HomeMy WebLinkAboutUAC Agenda Packet 06/14/2016 Utility Advisory Committee
Jack Pittis Conference Room
Port Angeles, WA 98362
June 14, 2016
3:00 p.m.
AGENDA
L Call To Order
II. Roll Call
III. Approval Of Minutes for May 10, 2016
IV. Late Items
V. Discussion Items:
A. Professional Services Agreement with Kennedy/Jenks Consultants, for WWTP Biosolids
Dewatering,Project WW0205
VI. Information Only Items:
A. Verbal update on discount customers
B. UAC site visits
VII. Next Meeting Date: July 12, 2016
VIII. Adjournment
N:AUAC\MEETINGS\UAC2016\UAC061416\061416 Agenda.docx
Utility Advisory Committee
Jack Pittis Conference Rooms
Port Angeles, WA 98362
May 10, 2016
3:00 p.m.
L Call To Order
Vice Chair Lee Whetham called the meeting to order at 3:02 p.m.
II. Roll Call
UAC Assigned
Councilmembers Present: Sissi Bruch, Cherie Kidd and Vice Chair Lee Whetham
Other Councilmembers Absent: Brad Collins, Mayor Patrick Downie, Dan Gase, and
Michael Merideth
UAC Members Present: Rob Feller
UAC Members Absent: Chair Lynn Bedford and Betsy Wharton
Staff Present: Craig Fulton, Gregg King, Bill Bloor, Kathryn Neal, and
Michelle Hale
Others Present: None
III. Approval Of Minutes
Sissi Bruch requested a motion to approve the minutes of April 12, 2016. Cherie Kidd seconded
the motion, which carried unanimously.
IV. Late Items:
One item to be discussed by Gregg King in VI Information Only Item C.
V. Discussion Items:
A. Professional Services Agreement with Kennedy/Jenks Consultants, for WWTP
Biosolids Dewatering, Project WW0205
Kathryn Neal, P. E, Engineering Manager provided background information and a review of the
Wastewater Treatment Plant Biosolids Dewatering project of replacing the aging belt press at the
plant with a new screw press, and upgrading the ancillary equipment to include the polymer feed
system. Kathryn stated Kennedy/Jenks Consultants have been selected to provide design
services and construction support, based on the firm's qualifications. Lengthy Discussion
followed.
Sissi Bruch moved to recommend to City Council to authorize the City Manager to sign the
Professional Services Agreement with Kennedy/Jenks Consultants for a maximum amount
not-to-exceed$268,040. Cherie Kidd seconded the motion. Rob Feller voted no.
Discussion followed the motion. The Committee requested additional information from staff.
Craig Fulton, Director,Public Works &Utilities will add additional information on the belt press for
the UAC members to consider in response to their good questions.
B. 2015 Hydrogeologic Services Feasibility Study, Phase 2
Craig Fulton, Director,Public Works &Utilities brought forward a request for Phase 2 of the
hydrogeologic services feasibility study. This follows Phase 1, the preliminary exploration for
the development of new ground water sources to supplement the current surface water sources
from the Elwha River. Craig briefed UAC members on how Phase 2 involves an assessment of
water rights in the vicinity of potential test wells. Discussion followed.
Sissi Bruch moved to recommend to City Council to authorize the City Manager to sign
Amendment 2 to the Professional Services Agreement with Robinson Noble in an amount
not to exceed $20,694, for a total contract amount of$48,004. Cherie Kidd seconded the
motion,which carried unanimously.
C. ADS Environmental Services Contract Amendment 1 for Combined
Sewer Overflow Flow Monitoring
Kathryn Neal, P. E, Engineering Manager reviewed the Wastewater Treatment Plant National
Pollutant Discharge Elimination System (NPDES)permit requiring the City to monitor all
Combined Sewer Overflows (CSO) events. Kathryn reported the City had entered into an
agreement with ADS Environmental Services in July 2014 to provide technical service support
to the City in order to meet its State NPDES Permit requirements to monitor and report the
frequency and volume of CSO's. As modifications to the CSO structures are made, ADS flow
monitoring field services will be phased out. The contract expires in July 2016 and the
amendment request is to extend the CSO Flow Monitoring contract with ADS Environmental
Services for the remainder of 2016. Discussion followed.
