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Solids Separation and Concentration of Shipboard Wastewaters and Residuals by a High Shear Rotary Membrane System HSR-MS

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Solids Separation and Concentration of Shipboard Wastewaters and Residuals by a High Shear Rotary Membrane System HSR-MS

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    1. Solids Separation and Concentration of Shipboard Wastewaters and Residuals by a High Shear Rotary Membrane System (HSR-MS) Project Number WP-1671 Tracy M. Carole Naval Surface Warfare Center, Carderock Division In-Progress Review Meeting 17 February 2010

    2. 2 Project Team Tracy Carole (PI) and Tracy Harasti DOD Laboratory at Naval Surface Warfare Center, Carderock Division Dr. Brian Reed (Co-PI) University of Maryland, Baltimore County, Civil & Environmental Engineering Dr. Douglas Frey and Dr. Tony Farquhar University of Maryland Baltimore County Chemical & Biochemical Engineering (Frey) Mechanical Engineering (Farquhar) John Bendick, P.E. UMBC PhD student William Greene SpinTek Filtration

    3. 3 Technical Objective Objective: Develop a robust shipboard treatment system to treat a variety of Navy solids-bearing wastewaters and residuals. Specific goals: Increase HSR-MS permeate flux/decrease system size by employing back pulsing and continuous membrane cleaning. Increase the active membrane packing density (active membrane area/system footprint/space) by using larger diameter disks operated at a lower rotation Conceptually design, fabricate and test a shipboard HSR-MS that incorporates back pulsing, continuous membrane cleaning, larger disks, and disk overlap. Outcome: A shipboard HSR-MS having increased waste treatment throughput, a smaller footprint/space requirements, be potentially portable, and constructed of lighter weight and cheaper materials.

    4. 4 Size of membrane disk is limited by ? Excessive backpressure at outer edge Difficulty in rotating large disk at high ? Need to reduce ? to increase disk size Reducing ? decreases surface scouring action which reduces J (gal/ft2-d) Loss of cleaning action from disk rotation replaced by continual cleaning/backpulsing Need baseline data to assess increase in efficiency during continuous cleaning/backpulsing

    5. 5 Technical Approach Items in red are covered for this meetingItems in red are covered for this meeting

    6. 6 Task 1. Develop Synthetic Wastes The project team worked with Carderock waste experts to identify the wastes that could be treated by HSR-MS. Current and future shipboard wastes were considered.

    7. 7 Membranes were identified using the following criteria: Must be commercially available Be attachable to HSRM disk Pore size between 0.1 and 5 um Durable Membranes underwent stirred cell testing Waste placed in kegs and stirred cells Paddle rotated and pressure applied Permeate mass measured every minute Turbidity of composite sample measured Membranes cleaned and procedure repeated Cleaning methods were developed Emphasis cleaning methodsEmphasis cleaning methods

    8. 8 Task 3. Baseline Testing SpinTek constructed 2 pilot-scale HSR units Here we had to give some credit to SpinTek but we hated doing it. Shipped one unit to Carderock for baseline testing Carderock facility space renovated with electric, water, heat, etc. 2nd unit remained at SpinTek to work on backpulsing mechanism Low rotation (500 rpm) used; pressures varied between 35 and 55 psi Permeate flux and quality measured for at least 3 runs Membrane cleaned in between treatment runs using methods developed in stirred cell testing Decided to keep 2n unit there once some results from baseline testing were ID as positive, save time and $ shipping unit back to spintek for backpulsing upgradeDecided to keep 2n unit there once some results from baseline testing were ID as positive, save time and $ shipping unit back to spintek for backpulsing upgrade

    9. 9 Task 1 Results Waste Selection/ Development

    10. 10 Task 2. Selected Membranes All membranes commercially available, durable and can be attached to membrane disk Pore sizes in target range (0.1 to 5 um) polytetrafluorothylene polytetrafluorothylene

    11. 11 Task 2 Results Raw Stirred Cell Data

    12. 12 Task 2 Results Reduced Stirred Cell Data

    13. 13 Task 2 Results Averaged Stirred Cell Data For all wastes membranes gave similar J although not the same membranes, Permeate quality similar for all membranes, carry all membranes into pilotscale testingFor all wastes membranes gave similar J although not the same membranes, Permeate quality similar for all membranes, carry all membranes into pilotscale testing

