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Treatment of secondary municipal wastewater by submerged hollow fiber microfiltration membrane for water reuse : pilot-scale evaluationKim, Eung D. 01 January 2004 (has links)
No description available.
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Modeling mass transfer in single membrane elementsLovins, William A. 01 January 1996 (has links)
No description available.
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Verification and modeling of mass transfer in single and multi-element nanofiltration arrays for pilot-and full-scale operationMulford, Luke A. 01 January 1999 (has links)
No description available.
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Correlation and modeling of laboratory and field scale integrated membrane system productivity and water qualityLovins, William Al 01 July 2000 (has links)
No description available.
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Development and evaluation of flux enhancement and cleaning strategies of woven fibre microfiltration membranes for raw water treatment in drinking water productionPikwa, Kumnandi 08 1900 (has links)
Thesis submitted in fulfillment of the academic requirement for the degree of (M.Tech.: Chemical Engineering), Durban University of Technology, South Africa, Durban, 2015. / Woven Fibre Microfiltration (WFMF) membranes have several advantages over its competitors with respect to durability, making it a favourable alternative for the developing world and operation during rough conditions. Wide application of membrane technology has been limited by membrane fouling. The durability of the WFMF membrane allows more options for flux enhancement and cleaning methods that can be used with the membranes even if they are vigorous. Therefore, the purpose of this work was to develop and evaluate flux enhancement and cleaning strategies for WFMF membranes.
Feed samples with high contents of organics and turbidity were required for the study. Based on this, two rivers which are Umkomaasi and Duzi River were identified to satisfy these criteria. A synthetic feed with similar fouling characteristics as the two river water was prepared and used for this study. The synthetic feed solution was made up of 2 g/ℓ of river clay in tap water and 0.5% domestic sewerage was added into the solution accounting for 2% of the total volume. A membrane filtration unit was used for this study. The unit consisted of a pack of five membrane modules which were fully immersed into a 100 litres filtration tank. The system was operated under gravity and the level in the filtration tank was kept constant by a level float. The study focused on evaluating the performance of the woven fibre membrane filtration unit with respect to its fouling propensity to different feed samples. It also evaluated and developed flux enhancement and cleaning strategies and flux restoration after fouling. The results were compared to a base case for flux enhancement and pure water fluxes for cleaning.
The WFMF membrane was found to be prone to both internal and external fouling when used in the treatment of raw water (synthetic feed). Internal fouling was found to occur quickly in the first few minutes of filtration and it was the major contributor for the loss of flux from the WFMF membrane. The fouling mechanism responsible for internal fouling was found to be largely pore blocking and pore narrowing due to particle adsorption on/in the membrane pores. The structure (pore size, material and surface layout) of the WFMF membrane was found to be the main cause that made it prone to internal fouling. The
IV
major fouling of the WFMF membrane was due to internal fouling, a high aeration rate of 30 ℓ/min had minimal effect on the fouling reduction. An aeration rate of 30 ℓ/min improved the average flux by only 36%, where a combination of intermittent backwashing with brushing and intermittent backwashing with aeration (aeration during backwashing only) improved average flux by 187% and 135% respectively. Pre-coating the WFMF membrane with lime reduced the effects of pore plugging and particle adsorption on the membrane and improved the average flux by 66%. The cleaning strategies that were most successful in pure water flux (PWF) recovery were high pressure cleaning and a combination of soaking and brushing the membrane in a 0.1% NaOCl (desired) solution. PWF recovery by these two methods was 97% and 95% respectively.
Based on these findings, it was concluded that the WFMF membrane is susceptible to pore plugging by colloidal material and adsorption/attachment by microbiological contaminants which took effect in the first hour of filtration. This led to a 50% loss in flux. Also, a single flux enhancement strategy proved insufficient to maintain a high flux successfully. Therefore, combined flux enhancement strategies yielded the best results.