Sissi Bruch moved to recommend to City Council to authorize the City Manager to sign
Amendment 1 to the Professional Services Agreement with ADS Environmental Services,
LLC for a bid amount of$26,870.96, for a new total agreement amount of$154,092.21, and
to make minor modifications to the agreement, if necessary. Rob Feller seconded the
motion,which carried unanimously.
VI. Information Only Item
A. UAC Site Visits—Landfill Bluff Project and Morse Creek(verbal report)
Gregg King reported on the site visits he is scheduling as requested for UAC and Council members.
Visits will scheduled over the course of the summer months to the Landfill, Morse Creek,the
Wastewater Treatment Plant and the Water Treatment Plant. Gregg will send invitations to UAC and
Council members with a few dates and times.
B. CFP Presentation—Council and UAC meeting 5:00 PM Tuesday, 17 May 2016
(verbal report)
Gregg King mentioned the May 17th, 2016 joint Council and UAC meeting and work session.
Finance will discuss the next five years capital finance plan. Requested the UAC to participate in
this work session. A packet will be put together for UAC members.
C. Energy Efficiency Project(verbal report)
Gregg King reported on upcoming energy efficiency LED rebate projects in the City. The City of
Port Angeles Civic field lighting will save 145,474 kWh hours (equivalent of 10 homes saved), and
will receive $28,553 rebate from Bonneville Power Administration -BPA funds. ACTI is also doing
a lighting project with a projected 93,000 kWh savings receiving a rebate of$33,965 from BPA.
Fairmont Grocery, Hotel and Restaurant is planning on a project to save 50,000 kWh with a$12,438
rebate from BPA. All these incentives are through the City of Port Angeles Ordinance 3.25 with the
Bonneville Power Administration energy efficiency.
D. Heat Pump Water Heater (verbal report)
Gregg King mentioned the May 25th "Improve the Odds" energy efficiency talk at the Vern Burton
Center. The topic will be on the heat pump water heater rebate program. The City of Port Angeles,
Clallam and Jefferson PUD will be onsite to provide information on the heat pump water heaters and
the rebate program.
VIL Next Meeting Date: June 14, 2016
VIII. Adjournment: 4:10 p.m.
Chair Lynn Bedford Michelle Hale, Administrative Specialist 11
El Discounts Summaries - IBM Cognos Viewer Page I ofl
Electric Discounts
Between Jan 1, 2015 and May 31 ,2015
I n"tu ct"r. Description i rransaa¡oJr Amounf |Jo oilcoul! | Transagllon Amount I Discount Amt Given
1..
I customer.'......,.
i
Count I
'.'.,.i
150 lD5 -25%
D6 - 35% .,256,687.80, $166,847.07 :
14,428'4.8
89,840.73
104,269.21
l
I
¡
566
716
Jun 6, 2016
El Discounts Summaries - IBM Cognos Viewer
Overall - Total
Between Jan 1,2016 and May 31,2016
314,401.71 $210,132.50
1 4:10:16 PM
Page I ofl
Electric Discounts
Rate Class Desctiption Transaction Amount No Discount Transaction Amount Discount Amt Given Customer Count
Ð5 - 25o/o ,.l_
D6-35%.
$16,574.88
$57,440.05
5,524.96
?0,??:126
36,454.22
79,
276
ì.
¡Overall - Total 1 $74,014.93 I
t
'f
l
ì
355
Jun 6, 2016 4:08:11PM
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El Discounts Summaries - IBM Cognos Viewer Page I of 1
Electric Discounts
Between Jan 1,2015 and MaY 31,2015
Rate Class DescriPtion Transaction Amount No Discount I'.'..',...-..1
Transaction Amount:
I
i
57,713.91.
