Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: South Africa is one of the world's major coal producers, resulting in the second highest foreign exchange earner for South Africa. However, the mining industry contributes negatively to (ground) water pollution, due to the formation of acid mine drainage (AMD). AMD originates from the bacterial oxidation (Thiobacillus ferrooxidans) of pyrite (FeS) and contains high levels of sulphate and metals. Sulphate rich waters can be treated applying the biological sulphate removal technology. This study concentrated on biologically removing sulphate from synthetic feed- and mine water, using the single-stage completely-mixed reactor system. The advantage of using this reactor system is that except for removing sulphate from about 2000 to less than 200 mg/t', it can also partly biologically remove the formed sulphides. It was established that both ethanol and sugar can be used, as the carbon and energy source, however ethanol is more cost effective than sugar. Ethanol dosage and Hydraulic Retention Time (HRT) studies were undertaken to investigate at what concentration, the highest sulphate and sulphide removal rates were achieved. It was found that the highest sulphate reduction rates were obtained when using 1mf ethanol/f feed and that the removal rates were dependent on the HRT: the lower the HRT, the higher the sulphate reduction rate. The highest sulphide oxidation rate was achieved at the HRT of 6 h. It was, furthermore shown that the single stage completely-mixed reactor system could successfully be used to remove sulphate from Schoongezicht mine effluent, not only removing the sulphate, but also most of the metals, thereby increasing the mine effluent pH from 2.5 to 7. The conclusion of this study was that a completely-mixed reactor system, as described in this thesis, can successfully be applied to treating acid mine drainage using ethanol (1 m.e etanol/f feed water) as the carbon and energy source at a hydraulic retention time as low as 4 hours. This technology has great potential for pilot- and full-scale treatment of sulphate rich effluents such as acid mine drainage. / AFRIKAANSE OPSOMMING: Suid Afrika is een van die vemaamste steenkool produseerders in die wereld, terwyl die uitvoer van steenkool die land se tweede hoogste verdiener is van buitelandse valuta. Ongelukkig dra hierdie industrie ook by tot die besoedeling van (grond) water, veral vanwee die vorrning van suur myn afloop. Bakteriese oksidasie (deur Thiobacillus ferrooxidansy van piried (FeS) is hoofsaaklik verandwoordelik vir die vorrning van suur myn afloop bevattende hoe konsentrasies van sulfaat en metale. . Die toepassing van biologiese sulfaatverwyderingsprosesse vir die behandeling van sulfaatryke waters is vroeer gedemonstreer. Die doel van hierdie studie was om 'n enkel-stadium reaktor met volledige vermenging te evalueer en te optimiseer om toegepas te word vir die biologiese verwydering van sulfaat vanuit sinteties bereide, sowel as mynwater. Hierdie reaktor is in staat om sulfaat te verwyder vanaf vlakke van ~ 2000 tot minder as 200 mg/P. 'n Verdere voordeel gepaard met die gebruik van hierdie reaktor is dat die sulfied wat gevorm word tydens sulfaatreduksie, gedeeltelik verwyder word deur die oksidasie daarvan na So. Die resultate wat behaal is in hierdie studie het aangedui dat beide etanol en suiker gebruik kan word as die koolstof en energiebron, terwyl etanol meer koste-effektief aangewend kon word. In teenstelling was metanol nie 'n geskikte koolstofbron vir sulfaatverwydering nie. Eksperimente is daarvolgens uitgevoer om toestande van optimum etanoldosering en hidroliese retensietyd (HRT) vir maksimum sulfaat- en sulfiedverwydering te bepaaJ. Die hoogste reduksie tempo's was verkry met 'n toediening van 1 mP etanol/f invloei, en die effektiwiteit van verwydering was afhanklik van HRT. Hoe laer die HRT, hoe hoer die tempo van sulfaatverwydering. Die beste sulfaatverwyderingstempo was behaal teen 'n HRT van 6 uur. Die resultate het verder aangetoon dat die enkel-stadium reaktor met volledige vermenging in staat was om sulfaat effektief te verwyder, en die pH te verhoog vanaf na 2.5 tot 7, in mynuitvloeisels van 'n plaaslike steenkoolmyn. Die gevolgtrekking uit hierdie werk is dat 'n volledig-gemengde reaktorstelsel, soos beskryf in die huidige studie, geskik is vir die suksesvolle behandeling van suur mynafloopwater met die gebruik van etanol (l mflP toevoerwater) as koolstof- en energiebron by 'n hidrouliese retensietyd tot so laag as 4 uur. Die tegnologie het groot toepassingspotensiaal vir volskaalse behandeling van sulfaatryke afloopwaters soos by. suur mynafloop.

Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: At the Mondi Kraft paper mill in Piet Retief, paper machine effluent is pre-treated by means of dissolved air flotation (DAF) and a mierostrainer prior to ultrafiltration (UF). Despite the rigorous pre-treatment of the effluent, severe fouling of the UF membranes still persisted, resulting in a sharp decrease in operational flux. In an attempt to improve the flux performance of the UF membranes an investigation was launched into the possible causes of membrane fouling. The study yielded the following results: Ultraviolet-visible (UV-Vis) spectrophotometric analyses of varIOUS effluent samples collected from different locations at the mill indicated the presence of aromatic compounds. Lignosulphonate appeared to be the main constituent in all the samples analysed. UV-Vis spectrophotometry was also performed on fouling extracted from membranes In order to evaluate the different approaches attempted to reduce membrane fouling. Most of the UV-Vis spectra obtained did not show the absorbance maxima below 210 nm that were seen for the paper machine effluent, DAF product, lignosulphonate and mierostrainer product. This indicated that the compounds with absorbance at lower wavelengths did not foul the membranes to the same extent as the aromatic substances with absorbance maxima between 230 and 400 nm. The influence of pH on the absorption of the various effluent samples was also investigated. An increase in pH resulted in (1) a "shift" in the wavelength scans from a lower to a higher wavelength, suggesting ionisation (deprotonation) with a subsequent delocalization of electrons and (2) an increase in the turbidity. The increase in turbidity which accompanied the Increase in pH could be explained by complex formation between the carboxylate ions, phenolic groups and divalent metal ions present in the effluent. Inductively coupled plasma analyses of several effluent samples with pH values 7 and 13 indicated the presence of significant amounts of Ca2+ ions in the effluent. There was a significant decrease in the Ca2+ levels with an increase in pH, which supported the hypothesis that Ca2+ might contribute to complex formation. This resulted in a decrease in solubility and an increase in turbidity. The addition of a chelating agent (ethylenediaminetetra-acetic acid disodium salt) to an effluent solution at pH 13 redissolved the precipitate and considerably reduced the turbidity. The subsequent addition of CaCh again induced precipitation and increased turbidity, confirming the role of Ca2+ in complex formation. Gel permeation chromatographic analyses of mierostrainer product at pH 13 showed the formation of high molecular mass organo-calcium complexes. The exact molecular mass of the complexes present in the mierostrainer product could not be determined by electro spray mass spectrometry because of their poor ionisation ability. Atomic force microscopy and scanning electron microscopy (SEM) showed distinct differences in the membrane surface texture before and after fouling. Furthermore, SEM images of the UF membranes exposed the limited ability of the 30 urn microstrainer, installed downstream from the DAF unit, to remove residual fibres from the DAF product. Static fouling experiments performed on all the flocculants and coagulants used In the paper-making process at the mill showed that none of these substances fouled the UF membranes. Cleaning of the UF membranes with Triton XIOO®, a nOn-IOnIC surfactant, caused a temporary increase in the operating flux to values higher than that of the initial flux. Mechanical cleaning of the UF membrane surface with spongebalIs proved to be one of the most effective and successful methods to prevent flux loss caused by fouling. Pre-coating of the UF membranes with Plutonic" FI08, another non-ionic surfactant, did not promote membrane productivity. Evaluation of various types of membranes indicated that hydrophilic or negatively charged membranes withstood membrane fouling more effectively than hydrophobic UF membranes under the same operating conditions. / AFRIKAANSE OPSOMMING: By Mondi Kraft se papier meule in Piet Retief word afloopwater vanaf die papiermasjiene vir hergebruik met behulp van ultrafiltrasie (UF) behandel. Opgeloste lugflotasie (OLF) en mikrosiwwing word as voorbehandeling vir die UF membraanproses ingespan. Ondanks die intensiewe voorafbehandeling wat toegepas word, vind daar geweldige aanvuiling van die UF membrane plaas wat tot die vinnige verlaging in bedryfsfluks aanleiding gee. 