Urine Pretreatmentfor Wastewater Recovery

SEI 2008-09Engineers who solved Apollo 13’s problems

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

Team Structure

Name Major Year Position

Moriah Thompson Biomedical Eng. 4 Project Lead

Sara Guest Chemical Eng. 4 Data and Simulation Lead

Elizabeth Joachim Biomedical Eng. 3 Lab Lead

David Moore Civil Eng. 1 Assistant Lab Lead

Sandhya Ramesh Biomedical Eng. 1 Logistics Lead and lab work

Marco Cienega Mechanical Eng. 3 Assistant Logistics Lead

Blesson John Biomedical Eng. 1 Webmaster

Water Use and Recovery

Water currently resupplied via shuttle

Not economical or practical to re-supply water for long term missions

ISS wastewater sources

Urination

Distribution

Consumption Hygiene

HumidityCondensate

PerspirationExhalation

Hygiene Waste

Urine pretreatment protects hardware and plumbing system form clogging

1. Solids precipitation

2. Biofilm formation

Current Urine Pretreatment

“String of Pearls”

Urine and Fecal collection Unit

Not compatible with reclamation

system

Problem Statement

The current pretreatment method utilizes a toxic chemical with little known

toxicological information that may be detrimental to astronaut health over time.

Previous workSupernatant Characterization from urine MAP precipitation:

• TOC > EPA drinking water limit

• Organics and Inorganics removal is needed

• High pH buffer

• Need to optimize precipitation reaction

Chemical urine pretreatment:

• Sulfuric Acid

• Sodium Benzoate

• Acetic Acid

• Glycolic Acid

• Sodium Permangante

• Phosphoric Acid

Work presented in the 11th International Conference on Engineering, Science, Construction, and Operations in Challenging Environments (Earth & Space Conference)

Cascade Distillation Subsystemcurrently used for water reclamation

Centrifugal vacuum distillation

Project Objective

Identify a non-toxic pretreatment alternative that is compatible with a distillation based water reclamation

system.

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

Task 1-Laboratory Test

– Chemical: pH– Physical: TSS, Turbidity– Biological: Protein, Ammonia, DO

Objective: Compare pretreatment chemicals to sulfuric acid in stored urine (1g/L)

Chemicals Selected• 1 g/L as active

ingredient • Chosen based on

solubilty, pKa, and toxicity

• Delivery system for solid chemicals depends on solubility

Sulfuric Acid

Fumaric Acid

Sorbic Acid

Boric Acid

Lactic Acid

Phthalic Acid

Experimental Methods

Urine collected

Samples are taken at predetermined times

Urine collection carboy

Analytical Methods

TSS

Turbidity

pH

Dissolved Oxygen

AmmoniaPhenate Method Protein Assay

Chemical Test Results

Physical Tests Results

Biological Tests Results

Biological Tests Results

Task 2- SimulationObjectives:

– Determine % water recovery at proposed operating conditions

– Determine % acid recovery at proposed operating conditions

FEED

VAPOR

LIQUID

FLASH

Feed ConditionsTemperature °C 40

Pressure psi 14.69Volume Fraction  

Chemical 0.04Water 0.96

Flash Operating Conditions

Temperature °C 25-50Pressure psi 0

One stage flash (worst case scenario)

Simulation Conditions

Simulation results• Sulfuric, fumaric, and boric are separable

from water in the flash operating range of 25-50°C

• Currently unable to simulate sorbic acid• Separation Efficiency:

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 25-50°C.– Preliminary simulations indicate that high % chemical

removal is possible

Future Tasks• Laboratory tests

– Lactic acid– Phthalic acids

• Simulation– Separation efficiencies– Lactic acid– Phthalic acids

Acknowledgements

Julianna Camacho

Dr. Autenreith

Dr. Pickering

Magda Lagoudas

Urine Video