Discount Amt Given
14,428.48
89,840.73
ñ4,269.21
I Customer Countt....i 150$43285.4: ,
$166,847.07 i
Overall - Total
Jun 6, 2016
El Discounts Summaries - IBM Cognos Viewer
D5 - 25o/o
D6 - 35%
Between Jan 1,2016 and May 31,2016
256,687.80
314,401.71 $2f 0,r32.50 1
¡
566
716
1 4:10:16 PM
Page I ofl
Electric Discounts
Rate Class Description Transaction Amount No Discount
D5
D6 35%
22,099.84
Transaction Amount Discount Amt Given Customer Count
25o/o
88,369.31
$16,574.88
$57,440.05
5,524.96
30,929.26
i *,tst.zz
79ì
276
355 I-,*.-..----. -*.JOverall - Total I
I 11 $74,014.93
Jun 6,2016 4:08:11PM
El Discounts Summaries - IBM Cognos Viewer Page I ofl
Electric Discounts
Between Jan 1,2015 and May 31,2015
Rate Class DescriPtion Transaction Amount No Discount Transaction Amount Discount Amt Given
ù5 - 25o/o :57,713.91 , $43,285.43 14,428.48
Customer Count
150 I
1
I
D6 - 35%.. ...$166r8a1-ol
$21 0,1 32.50
89,840.73 566
Overall - Total 104,269.2'l 716
Jun 6, 2016
El Discounts Summaries - IBM Cognos Viewer
1 4:10:16 PM
Page I ofl
Electric Discounts
Between Jan 1, 2016 and May 31 ,2016
Rate Class Description Transaction Amount No Díscount
D5 -25%22,099.U
D6 - 35%
Overall - Total
Transact¡on Amount Discount Amt Given Customer Count
$16,574.88 5,524.96 79.
$57,440 . 30'e11.26
36,454.22
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Jun 6, 2016 1 4:08:11 PM
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WAS HINGTON, U. S. A.
Utility Advisory Committee Memo
Date: June 14, 2016
To: Utility Advisory Committee
FROM: KATHRYN NEAL,P.E.,ENGINEERING MANAGER
SUBJECT: Professional Services Agreement with Kennedy/Jenks Consultants, for
Wastewater Treatment Plant Biosolids Dewatering, Project WW0205
Summary: The Wastewater Treatment Plant(WWTP) Biosolids Dewatering project will replace
the aging belt press at the plant with a new screw press, and upgrade ancillary equipment including
the polymer feed system. Replacement of this system is critical to the continued functioning of the
wastewater treatment plant. Kennedy/Jenks Consultants have been selected to provide design
services and construction support, based on the firm's qualifications. A contract price has been
negotiated, in an amount not to exceed $268,040.
Funding:
Funds are available in the 2016 budget, as part of the Biosolids Dewatering project, WW0205. The
project is included in the Capital Facilities Plan, and construction is scheduled for 2017, with a
planned total project cost of$1,350,000. If technical assistance is needed for other Wastewater
Utility issues, the funds will come from the wastewater operations budget, where funds are
available in an amount up to $20,000.
Recommendation: Approve and forward a favorable recommendation to City Council to
authorize the City Manager to sign the Professional Services Agreement with Kennedy/Jenks
Consultants for a maximum amount not-to-exceed $268,040.
Background/Analysis: The dewatering press and polymer feeding system at the wastewater
treatment plant(WWTP)were installed as part of the 1993 plant expansion project. Both the
dewatering press and polymer feed system are 23 years old and at the end of their service life. The
manufacturers of both pieces of equipment are no longer in business and replacement parts are
unavailable. WWTP personnel have reported frequent breakdowns and have had parts manufactured
at a local machine shop in order to keep the systems operating. The dewatering press is a critical
system at the WWTP which, if taken out of service, would necessitate the transport of biosolids to a
remote processing facility.
Page 2
After researching available dewaterng presses, it has been decided to select a screw press
manufactured by FKC as the most desirable press. This decision was based on a number of
considerations including: a)reliability, b) cost, c) low energy use, and, d) maintenance support.
FKC is located in Port Angeles, and can work closely with the engineering team during design and
construction, and is readily available to service the equipment.
