http://www.extension.org/67664 The closure of earthen lagoons associated with a caged egg-laying operation was used as a case study. This case study presents information on the steps taken to close the lagoons, including topographic survey needs, analysis of sludge and wastewater at different times during the closure process, methods for excavating and removing the sludge, and the costs associated with the closure of earthen lagoons. The sludge has a high fertilizer value for P2O5 and other micro- and macro-nutrients. The cost of the closure for this case exceeded the expected cost for the earthwork for the construction of a new facility
3. Background Information
Caged egg-laying operation with 6 houses
Lagoon size – unknown
11 to 12 acre-ft of storage (size of football field 10 feet
deep)
Operation began in late 1970’s
Operator chose to shut-down facility in May 2006
Demonstration project
Determine costs for other lagoons across the state
Address concerns in an impaired watershed
Properly close to mitigate water quality impacts
5. Methodology
Survey of existing site
Determine extents of lagoon
Approximate volumes
Utilities
Soil sampling to determine in-situ materials and check
for leakage
Construction Specifications
Site-specific
Compilation of appropriate portions of NRCS national
construction standards
6. Methodology (continued)
Draft Closure Plan and approval
Construction Plans
Contracting
Construction Oversight
Final Check-out
8. Digging for Information
Field Engineer Technician
Located the contractor that originally built the facility
Confirmed that there were two lagoons
No plans available
Found out when water was hooked up for the site 1978
10. Surveying Attempts
Tried to use Sludge Judge – nothing went into the tube
Tried pacing and using a range pole to establish depth
Used Survey Grade GPS unit
Took Surface Shot
Used range pole to probe and determined
Depth of sludge
Depth of wastewater
13. Survey Data Collected & CAD
Approximately 2,000 data points were collected or
calculated (34 different field codes were used)
Approximately 200 points were taken on the surface and
probed to obtain bottom of pond elevation and
wastewater level
Modeled
Existing Pond with Sludge
Bottom of Pond
Wastewater Level in Pond
Proposed Final Grade
Existing Concrete Slabs
14. Closure Plan
Meetings with TCEQ
Review of draft plan approved by TCEQ
Final closure plan to be completed after vegetation is
established
15. Site Specific Construction
Specifications – March 2008
Overview
Scope & Location
Utilities
Safety
Pollution Control
SWPPP
Mobilization and Demobilization
16. Site Specific Construction
Specifications – March 2008
Overview (continued)
Removal of litter, sludge and wastewater
Structure Removal
Earthfill and Excavation
Seeding and Mulching
Construction Survey
17.
18. Contracting – Turn Key
Sludge to be removed and land applied – 18,500 CY
Removal of Concrete Slabs
Earth moving – compacted fill estimated at 27,000 CY
Final Seeding of Site
Bids received began around $1.8M and exceeded $3M
19. Contracting – Phase 1
Modified to only include removal and stockpiling of
sludge in windrows on-site
Awarded Bid
$3.25 per CY of sludge removed
$10 per 1,000 gallons of water for pumping to neighbor
Local SWCD found neighbor to take water
Total cost $58,500
Completed September 2009
25. Phase 2 – Sludge Hauling and Land
Application
Local SWCD, NRCS and TSSWCB and found a
landowner that wanted the material
Landowner receiving sludge contracted out of their own
pocket to have sludge hauled and spread on their
property
Sludge hauler was from the Texas Panhandle
Some of the cost was for mobilization/demobilization
Application started January 2011 and was postponed
because of rainfall until April 2011
28. Phase 3 – Final Grading
Contract Awarded August 2011
Final grading completed September 2011
DOES NOT INCLUDE SEEDING AND
REVEGETATION – currently in a drought
Silt fencing is in place
29. Challenges for Final Grading
Power poles on-site
Agreement was from 3 years ago when initially bid
Had to renegotiate cost with power company
30. Photo of finished grade
Photo of work in progress
31. Phase 4 – Vegetation and
Paperwork
Vegetate the site – Indian Grass, Klein Grass, Switch
Grass, Sideoats Grama, Plains Bristlegrass, Wild Rye,
Rye Grass
Landowner deed recordation
Final Closure Plan
33. Sludge Analysis - 2009
% (dry basis)
N 1.5
P 5.7
K 1.6
