aerators that introduce oxygen by mechanical agitation to breakdown the wastes held in suspension. Clarifying Tanks: There are two clarifiers that remove suspended matter from the wastewater. Sludge is skimmed off the bottom by a rake pumped back to the aeration basins by return activated sludge (RAS) pumps. Waste activated sludge (WAS) pumps remove excess sludge and floating material that is skimmed off the top. UV Treatment: The clarified water is disinfected by UV light treatment prior to discharge to the ocean. Digester: The digester basin holds the sludge prior to dewatering and incineration. The digester has an aerator that introduces oxygen by mechanical agitation to breakdown the wastes held in suspension. Incineration: The sludge from JDWWTP is dewatered and incinerated. Dewatered sludge cake from the Mendenhall Wastewater Treatment Plant is also incinerated at JDWWTP. City and Borough of Juneau 3 JDWWTP Energy Audit

6 Energy Use Electricity The facility has two metered electric accounts. The Control Building has an electric meter and service that feeds all of the facilities except the Incinerator Building and UV Building. The Incinerator Building has an electric meter and service that feeds the Incinerator Building and UV Building. Table 1-1 provides a breakdown of the energy use. Table 1-1: Annual Electric Use and Cost 1 Usage Demand 2 Cost Cost Service kwh kw $ / kwh Main Plant Service 990, $75, Incinerator and UV Treatment 990, $84, Totals 1,980, $159, Costs based on AEL&P Rate Average monthly demand Fuel Oil There are two fuel oil tanks at the plant. The Control Building tank supplies a heating boiler in the Control Building and the Incinerator Building tank supplies the incinerator and heating boiler in the Incinerator Building. Table 1-2: Annual Fuel Oil Use and Cost Usage Cost Service gallons $ Control Building Boiler 1,100 $2,100 Incinerator Building Incinerator 95,100 $180,700 Boiler 2,900 $5,500 Totals 99,100 $188,300 Cost based on 2008 price of $1.90 per gallon City and Borough of Juneau 4 JDWWTP Energy Audit

7 ENERGY CONSERVATION OPPORTUNITIES The energy audit revealed energy conservation opportunities (ECOs) associated with the buildings, the wastewater process, and incineration process. The energy performance of the ECOs is evaluated, in Section 5, based on the operating parameters of the water system and facilities. Fort-four ECOs were found to reduce the life cycle cost of operating the plant. Behavioral or Operational Energy Conservation Opportunities First priority should be given to the following behavioral or operational ECOs that require minimal investment and offer immediate savings. The savings from these ECOs is variable and depends upon the level of implementation, which cannot be readily predicted. The ECOs are listed from highest to lowest priority. ECO-1: Turn Off Unneeded Lighting ECO-2: Improve Headworks Grit Removal ECO-3: Provide Energy Efficient Comminutor Motor ECO-4: Evaluate Feasibility of Heat Recovery from Ash Slurry Pond ECO-5: Set and Monitor Heating Setpoints ECO-6: Adjust and Monitor Exterior Lighting Photocells ECO-7: Install Control Building Exterior Lighting Controls ECO-8: Turn Lab Dryer and Furnace Off Overnight ECO-9: Calibrate Control Building Thermostat ECO-10: Reduce Incinerator Air Compressor Pressure ECO-11: Reduce Dry Sprinkler Air Compressor Pressure ECO-12: Change Control Building Boiler Operating Setpoints ECO-13: Install Incinerator Building Maintenance Platforms ECO-14: Insulate Control Building Generator Exhaust Duct and Louver ECO-15: Seal Control Building Cooling Louvers ECO-16: Weather-strip Exterior Doors High and Medium Priority Energy Conservation Opportunities Table 1-3 provides a listing of each recommended ECO that will require an investment of funds. The table lists the construction, maintenance, and energy costs of each ECO over a 25-year period. The ECOs are listed from highest to lowest priority. City and Borough of Juneau 5 JDWWTP Energy Audit

8 Table 1-3: Life Cycle Cost Analysis Summary Energy Conservation Opportunity Construction Maintenance Energy Total LCC 1 High Priority ECOs ECO-17: Replace Oversize Heaters $2,600 $0 ($92,500) ($89,900) ECO-18: Install Incinerator Bldg. CW Washdown $200 $0 ($2,500) ($2,300) ECO-19: Insulate Heating Piping $2,000 $0 ($16,800) ($14,800) ECO-20: Install AVs on Unit Heaters $300 $0 ($2,500) ($2,200) ECO-21: Replace NPW Tank and Controls $30,000 $3,500 ($211,000) ($177,500) ECO-22: Install Electrical Room Heat Recovery $5,500 $1,200 ($27,900) ($21,200) ECO-23: Replace EF-806 Motor in Incinerator Bldg. $700 $0 ($3,100) ($2,400) ECO-24: Replace RAS Pump Motors $5,200 $0 ($20,500) ($15,300) ECO-25: Repair UV Controls $15,000 $9,600 ($56,400) ($31,800) ECO-26: Replace Incinerator Boiler with Elect. Coil $53,000 ($28,900) ($157,500) ($133,400) Medium Priority ECOs ECO-27: Insulate HW Tanks (various locations) $800 $0 ($2,000) ($1,200) ECO-28: Interlock Heaters w/ OH Doors $3,000 $0 ($8,500) ($5,500) ECO-29: Replace AHU-855 Motor $1,100 $0 ($2,700) ($1,600) ECO-30: Replace AHU-859 Motor $600 $0 ($1,500) ($900) ECO-31: Insulate Control Bldg. Hot Water Piping $500 $0 ($1,100) ($600) ECO-32: Replace AHU-856 Motor $600 $0 ($1,200) ($600) ECO-33: Replace AHU-857 Motor $600 $0 ($1,200) ($600) ECO-34: Replace Pond Return Pump $3,500 $0 ($5,700) ($2,200) ECO-35: Install Control Room Natural Cooling Fan $6,500 ($3,500) ($6,800) ($3,800) ECO-36: Replace F-807 Motor $1,800 $0 ($2,800) ($1,000) ECO-37: Replace Belt Filter Press Motor $700 $0 ($1,000) ($300) ECO-38: Replace Ash Slurry Pump Motor $1,100 $0 ($1,600) ($500) ECO-39: Replace Cake Feed Pump Motors $5,700 $0 ($8,400) ($2,700) ECO-40: Replace Sludge Grinder Motor $700 $0 ($1,000) ($300) ECO-41: Replace Clothes Washer $800 $0 ($1,000) ($200) ECO-42: Replace Transformers (various locations) $45,200 $0 ($59,800) ($14,600) ECO-43: Upgrade Control Bldg. Lighting $3,900 $0 ($4,900) ($1,000) ECO-44: Replace Inj. Purge Blower Motor $1,800 $0 ($2,200) ($400) Totals $193,400 ($18,100) ($704,100) ($528,800) Note: Negative numbers, in parenthesis, represent savings. City and Borough of Juneau 6 JDWWTP Energy Audit

9 Energy Savings Table 1-4 shows the current energy costs and projected ECO energy savings. Table 1-4: ECO Annual Energy Cost Savings Fuel Oil Electricity Total Existing Energy Costs $188,000 $159,000 $347,000 High Priority ECO-17: Replace Oversize Heaters $0 ($5,000) ($5,000) ECO-18: Install Incinerator Bldg. CW Washdown $0 ($140) ($140) ECO-19: Insulate Heating Piping ($590) $0 ($590) ECO-20: Install AVs on Unit Heaters ($90) $0 ($90) ECO-21: Replace NPW Tank and Controls $0 ($11,000) ($11,000) ECO-22: Install Electrical Room Heat Recovery ($1,100) $110 ($990) ECO-23: Replace EF-806 Motor in Incinerator Bldg. $0 ($170) ($170) ECO-24: Replace RAS Pump Motors $0 ($1,100) ($1,100) ECO-25: Repair UV Controls $0 ($3,000) ($3,000) ECO-26: Replace Incinerator Boiler with Elect. Coil ($5,500) ($10) ($5,510) Medium Priority ECO-27: Insulate HW Tanks (various locations) $0 ($110) ($110) ECO-28: Interlock Heaters w/ OH Doors ($110) ($290) ($400) ECO-29: Replace AHU-855 Motor $0 ($150) ($150) ECO-30: Replace AHU-859 Motor $0 ($80) ($80) ECO-31: Insulate Control Bldg. Hot Water Piping $0 ($60) ($60) ECO-32: Replace AHU-856 Motor $0 ($70) ($70) ECO-33: Replace AHU-857 Motor $0 ($70) ($70) ECO-34: Replace Pond Return Pump $0 ($310) ($310) ECO-35: Install Control Room Natural Cooling $0 ($240) ($240) ECO-36: Replace F-807 Motor $0 ($150) ($150) ECO-37: Replace Belt Filter Press Motor $0 ($60) ($60) ECO-38: Replace Ash Slurry Pump Motor $0 ($90) ($90) ECO-39: Replace Cake Feed Pump Motors $0 ($450) ($450) ECO-40: Replace Sludge Grinder Motor $0 ($50) ($50) ECO-41: Replace Clothes Washer $0 ($60) ($60) ECO-42: Replace Transformers (various locations) $0 ($3,200) ($3,200) ECO-43: Upgrade Control Bldg. Lighting $0 ($270) ($270) ECO-44: Replace Inj. Purge Blower Motor $0 ($120) ($120) ECO Totals ($7,400) ($26,000) ($34,000) -4% -16% -10% Note: Negative numbers, in parenthesis, represent savings. City and Borough of Juneau 7 JDWWTP Energy Audit

