The goal of drinking water treatment is to produce and deliver safe water to the consumers. To achieve these objectives water treatment plants are designed based on the concept of the multibarrier approach which combines several drinking water treatment processes in order to increase the reliability of the system. The presence of pharmaceutically active compounds (PhACs), personal care products (PCPs) and endocrine disrupting compounds (EDCs) in drinking water sources is becoming a concern, because of chronic and indirect human exposure to contaminant mixtures at sub-therapeutic levels via drinking water consumption. Membrane filtration can be an efficient treatment process to remove microorganisms and/or trace organic contaminants from drinking water sources. However, membranes are confronted by a major limitation: membrane fouling. Fouled membranes suffer from a loss in performance either leading to a reduction in flux or a higher pressure requirement. Generally, membrane fouling increases the need for membrane maintenance measures such as backwashing and chemical cleaning which has a negative impact on the operating costs and membrane life time. Severe membrane fouling may even impact permeate quality and/or compromise membrane integrity. The aim of this study was to establish if biofiltration pretreatment without prior coagulation would be able to control membrane fouling in natural waters. The second objective investigated the removal of trace organic contaminants by individual treatment processes (i.e. biofiltration and membrane filtration). Parallel to this work, the presence and concentration of selected trace organic contaminants in Grand River (Ontario, Canada) were determined. The trace organic contaminants investigated included atrazine, carbamazepine, DEET, ibuprofen, naproxen, and nonylphenol. Direct biofiltration pretreatment (no coagulation) significantly reduced both reversible and irreversible fouling of ultrafiltration membranes. Results showed that the different degree of reduction of hydraulically reversible fouling was primarily attributed to the absolute concentration of a specific fraction of the dissolved organic matter (i.e. biopolymers) in the biofilter effluent (i.e. membrane feed). The study also suggests that the composition of biopolymers rather than their absolute concentration is important for the control of irreversible fouling. High pressure membranes such as nanofiltration membranes are also subjected to fouling. Results showed that biofiltration pretreatment was able to achieve fouling control but membrane characteristics (i.e. molecular weight cut off) influence the efficiency of the pretreatment. This study also showed that not only biopolymers but also humic substances and low molecular weight acids are being rejected by nanofiltration membranes. Selected trace organic contaminants were detected in Grand River water in the low ng/L range with detection frequencies between 48 to 100%. Seasonal occurrence patterns could be explained by compound use and possible degradation mechanisms. These results confirm the impact of human activities on the Grand River. This study showed that under the right conditions rapid biofiltration is capable of completely removing biodegradable emerging contaminants at ng/L concentrations. DEET, ibuprofen, and naproxen were biodegradable and therefore amenable to removal while carbamazepine and atrazine were recalcitrant. Factors such as empty bed contact time, influent concentration, and temperature influenced the biodegradation kinetics. Finally, both membrane and contaminant properties influenced the degree of rejection achieved by nanofiltration membranes. Results showed that steric hindrance and electrostatic repulsion were the major rejection mechanisms. Several benefits are associated with the use of direct biofiltration for drinking water treatment. These benefits include: the removal of easily biodegradable organic matter leading to biologically stable effluents; the removal of biodegradable trace organic contaminants contributing to the multibarrier approach; the absence of chemicals coagulation which is of advantage for operations in isolated areas; the simple operation and maintenance which is an advantage for locations with limited trained operators; and finally if used prior to membrane filtration biofiltration pretreatment can control membrane fouling.

Taiwan Water Supply Cooperation (TWSC) has upgraded traditional purification processes into advanced treatment systems in south Taiwan for many years. The removal efficiency of assimilable organic carbon (AOC) by ultrafiltration (UF) with reverse osmosis (RO) systems was 47% was lower than that of 62% by ozone with biological activated carbon system (BAC). In this work, we investigate the removal of AOC and disinfection by products formation potential (DBPFP) of raw water took from a water treatment plant by using BAC and membrane treatment units. BAC system of granular activated carbon(GAC) and powder activated carbon (PAC) showed two kind carbons have certain efficiency for AOC removal. Results we found could reach above 50% (from 44.28¡Ó9.84£gg acetate-C/L reduce to 20.93¡Ó4.25£gg acetate-C/L for GAC and from 45.92¡Ó17.75£gg acetate-C/L reduce to 21.23¡Ó4.25£gg acetate-C/L for PAC), when hydraulic retention time (HRT) in BAC reactor was at 1 hour. When HRT raised to 6 hours the concentration of AOC in effluent of BAC systems were reduced under 15 £gg/L, and removal efficiency could reach above 70%. The suggested limit level of AOC is 50 £gg/L of drinking water. In removal of DBPFP, BAC of two carbons has showed certain efficiency on trihalomethanes formation potential (THMFP) and haloacetic acids formation potential (HAA5FP). The results were done in removal of THMFP (from 20.54¡Ó6.48£gg/L reduce to 14.21¡Ó4.47£gg/L for GAC and from 24.64¡Ó6.74£gg/L reduce to 14.75¡Ó4.04£gg/L for PAC) and HAA5FP (from 39.64¡Ó10.38£gg/L reduce to 17.35£gg/L for GAC and from 17.86¡Ó5.13£gg/L reduce to 11.76¡Ó3.76£gg/L for PAC) in BAC reactors. They were all lower than national standard of drinking water (THMs 80£gg/L, HAAs 60£gg/L). It is believed that two kind carbons in BAC system could all reduce effectively on AOC and DBPFP to obtain high quality of drinking water with biological stability at HRT of 6 hours.

