M. Tech. Engineering: Chemical / Researches the usability and efficiency of the synthesized PPy/Al2O3 nanocomposite as adsorbent in Cr(VI) remediation from contaminated wastewaters.The specific objectives of the study are:to synthesise and characterize the PPy/Al2O3 nanocomposite ; to characterize the prepared nanocomposite using several sophisticated instruments such as, SEM, BET, XRD, et cetera ; to carryout batch adsorption equilibrium and kinetics studies for evaluating the performance of the nanosorbent and to gain insight into the underlying adsorption mechanisms.; to apply adsorption equilibrium and kinetic models.; to assess the breakthrough performance of the PPy/Al2O3 nanocomposite for Cr(VI) adsorption by varying operating parameters, in fixed bed column mode and to apply existing mathematical models to predict the performance of fixed bed adsorption systems and to obtain column design parameters.

The biological treatment of wastewater has evolved significantly from simple single sludge systems practicing organic carbon removal to ones which now include either nitrification/denitrification (N/DN) and / or phosphorus (P) removal. The inclusion of more biological processes have increased the complexity of current wastewater systems which has subsequently led to the development of more complex mathematical models. The operation of plants can be assessed and improved by the use of mathematical modelling tools which require accurate input data. Thus, knowledge of the wastewater characteristics is an important step towards the optimum modelling, design and operation of present and future plants. However, for these tools to be effective, the input data needs to be accurate which is dependent on the current methods used to determine them. Wastewater is a complex substrate consisting of compounds of differing biodegradability. Biokinetically, these compounds have been divided into readily biodegradable (RBCOD), slowly biodegradable (SBCOD) and unbiodegradable substrate groups. Compounds with intermediate biodegradability i.e. compounds which fall between the RBCOD and SBCOD groups, have been termed readily hydrolyzable organic substrates (RHCOD). The organic matter is discussed in terms of chemical oxygen demand (COD). The readily biodegradable and readily hydrolyzable COD fractions of wastewater can be determined by respirometric tests such as the oxygen utilization rate (OUR) and nitrate-N utilization rate (NUR) tests. The principal aim of this project was to investigate the NUR test as a tool for wastewater characterization and to study denitrification kinetics in batch reactors. In addition, an experimental readily biodegradable substrate, acetate, was used to determine the reliability of the NUR tests. Acetate was also used to ascertain utilization profiles and rates of a typical readily biodegradable substrate during denitrification. Biodegradable COD characterizations with enhanced biological phosphorus removal (EBPR) sludges were also investigated to determine the impact of anoxic phosphorus removal on NUR tests. The results obtained from the numerous NUR tests added to the undestanding of the NUR test. Samples from 22 wastewater treatment plants were tested, most of which were located in France. Four South African plants were also tested. Data obtained from the NUR tests were used to calculate the RBCOD and RHCOD fractions. The SBCOD, however, could not be determined directly from the 6 h NUR batch tests. The readily biodegradable COD (RBCOD) fractions ranged between 7 and 25 % of the total COD concentration of raw wastewater, with majority of those results falling within the 10-20 % (of the total COD) range. The results also showed that the initial rapid rate associated with readily biodegradable COD utilization was sometimes followed by a short intermediate phase (i.e. short duration, 2 to 3 h). The intermediate fraction was found to range between 5 and 29 % of the total COD concentration and was classed as a readily hydrolyzable COD component of raw wastewater since the magnitude of the RHCOD fraction was too small to be classed as slowly biodegradable COD which comprises approximately 30 to 60 % of the total COD found in raw wastewaters. The variability of the RHCOD fractions suggests that this fraction is either very variable or that the NUR test does adequately or accurately characterize it. Another possibility is that the RHCOD (or second biodegradable fraction) calculated from the NUR test is a component of the RBCOD of the influent wastewater. In this case, the bacteria may have used some of the RBCOD directly for energy and accumulated or stored the rest as part of a survival mechanism which allows them to be more competitive under dynamic operating conditions. Once the readily biodegradable COD becomes limiting, the bacteria will use the