10 Table 1-4 indicates that implementing the high and medium priority ECOs will provide a 10% reduction in annual energy costs. The resulting reductions in energy use are calculated to be 4%, 16% and 6%, for fuel oil use, electric use, and electric demand, respectively. Additionally, the behavioral and operational ECOs will also provide energy savings. These savings are not included in the predictions because their level of implementation cannot be accurately estimated. Two of these ECOs are of note ECO-1 (Turn Off Unneeded Lighting) predicts $950 in annual electric savings and ECO-2 (Remove Grit From Aerators) predicts $8,100 in annual electric savings. The following Low Priority ECOs are not recommended because they will not provide a life cycle savings: ECO 45: Replace Polymer Hot Water Tank ECO 46: Relocate Incinerator Control Room Condensing Unit ECO-47: Replace Motors A non-energy related recommendation is to modify the Incinerator Building ventilation systems. Previous modifications have resulted in a poor ventilation scheme. The systems should be modified to properly ventilate and cool the building. FACILITY GUIDELINES The following guidelines were developed based on the findings of the energy audit. Given the long service life of the facilities, they should also be applied when possible as part of ongoing facility maintenance or renovation. Building Envelope None of the existing buildings are optimally insulated for the current cost of heat. The optimal insulation level depends upon the type of construction and the cost of heat, which varies with each building. An envelope optimization analysis should be performed when determining insulation levels for buildings. Electric Heating Some buildings are heated with electric heating units. Controls include wall thermostats and integral thermostats supplied with the heater. In most cases, the electric heaters are oversized. While an oversized heater will supply the same amount of heat as a properly sized heater, it will incur higher demand changes. For example, a heater that is 2 kw oversized, will incur added, unnecessary demand charges of $235 annually when compared to a properly sized heater that supplies the same amount of heat. Integral thermostats provide poor control because they are influenced by the output of the heater, which causes them to turn off before the room has come up to temperature. City and Borough of Juneau 8 JDWWTP Energy Audit

11 The following guidelines are recommended for electric heating: Establish a reasonable indoor temperature. A setpoint of 55 F is likely to provide freeze protection and humidity control in unoccupied spaces. Properly size the heaters for the heating load. Install permanent heaters and control them from wall thermostats with temperature setpoints. Attached a nameplate to each thermostat with the setpoint. For heating loads of 3 kw or higher, reduce demand charges by installing two or more heaters with a maximum size of 3 kw. Provide each heater with a separate thermostat and stagger the thermostat setpoints with a minimum 3 F differential so the heating demand can vary with the heating load. Lighting Most of the spaces are occupied a minimal number of hours each year. Turning off the lighting in these spaces when they are unoccupied will produce immediate energy cost savings. Inexpensive fluorescent T-8 lighting is optimal for most interior spaces. High bay fluorescent lighting with high output T-5 lamps is more efficient and has a quicker startup than metal halide lighting. Exterior lighting operates about 50% of the year. Energy efficient metal halide lighting or high pressure sodium lighting with integral photocells is recommended for exterior lighting. Photocell controls should be fine tuned so the lighting is off during daylight hours. Transformers The buildings are supplied with 480V power. The benefit of a 480V service, when compared to 208V/120V service, is that smaller conductors are required and motors are slightly more efficient at higher voltages. The downside is that a step-down transformer that is downstream of the utility meter. The energy losses of the step-down transformer are paid by the owner. Most transformer losses are converted to heat. The heat gain to the building can be beneficial during the heating season, but is inefficient when it is not needed. There are two methods for reducing the transformer losses. First, the transformer should be right-sized. Losses are typically a percentage of the transformer capacity, so a smaller transformer costs less and has smaller losses. Second, highly energy efficient transformers should be used. Recommendations for transformers are: Right-size the transformer by establishing reasonable estimates of loads. Use energy efficient transformers. Transformers that are 15 kva and larger should meet the energy efficiency requirements of NEMA Standard TP There is no efficiency standard for smaller transformers. Locate the transformer near the floor where the heat output will create useful convective currents, spreading the heat though the facility. City and Borough of Juneau 9 JDWWTP Energy Audit

12 Operational Guidelines The following guidelines were developed based on energy conservation opportunities in the existing facilities and operations. The guidelines are recommended to improve the energy performance of the water system. Pumps The pumps should be right-sized and selected for optimal efficiency. Variable speed pumping allows pumps to operate for longer periods at lower flow rates, which reduces energy consumption and demand charges. The many energy and operational benefits of variable speed pumping should be implemented where appropriate. Motors Many of the existing motors are less efficient than modern motors. Replacing the motors with NEMA Premium efficient motors will reduce energy consumption and demand charges. The energy cost of operating a motor usually exceeds the purchase price. Whether an investment in an energy efficient motor should be made depends upon the cost of the motor, cost of electricity, and the number of operating hours each year. There is no one guideline that can cover all of these variables and NEMA Premium motors may not be available for all of the required frames. Table 1-5 provides the full load efficiencies of standard and NEMA Premium motors. Table 1-5: Motor Full Load Efficiency Horsepower Standard NEMA Premium to to to to to to to to to to to to to to to to Demand Control AEL&P determines the electric demand by averaging demand over a continuously sliding fifteenminute window. The highest fifteen-minute average during the billing period determines the peak demand. As a rule of thumb, each kw of peak load adds $10 in demand charges to the monthly electric bill. City and Borough of Juneau 10 JDWWTP Energy Audit

13 The following strategies are recommended to minimize demand: SUMMARY Implement the above facility and operational guidelines at each facility. Use variable speed pumping and establish control sequences that operate pumps for longer periods at lower flow rates. For systems with redundant pumps, limit simultaneous operation of pumps to emergencies and testing. Perform back-to-back tests within one billing cycle so the added demand charges are applied to a single month s bill. Use NEMA Premium energy efficient motors where operating hours warrant the investment. Right-size equipment such as pumps, transformers, and electric heaters. The JDWWTP energy systems are in good condition and appear to be well maintained. The age of the facilities played a factor into the number of ECOs. There is financial incentive to invest in energy efficiency and obtain a 10% reduction in energy costs. The energy auditor would like to express appreciation to the JDWWTP operation and maintenance personnel who provided assistance during this project. Their knowledge of the plant energy systems and interest in energy efficiency was invaluable. City and Borough of Juneau 11 JDWWTP Energy Audit

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15 Section 2 Introduction This report presents the findings of an energy audit of the Juneau Douglas Wastewater Treatment Plant (JDWWTP). The purpose of the energy audit is to identify energy conservation opportunities (ECOs) and determine if an investment in energy efficiency will provide a life cycle savings. The findings were gathered through on-site observations, review of construction documents, and interviews with operations and maintenance personnel. The energy audit was performed by Jim Rehfeldt, P.E. of Alaska Energy Engineering LLC with technical assistance by Jim Dorn, P.E. of Carson Dorn, Inc. BACKGROUND Plant Description The Juneau Douglas Wastewater Treatment Facility processed 500M gallons of influent and incinerated 1,020 metric tons of sludge in Influent wastewater flows through the following process facilities: Headworks: Consists of a receiving basin where sand and grit are removed by a grit ladder, a bar screen that is manually raked to remove rags, a comminutor that grinds solids, and a distribution box that divides the flow to the aerators. Aeration Basins: There are two aeration basins, each with two aerators that introduce oxygen by mechanical agitation to break down the wastes held in suspension. Clarifying Tanks: There are two clarifiers that remove suspended matter from the wastewater. Sludge is skimmed off the bottom by a rake and pumped back to the aeration basins by return activated sludge (RAS) pumps. Waste activated sludge (WAS) pumps transfer excess sludge and floating material to the digester. UV Treatment: The clarified water is disinfected by UV light treatment prior to discharge to the ocean. Digester: The digester basin holds the sludge and other wastes. The digester has an aerator that introduces oxygen by mechanical agitation to breakdown the wastes held in suspension. Incineration: The sludge from the digester is dewatered and incinerated. Dewatered sludge cake from the Mendenhall Wastewater Treatment Plant is also incinerated at the JDWWTP. Energy Use Summary Electricity The facility has two metered electric accounts. The Control Building has an electric meter and service that feeds all of the facilities except the Incinerator Building and UV Building. The Incinerator Building has an electric meter and service that feeds the Incinerator Building and UV Building. City and Borough of Juneau 13 JDWWTP Energy Audit

16 Each account is billed under AEL&P s Rate 34, Large Government which charges for both electrical consumption (kwh) and peak electric demand (kw). Electrical consumption is the amount of energy consumed and electric demand is the rate of consumption. AEL&P determines the electric demand by averaging demand over a continuously sliding fifteen minute window. The highest fifteen minute average during the billing period determines the peak demand. Table 2-1 lists the current electric charges: Table 2-1: AEL&P Large Government Rate Charge 1 On-peak (Nov-May) Off-peak (June-Oct) Energy Charge per kwh Demand Charge per kw $11.53 $7.35 Service Charge per month $99.24 $99.24 Four years of electrical energy usage data was obtained from AEL&P. The data and usage graphs are included at the end of the report. Control Building Service This service feeds the Control Building, Aeration Buildings, Clarifier Building, and Digester Building. Energy consumption: From 2005 to 2008, consumption averaged 990,000 kwh per year The monthly usage is consistent from month-to-month and from year-to-year. Plant energy use does not vary with plant flows, which typically increase during the summer tourist season. Electrical Demand: From 2005 to 2008, demand averaged 143 kw per month and has been consistent. The demand has decreased by 20 kw in Energy Costs: During , annual energy costs averaged $75,000 per year. The monthly electric bill has the following breakdown. 1. Energy consumption (kwh) = 77% 2. Electrical demand (kw) = 21% 3. Customer charges = 2% The effective cost (sum of energy and demand charges) was 7.8 per kwh. The plant has an annual load factor 81%. This is the ratio of the average load (kw) to the peak load (kw). This is a high load factor which indicates that loads are on for long periods and are not cycled for short durations. The primary benefit of a high load factor is relatively lower demand charges which result in a low effective cost per kwh. City and Borough of Juneau 14 JDWWTP Energy Audit

17 Incinerator Building Service This service feeds the Incinerator Building and UV Building. Energy consumption: From 2005 to 2008, consumption averaged 990,000 kwh per year The monthly usage is consistent from month-to-month and from year -to-year. Plant energy use does not vary with summer increases in sludge incineration and plant flows. This is because electric heating in the UV Building and sludge dewatering is less energy intensive in the summer. Electrical Demand: From 2005 to 2008, demand averaged 186 kw per month and was consistent. Demand is higher in the winter due to electric heating loads in the UV Building. Energy Costs: During , annual energy costs averaged $84,000 per year. The monthly electric bill has the following breakdown. 1. Energy consumption (kwh) = 72% 2. Electrical demand (kw) = 26% 3. Customer charges = 2% Electricity has an effective cost (sum of energy and demand charges) of 8.4 per kwh. The facilities have an annual load factor 62%. This is the ratio of the average load (kw) to the peak load (kw). The load factor is lower than the main plant because the main plant loads are continuous while the many incinerator loads operate hours per day during incinerator operation. Fuel Oil There are two fuel oil tanks at the plant: Incinerator Building tank and Control Building tank. Incinerator Building Tank The tank supplies the incinerator and the incinerator building boiler. The incinerator consumes an average of 95,000 gallons of fuel oil per year and the boiler 3,000 gallons per year. Usage is fairly consistent from year-to-year with a slight decrease in Control Building Tank The tank supplies the Control Building boiler and backup generator, which used an average of 1,100 gallons of fuel oil per year from Usage was not consistent from year-to-year because the tank is relatively large and the supplier only fills it when they have extra fuel after filling the incinerator tank. City and Borough of Juneau 15 JDWWTP Energy Audit

