HomeMy WebLinkAboutAgenda Report - August 4, 2010 J-01AGENDA ITEM 4� 1
CITY OF LODI
COUNCIL COMMUNICATION
AGENDA TITLE: Approve Plans and Specifications and Authorize Advertisement for Bids for
White Slough Water Pollution Control Facility Bio -Solids Dewatering Facility
MEETING DATE: August 4,2010
PREPARED BY: Public Works Director
RECOMMENDED ACTION: Approve plans and specifications and authorize advertisement for
bids for White Slough Water Pollution Control Facility Bio -Solids
Dewatering Facility.
BACKGROUND INFORMATION: The City has made substantial progress on the State -mandated
improvements at the White Slough Water Pollution Control Facility
(WSWPCF). One of the final improvements to be made, as
recommended in the 2001 White Slough Master Plan, is the addition
of bio -solids dewatering facilities.
As a result of the 2007 Waste Discharge Permit requirements and the recent treatment plant upgrades,
nitrate levels have been significantly reduced in the land -applied effluent and bio -solids. However,the
treatment plant has for many years produced more bio-solidsthan can be properly applied to the
agricultural fields, causing elevated nitrate levels in the storage ponds and in the shallow groundwater
below portions of the land application areas. Bio -solids storage capacity is limited and the proposed
dewatering facilities will allow for removal of 500 to 1,000tons annually that will be hauled to a regional
landfill. Additional operational goals include:
• Even distribution of bio -solids on the land application areas;
• Providing additional bio -solids storage capacity, thereby eliminating supernatant dischargeto
storage ponds; and
• Providing the capability to remove one bio -solids storage lagoon from service to perform
maintenance while the plant remains in operation.
Bio -solids contain nitrogen and other nutrients that are beneficial to crop growth and, if managed
properly, can reduce the need for commercial fertilizers applied to the fields. However, if any fertilizer is
applied at rates in excess of plant nutrient uptake (the agronomic rate), excess nitrogen can move into
shallow groundwater. Although the City attempts to apply liquid bio -solids at or below agronomic rates,
the process inherently results in the over -application at the head end of the fields and under -application
at the tail end of the fields, as illustrated in Figure 1 of the attached Technical Memorandum. Figure 1
shows a dark green (healthier) crop located at the head end (near the blue line) of the fields and a light
green (nutrient deficient) crop at the tail end of the field. Dewatering of the bio -solids produces a "cake"
that can be mechanically and evenly spread across the fields. If disposed of at a landfill, State
regulations require that bio -solids be dewatered. It is expected the future discharge permit requirements
will address these field application and offsite disposal issues.
APPIROVED :
Bartlam, Interim City Manager
K:\WP\PROJECTS\SEWER\WSWPCF\Biosolids Dewatering\CPSA.doc 7/23/2010
Approve Plans and Specifications and Authorize Advertisement for Bids for White Slough Water Pollution
Control Facility Bio -Solids Dewatering Facility
August 4, 2010
Page 2
The facility will consist of dewatering equipment, two skid -mounted rotary fan presses, and chemical feed
equipment. Appurtenant facilities will include piping, pumps, electrical controls, and covered bays for the
storage of dewatered sludge. City Council authorized the design of the facility in June 2009; that was
completed in 2010. Funding for the project, $5,100,000, is available from the 2007 Certificates of
Participation issued for the Phase 3 improvements at WSWPCF. A contract award must be made by
December 2010 or these funds must be paid back to the bond holders.
The WSWPCF Master Plan developed prior to the 2003 Phase I Improvements project acknowledged
that bio -solids dewatering, storage, and distribution to the land may become an issue during future permit
applications and discussed the dewatering facility.
Council is being asked to approve the plans and specifications and authorize advertisement for bids for
the project. A prequalification process is included to determine eligible bidders and ensure contractors
have the necessary experience to perform the work.
The plans and specifications are on file in the Public Works Department. The bid opening date will be in
October 2010.
FISCAL IMPACT: Operations and maintenance costs will increase by approximately $265,000
per year, including the costs for equipment operation and maintenance,
chemicals, seasonal land spreading, and wintertime off-site transportation
and disposal of approximately 900 dry tons of bio -solids each year.
FUNDING AVAILABLE: This project will be funded by the Wastewater Fund (172) using the remaining