accumulated or stored compounds. This hypothesis is substantiated by tests done with acetate as substrate. An intermediate phase was also observed when acetate was the sole substrate. Thus, it was possible with the 3-phase profiles to calculate a second biodegradable fraction. Results suggest that a significant part of the added acetate (as COD) was stored and the second phase is in fact an 'apparent or residual' phase brought about by the consumption of the stored or accumulated acetate products. This is suggested in two ways: (1) the calculation of the yield coefficient is lower and closer to the 0.5 mg/l values, cited in the literature, when the COD calculated from phases 1 and 2 are considered, and (2) the acetate mass balances were found to be approximately 100 % when phases 1 and 2 were used to calculate the amount of acetate utilized under anoxic conditions. The results obtained with sodium acetate as a readily biodegradable substrate were used to formulate several conclusions on acetate utilization during denitrification. Firstly, from acetate mass balances it was found that acetate may be used exclusively for denitrification (100 % acetate was accounted for). In this case, the sludge contains a significant proportion of denitrifiers and little or no polyphosphate accumulating organisms. This observation was made only when non-EBPR (enhanced biological phosphorus removal) sludges were used. Secondly, acetate mass balances which were found to be < 100 % suggest that acetate could be used for denitrification and the production of storage products like polyhydroxyalkanoates (PHA's). These sludges probably contained a higher proportion of polyphosphate accumulating organisms which competed for the available acetate in the bulk liquid. This observation was made for both EBPR and non-EBPR sludges. Thirdly, acetate could be used for denitrification by denitrifiers and for polyhydroxyalkanoate synthesis by denitrifying polyphosphate accumulating organisms. The stored PHA's in the denitrifying polyphosphate accumulating organisms are subsequently utilized during denitrification. This secondary utilization is manifested in the second denitrification phase and is supported by the observation of phosphorus uptake. These results showed that wastewaters high in volatile fatty acids (VFA's) were also subject to denitrifying polyphosphate accumulating organism activity even though the sludge was sampled from non enhanced biological phosphorus removal systems (non EBPR). Several of the NOx profiles revealed either 2 or 3 rates due to the control of the substrate to biomass ratio (S/X: :<_0.1 mgO2 / mgO2). Majority of the samples (i.e. 85%) tested produced initial maximum specific denitrification rates (k1) between 3 and 6 mgN/gVSS.h. The intermediate denitrification rate (k2) was found to vary between 2 and 3 mgN/gVSS.h. Denitrification rates (k3) obtained from utilization of influent and. endogenous slowly biodegradable COD (SBCOD) varied between 1.0 and 1.5 mgN/gVSS.h. This latter rate is significantly higher than the endogenous denitrification rates cited in the literature. One of the reasons for these higher rates could be be linked to the the reuse of stored or accumulated products by the microorganisms. In addition, a comparative study on RBCOD determination of wastewaters with enhanced biological phosphorus removal and non-EBPR sludges. It was found that the RBCOD values derived by NUR tests with EBPR sludge were consistently lower (4 to 5 %) than those with non-EBPR sludge. Thus, the NUR tests with EBPR sludge resulted in a 4 to 5 % underestimation of the RBCOD fraction of raw wastewaters. This loss in RBCOD to polyphosphate accumulating organisms appears to be linked to the influent raw wastewater acetate concentration. These tests showed that the RBCOD fraction could be adequately characterized using the NUR method. The accuracy of the tests appears to be compromised when enhanced biological phosphorus removal sludges are used in the NUR tests. Moreover, it was found that non-EBPR sludges can also consume some of the acetate that is present in the system for the production and replenishment of storage compounds. Fortunately, for the wastewaters tested, the acetate component of the RBCOD fraction was small and therefore, did not significantly affect the results. Mechanisms such as substrate accumulation and storage may also impact on substrate removal and hence, the determination of the readily biodegradable COD concentration of municipal wastewaters. Thus, while the results showed that the NUR is a useful characterization tool for wastewaters, it will continue to be a more tedious characterization tool than the oxygen utilization rate test, until a suitable nitrate/nitrite electrode is developed to automate the test. / Thesis (Ph.D.)-University of Natal, Durban, 1999.