18 METHODOLOGY Energy Conservation Opportunities (ECOs) Energy conservation opportunities were identified by evaluating the energy systems and the operating parameters of the water system. The process for identifying the ECOs acknowledges the limitations of modifying existing buildings and systems, most of which were constructed when energy costs were much lower. The ECOs represent practical measures to improve the energy efficiency of the system. Life Cycle Cost Analysis The ECOs are evaluated using life cycle cost analysis to determine if an energy efficiency investment will provide a savings over a 25-year life. The analysis incorporates construction, replacement, maintenance and repair, and energy costs to determine the total cost over the life of the ECO. Future maintenance and energy cash flows are discounted to present worth using escalation factors for general inflation, energy inflation, and the value of money. The methodology is based on the National Institute of Standards and Technology (NIST) Handbook 135 Life Cycle Cost Analysis. Life cycle cost analysis is preferred to simple payback for facilities that have long often perpetual service lives. Simple payback, which compares construction cost and present energy cost, is reasonable for short time periods of 2-4 years, but yields below optimal results over longer periods because it does not properly account for the time value of money or the effect inflation has on operating budgets. Accounting for energy inflation and the cost of money properly values the true cost of facility ownership and seeks to minimize the total cost over its life. Appendix C contains the life cycle cost calculations of each ECO. Construction Costs The cost estimates are derived based on a preliminary understanding of the scope of each ECO as gathered during the walk-through audit. The construction costs assume in-house labor at $60 for work typically performed by maintenance staff and contract labor for larger projects and electrical work. The estimates assume some efficiency gain by being incorporated into larger, energy efficiency or other construction projects. This will spread mobilization costs over a number of ECOs and minimize costs. When ECOs are taken for implementation, the cost estimate should be revisited once the scope and preferred method of performing the work has been determined. It is possible some ECOs will not provide a life cycle savings once the scope is finalized. Maintenance Costs Maintenance costs are based on in-house labor using historical maintenance efforts and industry standards. Maintenance costs are determined for the 25-year life of each ECO and represent realistic levels of effort to maintain the relative systems. Energy Analysis The energy performance of each ECO is evaluated using operating parameters of the water system and facilities. Appendix B contains the energy analysis calculations. City and Borough of Juneau 16 JDWWTP Energy Audit

19 Prioritization A prioritized ranking of the ECOs was calculated for each building using the following formula: Prioritization Factor = Life Cycle Savings / Capital Costs This factor puts significant weight on the capital cost of an ECO, which is aligned with budgeting realities that allow early implementation of low cost improvements while higher cost ECOs must wait for funding and implementation. The ECOs are grouped into the following prioritized categories: Behavioral or Operational: ECOs that need minimal capital investment but require operational or behavioral changes. A life cycle cost analysis is not performed of these ECOs because the energy savings is difficult to quantify and a life cycle savings is certain. High Priority: ECOs that provide a life cycle savings over 200% of the capital cost. Medium Priority: ECOs that provide a life cycle savings up to 200% of the capital cost. Low Priority: ECOs that will save energy but do not provide a life cycle savings. Economic Factors Economic factors are significant to the findings and should undergo careful scrutiny. Nominal Interest Rate: This is the nominal rate of return on an investment without regard to inflation. The analysis uses a rate of 5.0% which is the current cost of bonds for CBJ capital improvement projects. Inflation Rate: This is the average inflationary change in prices over time. The analysis uses an inflation rate of 3.0% which is the consumer price index average of the past 25-years. Real Discount Rate: This is the actual rate of return when the inflation rate is considered. The analysis uses a real discount rate of 1.9% which is a calculated value derived from the nominal interest rate and the inflation rate. Economic Period: This is the period of time in which costs are considered. The analysis is based on a 25-year economic period with construction beginning in Electricity The electric rates are determined by Alaska Electric Light & Power Company (AEL&P) based on the provisions of their tariff. AEL&P is a privately owned utility regulated by the Regulatory Commission of Alaska. Power generation facilities utilized by AEL&P include both hydroelectric and diesel plants. Currently, the hydroelectric plants generate most of the electricity and the diesel plants provide backup. Over recent history, electricity inflation has been less than 1% per year, which has lagged general inflation. This trend has been discontinued in recent years as fuel oil price increases led to more electric heating loads. The winter of 2007/2008 is the first extended period where AEL&P had to supplement with diesel generation. This caused a temporary Power Cost Adjustment of 1.2 per kwh. In the fall of 2009, the new Lake Dorothy Hydroelectric Facility will begin producing power. The power from Lake Dorothy will be more expensive than power from the existing hydroelectric facilities. It is assumed that the community will consume most of the Lake Dorothy Phase 1 power in the near future and that the blended generation cost will raise electric rates 1.5 per kwh. The life cycle cost analysis includes a 1.5 /kwh increase in electric costs. City and Borough of Juneau 17 JDWWTP Energy Audit

20 Even with Lake Dorothy, electric heating loads are likely to continue to place demands on the hydroelectric generation facilities. A recent CBJ energy balance report indicates that Juneau s heating loads which are currently met with fuel oil are 175% greater than non-heating electrical loads. Thus, there is a large potential heating load that may see some conversion to electricity if fuel oil heating prices rise above electric heating prices. In essence, electricity inflation is effected by fuel oil inflation. The life cycle cost analysis uses an electric inflation of 2.5%, which is higher than the historic average to account for future electric heating price pressures. Fuel Oil The CBJ is currently paying $1.90 of a gallon of heating fuel. Prices have stabilized after dropping dramatically over the past year. Fuel oil inflation has historically averaged 6% per prior to the rapid escalation and de-escalation of prices over the past five years. The analysis assumes the fuel oil inflation will once again continue to inflate at 6% Table 2-2: Summary of Economic and Energy Factors Factor Rate or Cost Factor Rate or Cost Nominal Discount Rate 5.0% Electricity Current rates /kwh General Inflation Rate 3.0% Electricity Inflation 2.5% Real Discount Rate 1.9% Fuel Oil Cost $1.90/gal Fuel Oil Inflation 6% City and Borough of Juneau 18 JDWWTP Energy Audit

21 Section 3 Buildings This section describes the building energy systems and identifies energy conservation opportunities. The individual buildings are: Control Building: Office and Headworks Two Aeration Buildings Clarifier Building UV Disinfection Building Digester Building Incinerator CONTROL BUILDING Building Envelope Description Table 3-1: Building Envelope Component Description (inside to outside) R-value Remarks Walls Gypsum Board; 1-1/2 rigid; 8 CMU R-7 Low R-value Roof Gyp. bd.; 2x12 joists; plywood; 3 rigid; metal R-17.5 Low R-value Floor slab Concrete slab-on-grade R-2 No insulation Perimeter Concrete footing; 2 rigid, inside face R-10 Doors Front Room Wood door/frame; single pane window R-2 Low R-value Front Room Wood door/frame; single pane window R-2 Low R-value Headworks Wood door/frame; single pane window R-3 Low R-value; poor weather-stripping OH Garage Uninsulated metal door/frame R-1 Low R-value OH Grit Insulated metal door/frame R-4 Front Break Wood door/frame; single pane window R-2 Low R-value; poor weather-stripping Back Break Insulated metal door; dbl pane window R-3 Front Tool Wood door/frame R-3 Poor weather-stripping Back Tool Insulated metal door; dbl pane window R-3 Poor weather-stripping Aux. Pump Wood door/frame R-3 Poor weather-stripping City and Borough of Juneau 19 JDWWTP Energy Audit

22 Analysis The walls and roofs are under insulated. Insulation can be added but the cost of removing items from the surfaces, adding insulation, and installing wall board typically more than offsets the life cycle energy savings. The floor slabs are under insulated. However, there is no economical way to add insulation to the floor slabs. Door weather-stripping can be installed or upgraded to seal the opening, minimizing infiltration. There is no economical way to replace doors and frames with thermally broken units. Heating System Description The office portion of the building is heated by an oil-fired boiler and hydronic heating system. A circulating pump distributes heating water to baseboard heaters and unit heaters. There are two heating zones with separate thermostats: office/lab/entrance and back office/storage. The Grit Room is heated by a 15 kw electric heater. The heater is controlled by a room thermostat set at 55 F. The Storage Room is heated by a 5 kw electric heater. The heater is controlled by a room thermostat set at 60 F. The room temperature was 70 F on a cool day. The Break Room is heated by a 15 kw electric heater. The heater is controlled by a room thermostat set at 68 F. Analysis The boiler operating thermostat is set to turn on at 160 F and turn off at 180 F. Increasing the off setpoint to 190 F will result in longer run cycles and greater efficiency. The heating supply and return piping is not insulated throughout the building. Heating water continuously flows through the unit heater coils, even when no heat is needed. A room thermostat operates the heater fan to supply heat to the room. When the fan is off, the hot coil continues to lose heat to the room. An automatic valve should be installed so the thermostat can turn off the heating water flow when heat is not needed. The Grit Room heater is not interlocked with the overhead door to turn the heater off when the door is open. Installing a limit switch to stop the heater will limit the amount of heat that escapes outdoors when the door is open. The Equipment Room thermostat is out of calibration. Cooling System Description The Electrical Room has a considerable amount of heat gain from the Main Distribution Panel. The room is cooled by opening the window and manually controlling a window exhaust fan. The Grit Room, Equipment Room, and Break Room each have a roof mounted exhaust fan and makeup air damper/louver. It was reported that they are not used. City and Borough of Juneau 20 JDWWTP Energy Audit