The proposed capital project will completely rehabilitate the dewatering system. Components will
include: a)replacement of the dewatering press, b)replacement of the polymer feed system, c)
replacement of the press feed pumps and motor controls, d)integrating the press and polymer feed
system into the newly rebuilt plant SCADA control system, e)replacement of process piping as
required, f)revision to the odor control systems required, and provisions for a temporary dewatering
press to maintain solids processing during construction of the new dewatering press.
A RFQ for design services was issued on December 29, 2015. Response was made by four firms:
A selection board reviewed the submitted proposals, contacted the consultant references and
selected Kennedy/Jenks Consultants as the best qualified consultant.
The design contract authorizes the preparation of plans, specifications, and estimates for the
construction of the necessary improvements, bid support, and design support during construction.
The following table summarizes the budget for each task, based on the estimated level of effort.
The City will be invoiced only for actual work performed. Task 6 is a provision of$20,000 for
unanticipated issues that may arise within the Wastewater Utility, and will be funded by the
appropriate project or operations budget item.
Design
Task 1 —Project Management $24,730
Task 2—Preliminary Design $63,480
Task 3 —Final Design $82,180
Task 4—Bid Services $7,650
Task 5 —Construction Services $70,000
Task 6—Directed Services $20,000
Total contract amount $268,040
In response to questions raised at the May 2016 Utility Advisory Committee meeting, a detailed
cost analysis is attached. The primary reason for pursuing the replacement of the biosolids
dewatering system at the WWTP at this time is the risk of downtime on a system that has no
redundancy. Aside from the cost of repairs and hauling biosolids out-of-area for disposal, the
operational savings that the City will gain as a result of the equipment replacement are $86,600 per
year on average, or $1,732,000 over the nominal 20-year life of the project. The net savings
anticipated over the life of the project are $560,000.
It is recommended that the Utilities Advisory Committee forward a favorable recommendation to
City Council to authorize the City Manager to sign the Professional Services Agreement with
Kennedy/Jenks Consultants for design services in an amount not to exceed $268,040.
WW 02-05 Biosolids Dewatering Project
Cost Analysis
M. Szatlocky, PE
May 26, 2016
PROJECT COMPONENTS
Project WW 02-05 will replace the existing Klein belt press with a new screw press; replace the
progressive cavity filter feed pump with a small progressive cavity feed pump that better matches the
press feed rate; replace the polymer injection system with a new system that optimizes the polymer
utilization; adds a conveyor system that allows for automatic feeding the pressed sludge into the drop
box; and, automates the dewatering process by integrating it into the existing plant SCADA control
system, and updates the HVAC/odor control system. The project will eliminate the compressed air
system used to regulate polymer feed to the existing belt press, reduce the amount of recycled water
used to clean and operate the press by 70,000 gallons per day, reduce energy costs, and greatly reduce
the cost of labor and handling. The component changes are discussed below.
Dewatering Press
The existing belt press was installed in 1993. While rated at 300 gallons per minute (gpm), the
press is being operated at 75 gpm, its point of maximum efficiency. The belt press manufacturer
is no longer in business. The once automated control system has failed and parts are not
available. The belt press is operated in manual mode. The press has had numerous
breakdowns. Components such as bearings and pneumatic cylinder actuators have been
replaced as needed. The drive shafts have experienced three failures which have been repaired
by welding. Since press operation is manual, press operations can occur only during the daytime
during normal operating hours.
The proposed screw press has an optimal production rate of 40 gpm and an upper production
rate of 80 gpm. The screw press operation FKC unit is automated and can be operating for a
longer time interval without operator assistance. The automation feature results in significantly
lower operating labor and maintenance costs. The screw press produces a pressed sludge with
a lower water content resulting in lower handling and disposal costs. Pilot tests have
demonstrated an increase in press sludge solids content from 20%for the existing belt feed
press to 35%for the screw press—a 75% increase in cake density. The screw press has fewer
working parts. The new press comes with replacement bearings and a transmission. The screw
press is manufactured in Port Angeles and the manufacturer can provide immediate assistance
in case of a press breakdown.
Page 1
Feed Pump
The current progressive cavity feed pump is a 20 HP pump that has a maximum rating of 300
gpm. It is currently operating at 75 gpm to keep pace with the belt dewatering press. The
replacement feed pump is also a 20 HP progressive cavity pump with a maximum rating of 80
gpm. It will be run at 40 gpm to keep pace with the new screw press. The pump has capacity to
increase the feed rate to match the screw press feed rate.
