The optimal usage of antiscalants and their effect on fouling of reverse osmosis membranes Thesis submitted in partial fulfillment of the requirements for the degree of “DOCTOR OF PHILOSOPHY” By Amer Sweity Submitted to The senate of Ben-Gurion University of the Negev March 2015 Beer-Sheba The optimal usage of antiscalants and their effect on fouling of reverse osmosis membranes Thesis submitted in partial fulfillment of the requerments for the degree of “DOCTOR OF PHILOSOPHY” By Amer Sweity Submitted to the senate of Ben-Gurion University of the Negev Approved by the advisors Prof. __________ Moshe Herzberg ____________Prof. Zeev Ronen Approved by the Dean of Kreitman School of Advanced Graduate studies ___________ March 2015 Beer-Sheba This work was carried out under the supervision of Prof. Moshe Herzberg1 and Prof. Zeev Ronen2 1) Department of Desalination and Water Treatment 2) Department of Environmental Hydrology and Microbiology Zuckerberg Institute for Water Research, Jacob Blaustien Institutes for Desert Research, Ben Gurion University of the Negev, Sde Boqer campus. Research-Student’s Affidavit when Submitting The Doctoral Thesis for Judgment I Amer Sweity, whose signature appears below, hereby declare that (Please mark the appropriate statements): _X_ I have written this Thesis by myself, except for the help and guidance offered by my Thesis Advisors. _X_ The scientific materials included in this Thesis are products of my own research, culled from the period during which I was a research student. __ This Thesis incorporates research materials produced in cooperation with others, excluding the technical help commonly received during experimental work. Therefore, I am attaching another affidavit stating the contributions made by myself and the other participants in this research, which has been approved by them and submitted with their approval. Date:__________18-3-2015 Student’s name: __Amer Sweity__ Signature:_________________ i ACKNOWLEDGMENTS Foremost, I would like to express my sincere gratitude to my supervisors, Prof. Moshe Herzberg and Prof. Zeev Ronen. Thank you for your invaluable guidance, encouragement, comments, criticism, support, and suggestions. Your incredible help was the key to my success in my Ph.D. research. With no doubt, this research hasn’t had to be done without your enthusiasm and you being patient with me. I am so grateful to The Jacob Blaustein Institutes for Desert Research for giving me the opportunity to conduct my Ph.D. study. Also, many thanks extended to all the faculty members of the Zuckerberg Institute for Water Research especially the staff of Department of Desalination and Water Treatment. My sincere appreciation goes to Prof. Yoram Oren, Prof. Jack Gilron and Prof. Amit Gross for their spiritual and professional support. I would like to thank and appreciate the help and the support that I got from the technical staff of the ZIWR people, special thanks to Dr. Anna Mamontov, Dr Naphtali Daltrophe and Itzik Lutvak for you being phenomenal. I would like sincerely to acknowledge my former and current lab colleagues at the Zuckerberg Institute for Water Research, who shared their knowledge, perceptive ideas and experiences with me. (Dr. Wang Ying, Oded Orgad, Nune Vanoyan, Tesfalem Rezene, Diana Ferrando, Adi Avni, Yael Shabtai, Eli Assa, Nofar Assa, Dr. Jenia Gutman and Dr. Chris Ziemba). Thanks also to my friends and neighbors in Sede Boqer campus, for their warmth and support specially Ashraf Alshhab, Omar Bawab, Suleiman Halssah, Bihter Bayramoglu, Ani Vardanyan and Hadeel Majid . ii Last, I want to applaud my family indeed, the ultimate keystone of my success and accomplishments. I want to express my thanks to my brother, my sisters, my nieces and my nephews for their support and being wonderful with me. I don’t know how to thank my parents. "My Lord! Bestow on them Your Mercy as they did bring me up when I was small." Thanks to my father who was my inspiration and my leader for his unwavering encouragement, patience and understanding, thanks for believing in me. I am so grateful to my mom, where all the words in the world stuck to describe how supportive she was and still, I am grateful to the mom who prayed days and nights at every stage in my life wishing me success and fortune where ever I go. iii TABLE OF CONTENTS………………………...iv ACKNOWLEDGMENTS……………………......ii LIST OF FIGURES and TABLES……………...v ABBREVIATIONS……………………………....vii ABSTRACT……………………………………….ix LITERATURE REVIEW ………………………..1 HYPOTHESIS and AIMS…………….