'n Ondersoek na die moontlike oorsake van membraan-aanvuiling het die volgende bevindinge opgelewer: Ultraviolet-sigbare (UV-Vis) spektroskopie van water monsters wat by die meule versamel is, het die teenwoordigheid van aromatiese komponente aangetoon, met lignosulfonaat die hoofkomponent in al die monsters wat ontleed is. Ekstrakte afkomstig van aangevuilde membrane is ook met behulp van UV-Vis-spektroskopie geanaliseer om verskeie benaderings te evalueer om 'n afname in membraan-aanvuiling te bewerkstellig. Die oorgrootte meerderheid spektra het nie die absorpsie maksima onder 210 nm aangetoon wat teenwoordig was in monsters van die papier masjien afloopwater, OLF uitvloeisel, lignosulfonaat en mikrosif produkwater nie. Dit het aangedui dat die komponente wat by laer golflengte absorbeer nie die UF membrane in dieselfde mate aanvuil as daardie komponente wat by hoër golflengtes (tussen 230 en 400 nm) absorbeer nie. Die invloed wat pH op die absorpsie van komponente teenwoordig in die onderskeie afloopwatermonsters het, is ook ondersoek. 'n Toename in pH het bygedra tot (1) 'n verskuiwing in die spektra vanaf 'n lae na 'n hoër golflengte vanweë ionisasie (deprotonering) met gevolglike delokalisasie van elektrone en (2) 'n toename in turbiditeit. Die toename in turbiditeit wat verband hou met die toename in pH was verduidelik aan die hand van kompleksvorming tussen die karboksilaat ione, fenoliese groepe en divalente metaal ione in die afloopwater. Induktief gekoppelde plasma analise van verskeie water monsters by pH 7 en 13 het die teenwoordigheid van 'n groot hoeveelheid Ca2+ aangetoon. 'n Verlaging in die vlakke van opgeloste Ca2+ het met die toename in pH verband gehou. Dit het die moontlike verbintenis tussen Ca2+ en kompleksvorming ondersteun wat bygedra het tot die afname in oplosbaarheid en toename in turbiditeit. Die byvoeging van etileendiamientetra-asynsuur-dinatriumsout, 'n kelerings reagens by afloopwater (pH 13) het die presipitaat weer in oplossing gebring en die turbiditeit merkwaardig verlaag. Die byvoeging van CaCh het weer presipitasie geïnduseer, met 'n gevolglike toename in turbiditeit. Hiermee is Ca2+ se rol in kompleksvorming bevestig. Gelpermeasie-chromatografiese analise van die mikrosif produk (pH 13) het die vorming van hoë molekulêre massa organo-kalsium komplekse bevestig. Dit was egter nie moontlik om met behulp van massaspektrometrie die korrekte molekulêre massa van die komplekse te bepaal nie vanweë hul onvermoë om te ioniseer. Atomiese krag mikroskopie en skandeer elektron mikroskopie (SEM) het duidelik die voor en na verskil getoon wat aanvuiling op die membraantekstuur gehad het. 'n SEM foto van die aangevuilde UF membraan het die onvermoë van die mikrosif blootgelê om oorblywende vesels vanuit die OLF produkwater te verwyder. Resultate bekom gedurende passiewe aanvuilingseksperimente het aangetoon dat al die in-proses flokkulante en koagulante wat gebruik word by die papier meule geen bydrae tot die aanvuiling van die UF membrane maak nie. Skoonmaak van die UF membrane met Triton XIOO® bring 'n verhoging in bedryfsvloed teweeg, maar die verhoging, wat hoër as die oorspronklike vloed is, is kortstondig. Meganiese skoonmaak van die buismembrane met behulp van sponsballe blyk die mees effektiewe skoonmaakmetode te wees. Voorafbehandeling van die UF membrane met Plutonic" F 108 het nie die membraanproduktiwiteit verhoog nie. Daar is ook bevind dat hidrofiliese of negatief gelaaide membrane groter weerstand bied teen aanvuiling in vergelyking met hidrofobiese UF membrane onder dieselfde bedryfstoestande.

Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: The choice of the sample preparation technique used in combination with a chromatographic technique in environmental analysis strongly influences the performance of the method as a whole. The main aim of this work was to evaluate methods like: micro liquid-liquid extraction (цLLE)and solid phase micro extraction (SPME) in combination with gas chromatography-electron capture detector (GCECD) and a recently developed technique named stir bar sorptive extraction (SBSE) combined with thermal desorption system-programmable temperature vaporizationgas chromatography-mass spectrometer (TDS-PTV-GC-MS) for the analysis of organochloro-pesticides (OCPs) in natural water and to make a comparison between them. The most suitable method was then selected for the analysis of water samples collected from Eritrea. An additional goal was to develop a sensitive method for the analysis ofOCPs in soil and sediment samples. цLLE-GC-ECD and SPME-GC-ECD methods were evaluated for the analysis of OCPs in water. The former allowed achieving a sensitivity of less than 100 ppt and the latter was able to detect down to the 1 ppt level. Both methods were found to be repeatable with %RSD of3% to 19% and 5% to 12% as well as linear with a range of 1:103 and 1:5x103 respectivey. SBSE-TDS-GC-MS was also investigated for the analysis of OCPs in water samples. With this technique a good sensitivity down to 1 ppt was also obtained. The less sensitive nature of the MS compared to ECD was hereby compensated for by the large amount of polydimethylsiloxane (PDMS) phase on the stir bar. The method was repeatable and linear with a range of 1:5000, which is similar to the one obtained for the SPME-GC-ECD method. All three methods were also tested with real contaminated water samples and a comparison of the three techniques in terms of sensitivity, linearity, repeatability, availability and cost effectiveness was done. As a method of choice in terms of the above criteria, SPMEGC- ECD was applied to the water samples collected from Eritrea. The presence of some oePs such as a-BBC (benzenehexachloride), heptachlor, heptachlor epoxide, endosulfan I, p,p'-DDE (dichlorodiphenylchloroethylene), endosulfan II, p,p'-DDD (dichlorodiphenyldichloroethane), endosu!fan sulfate and p,p'-DDT (dichlorodiphenyltrichloroethane) in some of the Eritrean water samples was demonstrated The SPME-GC-ECD technique for the analysis OCPs in soil and sediment samples was investigated. It was shown to be able to detect down to 1 pg/g (lppt) with good linearity and repeatability. The method was also evaluated for authentic soil samples. Due to a lack of time the method could not be applied for the analysis of the soil and sediment samples collected from Eritrea. / AFRIKAANSE OPSOMMING: Die keuse van 'n gepaste monster-voorbereidingsmetode wat gebruik word tesame met 'n chromatografiese skeidingtegniek in omgewings-analise het 'n beduidende effek op die algehele metode. Die doel van hierdie werk was om metodes soos mikrovloeistof- vloeistof ekstraksie (цLLE) en soliede fase mikro ekstraksie (SPME) in kombinasie met gaschromatografie met elektronvangs deteksie (GC-ECD) te ontwikkel vir die analise van organochloor-pestisiede (OCPs) in natuurlike water. Vervolgens is hierdie metodes vergelyk met die onlangs-ontwikkelde roerstaaf sorptiewe ekstraksie tegniek (SBSE) in kombinasie met termiese desorbsie-GCmassaspektrometriese deteksie (TDS-GC-MSD). Die mees geskikte metode is vervolgens gebruik vir die analise van Eritreaanse watermonsters. Daarbenewens was die doelook om 'n sensitiewe metode te ontwikkel vir die analise van OCPs in gronden sedimentmonsters. Beide цLLE en SPME-GC-ECD metodes is gekarakteriseer deur goeie herhaalbaarheid en lineariteit. Die sensitiwiteit van bogenoemde metodes was minder as 100 dele per triljoen (ppt) en 1 ppt, respektiewelik. Ook met SBSE-TDS-GC-MSD kon 'n deteksielimiet van 1 ppt bereik word. In hierdie geval is vir die verlies van sensitiwiteit van die MSD in vergelyking met die ECD, gekompenseer deur die groter hoeveelheid PDMS op die roerstaaf in vergelyking met 'n SPME apparaat. Die herhaalbaarheid en lineariteit van die metode is vergelykbaar met dié van die SPMEGC- ECD metode. Al drie metodes is vergelyk vir die analise van gekontamineerde watermonsters in terme van sensitiwiteit, liniêre bereik, herhaalbaarheid, toeganklikheid en kosteeffektiwiteit. SPME-GC-ECD is vervolgens gekies as metode van voorkeur vir die analise van Eritreaanse watermonsters. Die teenwoordigheid van sekere OCPs soos a-BHC, heptachloor, heptachloorepoksied, endosulfan I, p,p'-DDE, endosulfan II, p,p' -DDD, endosulfan sulfaat en p,p' -DDT in die monsters is gedemonstreer. Die toepasbaarheid van die SPME-GC-ECD metode vir die analise van OCPs in grond-en sedimentmonsters is ook geëvalueer, en dit was moontlik om so min as 1 pg/g waar te neem. Weens tydbeperkings was dit nie moontlik om Eritreaanse grondmonsters met die ontwikkelde metode te analiseer nie.