23 Analysis The louvers and dampers are not insulated or thermally broken, which allows heat a direct conductive path to the outside. The exhaust fans provide a convective path for heat to escape from the building. Domestic Hot Water Heating Description A 40 gallon electric hot water heater supplies domestic hot water to the Office portion of the building. A 55 gallon electric hot water heater supplies domestic hot water to the Break Room Analysis The hot water tanks are located in cool rooms. Wrapping each tank in an insulating blanket will reduce heat loss. The hot water piping is not insulated. Lighting Description Table 3-2: Lighting Fixtures and Lamps Room Fixture No. / Type Lamp No. / Type Control Remarks Office Area W. Toilet 2 / Surface 2 / 23W CFL Switch - 1 / Surface 2 / 60w Inc. Switch Inefficient M. Toilet 2 / Recessed 2 / T12 Switch Inefficient 1 / Surface 1 / T8 Switch Office/Lab/Hall 25 / Recessed 2 / T12 Switch Inefficient Janitors Closet 1 / Surface 1 / 60w Inc. Switch Inefficient Mechanical 11 / Suspended 2 / T12 Switch Inefficient Storage 10 / Suspended 2 / T12 Switch Inefficient, Always on Headworks Headworks 6 / Suspended 1 / HPS Wall switch Always on Grit Room 4 / Suspended 1 / HPS Wall switch Always on Equipment 3 / Suspended 1 / 30W CFL Switch Left on Break 4 / Suspended 2 / T12 Switch Inefficient, Always on Exterior 1 / Surface 1 / HPS Wall switch On during day 1 / Surface 1 / 60w Inc. Wall switch On during day City and Borough of Juneau 21 JDWWTP Energy Audit

24 Analysis The interior T12 and incandescent lighting has a much lower efficacy than T8 or CFL lighting. The lighting in the Storage Room, Headworks and Break Room is left on continuously, even though the rooms are lightly occupied. Turning off lighting when the rooms are not in use will reduce energy. Photocell control of the exterior lighting will turn them off during daylight hours. Electrical Equipment Description The lab has a dryer and a furnace for testing samples. There is a top loading washing machine in the Mechanical Room. There is an air compressor that supplies air to the dry sprinkler system. Analysis The lab equipment is kept continually hot at 105 C and 530 C even though the equipment is only used during the normal work week. Turning it off at night and on weekends will save energy. The top-loading washing machine is less-efficient and uses more water than front-loading washing machines. The air compressor maintains the storage tank at 90 psig, which is significantly higher than the 40 psig required by the dry sprinkler system. Backup Generator Description The backup generator discharges cooling air through an exhaust duct and louver. The duct and louver are uninsulated. Analysis The uninsulated exhaust duct and louver losses heat to the outdoors. Insulating the duct will reduce the heat loss. Transformers Description The building is supplied with 480V power for the pumps. A 30 kva transformer is installed to step down the 480V building power to obtain 208V/120V power. Analysis The transformer is less efficient than current equipment. City and Borough of Juneau 22 JDWWTP Energy Audit

25 AERATION BUILDINGS There are two aeration basins enclosed in unheated buildings. Lighting Description Table 3-3: Lighting Fixtures and Lamps Room Fixture No. / Type Lamp No. / Type Control Remarks Aeration Basin 1 6 / Suspended 1 / 50w HPS Wall switch Always on Aeration Basin 2 6 / Suspended 1 / 50w HPS Wall switch Always on Analysis The lighting in the Aeration Basins is left on continuously, even though the building is rarely occupied. CLARIFIER BUILDING The two clarifiers are enclosed on an unheated building. Lighting Description Table 3-4: Lighting Fixtures and Lamps Room Fixture No. / Type Lamp No. / Type Control Remarks Clarifier Building 16 / Suspended 1 / 50w Sodium Wall switch Always on Analysis The lighting in the Clarifier Building is left on continuously, even though the building is rarely occupied. City and Borough of Juneau 23 JDWWTP Energy Audit

26 UV BUILDING Building Envelope Description Table 3-5: Building Envelope Component Description (inside to outside) R-value Remarks Walls Vapor barrier, 3 fiberglass insulation, metal panel R-10 Low R-value Windows Double pane; vinyl R-2.5 Roof Vapor barrier, 6 fiberglass insulation, metal panel R-20 Low R-value Floor slab concrete slab on grade R-2 No insulation Perimeter concrete footing, 1 rigid R-6 Low R-value Doors Entrance Uninsulated metal door and frame R-1 Low R-value; no thermal break; poor weatherstripping OH Garage Uninsulated metal door, single pane window R-1 Low R-value; no thermal break Analysis The walls and roofs are under insulated. Insulation can be added but the cost of removing items from the surfaces, adding insulation, and installing wall board typically more than offsets the life cycle energy savings. The floor slabs are under insulated. However, there is no economical way to add insulation to the floor slabs. Door weather-stripping can be installed or upgraded to seal the opening, minimizing infiltration. There is no economical way to replace doors and frames with thermally broken units. Heating System Description The building is heated by electric heating units located in each room. All of the heaters are controlled by wall thermostats. The thermostat setpoints varied from 52 F to 70 F. Analysis Reducing the heating setpoint to 55 F will save energy while maintaining sufficient warmth for personnel, prevent freezing, and control humidity. City and Borough of Juneau 24 JDWWTP Energy Audit

27 The electric heaters are oversized in most of the rooms. While an oversized heater will supply the same amount of heat as a properly sized heater, it will incur higher demand changes. For example, a heater that is 2 kw oversized, will incur additional unnecessary demand charges of $235 annually. Table 3-6: Heating Units Building Capacity, kw Heat Loss, kw Oversized, kw UV Building Cooling System Description The UV Room has a wall mounted exhaust fan with discharge damper and louver. A makeup air damper/louver has been sealed off. Domestic Hot Water Heating Description There is a 10 gallon electric hot water heater that provides tempered water to the emergency shower. Analysis The hot water heater is installed in a cool room. Adding an insulating blanket will reduce heat loss. Lighting Description Table 3-7: Lighting Fixtures and Lamps Room Fixture No. / Type Lamp No. / Type Control Remarks Workshop/UV 11 / Suspended 1 / 250w MH Switch - Workshop 11 / Suspended 2 / T8 Switch - Exterior 4 / Surface 1 / 50w HPS Photocell On during day Analysis The photocells should be adjusted to turn the lights off during daylight hours. Electrical Equipment Description An air compressor provides compressed air for the shop equipment. The unit was not operational on the day of the audit. City and Borough of Juneau 25 JDWWTP Energy Audit

28 Backup Generator Description The backup generator cooling system has an exhaust and a return air damper that controls room temperature when the generator is operating. Transformers Description The building is supplied with 480V power for the UV equipment. A 75 kva transformer is installed to step down the 480V building power to obtain 208V/120V power. Analysis The transformer is less efficient than current equipment. DIGESTER BUILDING The digester basin is enclosed in an unheated building. Lighting Description Table 3-8: Lighting Fixtures and Lamps Room Fixture No. / Type Lamp No. / Type Control Remarks Digester 5 / Suspended 1 / 50w HPS Wall switch Always on Analysis The lighting is left on continuously, even though the building is rarely occupied. City and Borough of Juneau 26 JDWWTP Energy Audit

29 INCINERATOR BUILDING Building Envelope Description Table 3-9: Building Envelope Component Description (inside to outside) R-value Remarks Incinerator Building Walls 6 metal studs, insulated wall panel R-8 Low R-value Roof Metal frame, insulated roof panel R-14 Low R-value Floor slab Concrete slab-on-grade R-2 No insulation Perimeter Concrete footing; 2 rigid, inside face R-10 Doors Entrance Insulated metal door/frame R-4 Incinerator Uninsulated metal door and frame R-1 Low R-value; no thermal break; poor weatherstripping Boiler Room Uninsulated dbl metal door and frame R-1 Low R-value; no thermal break; poor weatherstripping OH Polymer Uninsulated metal door and frame R-1 Low R-value; no thermal break; poor weatherstripping Analysis The walls and roofs are under insulated. Insulation can be added but the cost of removing items from the surfaces, adding insulation, and installing wall board is prohibitive to obtaining a life cycle savings. The floor slabs are under insulated. However, there is no economical way to add insulation to the floor slabs. There is no economic incentive to replace doors and frames with thermally broken units. Door weather-stripping can be installed or upgraded to seal the opening, minimizing infiltration. Heating System Description A steam boiler and steam distribution system supply heat to the building. The steam is supplied to a steam heating coil in AHU-855. The coil is controlled by a room thermostat set at 65 F. Analysis Heat from the incinerator shell heats the building year-round. The building s boiler is only needed if the incinerator is down for maintenance during cold weather. This rarely occurs as the fuel use records show average boiler consumption of 8 gallons per day and no variation with outside temperature. The fuel consumption represents the standby losses associated with the heating system. City and Borough of Juneau 27 JDWWTP Energy Audit

30 Although the boiler is not supplying heat to the building, it is kept continuously hot because of concerns that it will develop leaks from thermal contraction and expansion of the joints during each cool down cycle. Control Room Heating/Cooling System Description A packaged air conditioning unit provides cooling for the Control Room. The unit can also supply heat, but the heat gain from the incinerator keeps the room warm. The unit is a split system with a ceiling mounted terminal unit consisting of a fan and DX coil and a remote condenser unit located indoors above the Control Room. A room thermostat operates the fan and compressor to recirculate and condition the room air. Analysis The air conditioning unit is a replacement for the original air-conditioner. That unit was connected to an outside air duct that supplied ventilation air to the Control Room. The current air-conditioner, which was installed in 2009, is not connected to the outside air duct. As such, there is no ventilation air supply to the room or ability to naturally cool when outside temperatures are favorable. The operators keep the window open for ventilation. The condensing unit is located in a warm (80-90 F) environment at the top of the building. Locating it in the cool basement would improve the unit efficiency and reject the heat to the cooler basement. Ventilation Systems Description AHU-855 (Incinerator Room): Originally designed as a full outside air unit supplying conditioned air to the incinerator room. The unit has a filter section, steam heating coil, and supply fan. A room thermostat controls the heating coil. The unit has been modified to be a full recirculating air system. AHU-856/857 (Sludge Press Room): Two air handling units, each with a mixing box, filter section, and supply fan. A room thermostat modulates the mixing box to provide heating by recirculating heated air from the incinerator room or provide natural cooling using outside air. AHU-856 has been modified to be a full recirculating system. AHU-858 (Polymer Mixing Room): Air handling unit with mixing box, filter section, and supply fan. A room thermostat modulates the mixing box to provide heating by recirculating heated air from the incinerator room or provide natural cooling using outside air. AHU-859 (Belt Filter Press Room): Air handling unit with mixing box, filter section, and supply fan. A room thermostat modulates the mixing box to provide heating by recirculating heated air from the incinerator room or provide natural cooling using outside air. F-807 (Incinerator Room): Natural cooling fan supplying 100% outside air to the incinerator room. A room thermostat operates the fan and opens relief air louvers in the incinerator room. The unit has been reconfigured to be an exhaust fan. The louvers are manually opened to provide makeup air. EF-806 (Building Exhaust): In-line exhaust fan drawing air from the Sludge Press Room, Polymer Mixing Room and Belt Filter Press Room. The fan originally drew air supplied by AHU-855 to these rooms and exhausted it. The unit is no longer used now that AHU-855 has been converted to a full recirculation system. City and Borough of Juneau 28 JDWWTP Energy Audit