The main objective of this study was to conduct a systematic investigation of the disinfection by-products (DBPs) formation in low-bromide and low- specific ultraviolet absorbance (SUVA) waters and the control of DBP precursors by nanofiltration (NF) and ultrafiltration (UF) processes in such waters. To this end, firstly, the effect of bromide ion on the formation and speciation of DBPs was investigated. In fractionated Alibeyk&ouml / y source water, increasing bromide concentrations in NOM fractions increased concentrations of trihalomethanes (THMs), haloacetic acids (HAAs) and adsorbable organic halides (AOX) and resulted in a shift toward the formation of brominated species. Secondly, the impacts of SUVA and differential UV spectroscopy (&amp / #916 / UV), which has been shown to correlate well with DBP formation has been elucidated in terms of DBP formation and speciation. Alibeyk&ouml / y and Karaca&ouml / ren waters were fractionated employing various separation methods and it has been shown that SUVA did not correlate well with the formation and speciation of THMs and HAAs in tested low-SUVA waters. Similarly, no correlations were found among THMs/HAAs formations and &amp / #916 / UV. Finally, the NOM rejection performances of NF and UF membranes were investigated. NF and UF membranes (&lt / 2000 dalton) was found to be suitable for the removal NOM from surface waters having low SUVA and low bromide contents. While higher molecular weight (HMW) fraction was successfully rejected (&gt / 90%) by all membrane types, lower molecular weight (LMW) fraction could be removed with ranging efficiencies from 1.5 to 30%. NF membranes provided DOC, UV254 absorbance, THM, and HAA reductions up to 90%.

Co-produced water from the oil and gas industry represents a significant waste stream in the United States. Produced water is characterized by high levels of total dissolved solids (TDS), dissolved organics and oil and grease. Among the wide variety of organics present in the water, the concentration of hazardous substances such as benzene, toluene, ethylbenzene, and xylenes (BTEX) can reach 600 mg/L and the concentration of non-hazardous carboxylate can be as high as 10,000 mg/L (API, 2002). Regulations governing the disposal of produced water are tightening and the interest in reusing treated produced water is increasing in the United States particularly in regions with scarce water supplies. In order to reuse produced water, removal of both the inorganic dissolved solids and hazardous organics such as BTEX may be necessary. The main goal of this research was to investigate the feasibility of using a combined physicochemical/biological treatment system to remove the organic constituents present in saline produced water. In order to meet this objective, two separate biological treatment techniques were investigated: a vapor phase biofilter (VPB) to treat the regeneration off-gas from an upstream surfactant-modified zeolite (SMZ) adsorption system and a membrane bioreactor (MBR) to treat the carboxylate and BTEX constituents that penetrate an upstream SMZ system. Each of the biological pretreatment systems was investigated first in the laboratory treating synthetic produced water and then in the field coupled to an SMZ adsorption system treating produced water. Both of the biological treatment systems were capable of removing the BTEX constituents both in the laboratory and in the field over a range of operating conditions. For the VPB, separation of the BTEX constituents from the saline aqueous phase yielded high removal efficiencies. However, carboxylates remained in the aqueous phase and were not removed in the combined VPB/SMZ system. In contrast, the MBR was capable of directly treating the saline produced water and simultaneously removing the BTEX and carboxylate constituents. The major challenge of the MBR system was controlling membrane fouling, particularly when the system was treating produced water under field conditions.