Membrane technology has been used in water purification for decades. However, membrane fouling remains a limiting factor. One way to control fouling is through surface modification. Several studies report that increasing surface hydrophilicity can reduce membrane fouling. Surface modification via physical coating (i.e., thin-film composite membrane) was explored in this research to prevent membrane fouling. Before making thin-film composite membranes, it was important to study structure/property relations in a series of potential coating materials. This research aims to contribute to a better fundamental understanding of the structure/property relations which govern water transport, rejection of model foulants (i.e., emulsified oil droplet or protein), and fouling characteristics in hydrogels based on poly(ethylene glycol) diacrylate (PEGDA) and N-vinyl-2-pyrrolidone (NVP). Crosslinked poly(ethylene glycol) (PEG) free-standing films were prepared by UV-induced photopolymerization of PEGDA crosslinker in the presence of varying amounts of water or monofunctional poly(ethylene glycol) acrylate (PEGA). The crosslinked PEGDA films exhibited polymerization induced phase separation (PIPS) when the water content of the prepolymerization mixture was greater than 60 wt%. Visible light absorbance measurements, water uptake, water permeability, and salt kinetic desorption experiments were used to characterize the structure of these phase-separated, crosslinked hydrogels. The films with PIPS exhibited a porous morphology in cryogenic scanning electron microscope (CryoSEM) studies. Dead-end filtration experiments using deionized water and bovine serum albumin (BSA) solutions were performed to explore the fundamental transport and fouling properties of these materials. The total flux of pure water through the films after prior exposure to BSA solution was nearly equal to that of the as-prepared material, indicating that these PEGDA films resist fouling by BSA under the conditions studied. Crosslinked NVP free-standing films were prepared by UV-induced photopolymerization in the presence of water, with NVP as the monomer and N,N’-methylenebisacrylamide (MBAA) as the crosslinker. A series of crosslinked films were polymerized at various prepolymerization water contents, NVP/MBAA ratios and at various levels of UV light intensity in the polymerization. Like PEGDA, the NVP films also underwent phase-separation during polymerization. The influence of monomer/ crosslinker ratio, prepolymerization water content, and UV intensities on membrane morphology and water transport was characterized with CryoSEM, bio-atomic force microscope (Bio-AFM) and dead-end filtration. Molecular weight cutoff (MWCO) measurements were used to characterize the sieving property of crosslinked NVP films polymerized at different UV intensities. UV intensity was found to have an impact on the interconnectivity of crosslinked membranes. Finally, tests of fouling resistance to protein solution (bovine serum albumin) and oily water emulsion were performed. The NVP crosslinked films had good protein and oily water fouling resistance. Overall, both crosslinked PEGDA and NVP films exhibit fouling resistance to oily water emulsions or protein solution. NVP films had more porous structure and higher water permeability than did PEGDA films, while the more compact structure of PEGDA films led to better rejection of model foulants (e.g., protein) than in NVP films. Based on different applications (e.g., oil/water separation, protein filtration), different coating materials must be chosen according to the membrane morphology, transport property, and rejection of model foulants to achieve the highest water flux and foulant rejection in membranes used for water purification. / text

Secondary effluent from the Roger Road Wastewater Treatment Plant undergoes tertiary treatment of dual media filtration and chlorination. The tertiary effluent is recharged and subsequently extracted for irrigation in Tucson, Arizona. The fate of chlorinated organics in this recharge system was investigated in this research. Nonpurgeable organic carbon was found to reach a constant level in the groundwater after being recharged. Not all of the organic carbon was removed from the water. Nonpurgeable organic halogens increased as they flowed away from the recharge basins. Reasons for this increase were not determined. Attempts were made to define the apparent molecular weight distribution of the NPOC and the NPOX. Measured values of the two parameters were consistently greater after the analytical processing than before, making the determination impossible.