31 Analysis The original design intent of the ventilation systems has been considerably altered. The new arrangement is not acceptable as it does not adequately ventilate the building. To take advantage of the incinerator heat gain essentially free heat and improve the indoor air quality in the building, the systems should be converted as follows: AHU-855 (Incinerator Room): Convert the unit to a mixed air system that supplies a minimum of outside air to provide adequate ventilation with the ability to modulate to full outside air for cooling. AHU-856/857 (Sludge Press Room): Operate the units in a lead/lag configuration so the lead fan operates continuously to provide ventilation and the lag fan operates only when needed to supply additional heating and cooling. Both units should be operated as mixed air systems that supply a minimum of outside air with the ability to modulate to full outside air for cooling. AHU-858 (Polymer Mixing Room): Continue to operate as designed. AHU-859 (Belt Filter Press Room): Continue to operate as designed. F-807 (Incinerator Room): Continue to operate as an exhaust fan. Open the manual dampers on the makeup air louvers when the fan operates so air is not drawn in through the building envelope. EF-806 (Building Exhaust): Convert to a variable air flow fan that draws ventilation air (heated by the incinerator) through the building. Modulate the exhaust air flow to maintain the building at a slight positive pressure. It was reported that AHU-858, AHU-859, and EF-806 are not regularly maintained because they are located high off the floor and are only accessible by long ladders. Access platforms are recommended to provide safe maintenance access to the units. Domestic Hot Water Heating Description A 6 gallon electric hot water heater supplies the service sink in the Belt Filter Press Room. A 120 gallon electric hot water heater with 9 kw heating element supplies the Polymer mixing station and building washdown. Analysis The hot water tanks are located in cool rooms. Wrapping each tank in an insulating blanket will reduce heat loss. Hot water is used to washdown the building because the hot water tank has a larger hose connection than the cold water hose bibbs. Adding a larger cold water hose bibb will allow cold water to be used for washdown. The Polymer hot water tank has one 9 kw heating element. A tank with three 3 kw elements will incur lower demand charges because one element will provide sufficient recovery during normal hot water use. City and Borough of Juneau 29 JDWWTP Energy Audit

32 Lighting Description Table 3-10: Lighting Fixtures and Lamps Room Fixture No. / Type Lamp No. / Type Control Remarks Varies 6 / Suspended 1 / 250w HPS Switch - Varies 14 / Wall mount 1 / 150W HPS Switch - Under stairs 1 / Surface 1 / 100w Inc. Switch Inefficient Varies 3 / Suspended 3 / T12 Switch Inefficient Boiler Room 4 / Suspended 2 / T12 Switch Inefficient Exterior 6 / Wall mounted 1 / 70w HPS Photocell - Analysis The interior T12 lighting has a much lower efficacy than T8 lighting. The incandescent lighting is also inefficient, but it is rarely used. Motors Description Table 3-11: Motors Service Horsepower Efficiency NEMA Premium Remarks AHU % 91.7 Less efficient AHU Less efficient AHU Less efficient AHU No replacement AHU Less efficient F Less efficient EF Less efficient Boiler Burner Less efficient Oil Pump (2) No replacement Condensate Pump (2) No replacement 1. New motor efficiency is based on NEMA Premium MG-1 efficiency motors. Analysis Replacing the less efficient motors with NEMA Premium efficient motors will reduce energy consumption. Some specialized service motors may not be available as NEMA Premium. City and Borough of Juneau 30 JDWWTP Energy Audit

33 Transformers Description The building is supplied with 480V power. The following transformers are installed to step down the 480V building power to obtain 208V/120V power. Table 3-12: Transformers Transformer Size Remarks T-1 (Sludge Pumps) 15 kva Less efficient T-2 (208v/120v service) 37.5 kva Less efficient T-3 (Lighting) 48 kva Less efficient Analysis The transformers are less efficient than current equipment. City and Borough of Juneau 31 JDWWTP Energy Audit

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35 Section 4 Wastewater Treatment Process HEADWORKS Description The headworks consists of a settling chamber and grit removal chain, a bar screen where rags are manually removed, a comminutor for grinding plastics, and a distribution box that divides the flow to the aeration basins. Analysis The wastewater is pumped into the headworks by lift stations in the collection system. No collection pumping costs are included in the plant energy costs. A considerable amount of sand and grit passes through the headworks to the aeration basins. The accumulation at the time of the audit was 2 deep in each basin. The grit accumulation reduces the effectiveness of the aeration basins so that two are operated year-round even though one has sufficient capability for 8 months of the year if no sand is present. The comminutor has not operated in years. It will be replaced in Given the continuous operation of the comminutor, a high efficiency NEMA Premium motor is warranted. AERATION BASINS Description There are two aeration basins, each with two aerators that introduce oxygen by mechanical agitation to breakdown the wastes held in suspension. Analysis The aerators are capable of two speed operation but are always operated on high speed to keep solids in suspension. The aerator motors operate continuously and are prime candidates for an upgrade to NEMA Premium. See the motor section later in the report. As mentioned previously in the Headworks section, a considerable amount of sand and grit passes through the headworks to the aeration basins. The grit accumulation reduces the effectiveness of the aeration basins so that two are operated year-round even though one has sufficient capability for 8 months of the year if no sand is present. City and Borough of Juneau 33 JDWWTP Energy Audit

36 CLARIFIERS Description The clarifiers remove suspended matter from the wastewater. Sludge is skimmed off the bottom by a rake and pumped back to the aeration basins by return activated sludge (RAS) pumps. Excess sludge and floating material is removed by waste activated sludge (WAS) pumps to the digester. Analysis The rake and RAS pump motors operate continuously. They are prime candidates for an upgrade to NEMA Premium. See the motor section later in the report. UV TREATMENT Description The clarified water flows through a channel where it is treated with UV radiation. Analysis The UV equipment operates continuously at full output. Variable output UV treatment will allow the system to vary output with effluent quality. DIGESTER Description The digester basin holds the sludge prior to dewatering and incineration. There is an aerator that introduces oxygen by mechanical agitation to breakdown the wastes held in suspension. Analysis The aerator motor operates continuously and is a prime candidate for an upgrade to NEMA Premium. INCINERATION Description The sludge incinerator receives sludge from the JDWWTP digester and the Mendenhall Wastewater Treatment Plant. Sludge from the digester passes through a sludge grinder and is dewatered by sludge presses into a dry cake. The MWWTP sludge is delivered as dry cake. The dry cake is fed into the fluidized bed incinerator where it is incinerated. The Incinerator operates an average of 14 hours per day in the summer and 10 hours per day the rest of the year. The incinerator burns 25 gallons of fuel oil each hour of operation. This heat is dissipated to the building as radiation off the incinerator walls, and is captured by water flow through the exhaust scrubbers and discharged to the ash slurry pond. The ash slurry pond serves as a settling basin and heat dissipater. Overflow from the pond is pumped back to the headworks for treatment. The pond return pump is out of service so the water drains to a drainage sump and is pumped by drainage pumps. City and Borough of Juneau 34 JDWWTP Energy Audit

37 A utility water system supplies non-potable effluent water for utility operations throughout the plant. The system consists of two water pumps that operate continuously. A hydro pneumatic tank that was installed to maintain system pressure and flow when the pumps are off is not in use. There is an air compressor that supplies instrumentation air to the facility. Analysis The amount of MWWTP sludge has increased in recent years from 290 to 700 dry metric tons per year. The increase is due to operational changes at the MWWTP that took place in The energy impacts will be addressed in a MWWTP energy audit report. Incinerator operation requires numerous motors for pumps, presses, etc. Many are prime candidates for an upgrade to NEMA Premium. See the motor section later in the report. The hydro pneumatic tank serving the non-potable utility water system was removed from service due to control failure. Operation was changed to continuous 24/7 operation of a utility water pump even during periods of no water use. The centrifugal pond return pump is more efficient at pumping the pond water to the headworks than the submersible drainage pumps. The exhaust scrubbers discharge 105 gpm of 170 F water to the ash slurry pond whenever the incinerator is burning. This is a considerable amount of heat that could be reclaimed and used for space heating, domestic hot water heating or some other use. For a radiant heating application based on 120 F water, the heat is equivalent to 120,000 gallons of fuel oil per year. While it is not feasible to capture all of the heat, there is considerable opportunity for heat recovery. The air compressor maintains the storage tank at 110 psig, which is significantly higher than the pressure required for instrumentation. City and Borough of Juneau 35 JDWWTP Energy Audit

38 Motors Description Table 4-1: Motors Service Horsepower Efficiency NEMA Premium Remarks Headworks Grit Chain No replacement Aeration and Digester Basins Aerators Less efficient Clarifiers Clarifier Rake No replacement RAS Pumps Less efficient WAS Pumps Less efficient Incinerator Sludge Feed Pump P Less efficient Utility Water Booster P Less efficient Cake Feed Pump P Less efficient Cake Feed Pump P Less efficient Polymer Feed Pump P No replacement Scrubber Water Pump P Less efficient Non-potable Water P Less efficient Non-potable Water P Less efficient Drainage Pump P Less efficient Drainage Pump P Less efficient Pond Return Pump P Less efficient Sludge Grinder ME Less efficient Belt Filter Press ME Less efficient Cake Feed Pump ME Cake Feed Pump ME Belt Filter Hyd. ME Less efficient Air Compressor Less efficient Fluidizing Air Blower Less efficient Injector Purge Blower Less efficient Ash Slurry Pump Less efficient 1. New motor efficiency is based on NEMA Premium MG-1 efficiency motors. 2. No motor data available; motor efficiency assumed. Analysis Many of the motors are operated a significant number of hours each year to warrant replacement with a NEMA Premium motor. Some specialized service motors may not be available as NEMA Premium. City and Borough of Juneau 36 JDWWTP Energy Audit