Stringent water quality regulations and general aesthetic issues have urged drinking water industry to apply advanced water treatment technologies that can meet multiple treatment objectives. Removal of significant amount of natural organic matter (NOM), including colour causing organics, to meet stringent disinfection by product (DBP) regulations from source water with low alkalinity and low turbidity is very challenging with conventional water treatment processes. Membrane filtration processes are effective in removing significant amount of NOM thus minimizing the formation of carcinogenic DBPs. However, fouling of membrane is a major problem affecting system performance. Improved pretreatment of feed water helps reduce or eliminate membrane fouling. This study characterized source water, examined fouling in nanofiltration (NF) membranes and explored various pretreatment options to reduce NF fouling. Resin fractionation was performed to characterize NOM and to identify the major fractions responsible for DBP formation in natural source water of the Tatamagouche water treatment plant (WTP) in Nova Scotia. The source water primarily comprised of hydrophilic neutrals (HIN) and hydrophobic acid (HOA) compounds, with the latter being a major contributor to the DBP formation. Fouling behaviour of the NF membranes was examined at bench- and full-scale levels to understand the impact of source water quality on membrane fouling in the Tatamagouche and Collins Park WTPs. Bench- and full-scale results revealed higher fouling in the Collins Park WTP which together supported ongoing membrane cleaning practices in the plant. Surface enhanced Raman spectroscopy (SERS), demonstrated here as a novel technique, suggested that carbohydrates and proteins are the main foulants in the source water. Bench-scale experiments conducted to evaluate the performance of ozone (O3), ultraviolet (UV), hydrogen peroxide plus ozone (H2O2/O3), H2O2 plus UV (H2O2/UV) and O3 plus UV (O3/UV) for reducing NOM and DBP precursors suggested that the O3/UV AOP offers the optimum reduction of NOM. Integrating AOP pretreatments with NF membrane resulted in an improved permeate flux but not permeate quality of the NF membrane.

Halten löst organiskt material (DOC) har under de senaste 20 åren ökat i våra sjöar. Det har också skett förändringar i karaktären. DOC ställer till problem för vattenverk som använder ytvatten som dricksvattenkälla genom att det kan ge lukt, smak och färg till vattnet. Det ger också ett ökat behov av fällningskemikalier, större slambildning och större bildning av potentiellt skadliga desinfektionsprodukter. I och med förändringarna i halt och karaktär av DOC behöver nuvarande reningstekniker förbättras och nya tekniker utvecklas. I den här studien undersöktes två konventionella reningstekniker; fällning med järnklorid och fällning med aluminiumsulfat, samt två modernare tekniker; jonbyte med MIEX® och membranteknik. Sex olika vatten med extrema typer av DOC användes, såsom algogent vatten, avloppsvatten och myrvatten, för att få en stor spridning i SUVA (specifik UV254-absorbans). SUVA är kvoten mellan absorbansen vid 254 nm och DOC-halten och ger en indikation på fördelningen mellan alloktont och autoktont material. Analys av DOC, absorbans, fluorescensparametrar, anjoner och järn utfördes för att få en uppfattning av hur mycket och vilken typ av DOC som renades för respektive teknik. Membrantekniken hade generellt högre reducering av DOC än övriga reningstekniker. Genomgående renades alloktont material i högre utsträckning än autoktont material. Vatten med högt SUVA-värde (>3), alltså större andel alloktont material, var mer lättbehandlat än ett med lågt värde, men sambandet var inte linjärt. Algogent vatten renades dåligt med MIEX® och fällning men bättre med membran. Det fanns ett tydligt samband mellan absorbans (245 nm) och DOC-halt som gör det möjligt att med online-mätning av absorbans få fram tillräckligt noggranna värden på DOC-halter. / The amount of dissolved organic carbon (DOC) has risen in our lakes during the past 20 years and it has also changed in character. DOC causes problems for water treatment plants that are using surface water as a drinking water source. It gives the water odour, taste and colour. It also leads to a higher need of precipitation chemicals, more sludging, and larger formation of potentially harmful disinfection products. With the changes in both amount and character in DOC, current water treatment techniques need to be improved and new techniques developed. In this study, two conventional water treatment techniques; precipitation with iron chloride and precipitation with aluminium sulphate, and two more modern techniques; ion exchange with MIEX® and membrane filtration, were examined. Six waters with extreme types of DOC were used, including algogenic water, wastewater, and water from mire, in order to have a wide range of SUVA-values (specific UV254-absorbance). SUVA is the ratio between absorbance at 254 nm and the content of DOC. SUVA gives an indication about the distribution of allochthonous and autochthonous matter. In each water treatment technique analysis of DOC, absorbance, fluorescence parameters, anions, and iron were performed to gather information regarding how much and which type of DOC were reduced, in each water treatment technique. Membrane filtration had generally higher reduction of DOC compared to the other techniques. Allochthonous matter was reduced to a higher extent than autochthonous matter. Waters with a high value of SUVA (>3), which means a larger proportion of  allochthonous matter, was more easily treated than water with lower values, but the relation was not linear. DOC in algogenic water was poorly reduced with MIEX® and the precipitation techniques, but better reduced with the membrane filtration. There was a correlation between absorbance (254 nm) and the amount of DOC, which makes it possible to do online reading of absorbance and translate the values into amount of DOC.