A water treatment unit consisting of two aeration basins, two settling tanks, a residence basinand a horizontal subsurface flow wetland were used to treat wastewater from an eggprocessing factory in Brazil. The aim of this paper was to determine the efficiency of thesystem in reducing nitrogen, phosphorus, BOD5 and TSS (among other parameters) andgetting a further understanding on different kinds of constructed treatment wetlands as well astheir nitrogen and phosphorus removal processes. The wastewater from the factory consistedof process water from manufacturing and water used for cleaning, no stormwater or sewagewater entered the system. Tests were taken three times a month from October 2013 ‘til April2014. The mean influent concentrations from wastewater directly from the factory were2,606 mg/L, 46.60 mg/L, 318.3 mg/L and 1,112 mg/L for BOD5, TP, TKN and TSS. Themean results of reduction through the wetlands gave the following results; BOD5 42 ± 351%,TP 66 ± 9.7%, TN 42 ± 13% and TS -11 ± 30%. Compared to other wetland systems treatingsimilar wastewater the reduction of BOD5 and TSS is low. Recommended solutions toincrease the reduction in the wetland are presented in the discussion. / Processvatten från livsmedelsindustrier och anläggningar med animalieproduktion har högakoncentrationer av organiskt material, suspenderat material och närsalter (Kadlec &amp; Wallace,2008). Förr släpptes mycket processvattnet direkt ut till närliggande dammar, floder ellerbäckar. I moderna tider finns riktvärden satta från till exempel svenska Naturvårdsverket och det brasilianska miljödepartementet, CONSEMA, som gör att processvattnet måste förbehandlas innan det kan släppas till recipienten. Våtmarker har visat sig vara ett bra val av reningsmetod när det kommer till rening av bland annat kväve, fosfor, BOD5 och TSS(Camino et al., 2011; Johansson, 2014; Knight et al., 2000; Lin et al., 2005; Mantovi et al.,2003). De olika typer av anlagda våtmarker har för- och nackdelar, till exempel har vissa typer en högre nitrifikationsprocess och andra har en högre denitrifikationsprocess. Genom attkänna till vilka för- och nackdelar de olika typer av anlagda våtmarker har går det att skräddarsy ett behandlingssystem som uppfyller de specifika reningsändamålen för just det processvattnet. Syftet med detta arbete är att avgöra hur pass effektiv NaturOvos våtmarkreducerar föroreningar, att får en bättre förståelse av olika typer av anlagda våtmarker samt deras kväve- och fosforreningsprocesser. NaturOvos äggfabrik ligger i Salvador do Sul, Rio Grande do Sul, Brasilien. Under juni år 2013 byggdes en horizontal subsurface flow (HSSF) våtmark för att öka kväve- och fosforrening av processvattnet från fabriken. Behandlingssystemet består av en aktivslamanläggning bestående av två luftningsbassänger och två sedimenteringstankar, en uppehållsbassäng och en HSSF våtmark. Recipienten är en närliggande damm. Behandlingsvattnet som renas genom systemet innehåller processvatten och vatten som används vidrengöring av fabriken. Obehandlat vatten direkt från fabriken har ett medelvärde på2 606 mg/l för BOD5, 46,60 mg/l för TP, 318,3 mg/l för TKN och 1 112 mg/l för TSS. Provtagning av inflödes- och utflödesvatten har skett tre gånger per månad från oktober 2013 till april 2014. Medelvärdesresultat av retention i våtmarken är följande; BOD5 42 ± 351 %,TP 66 ± 9,7 %, TN 42 ± 13 % och TS -11 ± 30 %. Jämfört med andra studier (Camino et al.,2011; Johansson, 2014; Knight et al., 2000; Lin et al., 2005; Mantovi et al., 2003) är retentionav kväve och fosfor hög, men retentionen av BOD5 och TS är låg. Förbättringsförslag för att öka reningen i våtmarken redovisas i diskussionen.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2018-05-18T13:18:03Z No. of bitstreams: 1 PDF - Luciana Leôncio Bertino Cabral.pdf: 26933991 bytes, checksum: 16582e8219a683ebcba28f0ec330a8cd (MD5) / Made available in DSpace on 2018-05-18T13:18:04Z (GMT). No. of bitstreams: 1 PDF - Luciana Leôncio Bertino Cabral.pdf: 26933991 bytes, checksum: 16582e8219a683ebcba28f0ec330a8cd (MD5) Previous issue date: 2018-02-27 / The present study had, as main objective, to evaluate the oxidation of sulfides usin g nitrified effluent as an electron acceptor in anaerobic reactors treating sanitary sewage. This process was possible because the interactions between the carbon, nitrogen and sulfur cycle that allow the practical