Polymer Feed
The existing dry polymer system is functionally obsolete. The manufacturer is no longer in
production. The proposed system uses liquid polymer which has the advantage of using more
complex polymers that provide better dewatering of the digester sludge. The liquid polymer
system also requires less operation and maintenance time as the polymer is premixed and
delivered in large containers which eliminate the cost of daily loading and mixing dry polymer.
The proposed system will reuse the aging and storage tanks that are already in use.
Conveyor System
Current operations require the press operator to move the drop box during press operations to
keep the drop box uniformly filled. The proposed screw conveyor system will allow the drop
box to be automatically uniformly filled. This will result in labor savings.
Compressed Air
The compressed air system currently provides compressed air to the pneumatic adjusters in the
Klein press, and to the polymer mixing valve in the digester sludge feed line to the press. The
FKC press uses no compressed air making the compressor obsolete. The compressor has two 3
HP motors. Elimination of the compressor will provide a minor energy savings.
Telemetry
The existing belt press control system was constructed as a standalone system. It no longer
works in automatic mode and requires manual adjustment during the press cycle. The proposed
screw press has a built in programing unit manufactured by TSI that integrates with the plant
SCADA control system. TSI is the contractor that is currently working with the City to reprogram
the wastewater treatment plant. Automation of the press and polymer feed system will reduce
the labor requirements for running the press system.
HVAC/ODOR CONTROL
HVAC requirements will be lower for the new screw press system. The screw press and the
external contact tank are enclosed. They will need connection to the HVAC odor control system
to provide a slightly negative air pressure inside the screw press in order to contain moisture
and 1-12S emissions. The existing press shroud will be removed as it will be unnecessary. The
new system will greatly reduce the humidity and odors in the press room.
Page 1 2
Wash Down System
The existing belt press uses a great amount of water during operation and post-operation
maintenance. Wash down water is added to the press to clean the belts during operation. It
takes two to three gallons of wash down water to treat one gallon of digester sludge. This
generates approximately 100,000 gallons per day of post-processing liquid that is fed back to
the plant headwords, increasing the plant liquid handling cost for pumping and treatment. Post-
pressing maintenance requires 15 minutes of exterior washing the press and another 30
minutes of belt cleaning. The screw press uses a programmed, sequential, internal wash down
during pressing using small quantities of wash down water. The press is designed to be turned
off while under load leaving digester sludge in the press. No post-pressing wash down is
required. There is a 3-inch wash down water line feeding the press room. This will be reutilized
to provide wash down water to the screw press and hose bibs.
LABOR RATES
The following table shows the breakdown of operations personnel. The rates are taken from
the 2015 ASFCME schedule. The current operating staff(WWTP II) are all at maximum range. It
is assumed that over the 20 year planning period that the personnel will likely average mid-
range due to personnel turnover.
Table 1: Labor Rates
Salary Average Hourly
Position Range Salary
w/Overheads
WWTP Operator III A23 $40
WWTP Operator II A19 $35
WWTP Operator I &OIT A16 $32
Utility Worker I A14 $31
OPERATION COSTS
Daily press operation is done by a licensed wastewater treatment plant operator level II. The
operator is responsible for the polymer system operation, press operation, delivery of press
biosolids to the City compost facility, and routine maintenance including equipment and press
cleaning. The existing belt press is functionally obsolete. The automatic control features do not
work, and replacement parts are unavailable. The press must be run in manual mode which
requires monitoring and frequent adjustment by the operator as the water content of the
digester sludge changes during each filter run. Typically the morning run has a thicker sludge
that the afternoon sludge.