This study investigates and compares the environmental burdens of two different methods for producing potable water by using the environmental life cycle assessment (LCA). The first method, for the production of potable water, is used by Umgeni Water at their Wiggins Waterworks and it involves conventional processes. The second method is based on a South African membrane technology and currently it is used in three pilot plants around the country. The life cycle concept gives the means understand the environmental impacts associated with a product. process or activity by considering all life-cycle stages, from cradle- to-grave. Formal methodologies for conducting such studies have been developed and in this project the methodological framework endorsed by the International Organisation for Standardisation (ISO) 14040 series of standards has been used. By using this methodology and by tracing all processes involved in the production of potable water, it was found that the main contribution towards the environmental burdens of potable water is due to electricity generation. This conclusion is valid for both methods in vestigated. and as a result the recommendations focus on increasing the energy efficiency of waterworks in order to increase their overall environmental performance. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2001.

In the following study, the potential role that microorganisms play in the removal of Mn (II) and Fe (II) was assessed using biofilter sand and water samples collected from a biofiltration system (operated by Umgeni Water in KwaZulu-Natal, Nottingham Road, at the Nottingham combined school, South Africa) treating borehole water containing manganese and iron. Initially the presence of Mn (II) and Fe (II) oxidizing bacteria was demonstrated in the biofiltration system. Thereafter, the contribution of individual microorganisms to the overall removal of manganese and iron was assessed in the laboratory by determining the difference in metal oxidation in the presence and absence of active bacteria at neutral pH, simulating conditions in the biofilter. Controls were run to verify the elimination via physiochemical reactions occurring within the biofiltration system. Finally a diversity snapshot of the bacteria present within the biofilter matrix was established via analysis of a clone library. Viable bacterial counts for the biofiltration system were established using MSVP (minimal salts vitamins pyruvate) medium - plus added manganese sulfate or iron sulfate targeting Mn (II) and Fe (II) oxidizing bacteria - and R2A for heterotrophic bacteria. In the first experimental chapter, batch tests using MSVP were employed to determine manganese oxidation, by measuring the pH and ORP (oxidation reduction potential) in experimental flasks and controls over time. There was a clear drop in pH and a concomitant increase in ORP when an isolated manganese oxidizing strain (designated LB1) was grown in MSVP plus added manganese sulfate, indicating manganese oxidation. Based on physiological characteristics established by the VITEK-2 system as well as by 16S rRNA gene sequence analysis and MALDI-TOF (Matrix assisted laser desorption ionization-time of flight mass spectrometry) mass spectrometry of cell extracts, the isolate was identified as a member of the genus Acinetobacter. EDX (energy dispersive X-ray analysis) analysis of crystals formed in batch culture tests, containing MSVP plus either added manganese or iron sulfate, confirmed the ability of the isolate to oxidize both Mn (II) and Fe (II). The leucoberbelin blue colorimetric assay and batch tests using MSVP both demonstrated that in the presence of the isolated strain, Acinetobacter sp. LB1, the rate of Mn (II) oxidation at neutral pH was enhanced as compared to abiotic controls. In the second experimental chapter the difference in Fe (II) oxidation between biological and abiological systems at neutral pH was determined using batch tests run with Acinetobacter sp. LB1 and Fe (II) in saline. In addition, the rate of Fe (II) oxidation was also determined at acidic pH and at alkaline pH in experimental and control flasks. To determine Fe (II) removal under conditions simulating those in the biofiltration system, batch tests were set up using borehole water freshly collected from the biofiltration system. In order to verify the contribution of native microorganisms in the borehole water to Fe (II) oxidation, these flasks were spiked with bacterial strains isolated from the biofiltration system - Acinetobacter sp. LB1 and Burkholderia sp. strain LB2 - and two known