Dry Matter 74%
34. WASTEWATER
ANALYSIS2006
N % 0.099
P ppm 172.4
K ppm 3171
Ca ppm 479.7
Mg ppm 147.7
Na ppm 901
Zn ppm 5.76
Fe ppm 7.04
Cu ppm 1.079
Mn ppm 4.967
pH 7.8
Conductivity umhos/cm 16580
Total Carbon % 0.282
NH4-N % 0.1525
Date Received 2/24/2006
Color Brown/ Pink
P2O5 ppm 391.348
35. EFFLUENT
ANALYSIS2007 N % 0.0174
P % 0.0073
K % 0.1619
Ca % 0.0051
Mg % 0.0098
Na % 0.0327
Zn ppm 0.13
Fe ppm 2.66
Cu ppm 0.05
Mn ppm 0.30
36. Cost
Component Quantity Cost per unit Cost
Sludge and Water Removal
– stockpile on-site
18,000 CY $3.25/CY $58,500
Wastewater None $10/1,000
gallons
N/a
Sludge Hauling and
Application
12,103 Tons $7.484/Ton $90,580 (basically
$5.03/CY)
Subtotal for removal $149,080
Concrete Slab Removal 1,800 CY $11.60/CY $20,880
Earthwork 27,200 CY $2.50/CY $68,000
Miscellaneous $2,100
Seeding 10 acres $180/Acre $1,800
Subtotal for Site Work $92,780
TOTAL TO DATE $241,860
37. Additional Costs
Engineering – Surveying, Civil 3D, Drawings,
Specifications, Design Report
Closure Plan Development
Contracting Time and Expenses
Meetings, coordination, and other communication
time
Soil, Waste, and Wastewater Analysis
Moving Power Lines
Final Establishment of Vegetation
I will be presenting some information on the closure of a poultry lagoon in Texas
This is a photo of the facility with the full lagoons in the foreground taken in Spring 2006.
This was a caged egg-laying operation which utilized 6 houses. It had converted to a dry waste management system. The lagoon size was initially unknown, but held approximately 11-12 acre-feet of storage, or 14,800 cubic meters of wastewater, which is one of the smaller lagoons in the area. The initial operation began in the late 1970’s and the operation shut-down in May 2006. This was a demonstration project between the Natural Resources Conservation Service (NRCS), the state soil conservation agency, Texas State Soil & Water Conservation Board (TSSWCB) and the local Soil & Water Conservation District. The purpose of the demonstration was to: establish costs for this practice as there are numerous similar situations across the state and remove a potential source of contamination from an impaired water shed.
After taking samples, we did some digging at the local field office. From this aerial photo, we were able to determine that there were two lagoons and one mini pond.
Now moving back to the actual methodology for the project. This consisted of surveying the existing site, soil sampling, construction specification and much more.
Sampling of Sludge material that was sent to Texas A&M for evaluation
This is a plan view of the operation. When the site was constructed initially the lagoon was built at the top of the hill, dirt for the lagoon was excavated and used as a building pad for the slab thus eliminating all outside drainage. The initial grade of the site prior to the installation of the facility is shown with green arrows. The grade is approximately 0.2% over the entire site.The entire site is less than 11 acres or 44,515 square meters, and the system was likely designed as a total evaporation system. The wastewater was recycled to flush the concrete alleys. The only freshwater was from the drinking nozzles.
The use of a local technician allowed us to track down the original contractor, water hook-ups and so forth. However, the contractor could not recall any of the dimensions or details on the construction of the lagoon.
Samples were taken to determine if the material was the same as indicated on the soils maps and to determine if there was any seepage into the surrounding soil at the sampling locations. The sampling indicated that the soils were acceptable for an in-situ lining material and there was not any indication of seepage from the lagoon.
In order to establish the boundaries of the lagoons under the sludge and wastewater, we tried several methods until we came up with one that worked. The sludge judge did not work because the waste was too thick and would not go into the tube. Attempted to pace and use a range pole to establish the depth while dragging a raft, but did not have an accurate surface elevation or horizontal control. Finally, utilizing a survey grade GPS unit, along with a range pole, we were able to obtain a surface elevation, probed to the bottom with the range pole and took readings for the depth of the sludge and the wastewater level.