use of the fundamentals already known about the process of denitrification and oxidation of sulfides at simultaneous moments. The experiments were perform in a Hybrid Anaerobic Reactor (HAR) with a useful volume of 60 liters and TDH of 24 hours. The HAR consists of a UASB reactor in the lower part and in the middle part an Anaerobic Filter, with polyurethane foam used as a support form. An equilibrium tank, designed at the top of the HAR, sent the effluent into an Intermittent Flux of Sand’s Filter - FaFint, allowing the formation of the nitrified effluent, with the purpose of recirculating this material to the anaerobic phase of the system. The research was developed in four phases. In the first phase, the HAR nourished with 100% of sewer from the Campina Grande – PB city, with the purpose of comparing its results with the other phases, in which different flows in each phase of the operation recirculated from the effluent produced in the FaFint. During phase 2, the HAR received a flow of 83% of sewer and 17% of nitrified effluent, in phase 3 the flow changed to 64% of raw sewer and 33% of the effluent recirculated from FaFint. While in phase 4, the ratio applied was 50% crude sewer and 50% nitrified effluent. Concentrations of sulfate, sulfide, elemental sulfur, nitrate, nitrite, organic nitrogen and ammoniacal nitrogen were monitored, as well as other parameters of interest. The results showed that the operational conditions imposed during phase 4 allowed the accumulation of 41% of the oxidized forms of sulfur in the anaerobic phase, 31% in the form of sulfate and 10% in the form of elemental sulfur. The addition of a higher amount of nitrified effluent in the HAR also favored the denitrification process, showing 38% of the nitrogen forms removed during the anaerobic stage and a 46% removal of nitrogen in the final effluent. Thus, it was concluded that the use of nitrate and nitrite can effectively treat the stinks generated by the treatment of anaerobic wastewater systems. / A presente pesquisa teve por principal objetivo, avaliar a oxidação de sulfetos utilizando efluente nitrificado como aceptor de elétrons em reatores anaeróbios tratando esgoto sanitário. Esse processo foi possível devido as interações entre o ciclo do carbono, nitrogênio e enxofre que permitem a utilização prática dos fundamentos já conhecidos sobre o processo de desnitrificação e oxidação de sulfetos em momentos simultâneos. Os experimentos foram realizados em um Reator Anaeróbio Híbrido – RAH – com volume útil de 60 litros e TDH de 24 horas. O RAH é constituído por um reator UASB na parte inferior e na parte intermediária um Filtro Anaeróbio, com espuma de poliuretano utilizado como meio suporte. Um tanque de equilíbrio, projetado na parte superior do RAH, lançava o efluente em um Filtro de Areia de Fluxo intermitente – FaFint, permitindo a formação do efluente nitrificado, com o propósito de realizar a recirculação desse material para a fase anaeróbia do sistema. A pesquisa foi desenvolvida em quatro fases. Na primeira fase o RAH foi alimentado com 100% de esgotos da cidade de Campina Grande – PB, teve a finalidade de comparar seus resultados com as demais fases, na qual, fora recirculado vazões, distintas em cada fase de operação, do efluente produzido no FaFint. Durante a fase 2, o RAH recebeu uma vazão de 83% de esgoto e 17% de efluente nitrificado, na fase 3 a vazão foi alterada para 64% de esgoto bruto e 33% de efluente recirculado do FaFint. Enquanto que na fase 4, a razão aplicada foi de 50% de esgoto bruto e 50% efluente nitrificado. Foram monitoradas as concentrações de sulfato, sulfeto, enxofre elementar, nitrato, nitrito, nitrogênio orgânico e nitrogênio amoniacal, além de outros parâmetros de interesse. Os resultados obtidos mostraram que, as condições operacionais impostas no decorrer da fase 4, possibilitaram o acúmulo de 41% das formas oxidadas de enxofre na fase anaeróbia, sendo 31% na forma de sulfato e 10% na forma de enxofre elementar. A adição de uma maior quantidade de efluente nitrificado no RAH, também favoreceu o processo de desnitrificação, apresentando remoção de 38% das formas de nitrogênio durante a etapa anaeróbia e 46% na eficiência de remoção de nitrogênio no efluente final. Dessa forma, foi concluído que o uso de nitrato e nitrito, podem tratar de forma eficaz os problemas de mal odor gerado pelo tratamento de sistemas anaeróbios de águas residuárias.