………...14 THE DISSIRTATION STRUCTURE………….15 PUBLISHED PAPERS………………………….17 PAPER 1……………………………………….....17 PAPER 2……………………………………….....27 PAPER 3………………………………………….35 DISCUSSION AND CONCLUSIONS………....51 SUPPLEMENTRY MATERIALS……………..59 REFRENCES…………………………………….68 HEBREW ABSTRACT…………………………76 iv LIST OF FIGURES AND TABLES Comment: This section includes only figures and tables that were not described in the published articles. Figure 1 Daily global water production by desalination currently and projection in the near future……………………………………………………………………………….3 Figure 2 SWRO desalination plant showing the various stages—seawater intake, pretreatment, reverse osmosis, post-treatment, and brine discharge—and their interactions with the environment adopted from Elimelech (2011)………………………………….4 Figure 3 Schematic illustration of scale formation schemes………………………….…9 Figure 4 Schematic illustration of antiscalant inhibition mechanisms…………………11 Figure 5 Chemical structure of some antiscalants used in RO desalination: (A) sodium hexametaphosphate (SHMP); (B) potassium pyrophosphate; (C) 2-Hydroxy phosphono acetic-acid; (D) polyacrylic-acid; (E) polyphosphonate; and (F) carboxylated dendrimeric polymer………………………………………………………………………………….13 Figure S1 paper 1 XPS analysis of carbon binding energy spectra on membrane surface: (A) virgin membrane, (B) membrane treated with seawater only, (C) membrane treated with seawater supplemented with carboxylic acid based antiscalants and (D) membrane treated with seawater supplemented with polyphosphonates based antiscalants…………………. Figure S2 paper 1 XPS analysis of nitrogen binding scan of 4 samples (A) virgin membrane, (B) membrane treated with seawater only, (C) membrane treated with seawater supplemented with carboxylic acid based antiscalants and (D) membrane treated with seawater supplemented with polyphosphonates based antiscalants reveals the presence of two types of nitrogen binding scans………………………………………………………………… Figure S3 XPS paper 1 O1s scan of 4 samples (A) virgin membrane, (B) membrane treated with seawater only, (C) membrane treated with seawater supplemented with carboxylic acid based antiscalants and (D) membrane treated with seawater supplemented with polyphosphonates based antiscalants reveals the presence of two type of Nitrogen…….. v Figure S4 paper 1 XPS analysis for the binding energy BE curve of P2p scan of 4 samples (A) virgin membrane, (B) membrane treated with seawater only, (C) membrane treated with seawater supplemented with carboxylic acid based antiscalants and (D) membrane treated with seawater supplemented with polyphosphonates based antiscalants reveals the presence of phosphorous………………………………………………………………… Table S1 paper 1 Chemical analysis of antiscalant solutions used in the study, antiscalant was prepared by dilution the antiscalant in double distilled water to final concentration of 10 ppm (v/v)……………………………………………………………………………… Figure S1 paper 3 Growth of bacterial biofilms with and without antiscalants in fixed bed plug flow bioreactors. The bioreactors were of 50 mL volume, packed with 0.5 mm glass beads, and operated continuously at hydraulic retention time of 5 hrs and influent flow rate of 0.17 mL / min. vi ABBREVIATIONS AFM atomic force microscopy ATP adenosine triphosphate AS antiscalants BSA Bovine serum albumin BWRO brackish water reverse osmosis desalination CA cellulose acetate CLSM confocal laser scan microscope CML carboxylated modified latex DOC dissolved organic carbon ED electro-dialysis EDTA ethylenediaminetetraacetic acid EPS extracellular polymeric substances FTIR fourier transform infrared spectroscopy gfp green florescent protein LPS lipopolysaccharides MATH microbial adhesions to hydrocarbon MED multi-effect distillation MF microfiltration MSF multi-stage flash distillation NF nanofiltration NOM natural organic matter OD optical density PA polyamide QCM-D quartz crystal microbalance with dissipation RO reverse osmosis SEM scanning electron microscope SHMP sodium hexametaphosphate SWRO seawater reverse osmosis desalination TDS total dissolved solid vii TFC thin film composite TN total nitrogen TOC total organic carbon TP total phosphorus UF ultrafiltration XPS X-ray photoelectron spectroscopy viii Abstract Antiscalants are surface active polyelectrolyte compounds commonly used in water treatment processes in general and in reverse osmosis (RO) desalination processes in particular to avoid membrane scaling. In spite of the significant roles of antiscalants in preventing membrane scaling, their potential side effects were scarcely investigated. The main finding of this study is that antiscalants are prone to enhance biofilm growth on RO membranes by either altering membrane surface properties or by serving as nutritional source for microorganisms. In the first chapter of the current research, the contribution of antiscalants to membrane biofouling in seawater desalination was investigated. The effects of two commonly used antiscalants, polyphosphonate- and polyacrylate-based, were studied. The effects of RO