iron oxidizing strains Leptothrix mobilis (DSM 10617) and Sphaerotilus natans (DSM 565) were used to determine the contribution of reference iron oxidizers to Fe (II) oxidation. A separate set of the same flasks with the addition of filter sand was used to qualitatively demonstrate iron oxidation as it would occur within the biofiltration system. The ferrozine assay was employed to quantify the amount of Fe (II) in batch tests employing saline medium and in batch tests employing borehole water. EDX analysis was employed to confirm the presence of Fe (II) in oxidation products in the batch test flask with filter sand spiked with Acinetobacter sp. LB1. In the presence of Acinetobacter sp. LB1 at neutral pH in saline medium, the rate of Fe (II) oxidation was very similar to that in the abiological controls thus demonstrating that the presence of metabolically active microorganisms does not per se enhance the oxidation of Fe (II) like in the case of Mn (II) at neutral pH. Surprisingly, in the heat inactivated control, apparently the highest amount of Fe (II) was oxidized. As expected, at acidic pH very little oxidation of Fe (II) took place and at alkaline pH almost all Fe (II) in the flasks was removed and small amounts oxidized as determined by the amount of Fe (III) produced. Batch tests using borehole water proved that native microorganisms within the biofiltration system were more efficient in the oxidative removal of Fe (II) from the system, in comparison to the reference iron oxidizing strains. In the final experimental chapter, the presence of biofilms with actively metabolizing cells was examined on a pooled sample of biofilter matrix from the manganese and iron filter using CLSM (confocal laser scanning microscopy) image analysis. DNA was extracted from the biofilm material associated with biofilter matrix to establish a diversity snapshot of the bacteria present within the biofilter matrix. ARDRA (amplified “rDNA” restriction analysis) analysis of the clone library revealed the presence of 15 unique OTU’s (operational taxonomic unit) based upon restriction patterns of amplified 16S rRNA genes of a total of 100 randomly selected clones. The majority of the clones were closely related to the genera Nitrospira and Lactococcus. Overall, 42% of the clones were assigned to the phylum Proteobacteria, 13% to the phylum Actinobacteria, 24% to the phylum Firmicutes and 21% to the phylum Nitrospirae. Overall, the results demonstrate that bacteria present within an established biofiltration system at neutral pH can contribute to the oxidative removal of Mn (II) and, apparently only to a smaller degree, to that of Fe (II) present in borehole water and that species within the proteobacterial genus Acinetobacter are potentially involved in the geochemical cycling of these two metals. Keywords: Biofiltration, iron and manganese oxidation, Acinetobacter sp. LB1, batch tests, 16S rRNA, MALDI-TOF MS analysis, Mn (II) and Fe (II) colorimetric assays, EDX analysis, biofilm formation, CLSM image analysis, 16S rRNA clone library Abbreviations: MSVP (minimal salts vitamins pyruvate), ORP (oxidation reduction potential), EDX (energy dispersive X-ray analysis), MALDI-TOF MS (Matrix assisted laser desorption ionization-time of flight mass spectrometry), rRNA (ribosomal RNA), ARDRA (amplified “rDNA” restriction analysis), CLSM (confocal laser scanning microscopy), OTU (operational taxonomic unit) / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

M. Tech. (Civil Engineering, Faculty of Engineering and Technology), Vaal University of Technolog / Textile industry effluents are carcinogenic and highly recalcitrant hence difficult to degrade especially through biological methods. Abattoir effluents are classified under high-strength wastewaters because of their characteristic high organic load hence highly biodegradable. Anaerobic co-digestion is the concept of degrading two effluent streams with complementary characteristics in order to improve the substrate removal rate. The feasibility of co-digesting abattoir and textile wastewater in a UASB reactor was evaluated at mesophilic and ambient temperature conditions. Preliminary experiments were conducted in 500 ml batch reactors to evaluate the optimum abattoir to textile synthetic wastewater ratio. The effect of COD, TVFA, alkalinity and pH on biogas yield was examined at both ambient and mesophilic temperatures. Anaerobic co-digestion of abattoir to textile wastewater in the ratio determined in the batch process was carried out in a 3 L UASB reactor by a continuous process. The continuous biodegradation