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-09-14T18:05:23Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao_Martina_Cezano_Corrigida.pdf: 1969919 bytes, checksum: 1fd1af7e30056d2160f46bf6bcc78e1e (MD5) / Made available in DSpace on 2016-09-14T18:05:23Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao_Martina_Cezano_Corrigida.pdf: 1969919 bytes, checksum: 1fd1af7e30056d2160f46bf6bcc78e1e (MD5) Previous issue date: 2016-02-16 / O Arranjo Produtivo Local (APL) do agreste pernambucano é um polo de confecção, especializado em jeans, que conta com aproximadamente 12 mil empresas distribuídas principalmente nos municípios de Toritama, Caruaru e Santa Cruz do Capibaribe. Em Caruaru, a principal atividade têxtil é a de lavagem de jeans, em que se utiliza grande volume de água, que é acompanhado do lançamento dos efluentes nos corpos d’água da região, sem tratamento adequado. Os efluentes despejados apresentam altas concentrações de corante, provenientes da não fixação no processo de tingimento. Com a finalidade de tratar estes efluentes de forma ambientalmente mais aceitável, do que os processos físico-químicos utilizados nas lavanderias de jeans, o tratamento biológico apresenta boa capacidade de remoção de cor e matéria orgânica (em torno de 80%). Nos processos biológicos, o uso de reatores anaeróbios de fluxo ascendente e manta de lodo (UASB) têm resultado em eficiências de remoção de cor e matéria orgânica (MO) em torno de 50% e 75%, respectivamente. Com intuito de prever o comportamento da remoção de cor e matéria orgânica em reatores do tipo UASB, neste projeto foi adaptado um modelo matemático simplificado para representar o comportamento de remoção de MO. O modelo matemático foi baseado no balanço de massa considerando o reator tipo UASB formado por 4 compartimentos de mistura completa em série, com fluxo contínuo. Tanto a remoção de MO como de cor foram representadas por cinética de 1ª ordem. O método numérico utilizado foi o de Runge-Kutta de 4ª ordem, utilizando a ferramenta Matlab®. Para calibração do modelo foram utilizados dados experimentais de operação de reator tipo UASB em escala piloto, alimentado com efluente têxtil real, apresentados por Ferraz Junior (2010) e Amaral (2011). Os resultados obtidos indicaram que o modelo matemático simplificado que foi ajustado representou o comportamento do reator tipo UASB para tratamento de efluente têxtil para ambos os parâmetros, cor e de MO. / The Local Productive Arrangement (LPA) from agrest of Pernambuco is a pole of cloth confections, specialized in jeans. There are approximately 12 thousand companies distributed in the municipalities of Toritama, Caruaru, and Santa Cruz do Capibaribe in this LPA. In the city of Caruaru the main textile activity is washing jeans. This activity demands huge amount of water, which is followed by wastewater discharges in water bodies, usually without the correct treatment. The textile effluent contains high concentration of dyes, not fixed during the dyeing process at the companies. Aiming to treat these effluents in a more environmental friendly way, in comparison with the physical-chemical process used by the jean companies, the biological treatment usually presents good performance for color and organic matter removal (around 80%). For biological processes the use of anaerobic reactors like Upflow Anaerobic Sludge Blanket (UASB) has been resulting in color and organic matter (OM) removal efficiencies around 50% and 75%, respectively. Aiming to estimate the behavior for color and organic matter removal in UASB reactors, in this project we made adjustments in a simplified mathematical model to represent the behavior of organic matter. The mathematical model was based in the mass balance considering the UASB reactor composed of 4 completely mixed compartments, in continuous flux. Both OM and color removal were well represented by the first order kinetic model. The 4th order Runge-Kutta numerical model was used through Matlab® tools. The adjusted simplified model was calibrated using the experimental data from UASB reactor operation in pilot scale, fed with real textile wastewater, presented by Ferraz Junior (2010) and Amaral (2011). The results indicated that the adjusted simplified mathematical model adequately represented the behavior of the UASB reactor treating textile wastewater for both, color and OM.