39 Section 5 Energy Conservation Opportunities Priorities The ECOs are grouped into the following prioritized categories: Behavioral or Operational: ECOs that need minimal capital investment but require operational or behavioral changes. A life cycle cost analysis is not performed of these ECOs because the energy savings is difficult to quantify and a life cycle savings is certain. High Priority: ECOs that provide a life cycle savings over 200% of the capital cost. Medium Priority: ECOs that provide a life cycle savings up to 200% of the capital cost. Low Priority: ECOs that will save energy but do not provide a life cycle savings. Behavioral or Operational First priority should be given to the following behavioral or operational ECOs that require minimal investment and offer immediate savings. The ECOs are listed from highest to lowest priority. ECO-1: Turn Off Unneeded Lighting Purpose: The lighting in some rooms is left on continuously, even though the rooms are lightly occupied. Turning off lighting will reduce energy. Scope: Turn off lighting in unoccupied rooms. This ECO applies to the Control Building (Storage Room, Headworks and Break Room), Aeration Buildings, Clarifier Building, and Digester Building. Analysis: Turning the lighting on for one hour per day, rather than leaving it on continuously for the work day will reduce annual electricity use by 14,994 kwh and costs by $945. Construction Maintenance Energy Total Life Cycle Cost $0 $0 ($17,500) ($17,500) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 37 JDWWTP Energy Audit

40 ECO-2: Improve Headworks Grit Removal Purpose: A considerable amount of sand passes through the headworks to the aeration basins, limiting their effectiveness. Improving grit removal will allow the operators to take an aerator off-line 8 months of the year, saving in aerator energy consumption. Scope: Methods for improving the headworks grit removal or removing the existing grit from the aerators are beyond the scope of this energy audit. Analysis: If the amount of grit in the aerators was reduced, one aerator could be turned off 6 months of the year. This will annually reduce electricity use by 49,146 kwh, electric demand by 269 kw and energy costs by $5,700. The life cycle savings is $106, 000. Recommendation: It is recommended that methods to reduce the grit in the aerators be pursued. ECO-3: Provide Energy Efficient Comminutor Motor Purpose: The comminutor will be replaced in Since the new unit will operate continuously, an energy efficient motor is recommended. Scope: Provide a high efficiency NEMA Premium motor with the new comminutor. Recommendation: This ECO is recommended without additional analysis. ECO-4: Evaluate Feasibility of Heat Recovery from Ash Slurry Pond Purpose: The exhaust scrubbers discharge 105 gpm of 170 F water to the ash slurry pond whenever the incinerator is burning. This is a considerable amount of free heat that could be reclaimed. For a radiant heating application based on 120 F water, the heat is equivalent to zz120,000 gallons of fuel oil per year. While it is not feasible to capture all of the heat, there is considerable opportunity for heat recovery. Scope: Heat recovery is only feasible if there are suitable heating loads located within a reasonable proximity of the incinerator. The heating and domestic hot water loads at the JDWWTP are too small to fully utilize the waste heat and justify the investment in infrastructure to distribute it. Analysis: A heat recovery analysis is outside the scope of this energy audit. Recommendation: An ash slurry pond heat recovery feasibility study is recommended. ECO-5: Set and Monitor Heating Setpoints Purpose: The heating thermostat setpoints exceed the temperature needed for freeze protection and humidity control. Establishing a consistent setpoint of 55 F will save energy and provide operating personnel a consistent standard to follow. Scope: Reset all heating thermostats at 55 F. This ECO is applicable to the UV Building and Control Building. Recommendation: This ECO is recommended without additional analysis. All heating units should be controlled from a separate wall thermostat with a setpoint of 55 F. City and Borough of Juneau 38 JDWWTP Energy Audit

41 ECO-6: Adjust and Monitor Exterior Lighting Photocells Purpose: Several exterior light fixtures remain on during daylight hours. Adjusting the internal photocell on each fixture so it turns off during daytime will save lighting energy. Scope: Adjust the exterior lighting photocells so the lamps are off during the day. This ECO is applicable to the UV Building. Photocells should be regularly monitored to ensure they are operating properly. Recommendation: This ECO is recommended without additional analysis. ECO-7: Install Control Building Exterior Lighting Controls Purpose: The Control Building exterior lighting is left on continuously. Installing a photocell control will limit operation to night hours. Scope: Install photocell control of the Control Building exterior lighting. Recommendation: This ECO is recommended without additional analysis. ECO-8: Turn Lab Dryer and Furnace Off Overnight Purpose: The lab dryer and furnace are kept continuously hot even though they are only used during normal Monday to Friday work hours. Turning them off overnight and on weekends will save energy. Scope: Turn off the dryer and furnace overnight and on weekends. Recommendation: This ECO is recommended without additional analysis. ECO-9: Calibrate Control Building Thermostat Purpose: The Storage Room thermostat is not calibrated, causing the room to be 10 F higher than the setpoint. Scope: Calibrate the Control Building storage room thermostat. Recommendation: This ECO is recommended without additional analysis. ECO-10: Reduce Incinerator Air Compressor Pressure Purpose: The incinerator air compressor maintains the storage tank at 110 psig which is higher than the pressure requirements of the instrumentation. Reducing the pressure will save energy. Scope: Change the air compressor controller to maintain the tank at a pressure 5 psig above the instrumentation pressure. Recommendation: This ECO is recommended without additional analysis. ECO-11: Reduce Dry Sprinkler Air Compressor Pressure Purpose: The dry sprinkler air compressor maintains the storage tank at 90 psig even though the system only requires 40 psig. Reducing the pressure to 45 psig will save energy. Scope: Change the air compressor controller to start at 45 psig and stop at 55 psig. This ECO is applicable to the Control Building. Recommendation: This ECO is recommended without additional analysis. City and Borough of Juneau 39 JDWWTP Energy Audit

42 ECO-12: Change Control Building Boiler Operating Setpoints Purpose: The Control Building boiler operates from F. Increasing the range to F will decrease boiler operating cycles, improving seasonal efficiency. Scope: Change the boiler setpoints so the burner turns on at 160 F and off at 190 F. Recommendation: This ECO is recommended without additional analysis. ECO-13: Install Incinerator Building Maintenance Platforms Purpose: AHU-858, AHU-859, and EF-806 cannot be properly maintained because they can only be accessed from a high ladder. Maintenance platforms are required to ensure proper maintenance of the units. Scope: Install maintenance platforms for AHU-858 and AHU-859 Recommendation: This ECO is recommended without additional analysis. ECO-14: Insulate Control Building Generator Exhaust Duct and Louver Purpose: The Control Building generator exhaust duct and louver is not insulated. Insulating the duct will decrease heat loss through the louver. Scope: Insulate the Control Room generator exhaust duct. Recommendation: This ECO is recommended without additional analysis. ECO-15: Seal Control Building Cooling Louvers Purpose: The cooling louvers provide a direct conductive path for heat to flow to the outdoors. Since the louvers are not used, installing insulated panels will reduce heat loss. Scope: Install insulated panels in the louver openings. This ECO is applicable to two louvers in the Control Building. Recommendation: This ECO is recommended without additional analysis. ECO-16: Weather-strip Exterior Doors Purpose: The weather-stripping on many of the exterior doors is in poor condition or does not exist. Adding weather-stripping will reduce heat loss and minimize infiltration of damp air into the building. Scope: Replace or add exterior door weather-stripping. This ECO is applicable to nearly all doors. Recommendation: This ECO is recommended without additional analysis. City and Borough of Juneau 40 JDWWTP Energy Audit

43 High Priority Energy Conservation Opportunities High priority energy conservation opportunities provide a high life cycle savings for the relative investment. The ECOs in this group are listed from highest to lowest priority. ECO-17: Replace Oversize Heaters Purpose: The electric heating units are oversized, creating higher demand charges while delivering the same amount of heat as a properly sized heater. Demand charges will be reduced if properly sized heaters are installed. Scope: Replace the following oversized heating units with properly sized heaters. Control Building Grit Room: Replace a 15 kw heat with a 3 kw heater that is currently located in the UV Building. Install a 2 kw heater with separate thermostat. Stage the thermostat setpoints at 58 F and 53 F. Control Building Break Room: Replace a 15 kw heat with a 3 kw heater that is currently installed in the UV Building. Install a 3 kw heater that is currently located in the UV Generator Room with separate thermostat. Stage the thermostat setpoints at 58 F and 53 F. Control Building Storage Room: Replace a 5 kw heater with a 2 kw heater. UV Building Garage: Replace a 3 kw heater with a 2 kw heater. UV Building Generator Room: Replace a 3 kw heater with a 2 kw heater. Analysis: Optimally sizing and staging the heaters will reduce annual electric demand by 509 kw and energy costs by $5,000 Construction Maintenance Energy Total Life Cycle Cost $2,600 $0 ($92,500) ($89,900) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-18: Install Incinerator Building Cold Water Washdown Purpose: Building washdown is currently being done with hot water because the hot water piping has a 1-1/2 hose connection. Installing a 1-1/2 hose connection in the cold water piping will allow cold water washdown, saving hot water energy. Scope: Install a 1-1/2 cold water hose connection in the Polymer Room. Analysis: Installing a cold water hose connection will annually reduce electricity use by 2,156 kwh and energy costs by $140. Construction Maintenance Energy Total Life Cycle Cost $200 $0 ($2,500) ($2,300) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 41 JDWWTP Energy Audit

44 ECO-19: Insulate Heating Piping Purpose: The heating piping is not insulated, resulting in continuous heat loss. While some heat loss can be beneficial, most is not because the piping is mounted up out of the occupied area. Installing pipe insulation is a proven ECO. Scope: Insulate the heating piping in the Control Building. Analysis: Insulating the heating piping will annually reduce fuel use by 312 gallons and energy costs by $600. Construction Maintenance Energy Total Life Cycle Cost $2,000 $0 ($16,800) ($14,800) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-20: Install Automatic Valves on Unit Heaters Purpose: The unit heater coil is kept continuously hot. Installing an automatic valve that shuts of heating supply flow when heat is not needed will reduce standby losses. Scope: Install an automatic valve in the unit heater heating supply. This ECO is applicable to the Control Building storage room. Analysis: The analysis assumed that 33% of the heat loss from the coil is not beneficial. Installing an automatic valve will annually reduce fuel use by 46 gallons and energy costs by $90. Construction Maintenance Energy Total Life Cycle Cost $300 $0 ($2,500) ($2,200) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-21: Replace Non-potable Water Tank and Controls Purpose: A non-potable water pumps operate continuously to maintain water pressure. Replacing the hydro pneumatic tank and controls to allow the pump to cycle on and off to maintain pressure will reduce pump energy. Scope: Replace the non-potable water pneumatic tank and controls. Analysis: Replacing the pneumatic tank and controls will annually reduce electricity use by 180,454 kwh and energy costs by $11,400. Construction Maintenance Energy Total Life Cycle Cost $30,000 $3,500 ($211,000) ($177,500) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 42 JDWWTP Energy Audit