Antibiotics are a group of compounds used in large quantities for both human therapy and animal food production. In recent years, antibiotics have been detected at low levels (up to μg/L) in wastewater effluents and surface waters in the US, Canada, and parts of Europe. The presence of such contaminants in the environment is of concern due to their potential to promote bacterial resistance as well as to trigger long-term adverse human health effects. Chemical disinfection, one of essential water treatment processes, may aid in their removal but may also form byproducts that can remain biologically active. Nanofiltration is another water treatment process that may provide an effective physical barrier for these contaminants. The goal of this study was to understand the effect chlorination and nanofiltration processes have on the fate of select antibiotics during water treatment, especially under varying water quality conditions. Changes in pH were found to significantly influence the reaction rate of one veterinary antibiotic, carbadox, with aqueous chlorine while also influencing the byproducts formed. The pH was also found to significantly alter the removal efficiency of several antibiotics by different nanofiltration membranes of varying pore size in which dependence was mechanistically investigated using transport models. In addition, the presence of tertiary amines was found to enhance transformation of antibiotics during chlorination. Overall, fundamental understanding regarding their fate during such water treatment processes will help industries develop better strategies for effectively controlling this emerging group of contaminants.

Thesis (Master of Engineering in Chemical Engineering))--Cape Peninsula University of Technology, 2018. / Fresh, clean water has always been critical for the world's social development. Supply of water can be reinforced through recycling and reuse; and secondary treatment of municipal wastewater effluent with a membrane bioreactor (MBR) followed by a reverse osmosis (RO) process, has emerged as a crucial treatment process for water reuse. However, fouling of RO membranes in such process is unavoidable. This leads to poor performance, increase in operational cost and degradation of the membrane material, which reduces the membrane life span. Various researches have been conducted to provide an understanding of the mechanism of fouling, and methods have been developed to minimize it. In this research, the effect of surface modification to minimise fouling on a thin film composite polyamide RO membrane was investigated. This study was divided into three parts, namely: membrane modification, biofouling and filtration using RO. Two modifying agents, PVA and DMAEMA, were used as grafting solutions. Escherichia coli (E. coli) were used as the biofoulant to study the ant-biofouling properties of the membranes. A make-up synthetic MBR secondary effluent feed was used in a bench scale RO process. During the membrane modification process, the membrane was treated using two different approaches. Firstly, the covalent attachment of polyvinyl alcohol (PVA) through Glutaraldehyde (GA) onto the surface and secondly the redox initiated grafting of dimethyl amino ethyl methacrylate (DMAEMA PVA and DMAEMA grafting solutions were applied at four different concentrations). The PVA and DMAEMA modifying agents were successfully grafted onto the membrane top layers and were confirmed by the functional groups, present, using the Attenuated Total Reflectance–Fourier Transform Infrared spectroscopy (ATR-FTIR) spectra. The morphology of the membrane surfaces was investigated using Scanning Electron Microscopy (SEM), before and after treatment. SEM analysis showed better membrane structures with PVA grafting compared to DMAEMA.