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Evaluation of micro-scaled TiO b2 s on degradation and recovery of mTiO b2 s from treated drinking waterDlamini, Chazekile Precious January 2016 (has links)
Submitted in fulfillment of the requirements of the degree of Master of Engineering: Chemical Engineering, Durban University of Technology, Durban, South Africa, 2016. / River water is a life supporting watercourse to most communities in rural areas. It is used for both human and animal consumption, and is well becoming a collection channel for defecation and urination due to shortage or lack of access to running water and sanitation facilities. This has resulted to the contamination of water sources, which poses a great risk to human health. This has motivated researchers to study simple but yet robust systems to produce safe drinking water. Photocatalysis is one of such emerging disinfection technologies.
Titanium dioxide (TiO2) which is one of the basic materials used for paint manufacturing has emerged as an excellent photocatalyst material for water purification. TiO2 was selected in this study because it is locally available with a potential to open a new market in water purification for the manufacturers. The setback in previous studies is the recovery of nano-scaled TiO2 (nTiO2) after purification when used as a suspension in treated water. Thus this study evaluates the performance of four grades of micro-scaled TiO2 (mTiO2) on the degradation of organic matters, Escherichia coli (E. coli) and total coliform in river water and to investigate the percentage recovery of the mTiO2 using a locally manufactured Polyester Woven Fabric Microfiltration (PWFMF) membrane. The PWFMF though uncharacterized has been used in a number of studies for treating domestic and industrial waste waters. The best-performing grade was used to optimize the degradation efficiency of E. coli in river water using the Design of Experiments (DOE) methodology.
Grade 2 of the mTiO2, which is hydrated titanium dioxide with additions (ahTiO2) of particle size range of 0.2 – 53 µm at a concentration of 2.5 g/l displayed an advantageous photocatalytic activity. The results show that 80 % of the organics were removed in 3 hours and increased to 93% after 6 hours. Two particle size ranges of 0.2 – 53 µm and 54 – 75 µm at a concentration of 5 g/l degraded organic matters to 90 % and 77 % in 3 hours respectively. The particle size range of 0.2 – 53 µm at a concentration of 5 g/l was then filtered using a PWFMF and turbidities went below 1 NTU after 20 minutes from feed turbidity of 470 NTU for all three trials. The average percentage recovery in 2 hours was 98.91 %.
The four grades of mTiO2 were analyzed for E. coli and total coliform for 4 hours at concentrations of 2, 5 and 7 g/l. Grade 2 achieved the E. coli specification of 0 count/ 100 mL at 5 g/l in 2 hours and at 7 g/l in 0.5 hours. Grade 4 E. coli specification was achieved with 7g/l in 4 hours. Grades 2 and 4 performed better since they both achieved the E. coli and total coliform specifications. Grade 2 was the best performing grade and was considered for statistical studies.
Grade 2 was then used on a comparative study between the Central Composite Design (CCD) and Box-Behnken Design (BBD), which are two of the major Response Surface Methodologies (RSM). The CCD compared to BBD provides high quality predictions over the entire design space. The CCD obtained optimum results for concentration of mTiO2 (X1), temperature (X2), initial pH (X3) and aeration (X4) which were 6.94 g/l, 28.75 OC, pH = 6.04, and 13.35 L/min for the maximum degradation efficiency of 99.85 % which showed comparable optimum results to the BBD that were 6.45 g/l, 28.28 OC, pH = 6.02 and 12.21 L/min for the maximum degradation efficiency of 99.80%. These theoretical model results were validated by practical experiments that produced the maximum degradation efficiency for CCD and BBD of 99.67 and 99.26 % respectively.
Grade 2 of the mTiO2 can be used as a photocatalyst for river water purification due to its strong ability for the removal of E. coli. The additions used in grades 2 and 4 during production improved the photocatalytic activity. The PWFMF membrane showed a great performance of above 98 % particle recovery of mTiO2 from treated water, although there was an indication that the smallest particles were passing through the membrane. The RSM results gave approximately the same optimum results that were well within the limits, which were experimentally validated and showed that the models were sustainable. It is recommended that the effect of additions be studied on the structures or the charge stability of the two grades. / M
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UF membranes operated on paper machine wastewater : fouling tendencies and characterisationDomingo, Garth Selby 12 1900 (has links)
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.
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Environnmental life cycle assessment of potable water production.Friedrich, Elena. January 2001 (has links)
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.