45 ECO-22: Install Electrical Room Heat Recovery Purpose: The Electrical Room has a considerable amount of heat gain from the Main Distribution Panel. Recovering the heat rather than discharging it outside will save energy. Scope: Install a mixed air ventilating unit that supplies natural cooling air to the Control Building Electric Room. Relieve the air to the rest of the building, thus providing needed ventilation. Analysis: Recovering heat from the electric room will annually reduce fuel use by 556 gallons, increase electricity use by 1,752 kwh, and reduce energy costs by $950. Construction Maintenance Energy Total Life Cycle Cost $5,500 $1,200 ($27,900) ($21,200) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-23: Upgrade EF-806 Motor in Incinerator Building Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Once EF-806 is returned to service, replace the motor with a NEMA Premium energy efficient motor. Analysis: Replacing the motor will annually reduce electricity use by 2,180 kwh, electric demand by 3 kw, and energy costs by $165. Construction Maintenance Energy Total Life Cycle Cost $700 $0 ($3,100) ($2,400) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 43 JDWWTP Energy Audit

46 ECO-24: Replace RAS Pump Motors Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium will reduce energy and demand costs. Scope: Replace the RAS pump motors with NEMA Premium motors. Analysis: Replacing the motor will annually reduce electricity use by 12,346 kwh, electric demand by 34 kw and energy costs by $1,100. Construction Maintenance Energy Total Life Cycle Cost $5,200 $0 ($20,500) ($15,300) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-25: Optimal UV Control Purpose: The UV system is currently operated with both banks on continuously. The system has an auto controller that could be repaired and programmed to automatically stage bank operation. Scope: Repair the non-functional auto controller and implement an optimal control strategy. Analysis: Based on discussions with operating personnel, the analysis assumed auto operation would result in one bank operating 90% of the time and 2 banks operating 10% of the time. This operating strategy will annually reduce electricity use by 40,997 kwh, electric demand by 47 kw and energy costs by $3,000. Construction Maintenance Energy Total Life Cycle Cost $15,000 $9,600 ($56,400) ($31,800) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-26: Replace Incinerator Boiler with an Electric Heating Coil in AHU-855. Purpose: The steam boiler in the Incinerator Building, which is not needed to heat the building as long as the incinerator operates daily, is kept continuously hot. Removing the boiler and installing an electric heating coil in AHU-855 will provide backup heating and reduce standby losses. Scope: Replace the steam boiler with an electric heating coil in AHU-855. Analysis: Replacing the boiler with an electric heating coil will reduce annual energy use by 2,920 gallons of fuel oil, 158 kwh of electricity, and energy costs by $5,600. Construction Maintenance Energy Total Life Cycle Cost $53,000 ($28,900) ($157,500) ($133,400) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 44 JDWWTP Energy Audit

47 Medium Priority Medium priority energy conservation opportunities provide life cycle energy savings that exceed the investment cost required to implement the change. These ECOs have a lower priority because the cost of implementation is high or the savings is minimal. ECO-27: Insulate Hot Water Tanks (various locations) Purpose: The hot water tanks are located in cool rooms which increase the amount of tank heat loss. Wrapping the tanks in insulating blankets will decrease heat loss. Scope: Wrap each hot water heater in an insulating blanket. This ECO is applicable to the Control Building (2), UV Building, and Incinerator Building (2). Analysis: Installing additional HW tank insulation will annually reduce electricity use by 1,731 kwh and energy costs by $110. Construction Maintenance Energy Total Life Cycle Cost $800 $0 ($2,000) ($1,200) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-28: Interlock Heating Units with Overhead Doors Purpose: The heating units operate when the overhead doors are open, which allows heated air to be lost to outside. Installing interlocks to shut off the heaters when the doors are open will reduce heat loss. Scope: Install control interlocks to prevent the heating units from operating when the doors are open. This ECO is applicable to the Grit Room, UV Building, and Incinerator Building. Analysis: Interlocking the heaters with the overhead doors will annually reduce fuel use by 58 gallons, electricity use by 4,635 kwh, and energy costs by $400. Construction Maintenance Energy Total Life Cycle Cost $3,000 $0 ($8,500) ($5,500) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 45 JDWWTP Energy Audit

48 ECO-29: Replace AHU-855 Motor Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motor with a NEMA Premium energy efficient motor. Analysis: Replacing the motor will annually reduce electricity use by 1,933 kwh, electric demand by 2.6 kw, and energy costs by $150. Construction Maintenance Energy Total Life Cycle Cost $1,100 $0 ($2,700) ($1,600) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-30: Upgrade AHU-859 Motor Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motor with a NEMA Premium energy efficient motor. Analysis: Replacing the motor will annually reduce electricity use by 1,066 kwh, electric demand by 1.4 kw, and energy costs by $80. Construction Maintenance Energy Total Life Cycle Cost $600 $0 ($1,500) ($900) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-31: Insulate Control Building Domestic Hot Water Piping Purpose: The domestic hot water piping is not insulated in the Control Building, resulting in continuous heat loss. While some heat loss can be beneficial, most is not because the piping is mounted above the occupied area. Installing pipe insulation is a proven ECO. Scope: Insulate the Control Building domestic hot water piping. Analysis: Insulating the hot water piping will annually reduce electricity use by 974 kwh and energy costs by $60. Construction Maintenance Energy Total Life Cycle Cost $500 $0 ($1,100) ($600) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 46 JDWWTP Energy Audit

49 ECO-32: Upgrade AHU-856 Motor Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motor with a NEMA Premium energy efficient motor. Analysis: Replacing the motor will annually reduce electricity use by 877 kwh, electric demand by 1.2 kw, and energy costs by $65. Construction Maintenance Energy Total Life Cycle Cost $600 $0 ($1,200) ($600) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-33: Upgrade AHU-857 Motor Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motor with a NEMA Premium energy efficient motor. Analysis: Replacing the motor will annually reduce electricity use by 877 kwh, electric demand by 1.2 kw, and energy costs by $65. Construction Maintenance Energy Total Life Cycle Cost $600 $0 ($1,200) ($600) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-34: Replace Pond Return Pump Purpose: The pond return pump is out of service so less efficient drainage pumps are used to pump the pond water to the headworks. Replacing the pond return pump to service will reduce energy consumption. Scope: Replace the pond return pump. Analysis: Replacing the pump will annually reduce electricity use by 3,023 kwh, electric demand by 1 kw and energy costs by $310. Construction Maintenance Energy Total Life Cycle Cost $3,500 $0 ($5,700) ($2,200) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 47 JDWWTP Energy Audit

50 ECO-35: Install Incinerator Control Room Natural Cooling Fan Purpose: The Control Room requires cooling year-round when the incinerator is operating. The airconditioning unit provides mechanical cooling but is not designed to bring in outside air for natural cooling. Installing a natural cooling supply fan will reduce the amount of mechanical cooling required. Scope: Install a mixed air ventilation system to naturally cool the control room. Analysis: Naturally cooling the incinerator room will annually reduce electricity use by 3,853 kwh, electric demand by 13 kw, and energy costs by $360. Construction Maintenance Energy Total Life Cycle Cost $6,500 ($3,500) ($6,800) ($3,800) Note: Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-36: Replace Fan F-807 Motor Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motor with a NEMA Premium energy efficient motor. Analysis: Replacing the motor will annually reduce electricity use by 844 kwh, electric demand by 9.7 kw, and energy costs by $150. Construction Maintenance Energy Total Life Cycle Cost $1,800 $0 ($2,800) ($1,000) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-37: Replace Belt Filter Press ME-661 Motor Purpose: Motor efficiencies have improved due to standards such as NEMA Premium MG-1. Replacing a less efficient motor with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motor with a NEMA Premium motor. Not all motors will have a NEMA Premium replacement. Analysis: Replacing the motor will annually reduce electricity use by 518 kwh, electric demand by 2 kw and energy costs by $55. Construction Maintenance Energy Total Life Cycle Cost $700 $0 ($1,000) ($300) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 48 JDWWTP Energy Audit

51 ECO-38: Replace Ash Slurry Pump Motor Purpose: Motor efficiencies have improved due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motor with a NEMA Premium motor. Analysis: Replacing the motor will annually reduce electricity use by 850 kwh, electric demand by 4 kw and energy costs by $90. Construction Maintenance Energy Total Life Cycle Cost $1,100 $0 ($1,600) ($500) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-39: Replace Cake Feed Pump P-605/606 Motors Purpose: Motor efficiencies have improved due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motors with NEMA Premium motors. Analysis: Replacing the motors will annually reduce electricity use by 3,100 kwh, electric demand by 26 kw and energy costs by $450. Construction Maintenance Energy Total Life Cycle Cost $5,700 $0 ($8,400) ($2,700) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-40: Replace Sludge Grinder ME-651 Motor Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motor with a NEMA Premium motor. Analysis: Replacing the motor will annually reduce electricity use by 441 kwh, electric demand by 2 kw and energy costs by $50. Construction Maintenance Energy Total Life Cycle Cost $700 $0 ($1,000) ($300) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 49 JDWWTP Energy Audit

52 ECO-41: Replace Clothes Washer with Front-loading Model Purpose: The top-loading washing machine is less-efficient and uses more water than front-loading washing machines. Installing a front-loading model will save energy and hot water. Scope: Replace the Control Building clothes washer with a front-loading model. Analysis: A load of clothes is washed in hot water once per day. The clothes washer will annually reduce electricity use by 869 kwh and energy costs by $55. Construction Maintenance Energy Total Life Cycle Cost $800 $0 ($1,000) ($200) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-42: Replace Older Transformers Purpose: The step down transformers in the buildings have lower efficiencies than modern, energy efficient transformers. Replacing the transformers will save electricity. Scope: Replace the following older dry-type transformers with newer energy efficient models: Control Building: Replace a 45 kva transformer. UV Building: Replace a 745 kva transformer. Incinerator Building: Replace the 15, 37.5, and 45 kva transformers. Analysis: Replacing the transformers will annually reduce electricity use by 41,851 kwh, electric demand by 60 kw, and energy costs by $3,200. Construction Maintenance Energy Total Life Cycle Cost $45,200 $0 ($59,800) ($14,600) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. ECO-43: Upgrade Control Building Lighting Purpose: The T12 lighting has a lower efficacy than T-12 lighting. Reballasting and relamping the fixtures with T8 lamps will save energy. Scope: Reballast and relamp Control Building T12 lighting with T8 lamps. Analysis: Upgrading the lighting will reduce electricity use by 2,923 kwh, electric demand by 8 kw, and energy costs by $270. Construction Maintenance Energy Total Life Cycle Cost $3,900 $0 ($4,900) ($1,000) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. City and Borough of Juneau 50 JDWWTP Energy Audit