Double decker rows of buzzards are missing now!
Using old aerial photos and the United States Geological Survey quadrangle map which provides contours , we were able to determine what the site looked like prior to the installation of the poultry operation.
It is important to remember both above ground and below ground utilities. In this case, the contractor had to obtain permission from the utility company in order to work under the line and this had to be address in the plans and specifications
After all surveying work was completed, there were approximately 2,000 data points that were used to model using Eagle Point at the time the various levels of sludge, wastewater and then develop a final grading plan and associated quantities.
Additionally, a draft closure plan was developed prior to any work for TCEQ review and approval. The final closure plan will be completed after vegetation is established on-site.
These construction specifications addressed typical items that would be seen in most construction projects for NRCS.
Additionally, the specifications included requirements for the removal of litter, sludge and wastewater, structure removal, earthfill and excavation, seeding and mulching, and final construction survey
A design report, along with engineering drawings and construction specifications were prepared. I have included a handout with sample construction specifications for the entire project.
Once all the engineering and technical work was completed, the initial thought for contracting the work was to have a turn key package where the contractor took care of all sludge hauling and land application, including finding the land to apply the sludge. The bids started at $1.8 million….. since there was not that much funding available, the project was split into various phases with our local offices doing much of the legwork.
The project was broken into three phases initially; however, it is in its fourth phase at this time. Phase 1 consisted of removing the litter and stockpiling on-site
As soon as the bid was closed, the site received 5-6 inches of rain. The contractor was responsible for all costs associated with this water; however, a stipulation was added that the contractor would be paid $10/1000 gallons if there was any additional rainfall.
Here are some photos of the dewatering of the lagoon in phase 1
The contractor used multiple types of equipment and conveyors to remove and stack the material on-site. Note: The sludge looks like a typical clay soil.
Initially, a stationary hopper as shown on the left was used. The contractor switched after the first couple of days to a vibrating hopper to address the material sticking to the sides of the hopper.
Here are some photos of the sludge stockpiled on-site and the empty lagoons.
For phase 2, the local offices were able to find a landowner that wanted the material and was willing to pay for the transportation and spreading of the material. There was a significant amount of time spent finding this landowner, as the local applicators in the area were accustomed to poultry litter, but did not have equipment for spreading the sludge.
The sludge applicator did a terrific job of removing all of the sludge from the site.
The only thing remaining was the slabs to be demolished in Phase 3.
Phase 3 was initially to include final grading and vegetation establishment. However, with the current drought situation in Texas, it was decided to remove the vegetation requirements from the contract. The site has an average slope of 0.2%, and silt fence was installed to reduce the possibility of erosion.
One of the challenges for the final grading was moving the power poles that were on-site to avoid miniature islands around the poles. The agreement was from 3 years prior and the costs for moving the poles had more than tripled. With some good notes and negotiating skills, the local technician was able to reduce the cost to close to the original quote from 2008.
This is a photo of the final site after grading and a close-up of the silt fence.
The last phase consists of establishing the vegetation on-site. Since the site received some rainfall earlier this month. We decided to go with a native mixture for the site and planting should be completed by the end of the day. Additionally, the landowner will need to deed record the location of the lagoon as the designed earthfill and compaction requirements were not intended to support a structure and some shrinkage is expected. After vegetation is established, a final closure plan will be documented.
Saqib Mukhtar from Texas A&M had agreed to perform the analysis of the sludge along with one of his graduate students. There were 8 samples taken. The sludge resembled dirt and had very little odor to it. This chart shows an average of the samples for the sludge.
As the sludge was stockpiled, the local office took samples of sludge and had them analyzed. This is the average of approximately 20 samples that were taken, which is approximately 1 sample for every 1,000 CY.
There were a few samples of wastewater that were collected and analyzed at the same time as well. This shows the results from the analysis in 2006.
There were a few samples of wastewater that were collected and analyzed at the same time as well. This shows the results from the analysis in 2006.
Here are the contractor costs to date… the $90,580 for sludge hauling and application was paid by the landowner receiving the sludge. The total spent by NRCS and TSSWCB to date is approximately $150k
There is a significant amount of time and staff resources spent on this project that correlate to additional costs that are not included in the contracting costs.