Urine Pretreatment for Wastewater Recovery SEI 2008-09 Engineers who solved Apollo 13’s problems Blesson

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

Team Structure Name Major Year Position Moriah Thompson Biomedical Eng. 4 Project Lead Sara Guest Chemical Eng. Data and Simulation Lead Elizabeth Joachim 3 Lab Lead David Moore Civil Eng. 1 Assistant Lab Lead Sandhya Ramesh Logistics Lead and lab work Marco Cienega Mechanical Eng. Assistant Logistics Lead Blesson John Webmaster Blesson 3

Water Use and Recovery Water currently resupplied via shuttle Not economical or practical to re-supply water for long term missions Blesson

ISS wastewater sources Distribution Consumption Hygiene Exhalation Perspiration Humidity Condensate Urination Hygiene Waste Moriah Urine pretreatment protects hardware and plumbing system form clogging Solids precipitation Biofilm formation

Current Urine Pretreatment “String of Pearls” Not compatible with reclamation system Moriah Urine and Fecal collection Unit 6

Problem Statement The current pretreatment method utilizes a toxic chemical with little known toxicological information that may be detrimental to astronaut health over time. Moriah 7

Previous work Supernatant Characterization from urine MAP precipitation: Chemical urine pretreatment: TOC > EPA drinking water limit Organics and Inorganics removal is needed High pH buffer Need to optimize precipitation reaction Sulfuric Acid Sodium Benzoate Acetic Acid Glycolic Acid Sodium Permangante Phosphoric Acid So far we have worked on this problem and this is what we have done so far. Explain the objective for each of the previous work and say it was presented in E&S. Work presented in the 11th International Conference on Engineering, Science, Construction, and Operations in Challenging Environments (Earth & Space Conference) 8

Cascade Distillation Subsystem currently used for water reclamation Marco Centrifugal vacuum distillation

Project Objective Identify a non-toxic pretreatment alternative that is compatible with a distillation based water reclamation system. marco 10

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 Marco 11

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 Sandhya Monitor the biological, chemical, and physical changes occurring in the stored urine following the addition of pre-treatment agent. Metrics of success: Chemical- constant pH, Physical- constant TSS, Biological- constant protein, ammonia and DO

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 Sandhya

Experimental Methods Urine collected Urine collection carboy Sandhya This is how we started the experiments. Urine was collected no earlier that 4hr before according to…then explain the flowchart including Urine is equally distributed in the reactors and pretreatment chemical is added Samples are taken at predetermined times 14

Analytical Methods pH TSS Dissolved Oxygen Turbidity Ammonia Sandhya The pH, or acidity, of each sample should fall within a certain range to keep solids from precipitating and bacteria from forming. Dissolved Oxygen (DO), a measure of the amount of oxygen dissolved in the solution, indicates the amount of bacteria activity in the sample. The Phenate Method measures the amount of ammonia in a solution, indicating the activity of bacteria in the sample. Total Suspended Solids (TSS), a measurement of the amount of solid particles suspended in a liquid, is used to measure the amount of precipitation that occurs in the urine sample over time. Turbidity, a measure of the cloudiness of a fluid, also indicates the amount of particles suspended in the solution. Protein Assay measures the amount of protein in a solution, indicating the presence of the enzymes bacteria use. Ammonia Phenate Method Protein Assay

Chemical Test Results Libby

Physical Tests Results Libby

Biological Tests Results Libby

Biological Tests Results Libby

Task 2- Simulation Objectives: Determine % water recovery at proposed operating conditions Determine % acid recovery at proposed operating conditions Sara Monitor the biological, chemical, and physical changes occurring in the stored urine following the addition of pre-treatment agent. Metrics of success: Chemical- constant pH, Physical- constant TSS, Biological- constant protein, ammonia and DO

Flash Operating Conditions Simulation Conditions One stage flash (worst case scenario) Feed Conditions Temperature °C 40 Pressure psi 14.69 Volume Fraction   Chemical 0.04 Water 0.96 Flash Operating Conditions Temperature °C 25-50 Pressure psi Sara The simulation operating conditions are based off information from NASA papers. There was not an exact feed description in terms of flowrates to the CD system. There is a description of the urine pretreatment chemical volume and the urine volume. We can only model an acid, water separation in Aspen. So, I treated the urine as if it were all water. The numbers from the paper are 1000ml urine and 40 ml of pretreatment chemical. From that I decided the feed would be 960 ml of water and 40 ml acid. There was no feed pressure, so I assumed 1 atm or 14.696 psi. The important pressure is the flash pressure which is zero. Our goal is to show the effect of the acid on the recovery of water. Are we able to recover the water in the operating range of the CD system (max 50°C). Also, is there one acid that is easier to separate than the others and how do the acids compare with the effect sulfuric acid would have on the separation. The system was modeled as a one stage flash even though there are possibly 5 cascades. One flash assumes worst case scenario. So far, sulfuric, fumaric, and boric are separable from water in the flash operating range of 25-50°C. The lower the flash temperature the less acid is recovered with the water and more water is lost with the acid/waste/liquid stream. However, the differences are very small 5E-5 to 5E-4 mass fraction of sulfuric acid in water. Results so far indicate that the acid should not negatively effect water recovery. It would be nice to have a specification for the maximum acid content in the recovered water. 21

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: Sara 22

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 David

Future Tasks Laboratory tests Simulation Lactic acid Phthalic acids Separation efficiencies David

Acknowledgements Julianna Camacho Dr. Autenreith Dr. Pickering Magda Lagoudas Urine Video David