2007 Certificates of Participation (approximately $5,100,000).
db otim
F. Wally San elin
Public Works Director
Prepared by Gary Wiman, Construction Project Manager
FWS/GW/pmf
Attachment
cc: Charles Swimley, Deputy PublicWorks Director- Utilities
Del Kerlin, Wastewater Treatment Superintendent
K:\WP\PROJECTS\SEWER\WSWPCF\Biosolids Dewatering\CPSA.doc 7/23/2010
WEST YOST
ASSOCIATES -�
TECHNICAL MEMORANDUM
DATE: July 21, 2010
TO: Mr. Charlie Swimley, Jr. P.E
City of Lodi
Project No.: 213-04-09-23
FROM: Kathryn Gies, R.C.E. #65022 Reviewed By: Ken Loy, PG
SUBJECT: Biosolids Dewatering Facility Recommendations
This Technical Memorandum (TM) provides a discussion of the reasons the City of Lodi should
consider constructing a biosolids dewatering facility at the City's Water Pollution Control Facility
(WPCF). The City's current practice for biosolids disposal involves mixing the liquid biosolids
with recycled water and applying this "slurry" to the land application area via the flood irrigation
system. (As discussed further below, the City has also recently had to retain the services of an
outside contractor to remove, dewater and haul offsite a portion of the biosolids during the winter
months.) The current land application practice has the potential to cause odor problems at the
WPCF and to allow unacceptable amounts of nitrogen to migrate into the groundwater. These
concerns are further detailed below. Future offsite hauling of biosolids will also be more
expensive if the City does not construct a dewatering facility.
WHY DEWATERING
Dewatering often is a process used in preparing biosolids for land application. This is because
dewatering decreases biosolids volume and weight by removing some of the water content. For
facilities that use trucks to distribute biosolids on land application areas, dewatering results in
transportation costs that are significantly decreased. Dewatering also makes handling of the
biosolids easier because it converts the liquid biosolids to a damp cake. The biosolids "cake" can
then be evenly distributed onto field areas using spreader trucks, which can then be incorporated
into the soil — thus avoiding the potential for nitrogen overloading and odor generation.
Using trucks to distribute liquid biosolids is also an option to evenly spread the material over a
field area; however, for Lodi the number of truckloads needed to distribute the liquid biosolids
would be substantial and costly. West Yost Associates is not aware of any facility in the Central
Valley that is the size of Lodi (or larger) that currently land applies liquid biosolids, and we
believe this is in part due to the high cost of transporting the liquids.
2185 N. Califomia Boulevard, Suite 315 Walnut Greek, CA 94596 Phone 925-461-6790 Fax 925 426-2585 westyost.00m
Technical Memorandum
July 21, 2010
Page 2
Dewatering also is a necessary treatment step for biosolids that are disposed of in landfills.
Therefore, the construction and operation of a dewatering facility will allow the City to dispose of
solids offsite in the event that such practices are necessary. For the City, the following factors
may require off hauling biosolids in the future: the need to reduce loadings to the agricultural
fields; the need to remove solids from the lagoons due to limited winter -season storage capacity;
and/or a prohibition on land application of biosolids on the City's property. Although a
prohibition of biosolids land application is not currently anticipated, there are a number of
potential reasons specific to the WPCF that could result in a prohibition such as: the land
application site experiences high groundwater levels, a portion of the area is subject to flooding,
and the entire area is located within the legal boundary of the Sacramento -San Joaquin Delta.
GOOD MANAGEMENT PRACTICES (GMPS)
The City's permit states that the "Discharger is encouraged to comply with the "Manual of Good
Practice for Agricultural Land Application of Biosolids" (California Water Environment
Association, 1998). The Manual provides a summary of the applicable regulatory requirements
and recommended Good Management Practices (GMPs) for biosolids land application. The City
would be able to readily comply with all of the recommended GMPs, if dewatered solids were
applied to the land application area.
With the current application method, the City can generally comply with most of the
recommended GMPs. However, there are two important exceptions. The very nature of the City's
application practices result in ponding at the heads of the fields where solids are applied.
Moreover, following a land application event, the ground is too moist for equipment to enter the
field areas to incorporate the biosolids. Therefore, the City is not able to practice the GMP of
minimizing ponding of applied liquid solids, or the GMP of incorporating the biosolids into the
soil as soon as possible after application.
Both of the above mentioned GMPs are recommended to minimize adverse impacts associated
with odors, improve site aesthetics, and increase public acceptance. As development around the
WPCF land application area increases, odor control and public acceptance of the City's practices
will become an even more important issue.
GROUNDWATER PROTECTION
One of the greatest advantages associated with the land application of biosolids is the reduction in
the amount of commercial fertilizers that must be used. Biosolids contain nitrogen (as well as
phosphorus and many micronutrients that can be beneficial to crop growth) that is released slowly
over time. However, as with any type of fertilizer, if biosolids are applied at rates in excess of
plant nutrient uptake, excess nitrogen can move into groundwater. Although the City strives to
apply the liquid biosolids at a rate that is appropriate to meet the crop's nitrogen need, the
application of biosolids "slurry" using the City's flood irrigation system inherently results in the
potential for over application at the head of the fields and under application at the tail of the
fields. This uneven application also poses problems for the farmers that lease the City's property,
as some crops do not receive the amount of nutrients needed for proper growth (see attached
Figure 1).
West Yost Associates o:\c\213\04-09-23\wp\072010_1TM
Technical Memorandum
July 21, 2010
Page 3
The City is currently working to complete a Background Groundwater Characterization Report in
accordance with the City's permit. Based on an initial review of the data, it appears that the
nitrate concentrations in one of the wells within the land application area exceed the background
concentrations. This well is located near the head end of a field that has received biosolids over
the last 5 year period. There also appears to be a connection between when the nitrate
concentrations started to be elevated in this well and the when the adjacent field started receiving
biosolids.