The quantity of digester sludge and septic hauler volume has remained relatively stable for the
period from 2010 through 2015. Press statistics are shown in the following table:
Page 13
Table 2: Press Statistics
Year Processed Septic Press Processed Truck Trips to
Digester Hauler Days Wet Tons Compost
Sludge (gal) Volume (gal) Facility
2010 3,194,865 2,255,600 128 1917 287
2011 3,307,993 2,198,180 124 1757 256
2012 3,197,600 2,295,100 118 1690 234
2013 3,849,430 2,333,600 136 1698 247
2014 3,813,040 2,187,100 157 1664 242
2015 4,414,380 2,687,340 166 1807 263
Average 3,629,551 2,326,153 138 1755 255
The typical daily time breakdown for the WWTP operator is as follows:
Press operation 5.35 hr
Truck Trips A@ 2 per day 1.9 hr
Press maintenance .75 hr
Total Time 8 hr
The 20 year manpower cost of belt press operation for a Level II operator including
overheads for 138 press days per year is$773,920 excluding inflation.
The screw press system has several cost cutting features including: 1) a liquid polymer
system that requires changing every 2 months; 2) SCADA controlled press operation that
requires occasional monitoring which can be done at any of the remote terminals in the
treatment plan; 3) increased biosolids solids content which reduces the truck trips to 1
per press day, and 4) automatic wash down procedures that eliminates the 45 minute
daily cleaning maintenance cost. Additional features include the ability to automate the
press cycle that allows the operation of the press when unattended in the evenings or
the weekend when there is no staff on site.
The typical daily time breakdown for the new system is as follows:
Polymer Makeup 1 min
Press operation 30 min
Truck Trips @ 1/day 1 hr
Wash down 2 min
Total Time 1 hr 33 min
The 20 year manpower cost of screw press operation for a Level II operator including
overheads for an equivalent 138 press days per year is$157,686 excluding inflation.
This results in a savings of$616,234 in operator costs.
Page 14
Sludge Hauling Cost
Sludge hauled to the compost facility has 2 costs—tipping fees at the transfer station
($50.85/wet ton) and vehicle transport cost of$10/mile for a 14 mile round trip
between the wastewater treatment plant and the compost facility. The cost per mile
includes vehicle depreciation, fuel, maintenance, overheads, tire replacement, and field
repairs. The average wet tons of sludge hauled for the 2010-2015 time period was
1,755 wet tons of 20% solids pressed sludge. The average number of truck trips for the
same period was 255 per year. The cost of transporting and disposing wet belt feed
sludge for a 20 year period computes as follows:
Tipping fees: $1,772,954
Equipment transfer: $714,000
Total 20 year cost = $2,486,954
The screw press will produce a 35% solids pressed sludge. This will reduce the sludge
hauling cost for the 20 year period to $1,421,117 - a savings of$1,065,837.
Maintenance Costs
The existing belt press is functionally obsolete. Replacement parts for the mechanical and electrical
components are not available from the manufacturer. Moving components such as bearings and drive
shafts are worn or subject to fatigue fracturing. Of particular concern are the drive shafts which have
failed and been repaired 3 times in recent history. The filter belts lose porosity and need to be replaced
every other year. Other components such as safety switches and pneumatic cylinders that adjust belt
tension have failed. The principal problem is that, since spares are not obtainable from the press
manufacturer, staff have had to obtain new sources for parts which delays repairs.
The belt drive shaft has broken 3 times and was repaired in place. Should either drive shaft fail, a
replacement drive shaft will need to be fabricated. This will require partial disassembly of the belt press
to remove the failed shaft, taking measurements of the shaft to provide a plan for machining a new
drive shaft, obtaining appropriate feed stock for shaft manufacture, machining a replacement drive
shaft, and reassembly of the screw press. It is estimated that this repair could take up to two weeks.
While this is occurring, the accumulated digester sludge will need to be trucked to a receiving facility,
the nearest on being in Bremerton.
Belt replacement:
The press requires a belt change of both the upper and lower belts every two years. Belt
replacement takes an average of 3 days for a 5 person crew consisting of 3 WWTP II's, 1 WWTP
Page 15
I, and 1 Utility Worker I for a daily cost of$1,570. The following table itemizes the cost of belt
replacement for a 3 day event.
Belt Cost $4,000
Labor 4710
Total Cost per event $8,710
The manpower cost of belt replacement based on replacement on a two year cycle for a 20 year
time period is$87,100 excluding inflation.
