Urine Pretreatment for Wastewater Recovery

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Urine Pretreatmentfor Wastewater Recovery

• SEI 2008-09

Engineers who solved Apollo 13s problems
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Overview

• Background
• Objectives
• Laboratory Tests
• Distillation Simulation
• Results Summary
• Team Accomplishments
• Future Tasks
• Acknowledgements

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Team Structure
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Water Use and Recovery
Water currently resupplied via shuttle Not
economical or practical to re-supply water for
long term missions
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ISS wastewater sources
Distribution
Consumption
Hygiene
Perspiration
Exhalation
Humidity Condensate
Hygiene Waste
Urination
Urine pretreatment protects hardware and plumbing
system form clogging

• Solids precipitation
• Biofilm formation

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Current Urine Pretreatment
String of Pearls
Not compatible with reclamation system
Urine and Fecal collection Unit
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Problem Statement
The current pretreatment method utilizes a toxic
chemical with little known toxicological
information that may be detrimental to astronaut
health over time.
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Previous work

• Supernatant Characterization from urine MAP
  precipitation

• Chemical urine pretreatment

• Sulfuric Acid
• Sodium Benzoate
• Acetic Acid
• Glycolic Acid
• Sodium Permangante
• Phosphoric Acid

• TOC gt EPA drinking water limit
• Organics and Inorganics removal is needed
• High pH buffer
• Need to optimize precipitation reaction

Work presented in the 11th International
Conference on Engineering, Science, Construction,
and Operations in Challenging Environments (Earth
Space Conference)
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Cascade Distillation Subsystemcurrently used for
water reclamation

• Centrifugal vacuum distillation

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Project Objective
Identify a non-toxic pretreatment alternative
that is compatible with a distillation based
water reclamation system.
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Project Tasks

• Task 1- Laboratory tests
• Select pretreatment chemicals
• Toxicity data, HMIS, pKa, Volatility
• Test chemicals pretreatment ability
• Task 2- Distillation simulation (Aspen)
• Research Cascade Distillation Subsystem
• Determine simulation operation conditions
• Simulate chemicals tested in Task 1

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Task 1-Laboratory Test
Objective Compare pretreatment chemicals to
sulfuric acid in stored urine (1g/L)

• Chemical pH
• Physical TSS, Turbidity
• Biological Protein, Ammonia, DO

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Chemicals Selected

• 1 g/L as active ingredient
• Chosen based on solubilty, pKa, and toxicity
• Delivery system for solid chemicals depends on
  solubility

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Experimental Methods
Urine collected
Urine collection carboy
Samples are taken at predetermined times
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Analytical Methods
pH
TSS
Dissolved Oxygen
Turbidity
Ammonia Phenate Method
Protein Assay
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Chemical Test Results
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Physical Tests Results
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Biological Tests Results
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Biological Tests Results
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Task 2- Simulation

• Objectives
• Determine water recovery at proposed operating
  conditions
• Determine acid recovery at proposed operating
  conditions

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Simulation Conditions
One stage flash (worst case scenario)
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Simulation results

• Sulfuric, fumaric, and boric are separable from
  water in the flash operating range of 25-50C
• Currently unable to simulate sorbic acid
• Separation Efficiency

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Results Summary

• Laboratory tests results
• Chemicals tested do meet pretreatment
  requirements for short term storage
• Chemicals tested do not meet pretreatment
  requirements for long term storage
• Distillation results
• Chemicals are separable from water in the flash
  operating range of 25-50C.
• Preliminary simulations indicate that high
  chemical removal is possible

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Future Tasks

• Laboratory tests
• Lactic acid
• Phthalic acids
• Simulation
• Separation efficiencies
• Lactic acid
• Phthalic acids

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Acknowledgements

• Julianna Camacho
• Dr. Autenreith
• Dr. Pickering
• Magda Lagoudas
• Urine Video