Membrane technology has become a predominant process in providing one of the key components of life (water), either through water and wastewater treatment for water quality purposes or desalination as seen in Ultra-filtration, Nano-filtration, Reverse osmosis, Membrane distillation, Pervaporation, among others. With the ever-increasing demand for portable water due to population increase, constant research has focused on the improvements of the performances of the different water treatment systems including enhancing the performance of the membrane. Among all the different membrane performance enhancement techniques exploited, incorporation of filler has gained much grounds in the last decades. Traditional fillers like silica gel, activated carbon, metal oxides and zeolites are now being challenged by the recent class of mesoporous materials known as Metal Organic Frameworks (MOFs), which are built of metal ions or metal ion clusters linked together by organic ligands giving these materials tunable pore geometries and pore volume, greatly improved surface area with extraordinary adsorptive properties. The membrane incorporating MOFs demonstrate enhance performances more than the other fillers due to the good coordination of the organic moiety and polymers. The overall objective of this project is to develop and study a membrane incorporated MOFs nanofiber system vis-à-vis their applications in heavy metal contaminated water treatment, stability in aqueous media and the advantages and drawbacks of these composite membranes with regards to the quality of the water produced. The developed materials were characterized by SEM, FTIR, TEM, XPS, DSC, and TGA. The heavy metals earmarked for this study include; Lead, Mercury, Cadmium, and Zinc and were studied using flame atomic absorption spectrometry (FAAS). Upon successful fabrication of the nanofiber membranes, detailed adsorption studies were conducted (pristine MOF, pristine nanofibers, enmeshed MOFs) to establish adsorption kinetics and isotherm, which were used further to select the best performing membranes for filtration application. Two different MOFs were used, MOF808; made of Zirconium and Benzene Tricarboxylate) and MOF F300; made of Iron and Benzene Tricarboxylate) The adsorption capacities of the MOFs for the different heavy metal analyzed were; MOF 808 (Pb-170.74 mg g-1, Zn-287 mg g-1, Cd-225.05 mg g-1, Hg-276.96 mg g-1) and MOF F300 (Pb-148.13 mg g-1, Hg-229.66 mg g-1), while the membrane adsorption capacities were; PA808 (MOF 808 embedded within polyacrylonitrile (PA) nanofibers, (Pb-23.98 mg g-1, Hg-50.88 mg g-1), PA300, MOF F300 embedded within polyacrylonitrile nanofibers, (Pb-30.19 mg g-1, Hg-53.09 mg g-1). Upon activation of MOF 808 by water (hydractivation), the removal efficiency of MOF 808 was improved by 10% while the MOF membrane efficiency was increased by 30%. Filtration experiments could produce 577.5 L of treated water with a single layer of PAN/ MOF808 membrane at 0.1 bar using a 50 ppb Pb ion feed solution.

O cultivo de microalgas é uma matéria prima para produção de biocombustível e de captura de carbono devido a vantagens como alta produção de biomassa e rápido crescimento quando comparado com outras fontes de energia e não necessitar de terra fértil. O presente trabalho teve como objetivo estudar métodos de concentração da biomassa. A microalga utilizada foi a Isochrysis galbana. Os cultivos tiveram duração de 20 dias e concentração inicial de 7.104 cel/mL no meio de cultivo F2/Guillard. e foram realizados em fotobioreatores de 500 mL, 3 L e 12 L. Os experimentos foram conduzidos em foto-período de 12 h claro/escuro, com temperatura de 27 a 29 C. Ao final dos cultivos, as amostras foram levadas para a sequência de processos de separação. Inicialmente, foram realizados ensaios de microfiltração em membrana com porosidade de 0,45 m em procedimento do tipo dead-end e constatou-se a rápida e intensa formação de camada de fouling. Acrescentou-se uma etapa de separação por floculação preliminar à microfiltração, utilizando-se Al2(SO4)3 como agente floculante. O meio coagulado foi então filtrado e microfiltrado. O estudo combinado das 3 etapas de separação possibilitou 99% de remoção de biomassa.O teor de óleo obtido foi de 22,4%. Portanto, o trabalho apresenta uma configuração de concentração da biomassa Isochrysis galbana visando o processo de produção de biocombustíveis / The cultivation of microalgae is a feedstock for biofuel production and carbon sequestration due to advantages such as high-biomass production and, fast growth when compared to other energy sources and does not require fertile land. This work aimed to study methods for biomass concentration. The microalgae used was Isochrysis galbana. The cultivation lasted 20 days and initial concentration of 70,000 cells / mL F2/Guillard culture medium and were performed in. Photobioreactors of 500 mL, 3 L and 12 L. The experiments were conducted in photoperiod of 12 h light / dark, temperature of 27-29 C. At the end of cultivation, samples were taken for the sequence of separation processes Initially, tests were performed on microfiltration membrane with 0.45 μm pore diameter in a dead-end procedure, and the rapid and intense formation of fouling layer was noted. One step of preliminary separation by flocculation previous to microfiltration was added to the process, using Al2(SO4)3 as flocculant agent. The coagulated medium was then filtered and microfiltered. The combined study of three separation steps allowed 99% removal of biomassa.O oil content obtained was 22.4%. Therefore, the work presents a configuration in biomass concentration of Isochrysis galbana aiming at the process of production of biofules