The screw press uses a stainless steel screen. The installed presses have operated up to 25
years in wastewater systems have not required screen changes. Savings of$87,100 are
anticipated for the 20 year design life.
Broken Drive Shaft:
The belt press drive shafts have failed a number of times (3) due to metal fatigue. The location
of the shaft fractures was outside of the press body and repairs were made in place rather than
disassembling the entire press. This is a 2 day activity requiring two operators, and the services
of a specialty welding company. The last breakdown was in 2013. The cost of repair is as
follows:
Welding contractor $2,750
WWTP Operator Cost $1,120($35/operator hr x 2 operators x 16 hr)
Total Cost $3,870
The cost of 4 anticipated repairs in the 20 year design life is$15,480. The total anticipated costs
of maintaining the existing belt feed press for the 20 year design period is$102,580.
Repairs to the new screw press are limited to either bearing or gearbox replacement.
Replacement for both of these components will be provided at the time of purchase. The
manufacturer states that either component can be replaced by two workers in one day.
Assuming one repair will be needed in the 20 year period, the cost of repair will be$560. The
cost of maintaining the new screw press will be$102,020 lower than the cost of maintaining the
current belt press. .
ENERGY COSTS
There are two basic energy costs—the cost of consumption and the will serve cost.
Consumption costs, the cost of running equipment,for industrial users are 5.13 cents per
kilowatt hour. Direct costs include the cost of running the dewatering press system and the cost
of recirculating process water to the plant headworks and the trickling filters. Will serve costs
are a monthly fee based on a user's highest energy use in kilowatts. The following tables
compare the energy costs for a 20 year period for the Klein filter press and the proposed screw
Pagel 6
filter press,
Table 3: Belt Press Direct Energy Costs
Belt Dewatering Press
Component HP Hours per Presses per 20 year
press 20 years direct cost
Press Belt Drive 5 6 2,764 $43,284
Press Screw Conveyor 2 6 $17,303
Press Hydraulic Pump 1.5 6 $12,991
Press Compressed Air Pump 6 6 $51,396
Wash Water Booster Pump 7.5 6 $89,332
Press Feed Pump 20 6 $173,137
Tank Drain Pump 3 8.33 $36,043
Trickling Pump 75 .83 $89,802
Total Direct Energy Cost $513,828
Table 4: Belt Press Will Serve Energy Costs
Component HP Kw
Press Belt Drive 5 3.73
Press Screw Conveyor 2 1.49
Press Hydraulic Pump 1.5 1.12
Press Compressed Air Pump 6 4.48
Wash Water Booster Pump 7.5 5.60
Press Feed Pump 20 14.92
Tank Drain Pump 3 2.24
Trickling Pump 75 55.95
Tota 1 120 89.5
The monthly will serve cost per Kw is$0.0438. The total will serve cost for the belt press for a
20 year period is$942. The total energy cost for the belt feed press for a 20 year period is
$514,770.
The screw press has a lower power demand and, therefore, a lower 20 year cost as shown in
Table 5 below.
Page 17
Table 5: Screw Press Direct Energy Cost
FKC Dewatering Press
Component HP Hours per Presses per 20 Year
press 20 years Direct Cost
Screw Press Drive 2 11.25 2,764 $50.433
FKC Sludge Conveyor 1 11.25 $25,222
Wash Water Booster Pump 7.5 .5 $89,332
Press Feed Pump 20 11.25 $173,137
Tank Drain Pump 3 2.5 $36,043
Trickling Pump 75 .24 $89,802
Total Energy Cost $463,979
Table 6: Screw Press Will Serve Energy Costs
Component HP Kw
Screw Press Drive 2 1.49
Press Sludge Conveyor 1 0.74
Wash Water Booster Pump 7.5 5.60
Press Feed Pump 20 14.92
Tank Drain Pump 3 2.23
Trickling Pump 75 55.95
Tota 1 108.5 80.94
The monthly will serve cost per Kw is$0.0438. The total will serve cost for the screw press for a
20 year period is$851. The total energy cost for the screw press for a 20 year period is
$464,830. Energy cost savings for the screw press for a 20 year period are$49,940.