53 ECO-44: Replace Injector Purge Blower Motor Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the motor with a NEMA Premium motor. Not all motors will have a NEMA Premium replacement. Analysis: Replacing the motor will annually reduce electricity use by 1,140 kwh, electric demand by 5 kw and energy costs by $450. Construction Maintenance Energy Total Life Cycle Cost $1,800 $0 ($2,200) ($400) Note: Life cycle construction, maintenance, and energy costs. Negative numbers, in parenthesis, represent savings. Recommendation: This ECO is recommended. Low Priority The following low priority energy conservation opportunities do not offer a life cycle energy savings and are not recommended. Although these ECOs will not provide a life cycle savings, it may be appropriate to implement them when the individual components require replacement. ECO-45: Replace Polymer Hot Water Tank Purpose: The Polymer hot water tank has a single 9 kw heating element. A heater with three 3 kw elements and a demand controller will reduce demand charges because one element will provide sufficient recovery most of the time. Scope: Replace the polymer hot water tank with a tank with several heating elements and a demand controller. Analysis: Replacing the tank will annually reduce electric demand by 54kW and energy costs by $530. However, the savings does not offset the investment in a new tank. If tank replacement is someday warranted, this ECO is then recommended. Recommendation: This ECO is not recommended. ECO-46: Relocate Incinerator Control Room Condensing Unit Purpose: The air-conditioner for the control room has a condensing unit located in the warm environment at the top of the building. Relocating the condenser to the basement would allow it to operate more efficiently in a cooler environment and discharge heat to the cool basement. Scope: Relocate the condensing unit to the basement. Recommendation: This ECO is not recommended because installation of a control room natural cooling fan offers a greater life cycle savings. (See ECO-35). City and Borough of Juneau 51 JDWWTP Energy Audit

54 ECO-47: Replace Motors Purpose: Motor efficiencies have improved in recent years due to standards such as NEMA Premium MG-1. Replacing less efficient motors with NEMA Premium motor will reduce energy and demand costs. Scope: Replace the following motors with a NEMA Premium motors. Sludge Feed Pump P601 Motor Utility Water Booster Pump P-603 Motor Scrubber Pump P-610 Motor Non-potable Water Pump P-111/112 Motors Belt Filter Hydraulic Pump ME-663 Motor Replace Fluidizing Air Blower Motor Analysis: These motor replacements will not provide a life cycle savings. If the motors fail, replacement with a NEMA Premium motor will provide a life cycle savings. Recommendation: This ECO is not recommended. Non-Energy Related Recommendation Modify the Incinerator Building Ventilation Systems Previous modifications to the ventilation systems have resulted in a poor ventilation scheme. The systems should be modified to improve ventilation and cooling in the Incinerator Building. Convert the ventilation systems in the following manner: AHU-855 (Incinerator Room): Convert the unit to a mixed air system that supplies a minimum of outside air to provide adequate ventilation with the ability to modulate to full outside air for cooling. AHU-856/857 (Sludge Press Room): Operate the units in a lead/lag configuration so the lead fan operates continuously to provide ventilation and the lag fan operates only when needed to supply additional heating and cooling. Both units should be operated as mixed air systems that supply a minimum of outside air with the ability to modulate to full outside air for cooling. AHU-858 (Polymer Mixing Room): Continue to operate as designed. AHU-859 (Belt Filter Press Room): Continue to operate as designed. F-807 (Incinerator Room): Continue to operate as an exhaust fan. Open the manual dampers on the makeup air louvers when the fan operates so air is not drawn in through the building envelope. EF-806 (Building Exhaust): Convert to a variable air flow fan that draws ventilation air (heated by the incinerator) through the building. Modulate the exhaust air flow to maintain the building at a slight positive pressure. Recommendation: These modifications will not result in energy savings. They are recommended as an improved ventilating and cooling scheme for the building. City and Borough of Juneau 52 JDWWTP Energy Audit

55 Appendix A Energy Use Data City and Borough of Juneau JDWWTP Energy Audit

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57 25200 Amalga Harbor Road Tel/Fax: Juneau, Alaska Electric Use Data March 24, 2009 Juneau Douglas Wastewater Treatment Plant - Main Plant ELECTRIC RATE AEL&P Electric Rate 34 On-Peak Nov-May Off-peak Jun-Oct Electricity ($ / kwh ) Demand ( $ / kw ) Customer Charge ( $ / mo ) Power Cost Adjustment ( $ / kwh ) Regulatory Cost Charge ( $ / kwh ) Sales Tax ( % ) 0.0% 0.0% ELECTRICAL CONSUMPTION AND DEMAND Month kwh kw kwh kw kwh kw kwh kw Average Jan 69, , , , ,640 Feb 63, , , , ,560 Mar 66, , , , ,240 Apr 73, , , , ,240 May 95, , , , ,800 Jun 87, , , , ,400 Jul 83, , , , ,200 Aug 89, , , , ,160 Sep 85, , , , ,480 Oct 89, , , , ,360 Nov 86, , , , ,120 Dec 92, , , , ,680 Total 980,480 1,081, , , ,970 Average 81, , , , ,748 Load Factor 73.9% 80.2% 82.4% 81.3% 143 ELECTRIC BILLING DETAILS Electrical costs are based on the current electric rates Month Energy Demand Cust & Tax Total Energy Demand Cust & Tax Total % Change Jan 6,042 1, ,824 4,553 1, , % Feb 5,595 1, ,389 4,734 1, , % Mar 4,403 1, ,139 5,054 1, , % Apr 3,902 1, ,200 4,541 1, , % May 3,571 1, ,835 4,899 1, , % Jun 4, ,200 5, , % Jul 4, ,013 4, , % Aug 4,789 1, ,888 4, , % Sep 4,962 1, ,083 4, , % Oct 4,979 1, ,092 4,667 1, , % Nov 5,304 1, ,971 5,392 1, , % Dec 5,210 1, ,889 5,141 1, , % Total $ 57,815 $ 15,518 $ 1,191 $ 74,523 $ 57,550 $ 15,829 $ 1,191 $ 74, % Average $ 4,818 $ 1,293 $ 99 $ 6,210 $ 4,796 $ 1,319 $ 99 $ 6, % Cost ($/kwh) % 21% 2% % Page 1

58 25200 Amalga Harbor Road Tel/Fax: Juneau, Alaska Yearly Comparison March 24, 2009 Juneau Douglas Wastewater Treatment Plant - Main Plant 120,000 Energy Use Comparison 100,000 kwh 80,000 60,000 40,000 20, Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec kw Energy Demand Comparison Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Page 2

59 25200 Amalga Harbor Road Tel/Fax: Juneau, Alaska Annual Comparison March 24, 2009 Juneau Douglas Wastewater Treatment Plant - Main Plant Energy Cost Breakdown $ 8,000 $ 7,000 $ 6,000 $ 5,000 $ 4,000 $ 3,000 $ 2,000 $ 1,000 $ 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Energy (kwh) Costs Demand (kw) Costs Customer Charge and Taxes Energy and Demand Comparison 100, , Energy Use (kwh) 80,000 70,000 60,000 50,000 40, Demand (kw) 30,000 20,000 10,000 Energy Demand Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 110 Page 3

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61 25200 Amalga Harbor Road Tel/Fax: Juneau, Alaska Electric Use Data March 24, 2009 Juneau Douglas Wastewater Treatment Plant Incinerator ELECTRIC RATE AEL&P Electric Rate 34 On-Peak Nov-May Off-peak Jun-Oct Electricity ($ / kwh ) Demand ( $ / kw ) Customer Charge ( $ / mo ) Power Cost Adjustment ( $ / kwh ) Regulatory Cost Charge ( $ / kwh ) Sales Tax ( % ) 0.0% 0.0% ELECTRICAL CONSUMPTION AND DEMAND Month kwh kw kwh kw kwh kw kwh kw Average Jan 78, , , , ,960 Feb 74, , , , ,880 Mar 80, , , , ,680 Apr 79, , , , ,640 May 89, , , , ,040 Jun 70, , , , ,000 Jul 67, , , , ,960 Aug 81, , , , ,360 Sep 73, , , , ,440 Oct 75, , , , ,680 Nov 77, , , , ,880 Dec 77, , , , ,440 Total 924,160 1,007,040 1,020, , ,990 Average 77, , , , ,249 Load Factor 57.5% 60.9% 62.7% 61.8% 186 ELECTRIC BILLING DETAILS Electrical costs are based on the current electric rates Month Energy Demand Cust & Tax Total Energy Demand Cust & Tax Total % Change Jan 5,775 2, ,111 5,449 2, , % Feb 5,587 2, ,866 5,360 2, , % Mar 5,210 2, ,581 5,637 2, , % Apr 5,953 2, ,150 5,370 2, , % May 5,114 2, ,392 4,975 2, , % Jun 4,838 1, ,245 4,800 1, , % Jul 4,557 1, ,008 4,247 1, , % Aug 4,566 1, ,981 4,632 1, , % Sep 4,547 1, ,940 4,932 1, , % Oct 4,660 1, ,075 4,660 1, , % Nov 5,291 2, ,581 4,906 2, , % Dec 5,637 2, ,973 5,272 2, , % Total $ 61,735 $ 21,978 $ 1,191 $ 84,904 $ 60,241 $ 21,800 $ 1,191 $ 83, % Average $ 5,145 $ 1,832 $ 99 $ 7,075 $ 5,020 $ 1,817 $ 99 $ 6, % Cost ($/kwh) % 26% 1% % Page 1

62 25200 Amalga Harbor Road Tel/Fax: Juneau, Alaska Yearly Comparison March 24, 2009 Juneau Douglas Wastewater Treatment Plant Incinerator 120,000 Energy Use Comparison 100,000 kwh 80,000 60,000 40,000 20, Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec kw Energy Demand Comparison Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Page 2

63 25200 Amalga Harbor Road Tel/Fax: Juneau, Alaska Annual Comparison March 24, 2009 Juneau Douglas Wastewater Treatment Plant Incinerator Energy Cost Breakdown $ 9,000 $ 8,000 $ 7,000 $ 6,000 $ 5,000 $ 4,000 $ 3,000 $ 2,000 $ 1,000 $ 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Energy (kwh) Costs Demand (kw) Costs Customer Charge and Taxes Energy and Demand Comparison 100, , , Energy Use (kwh) 70,000 60,000 50,000 40, Demand (kw) 30, ,000 10,000 Energy Demand Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 155 Page 3