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Récupération et valorisation de biomolécules d’effluents de papeterie par procédés membranaires / Recovery and valorization of biomolecules from paper mill effluents by membrane processesCourbalay, Matthieu 11 July 2018 (has links)
L'objectif est la valorisation de biomolécules issues des eaux du procédé thermomécanique de fabrication de pâte à papier. La séparation des familles de biomolécules doit permettre de générer plusieurs fractions ayant un intérêt pour l'industrie cosmétique et phytosanitaire. Les terpènes, hémicelluloses, lignine et lignanes ont été identifiés dans ces eaux. Cependant, le choix s'est porté sur la valorisation de la lignine et des lignanes pour des raisons de sélectivité et de valeur ajoutée. La flottation et la filtration par membrane 150 kDa permettent d'effectuer une clarification par élimination de 100% des terpènes et de 59% des hémicelluloses. Le fractionnement de la lignine et des lignanes est effectué avec des membranes de 1 kDa et 300Da à pH 4 pour obtenir deux rétentats contenant respectivement 96% de lignine et 58% de lignanes par rapport aux polyphénols totaux. Une étude technico-économique de faisabilité de la filière de séparation est réalisée à l'échelle semi-industrielle . / This thesis work is part of a dynamic industrial ecology around the paper industry. The objective is the valorization of biomolecules coming from thermomechanical process waters of manufacture of paper pulp. The separation of biomolecule's families must allow generate several fractions having an interest for cosmetic and phytosanitary industry. Terpenes, hemicelluloses, lignin and lignans have been identified in these waters. However, the choice has worn on the valorization of lignin and lignans for reasons of selectivity and added value. Flotation and 150 kDa membrane filtration allow for clarification by removal of 100% of terpenes and 59% of hemicelluloses. Fractionation of the lignin and lignans is carried out with membranes of 1 kDa and 300 Da at pH 4 to obtain two retentates containing respectively 96% of lignin and 58% of lignans relative to the total polyphenols. A technical-economic study of feasibility of separation process is carried out on semi-industrial scale.
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Avaliação dos efeitos da adição de L-cistina e sais biliares na técnica de H2S na detecção de contaminação fecal em ambientes aquáticos. / Effect evaluation of L-cystine and bile salts in H2S method for fecal contamination detection in water environment.Silva, Thiago Nepomuceno 13 June 2016 (has links)
As fontes hídricas disponíveis para o consumo humano vêm sendo comprometidas. Para resolver este problema, várias técnicas de detecção de contaminação fecal foram desenvolvidas. Em 1982, Manja e colegas desenvolveram método H2S que é simples, rápida e de baixo custo e detecta bactérias produtoras de H2S e, assim, a contaminação fecal. Neste trabalho foi analisada a eficácia de detecção de micro-organismos produtores de H2S frente a adição de L-cistina (125mg/L e 250mg/L) e desoxicolato de sódio (DS) (0,1% e 0,3%) e na presença de bactérias não produtoras de H2S para verificar se a presença destas bactérias interferem na detecção dos isolados H2S+. Assim, comparou-se o teste H2S com a membrana filtrante e o Colilert®. Os resultados deste estudo indicam que o meio H2S com adição de 0,3% de desoxicolato de sódio se mostrou mais rápido e sensível. Quando comparado com outras metodologias clássicas, o meio com 0,3% apresentou uma ligeira queda na sensibilidade mas o método H2S se mostrou mais sensível que o Colilert. / Water supply for human consumption have been compromised. Several detection methods for fecal contamination have been developed to solve this problem. Manja and co-workers (1982) developed a simple, fast and low-cost method for fecal contamination based on detection of sulfate-reducing bacteria, the H2S method. This work aimed to analyse the detection efficiency of the H2S method under different conditions: with L-cystine (125mg/L e 250mg/L) and sodium deoxycholate (0.1% e 0.3%). Also, non-sulfate-reducing bacteria interference were evaluated. Comparison tests were made through membrane filtration and Colilert®. Our results indicate a faster and more sensible for the 0.3% sodium deoxycholate condition. Compared to other classic methodologies, the 0.3% sodium deoxycholate condition slightly decrease the sensibility. However the H2S method was more sensitive than the Colilert one.
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