M.Sc. / The contamination of water by toxic compounds is one of the most serious environmental problems today. These toxic compounds mostly originate from industrial effluents, agriculture runoff, natural sources (e.g. heavy metals in water from rocks and soil erosion) and human waste. The contamination, which is both “organic” and “inorganic” has an impact on the environment and human health. The demand for water and the pressure to re-use this valuable resource has increased the need for improved techniques and materials to remove pollutants from water. The Nanomaterials Science research group at the University of Johannesburg has focused on developing synthetic polymers that can be employed in water treatment and pollutant monitoring. Recently, cyclodextrins (CD) and carbon nanotubes (CNTs) have been included in polymers for this application. For example, CD-co-hexamethylene-/toluene-diisocyanate polyurethanes and CNT-modified equivalents have been developed and have been successfully applied in removing organic contaminants from water to very low levels.1 Calixarenes are synthetic analogues of cyclodextrins that can be exploited via chemical modification to express a range of properties. In the present study, calixarenes, thiacalixarenes and carbon nanotube-based polymeric materials incorporating these molecules have been synthesised, characterised and tested for removing both organic pollutants (such as p-nitrophenol) and inorganic pollutants (Cd2+, Pb2+) from water. Lead(II) and Cadmium(II) are a threat in South Africa because of their toxicity, and while p-nitrophenol is much less of a problem it represents a useful model organic pollutant. The absorption capacity of the polymers towards heavy metals and organic contaminants was tested by mixing the polymer with synthetic water containing known concentration of the contaminants at about 10 mg/L. Atomic absorption spectrometry (AAS) and ultraviolet-visible spectrometry (UV-vis) were used to determine the levels of heavy metals and organic contaminants, respectively. The target pollutants (Cd2+, 1 see KL Salipira MTech dissertation, University of Johannesburg 2008 Pb2+ and p-nitrophenol) were all successfully removed from water by the various polymers, however the degree of removal and loading capacities of the polymers differed. This information gives some insight into what functional components are needed for making successful adsorbents. It was observed, for example, that ptert- butylcalix[8]arene/hexamethylene diisocyanate (C8A/HMDI) had a higher adsorption capacity towards p-nitrophenol and Pb2+ than towards Cd2+, and also a higher capacity than the corresponding calix[4]arene polymers with smaller calixarene cavities.

M.Tech. / Studies on the removal of nickel and platinum are increasing due to the toxicities of these metals. Several methods are currently used to extract these metals however they present limitations. There is hence a need to develop an efficient method for the removal of nickel and platinum from aqueous solution. A study on the use of purified multiwalled carbon nanotubes (purified MWCNTs) and a phosphine derivatized multiwalled carbon nanotubes for the extraction of these metal ions from solution was therefore undertaken. Multiwalled carbon nanotubes (MWCNTs) were produced by nebulised spray pyrolysis, purified by a multi-step technique and functionalized. Phosphine moieties were attached to the bromoarylated- MWCNTs by metallated phosphide route leading to triphenylphoshine linked MWCNTs (Tpp-MWCNTs). As produced, purified and triphenylphosphine linked multiwalled carbon nanotubes were characterized by various techniques, including microscopic and spectroscopic techniques, thermal, elemental and surface analysis. Transmission and scanning electron microscopy used revealed purified MWCNTs had insignificant impurities. X-ray photoelectron spectroscopy (XPS) results showed that triphenylphosphine linked multiwalled carbon nanotubes had 2.6% phosphorus. Zeta potential results demonstrated that purified MWCNTs had positive surface charges at acidic pH. Triphenylphosphine linked multiwalled carbon nanotubes were negatively charged on the surface in acidic media. Batch adsorption experiments were carried out to investigate the removal of nickel and platinum from aqueous solutions. Several parameters which influence the adsorption process were studied, including the effect of pH, the contact time and the effect of initial concentration on adsorption. The adsorption models for the Freundlich and Langmuir isotherms were employed to fit the experimental data. Triphenylphosphine linked MWCNTs removed more nickel (84.68 mg/g) than purified MWCNTs (77.39 mg/g). In contrast, purified MWCNTs removed more platinum (10.5 mg/g) than triphenylphosphine linked MWCNTs (6.01 mg/g). Experimental data for nickel fitted both Freundlich and Langmuir models well whereas only Langmuir model fitted well for platinum. The adsorption of nickel and platinum was indeed found to be pH, time and initial concentration dependent. Metal species (nickel and platinum) in solution had also influenced the uptake of these metals using purified-and Tpp-MWCNTs.