process was executed at three different HRTs (22, 18 and 14 hrs) over a 60 day operation period. UASB reactor efficiency was achieved at organic loads ranging from 3.0 – 10.8 gCOD L-1 day-1. Continuous mode experiments were carried out at influent flow rates which corresponded to HRTs ranging between 1 to 8 days in order to evaluate the steady state operating parameters for the co-digestion process. The abattoir to textile effluent ratio was found to be 60:40 respectively. The COD, TVFA, alkalinity and pH and biogas yield followed a similar pattern over time at both mesophilic and ambient temperature conditions. Experimental data adequately fit the Grau first order kinetic model and average COD removal efficiencies of 85% and BOD5 of around 96% were achieved. The average biogas yield remained essentially constant, around 0.19 L/g CODremoved. The co-digested mixture was found to be biodegradable judging from the BOD:COD ratio of 0.53. TCOD removal efficiency decreased from 93% to 16% as HRT decreased from 8 days to 1 day. The kinetics of a UASB reactor co-digesting the mixture of synthetic abattoir and textile wastewater was evaluated in this study using Grau second order multicomponent substrate removal kinetic model. The Grau second order kinetic model, whose kinetic coefficient (ks) was 0.389, was found to be suitable for predicting the performance of a lab-scale UASB reactor.

Recently, due to the unique properties and structures such as large geometric surface area, electrical conductivity and light weight, 3D structured carbon materials have been attracting extensive attention from scientists. Moreover, the materials, which can provide well-defined pathways for reactants to easily access active sites, are extremely useful for energy conversion as well as environmental and catalysis applications. To date, many precursors have been used for fabrication of 3D structured carbon materials including pitch, carbon nanotubes, graphene, and polymer foams. This thesis, as shown in the thesis title, focus on two main aspects: the study of the characteristics of melamine based carbon foam synthesized at different conditions and their applications. In paper I, it was revealed that through a simple, one-step pyrolysis process, flexible carbon foam synthesized from melamine foam (BasotectÒ, BASF) was obtained. Additionally, through a pyrolysis-activation process, activated carbon foam which possesses hydrophilic nature and high surface area was successfully synthesized. The characteristics of carbon foam such as the hydrophobic/hydrophilic nature, electrical conductivity, mechanical properties and surface chemistry were studied. It was shown that carbon foam could be successfully used as an absorbent in environmental applications e.g. removing of spill oil from water (paper I) or as support for heterogeneous catalysts, which in turn was used not only in gas phase reactions (paper I and IV) but also in an aqueous phase reaction (paper II). Importantly, when combined with a SpinChem® rotating bed reactor (SRBR) (paper II), the monolithic carbon foam/SRBR system brought more advantages than using the foam alone. Additionally, the work in paper III showed the potential of carbon foam in an energy conversion application as anode electrode substrate in alkaline water electrolysis. In summary, the versatility of the carbon foam has been proven through abovementioned lab scale studies and due to the simple, scalable and cost effective pyrolysis and activation processes used for the production, it has potential to be used in large-scale applications.

This paper presents the results of the spike tests performed in the alternative water supply pilot testing program for the City of Pembroke Pines. It establishes the effectiveness of a protocol that can be used to gain further insight on the rejection capacities of RO membranes. An in-depth study of the molecular descriptors affecting rejection by RO membranes is presented and used in the development of a discriminant function analysis. This analysis proved to be an effective way to predict the passage of Emerging Substances of Concern (ESOCs) through RO membrane. Further, a principal component (PC) analysis was performed to determine which factors accounted the largest variation in RO permeability. Additionally, this paper defines the groundwork for a discriminant analysis model that, if further developed, could serve as an important tool to predict the rejection capabilities of RO treatment when handling with ESOCs. / by Fernando J. Pleitez Herrera. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.