Grantee Research Project Results
Final Report: OSMOsis-Driven ReclAmation of Water (OSMODRAW)
EPA Grant Number: SU839457Title: OSMOsis-Driven ReclAmation of Water (OSMODRAW)
Investigators: Sadmani, Dr AHM Anwar , Villarruel-Moore, Angel , Tanelus, Johnci , Smith, Susanna , Olimattel, Kunal
Institution: University of Central Florida
EPA Project Officer: Callan, Richard
Phase: I
Project Period: January 1, 2019 through December 31, 2019 (Extended to April 30, 2020)
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet (2018) RFA Text | Recipients Lists
Research Category: P3 Awards , P3 Challenge Area - Safe and Sustainable Water Resources
Objective:
The objective of this study was to investigate a functionalized OSMODRAW (OSMOsis Driven ReclAmation of Water) system to reclaim water from urban runoff using a composite forward osmosis (FO) membrane with multiple functionalities. The overarching goal is to develop an osmosis-driven integrated approach to treat an impaired quality water, urban runoff while utilizing another impaired quality water, for instance, brackish water reverse osmosis (BWRO) concentrate using polyelectrolyte (PE) functionalized FO membranes.
Summary/Accomplishments (Outputs/Outcomes):
This project proposes to develop an integrated osmotically driven water reclamation process (OSMODRAW) that is equipped with a functionalized FO membrane to reclaim water from urban runoff while rejecting the runoff-derived pollutants. The urban runoff would serve as the feed solution (FS) to one side of the FO membrane and a draw solution (DS) with concentrations representative of those of concentrates from BWRO plants would be diluted due to osmotic pressure differential. Commercial FO membrane specimens were modified by depositing oppositely charged polyion complex followed by crosslinking to ensure stability of the coatings. Multiple layers of coatings/films (polyelectrolyte multilayer films [PMF]) were deposited following both fluidic assembly and dip-coating methods. Zero valent iron (nZVI) was then loaded within the PMFs. The number of ‘bilayers’ (BL) was varied (from 3 to 14) to test their effectiveness in immobilizing nZVIs. During our initial trials, the fluidic assembly method was not yielding uniform bilayers and was deemed resource consuming. Hence, we employed dip coating method for the remaining experiments.
PMFs with different number of ‘bilayers’ were successfully deposited onto the commercial FO membrane surfaces, which became slightly rougher due to the deposited layers. The immobilization of nZVI within the PMFs increases with increasing number of bilayers. The PE functionalized membrane became more negatively charged when compared to the virgin membrane, implying that the membrane can develop enhanced resistance to organic fouling due to electrostatic repulsion.
A bench-scale FO system was used to determine the water flux performance and the removal of nutrients, selected metals, and selected organic contaminants from stormwater using unmodified and modified FO. Synthetic stormwater runoff was prepared in lab by spiking selected metals (Cu, Cd, Pb), nutrients, organics, and humic acid. Humic acid was spiked as the representative of natural organic matter. To represent contaminants of emerging concern, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) were spiked in the FS. PFOA and PFOS concentrations in FSs were analyzed by a SPE-LC-MS/MS method developed based on the EPA Method 537 Rev. 1.1. The draw solution was prepared by spiking NaCl into deionized water. Preliminary flux measurements using synthetic FS and DS demonstrated that feedwater recovery was not markedly impacted by the coating of PE complex. Following a series of BL depositions, it was deduced that 14 BL coatings resulted in the most uniform layers with maximum surface overage. Scanning electron microscopy (SEM) images demonstrated that the membrane coverage and uniformity of coating improved as more BL coatings were applied. Flux decline by the modified membrane that may be anticipated owing to the additional layers on the membrane was probably offset by the hydrophilicity rendered by the PAA/PAH functional groups and less foulant accumulation.
NO3- and PO43- removals were already very high when using the unmodified membrane; however, a slight increase in the removal of NO3- with increased BL numbers (8 and 14 BLs) was observed. The removal of selected heavy metals (Cd, Pb, and Cu) by both the unmodified and modified membranes was very high, with a higher number of coating resulting in a higher retention of heavy metals by the functionalized FO membranes. This could be attributed to the complexation of metal ions with carboxylate and amine groups from the PAA/PAH bilayers. Furthermore, the removal of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) by the membranes was also very high.
Conclusions:
The project relates to pollution prevention/control by proposing an innovative integrated approach to remove pollutants from two impaired quality waters (e.g., urban runoff and concentrate from brackish water desalination plant) that would otherwise be typically discharged into the environment with little or no treatment. The objective of this study can be linked to EPA’s authorizing statute CWA: Clean Water Act--Section 104.
This project demonstrates an integrated osmotically driven water reclamation process (OSMODRAW) that is equipped with a functionalized FO membrane to reclaim water from urban runoff while rejecting the runoff-derived pollutants. The urban runoff would serve as the feed solution (FS) to one side of the FO membrane and a draw solution (DS) with concentrations representative of those of concentrates from BWRO plants would be diluted due to osmotic pressure differential. Flux decline by the modified membrane that may be anticipated owing to the additional layers on the membrane may be offset by the hydrophilicity rendered by the PAA/PAH functional groups and less foulant accumulation. Runoff derived pollutants can be removed by the system effectively while reclaiming water from another impaired source.
For detailed economic assessment of the proposed system, a pilot-scale study coupled with pretreatment steps should be conducted. It is recommended that the investigated approach to membrane functionalization and its efficiency in water recovery should be extended to the hollow fiber FO membranes that are being currently produced by the manufacturers.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
Forward osmosis, draw solution, feed solution, membrane, polyelectrolyte, reclamation, urban runoff, zero valent iron nanoparticleProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.