    14. 14 Task 2 Results Summary of Stirred Cell Tests All membranes performed well based on permeate flux/quality Carry forward all membranes-waste combinations to baseline pilot-scale testing Cleaning methods established Bilge; Black/gray; Biosolids 2 step process BIZ, Dawn, pH =11.5; citric acid, pH 2.5 Cl2 (1%) only effective for PTFE PAWDS: warm water flush Virgin membrane resistances determined for all membranes and can be used as tracking of membrane fouling Point #1 peroformance did not decrease with run #Point #1 peroformance did not decrease with run #

    15. 15 Status of Task 3 Baseline Testing Permeate quality and quantity similar for all membranes, carry all membranes into pilotscale testingPermeate quality and quantity similar for all membranes, carry all membranes into pilotscale testing

    16. 16 Task 3 Example Pilot-Scale Results Point out Point out

    17. 17 Task 3 Example PAWDS Results J did not decline initially J higher than other wastes due to type of solids: PAWDS inert particles (avg size = 22 um) Other waste either biologically active or deformable particles Higher fluxes possible if rotation increased and continuous cleaning/ backpulsing used Possible that HSR system can be used as is for PAWDS waste Repeat tests at higher rotations Other wastes, solids promote membrane foulingOther wastes, solids promote membrane fouling

    18. 18 Modification of Unit #2 for Backpulsing Treatment: valves 1 and 3 open, 2 closed Permeate flows into 4 L chamber Backpulsing: valve 1 closes, valve 2 opens and pressure forces permeate stored in chamber to flow back into membrane chamber Significantly reduce buildup of solids on membrane surface

    19. 19 Effect of Backpulsing Conceptual J-time

    20. 20 Go/No-Go End of Task 3 GO Decision: if baseline testing demonstrates sufficient permeate water quality and permeate flux performance to warrant further investigation into continual physical cleaning and backpulsing Fluxes observed at the beginning of runs were relatively high despite the low rotation used The decline in flux was due to buildup of solute boundary layer at the membrane surface Backpulsing/continuous cleaning will minimize solids buildup producing an increase in flux at low rotational speeds Lower rotational speed will allow larger disks to be used We believe that a GO decision for further work is warranted

    21. 21 Issues and Resolution Space at Carderock needed to be renovated ? Resolved Difficulty in securing black-gray WW and biosolids from ongoing Carderock research ? used LPRWRP as source for these wastes 2nd Unit remained at SpinTek for backpulsing development ? 2nd unit shipped this month General contract delays Issues with locating students/post doc at Carderock (citizenship and distance) ? Intern from Univ. of Pitt./Reed working at Carderock, full-time person will be hired to work at Carderock to accelerate testing Membrane attachment method needed to be refined ? Resolved

    22. 22 Transition Plan Interim Results Poster at SERDP December 09 conference John Bendick Ph.D pre-proposal Use of HSR-MS for PAWDS waste treatment will be discussed with navy personnel Research Transition Continue with work to quantify increase in efficiency realized by continual cleaning/backpulsing Begin conceptualized design of overlapping disks

    23. BACKUP MATERIAL These charts are required, but will only be briefed if questions arise.

    24. 24 Bilge Water Stirred Cell Results

    25. 25 Black/Gray Wastewater Stirred Cell Results

    26. 26 PAWDS Stirred Cell Results

    27. 27 Biosolids Stirred Cell Results

    28. 28 Bilge Water Pilot-Scale Results

    29. 29 Black/Gray Wastewater Pilot-Scale Results

    30. 30 PAWDS Pilot-Scale Results

    31. 31 Effect of Backpulsing

    32. 32 Effect of Continuous Cleaning

    33. 33 Membrane Pressures in HSR-MS

    34. 34 Collection of PAWDS Waste

    35. 35 Acronyms and Symbols ? = disk rotational speed, rpm J = membrane flux, permeate volume/membrane area per time. (gal/ft2-d) LPRWRP = Little Patuxent River Water Reclamation Plant TSS = total suspended solids PAWDS = plasma arc waste destruction system AP = applied pressure, psi

    36. 36 Publications Provide a list of all publications, oral presentations, patents, awards, etc. that already have resulted from this work. Poster at SERDP December 09 conference Provide a list of publications that are in progress or planned (including venue for publication) and oral presentations that are scheduled. Use of Backpulsing and Continuous Cleaning to Improve Performance of High Shear Rotary Membrane System Journal of Environmental Engineering, ASCE

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