Finally, the City historically allowed the discharge of biosolids supernatant to the storage ponds.
In an effort to provide "Best Practicable Treatment and Control" for the supernatant, the City
began the practice of directing the supernatant flows to the WPCF for additional treatment in July
2008. This modification has significantly reduced supernatant discharges to the storage ponds. A
review of groundwater and pond data collected before and after this change confirms that this
practice has significantly improved groundwater quality at the WPCF.
However, the City was forced to send the overflow from the biosolids lagoon to the storage ponds
for 21 days in January 2009, because the sludge lagoon had reached its capacity. The overflow of
supernatant for just this short period significantly increased nitrogen concentrations in the
storage ponds. Therefore, the City brought a second sludge lagoon online to increase the storage
capacity. In addition, the City retained the services of an outside contractor to remove, dewater
and haul offsite excess solids during the winter months to avoid overflow.
In 2010, the City paid this contractor to dewater and haul offsite 246 dry tons of biosolids
(approximately 1/3 of the total volume of solids that have historically been land applied) from the
WPCF site. (This amount of biosolids weighed 1,207 tons when hauled offsite. It would have
weighted 4,920 tons without dewatering.)
West Yost Associates o:\c\213\04-09-23\wp\072010_1TM
Figure 1. Irrigation Water Flow Schematic for a Portion of the City -Owned Irrigation Area
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Presentation Outline
FACTS
• WSPCF produces more biosolids than can
be properly handled
• Background Groundwater Report indicates
facility has impacted shallow groundwater
• Facility is located in very sensitive area
• Prohibition of biosolids application
possible
• Available funding and bidding climate is
right
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• Approve Plans and Specifications and
Authorize Advertisement for Bids for the
WSPCF7--B-i-osolids Dewatering Facility
— Constructed at White Slough.
— Consist of 2 rotary fan presses-
and required
processing equipment
— 3 covered storage bays (23,000 SF)
—
F;es
2 months of storage at 8.5 mgd
History
• 1976 — Improvement
project included
dewatering facility — not
constructed
• 2001 — WSPCF Master
Plan noted bio -solids
handling deficiencies —
recommended
improvements
• June 3, 2009 — Council
Authorized Design of
Biosolids Dewatering
Facility $ 198,000
• September 23, 2009 —
Environmental Document
Certified
• March 3, 2010— Council
voted not to approve
plans and specifications
• June 15, 2010 — Permit
Update presentation
discussed
benefits/necessity of
dewatering
Presentation Outline
and ADDI-IC2fion Fac-11-1file
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- Industrial Wastewater --�
Application of Liquid Biosolids
Causes Excessive Loading of
Nitrogen At One End of the
Agricultural Fields
Uneven Crop Growth
(Aerial Photo -July 2010)
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Presentation Outline
Biosolids Before Dewatering
r1 1
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Biosolids "Cake"
("You can have your cake and eat it too!")
Bio -Solids Spreading
- Even Application of Nutrients
- Controlled Application Rates
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Landfill Disposal
Proposed Dewatering Facility
Location
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e solids
Facility
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Terti yiltbrs and
UV Di i ection
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Outside Dewatering Services
(Not Recommended)
• City Contracted for 500
Dry Tons in 2009
— —250 Dry Tons Removed
• Not very efficient
— Optimization takes time
• Cost: $430 /Dry Ton
— Processing
— Off-site Disposal
Presentation Outline
Regulatory Considerations
• Background Groundwater Report
— Nitrate and EC shown to exceed background
• Land Application Practices Report
—Required to demonstrate Basin Plan
compliance (and Title 27 exemption)
• Good land application
practices Critical
• Potential for Prohibition
— High Groundwater
— Proximity to Delta
Presentation Outline
Proposed Dewatering Facility Cost
Estimated Construction Cost:
— 2 rotary fan presses
$5, 100,000
— 3 covered storage bays (2 months storage)
— Electrical controls, piping and pumps
— Includes inspection and in-house CM services
Estimated Annual Operating Cost:
— Staff time, chemicals, energy,
— Wintertime disposal (-1000 DT)
— Land spreading (-800 DT)
$265,000
40
40
Schedule
Bid Opening: October 2010
Start Work: December 2010
Start Up: July 2011
Why Dewatering ?
Generate > Dispose • Regulatory Pressure
— It will get worse, never
better
• Enhanced
Operational Control
— Even Application,
accurate accounting,
healthier crops,
— Off -Haul during winter
— Preserves water
quality of storage
ponds
— State Board Order
— Potential for bio -solids
prohibition
— Studies show nitrate,
EC exceed
background
• Pay Now or Pay Later
— Great bidding climate
— Current debt service
includes project cost
DIIP_StIC
State Board Order
• Groundwater Background Report is
complete — Submitted July 30th.
—After Regional Board review — Permit
revisions will move forward
• Lodi will be required to prepare a Land
Application Practices Report to
demonstrate compliance with Title 27
• Settlement Negotiations are in progress
between CVCWA and State Board
Al 4ir
-41