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Apache NitrogenZero Liquid Discharge Project
Mr. Shawn RanaMr. Jim Madole
Mr. Joel Peterson
Apache Nitrogen Apache Nitrogen -- Zero Liquid Discharge (ZLD) ProjectZero Liquid Discharge (ZLD) Project
• Presentation Overview:
• Plant Background• Project Background
• Project Goals
• Membrane ZLD System Design
• Project Status
• Lessons Learned
• Project Refinements
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Project Background:
Apache Nitrogen – Benson, ArizonaBrine Concentration System fully depreciatedSignificant maintenance reinvestment scheduled for BC.Historical reliability concerns Incentive for investigating alternatives with emerging technologies.Opportunity to improve overall plant efficiency.
Water quality Equipment reliability Heat transfer efficiencyEnergy efficiency
(Insert Photos and Brief Overview of Apache Nitrogen?)
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Project Background:
Previous “As Was” System Configuration
Well Supply to C/T make-up and BFW
No Wastewater Discharge Permitted
60 – 90 gpm of Cooling Tower Blow-Down
Brine Concentrator (BC) applied to all discharge
Approx. 1 gpm of BC Concentrate Hauled Away by Truck
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
90 gpm 68 gpm
22 gpm
17 gpm
17 gpm
31 gpm
3 gpm
8 gpm
Recycle to RO 1 FeedVSEP 1
VSEP 2
RO 1
VSEP 3
CoolingTower
Make Up
Haul Off
BoilerFeedWater
51 gpmT-932Feed
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Project Goals
Replace BC with Membrane Separation Technology
Improve or Maintain Quality of Reclaimed Water
Reduce Energy Consumption
Reduce Maintenance Costs
Reduce Operator Touch Time
Reduce Chemical Additions
Reduce Overall Operating Costs
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Membrane ZLD System Design
Major New Unit Operations
Vibratory Shear-Enhanced Membrane Process (VSEP)
Vibrating Membrane Surface Reduces Fouling by Imparting Shear Force Directly at the Membrane/Fluid Interface, Where Fouling Typically Occurs
Atlantium Ultraviolet Light Disinfection
Next generation UV Oxidation Inactivates Biological Materials and Prevents Growth (5-8 Log Disinfection to include cryptosporidium) without Chemical Oxidants (Incompatible with Membrane Material) or Biocides
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
90 gpm 77 gpm
13 gpm
11 gpm
19 gpm
27 gpm
3 gpm
5 gpm
VSEP 1
VSEP 2
RO 1
VSEP 3
CoolingTower
Make Up
Haul Off
58 gpm
T-932Feed
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
ExistingBFW RO
RO 2
40 gpm
50 gpm
53 gpm
67 gpmBoilerFeedWater
BoilerFeedWater
13 gpm
WellWater
Make Up
WellWater
Make Up
17 gpm
T-932
T-932
Boiler FeedWater (ifnecesary)
WellWater
Make Up
Na X
Na X
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• VSEP Unit Operation50Hz vibration
• 95% of energy input @ membrane surface
• 10X shear of conventional crossflow
• Fouling easily reversed with cleaning in place
• Modular
• TSS fouling resistant
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Atlantium UV Unit Operation
•• 5 to 8 Log disinfection5 to 8 Log disinfection
•• Quartz reactor Quartz reactor chamberchamber
•• ““OutOut--ofof--the waterthe water”” UV UV bulbsbulbs
•• Redundant twoRedundant two--bulb bulb systemsystem
•• Dual sensor Dual sensor transmittance monitortransmittance monitor
•• Output: 50Output: 50--700 mj/cm700 mj/cm22
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
Computer Simulations Illustrate HOD Maximum Uniform Dose Distribution
CFD Modeling by Atlantium
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Reverse Osmosis Unit Operation
Final Polishing Stage Prior to Wastewater Reuse• 100 GPM capacity• 75% Recovery• Reject to Stage 3 VSEP• Permeate to product
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Implementation
Bench-Scale Testing
Unit operations and treatment approach proved viable
Abbreviated Pilot-Scale “batch testing”Conducted by manufacturer to confirm design projections.
Full-scale Pilot operability testing Conducted in parallel with existing system.
Planned implementation for improvements “Work-in-progress”
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Project Status…. Best Considered in Context of Project
Goals:
Improve or Maintain Quality of Reclaimed WaterReduce Energy ConsumptionReduce Maintenance CostsReduce Operator Touch TimeReduce Chemical AdditionsReduce Overall Operating Costs
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Project Status
Improve or Maintain Quality of Reclaimed Water
Permeate quality proved to be inferior to distillate from BC but acceptable for BFW at steam pressure of 400PSIG.
Inlet hydraulic capacity meets design criteria.
Overall system recovery not yet equivalent to BCCurrent recoveries being balanced with cleaning frequencies for sustainable operation.
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Project StatusReduce Energy Consumption
BC load reduced and trending down
Reduce Maintenance CostsBC reinvestment maintenance postponed
Reduce Operator Touch TimeNot yet realized in start-up phases
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Project Status
Reduce Chemical AdditionsSignificant ongoing reductions in chemical spend (>25%)
Reduce Overall Operating CostsProject optimization “work-in-progress”
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• “Lessons Learned”
Flux decline too rapid without pH depression of feedCleaning frequencies twice/day without pH control @ 5.5
Pretreatment of feed with macro- or micro-filtration had no appreciable affect on flux decline rate.
Primary fouling constituent identified to be BaSO4 , using bench-scale equipment.
Replacement of H2SO4 with HCl acid for pH control of membrane feed doubled run-lengths. (once/day)
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• “Lessons Learned”
Reductions in initial feed pressure and recovery doubled run-lengths again. (every other day +)
Addition of pH control chemicals degraded the quality of the permeate further away from the “distillate quality goal”.
Replacement of H2SO4 with HCl for CT pH control unviable due to chloride addition and subsequent reduction in concentration ratio for CT’s.
Plant has several critical stainless metallurgy heat exchangers.Cost multiplier would have been 6X as well.
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Project RefinementsDedicate 100% of recovered permeate to cooling
tower make-up to displace well water.
C/T make-up supply “M-alkalinity” dramatically reduced
C/T H2SO4 acid feed dramatically reduced (or eliminated)
Scaling tendency of cooling water significantly reduced.
Concentration Ratios for CT’s increase from 5 to 7.
Reduced CT blow-down reduces hydraulic load on wastewater recovery, Reduced chemical feed, Reduced make-up requirements
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
• Project Refinements
Dedicate 100% of recovered permeate to cooling tower make-up to displace well water.
Well water intake shifted to BFW Reverse Osmosis UnitspH control chemistry option for RO shifted to CO2Sulfate balance in wastewater recovery dramatically reduced.
BFW supply to be 100% Reverse Osmosis (more reliable)
Overall fewer contaminants added to system for removal during recovery
Apache Nitrogen Apache Nitrogen -- ZLD ProjectZLD Project
QUESTIONS ??
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