zero discharge technology discharge technology.pdf · apache nitrogen zero liquid discharge project...

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?)


• 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


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


• 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


• 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


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


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


• 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


• 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


Computer Simulations Illustrate HOD Maximum Uniform Dose Distribution

CFD Modeling by Atlantium


• Reverse Osmosis Unit Operation

Final Polishing Stage Prior to Wastewater Reuse• 100 GPM capacity• 75% Recovery• Reject to Stage 3 VSEP• Permeate to product


• 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”


• 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


• 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.


• 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


• Project Status

Reduce Chemical AdditionsSignificant ongoing reductions in chemical spend (>25%)

Reduce Overall Operating CostsProject optimization “work-in-progress”


• “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)


• “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.


• 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


• 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


QUESTIONS ??

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