CONTINGENCY COST OF BREAKDOWN
In the event of breakdown of a critical press component such as a drive shaft inside the belt press, the
press would require disassembly, machining of a new shaft, and press reassembly causing a long time
delay. Because it is not possible to shut down the plant incoming flow,the only feasible solution to
digester sludge disposal is to truck the sludge to a receiving facility. This would require costs for 6 to 8
daily tanker truckloads to be hauled off site and the cost of processing 30,000 gallons of sludge at the
remote site. The closest identified disposal site is in Bremerton. Assuming a one week breakdown, the
cost of hauling 120,000 gallons of liquid sludge is estimated at$13,540, and the cost of treatment of
120,000 gallons of liquid sludge is $41,800. The total cost for trucking and disposal would be$60,304.
In addition, a major breakdown would require press disassembly to remove the broken drive shaft, and
reassembly which includes a belt replacement after installing the new drive shaft. This would amount to
a direct labor cost of$6,300. Machining and shipping costs for the drive shaft manufacturer is
estimated at$10,000. Although it is desirable to manufacture replacement parts such as main drive
shafts ahead of time, this is not possible because there are no available plans that provide part
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dimensions. The only way to pre-manufacture these parts would be to cease production and
disassemble the press. The disassembly and machining is estimated at total $16,300 making the total
cost for a major equipment breakdown $76,040. Of necessity, this estimated cost is not definitive—the
risk of much higher costs exists, including a breakdown that cannot be feasibly repaired.These risks are
not quantified in this analysis.
COST COMPARISON
Cost comparisons are based on a number of simplifications:
1. There has been no factoring for inflation
2. Labor rates are based on the 2015 AFSCME contract and are not up to date.
3. Energy statistics are based on a 2010 study and may not reflect current usage.
4. Repairs are based on current past history with the belt press. No breakdown costs have
been applied to the screw press.
5. Transfer station tipping fees at$50.50 per wet ton reflect current contract conditions with
Waste Management. These rates may be subject to change.
6. System demand is based on a 6 year study. It is not been determined whether the 2014 and
2015 quantity of digester sludge and process wet tons indicates an increasing growth trend
that will cause increased production costs. The 2016 septic hauler volume at the end of
April 2016 was 40% higher than anticipated. If solids volumes are increasing, than the cost
savings of upgrading the Biosolids dewatering system will be more than stated below.
Table 7: Cost Comparison Summary—20 Year Period
Existing Belt Press Proposed Screw
Press
Operation & Maintenance $773,920 $157,686 $616,234
Sludge Handling $2,486,954 $1,421,117 $1,065,837
Energy Costs $514,770 $464,830 $49,940
Subtotal, Operations $3,775,644 $2,043,633 $1,732,011
Repairs $102,580 $560 $102,020
Contingency Cost of
Breakdown (one week) $76,040 $0 $76,040
Subtotal, Repairs $178,620 $560 $178,060
Total Cost $3,954,264 $2,044,193 $1,910,071
Estimated Project Cost (design and construction) $1,350,000
Savings 560,071
The cost comparisons show a clear financial advantage in favor of replacing the existing biosolids
dewatering system (belt press). Current construction costs are estimated at$1,350,000. The reasons
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for replacing the existing biosolids dewatering system are even more compelling given that the cost
comparison does not quantify all significant risks. It is possible that a complete failure of the existing
press could occur, requiring complete replacement of the press and long term hauling of sludge.That
would cause significant system disruption as well as high costs. The dewatering press is old,
components are failing, and the dewatering press is the critical component in the solids treatment
portion of the wastewater treatment plant. It is the only component in the wastewater treatment plant
process that has no redundancy(no parallel back-up system). Should the press experience a major
failure, processing biosolids will stop. In the initial project scoping, an alternative of installing two
presses in order to provide redundancy was explored, but discarded after it became clear that the cost
of a second gear box and bearings can be included in the project cost.This option allowed the City to
reduce the estimated project cost significantly because it minimizes equipment costs and structural
alterations to the press buildings while providing a highly desirable increase in system reliability.
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