biosolids enhancements at the dos rios wrc sludge … · 2018-09-25 · biosolids enhancements at...
TRANSCRIPT
BIOSOLIDS ENHANCEMENTS AT THE DOS RIOS WRC – SLUDGE BLEND TANKS AND CENTRIFUGESGarrett Kehoe, P.E.
September 21, 2018
© Arcadis 2017
Agenda
• Background
• Issues
• Phased Solution Approach
o Phase I – Sludge Blend Tank Improvements
o Phase II – Thickening Centrifuges
• Lessons Learned and Implemented
© Arcadis 2017
• 1984/85 – Dissolved Air Flotation Thickening
• 2006- Gravity Belt Thickeners 1 & 2
• 2009 – Gravity Belt Thickeners 3 & 4
• Dos Rios WRC Sludge consists of:
o Excess Activated Sludge (WAS)
o Dos Rios Primary Sludge
o Leon Creek Sludge (Primary + WAS)
Background
© Arcadis 2017
The issues
(Prior to Upgrades)
Inconsistent Feed Rate
Inconsistent Thickness
Lack of Automation
Lack of Redundancy
Capacity Limitations
© Arcadis 2017
Existing SystemPrimary Sludge
DIGESTERS
DIGESTERS
DIGESTERS
EAS
EAS
EAS
Leon
Primary
Sludge
Leon
Blended
Thickened
© Arcadis 2017
“The Issues”Primary Sludge
DIGESTERS
DIGESTERS
DIGESTERS
EAS
EAS
EAS
Leon
Primary
Sludge
Leon
Blended
Thickened
Centrifugal Pumps
(Inconsistent Flow)
Not Being Thickened
In Pipe Sludge Blending
(Inconsistent Thickness)
© Arcadis 2017
Phase I – Sludge Blending Tank
• Fix consistency of flow and thickness
• Increase operational flexibility
Phase II – Centrifuges
• Add redundancy
• Add capacity
• Automation
• Reduce Operational Costs
Phased Approach
© Arcadis 2017
New Gravity Belt Thickeners Feed Pump Station
New Recirculation Pump Station
New Blending Tank
Overflow Protection
Bypasses for Operational Flexibility
Phase I – Sludge Blend Tank
© Arcadis 2017
Primary Sludge
DIGESTERS
DIGESTERS
DIGESTERS
EAS
EAS
EASLeon
Primary
Sludge
Leon
Blended
Thickened
Proposed System
New Feed Pump Station
(Improved Flow Rate Control)
New Blending Tank
(Improved Consistency)
© Arcadis 2017
Completion Pictures
© Arcadis 2017
• Two new Centrifuges
• New Polymer System
• New Centrate Pump Stations
• Automation
• Facilities for Future Centrifuges
Phase II
© Arcadis 2017
• Solids Loading Capacity vs Flow Capacity
• Thickening equipment needs to be evaluated for both
Capacity Evaluation
© Arcadis 2017
Phase II – Sludge Flows
GBT’s @ 750 gpm each
0
500
1000
1500
2000
2500
3000
3500
2014 2016 2018 2020 2022 2024 2026 2028 2030 2032
Slu
dge F
low
(gpm
)
Year
2% Growth Sludge Flow
Average Flow (gpm) 3 Operating GBT 4 Operating GBT
© Arcadis 2017
Phase II - Solids Thickening Needs
GBT’s @ 3750 lb/hr | Centrifuge @ 6500 lb/hr
0
100000
200000
300000
400000
500000
600000
700000
800000
2014 2016 2018 2020 2022 2024 2026 2028 2030 2032
Dry
Solid
s (
ppd)
Year
2% Growth Solids Handling Capabilities
Average Flow Loading Rate (ppd) 3 Operating GBT 4 Operating GBT One Additional Centrifuge Two Additional Centrifuge
© Arcadis 2017
Phase II
New Feed Pumps
New Polymer Building
New Electrical Building
New Centrate Pumps
New Centrifuges Future Centrifuges
© Arcadis 2017
Ongoing Construction
© Arcadis 2017
Ongoing Construction
© Arcadis 2017
Scoping/Procurement Differences
General Contractor
Centrifuge
Backwash Pump
Thickened Sludge Pump
Polymer System
TYPICAL
Centrifuge
General Contractor
Backwash Pump
Thickened Sludge Pump
Polymer System
DOS RIOS THICKENING
Lessons Learned
© Arcadis 2017
• Available underground space extremely limited
• Exposed piping can be your friend
Lessons Learned
© Arcadis 2017
• I&C Workshops, I&C Workshops, I&C Workshops…
• 3 Instrumentation and controls workshops during design
• 1 Network workshop during construction
• 1 Control panel workshop during construction
• 1 Graphics workshop during construction
Lessons Learned
Record drawings are not always right!
© Arcadis 2017
• Thickened sludge pumping is an art.
• Non Newtonian fluid.
• Highly recommend viscosity testing sludge for >5% solids.
Lessons Learned
© Arcadis 2017
Lessons Learned – Control Maps
© Arcadis 2017
Housekeeping and Safety By Design
Confined Space, no access provided
Tapered edge to prevent storm water entry
Grating above entire centrifuge area to clear spilled sludge easily
© Arcadis 2017
Questions?