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Manganese is a problem at the Ni River Water Treatment Plant in Spotsylvania County, Virginia. The Ni River Reservoir (the water source) is a eutrophic reservoir. In the summer, the dissolved oxygen decreases to near or zero at depths greater than two meters. As a result, soluble manganese increases to levels of nearly 6.0 mg/L at the bottom. It is released from the sediments under anaerobic conditions. Total organic carbon levels ranging from 4.0 to 7.25 mg/L were noted with increasing depth. Plant profiles were developed to indicate the performance of the sedimentation and filtration units in reducing manganese concentration. Essentially, all the particulate manganese was removed by sedimentation, and some removal of soluble manganese was evident. The filters removed additional soluble manganese. Soluble manganese removal probably was due to the adsorption of manganese on solid manganese dioxide in the sludge blanket and on the filter media with subsequent further oxidation. Ozone was effective at a dose of approximately 5 mg/L. Chlorine and chlorine dioxide were marginally effective as pretreatments at dosages of 5 and 2 rng/L, respectively. Potassium permanganate proved effective at dosages of 0.5 to 0.625 mg/L (1.5 to 1.9 times the theoretical requirement). Aeration proved effective in reducing levels of approximately 0.1 mg/L to below the secondary maximum contaminant level (0.05 mg/L) and, in addition, somewhat effective in reducing a concentration of nearly 2 mg/L by 31 percent. Aeration appears to be a viable means of reducing the anaerobic conditions in the reservoir that lead to the high soluble manganese concentrations. / M.S.

O presente trabalho de pesquisa teve como objetivo principal avaliar a remoção de fitoplancton e microcistina em cinco fluxogramas de tratamento de água para abastecimento, que tiveram como seqüência básica as etapas de coagulação, floculação, flotação por ar dissolvido e filtração, complementados com oxidação química em diferentes pontos da seqüência básica de tratamento estabelecida. Os ensaios foram realizados em escala de laboratório, utilizando água de estudo preparada mediante a mistura de água coletada no reservatório de Barra Bonita, no Estado de São Paulo, e cultura com elevada concentração de microcistina preparada em laboratório. A concentração de microcistina na água de estudo foi mantida no intervalo de 14 a 17 µg/L. O cloreto férrico foi utilizado como agente coagulante, o permanganato de potássio e o cloro, na forma de hipoclorito de sódio, foram utilizados como agentes oxidantes. Foi observada eficiência de remoção de fitoplancton de cerca de 99,9% devido às etapas de coagulação, floculação e flotação por ar dissolvido e, conseqüentemente, remoção de microcistina contida no interior das células íntegras. A oxidação com cloro realizada após a filtração, bem como a oxidação com a associação do permanganato de potássio e cloro realizada após a flotação, resultaram em eficiência de remoção de microcistina extracelular (microcistina livre no meio líquido) da ordem de 95%, atendendo ao padrão de potabilidade com cocentrações de microcistina menores que 1,0 µg/L. A oxidação da água bruta com permanganato de potássio associada à oxidação da água flotada com cloro, apresentou o melhor desempenho de remoção de microcistina extracelular, com eficiência superior a 98%. Em todos os ensaios de oxidação química foi constatada a influência da variação do pH na remoção de microcistina, sendo que o aumento de eficiência foi associado à diminuição dos valores de pH. Foram observados indícios de remoção de trihalometanos pela flotação por ar dissolvido e redução da formação de trihalometanos quando a oxidação química foi feita com a associação do permanganato de potássio e cloro. / The aim of this research was to study the phytoplankton and microcystin removal at different treatment conditions, all based in coagulation, flocculation, dissolved air flotation and filtration, complemented by chemical oxidation applied at different points of the basic treatment sequency. The lab scale experiments was conduted with raw water prepared by a mixture of natural water, collected in Barra Bonita reservoir at São Paulo State, Brazil, and a high concentrated Microcystis culture prepared in laboratory. The microcystin concentration in raw water was kept in a range of 14 to 17 µg/L. Ferric chloride was used as coagulant, and, potassium permanganate and chlorine (sodium hypochlorite) were used as oxidants. The results showed phytoplankton removal efficiency about 99,9% by the sequency of coagulation, flocculation and dissolved air flotation, resulting a great removal of microcystin retained into the whole cells. The chlorine oxidation after filtration, as well as the oxidation with potassium permanganate and chlorine after dissolved air flotation, resulted in a microcystin removal of about 95% and concentrations under the World Health Organization drinking water guideline value of 1,0 µg/L. The raw water potassium permanganate oxidation associated with the chlorine oxidation after flotation, leaded to the best results concerning microcystin removal, with efficiency above 98%. All experimental conditions with chemical oxidation showed a relevant effect of the pH on the microcystin removal, the decrease of pH values contributed to the increase of microcystin removal. It was observed signs of THM´s removal by the dissolved air flotation and reduction of THM´s production when the chemical oxidation took place with the association of potassium permanganate and chlorine.