Dissertations / Theses on the topic 'Flotation waste'

This study was aimed at recovering lithium from china clay waste using a combination of froth flotation, magnetic separation, roasting and leaching. The china clay waste produced by Goonvean Ltd contains about 0.84% Li2O and 0.36% Rb2O, present in some of the mica minerals. Among the mica minerals, zinnwaldite is the major source of lithium with smaller amounts being contributed by muscovite. The results of the flotation tests showed that the dodecylamine collector dosage had a greater effect on the recovery and grade of mica minerals to concentrate than pH over the range tested. It was found that a mica concentrate containing 1.45% Li2O, 0.55% Rb2O and 4.47% Fe2O3 could be produced at a recovery of 98.6%, 85.2% and 92.8% respectively. Mineralogical analysis of the flotation products showed that the concentrate consisted mainly of muscovite, zinnwaldite and kaolinite with minor amounts of K-feldspar and quartz. The tailing consisted of mainly quartz, K-feldspar and kaolinite with minor amounts of apatite, topaz, zinnwaldite and muscovite. Further upgrading of the concentrate was found to be possible using a wet high intensity magnetic separator producing a magnetic fraction containing 2.07% Li2O, 0.74% Rb2O and 7.42% Fe2O3 with a recovery of 73%, 67% and 77% respectively. A mineralogical analysis of the separation products showed that the magnetic fraction consisted of predominantly zinnwaldite with muscovite as the main contaminant. The non-magnetic fraction consisted of muscovite and kaolinite as the main minerals while zinnwaldite, K-feldspar and quartz were subordinate. Electron-microprobe analysis on individual mica grains have shown that zinnwaldite and muscovite contain on average a calculated Li2O content of 3.88% and 0.13% respectively. Lithium extraction from the concentrate is only possible after the lithium has been converted into a water-soluble compound. Thus, in order to convert the lithium in concentrate into a water-soluble compound, the gypsum and limestone lithium extraction methods together with the new method of using sodium sulphate were investigated. The process involved roasting a predetermined amount of lithium-mica concentrate with either gypsum, limestone or sodium sulphate at various temperatures and subsequently leaching the pulverised materials in water at 85oC. A lithium extraction efficiency of about 84% was obtained using gypsum at 1050oC while rubidium extraction was very low at 14%. It was found possible to extract about 97% Li and 16% Rb if the concentrate was roasted with sodium sulphate at 850oC. Processing the concentrate with limestone resulted in very low lithium extraction. Iron co-extraction was low in all cases. The XRD analysis of the gypsum and sodium sulphate roast-products showed that the water soluble lithium species were KLiSO4 and Li2KNa(SO4)2 respectively. Preliminary tests on the leach solution obtained by using sodium sulphate as an additive have shown that a Li2O3 product with a purity of > 90% could be produced by precipitation with sodium carbonate although more work is required to reach the industrial target of > 99%. The lithium carbonate obtained with Li2CO3 content of about 90% is still suitable for use in the glass and ceramic industries, and as feedstock for the production of high-purity lithium compounds. An economic evaluation of the proposed lithium carbonate production plant has indicated an annual rate of return on the investment before tax of 7.2%.

Biosurfactants are compounds that exhibit surface activity (e.g., reduce surface and interfacial tension) and are derived from natural, biological sources. They are considered green substances due to their natural derivation, biodegradability, and relatively low toxicity. Biosurfactants from multiple classes have been shown to interact with metals, and a review of these interactions is provided. Rhamnolipids produced by Pseudomonas aeruginosa are attracting attention for metal remediation applications. The purpose of this dissertation is to evaluate rhamnolipids' ability to complex rare earth elements, determine the environmental compatibility of novel rhamnolipid diastereomers, and assess the efficacy of rhamnolipid as a collector in ion flotation. Previous research shows rhamnolipids selectively bind elements of environmental concern over common soil and water cations, but there had been no examination of transition metals from the f-block of the periodic table. The f-block elements include the rare earth elements, which are a vital component of nearly every modern technology and subject to supply risk. The interaction between monorhamnolipids and the rare earth elements was investigated by determining conditional stability constants using a resin-based ion exchange method. For the 27 metals examined, the conditional stability constants could be divided into three groups, albeit somewhat subjectively: weakly, moderately, and strongly bound. UO22+, Eu3+, Nd3+, Tb3+, Dy3+, La3+, Cu2+, Al3+, Pb2+, Y3+, Pr3+, and Lu3+are strongly bound with conditional stability constants ranging from 9.82 to 8.20; Cd2+, In3+, Zn2+, Fe3+, Hg2+, and Ca2+ are moderately bound with stability constants ranging from 7.17 to 4.10; and Sr2+, Co2+, Ni2+, UO22+, Cs+, Ba2+, Mn2+, Mg2+, Rb+, and K+ are weakly bound with stability constants ranging from 3.95 to 0.96. The uranyl ion is reported twice due to the ion demonstrating two distinct binding regions. The conditional stability constants were demonstrated to be an effective predictor of metal removal order. The metal parameters of enthalpy of hydration and ionic charge to radius ratio were shown to be determinants of complexation strength. Naturally produced rhamnolipids are a mixture of congeners. Synthetic rhamnolipid synthesis has recently enabled production of four monorhamnolipid diastereomers of a single congener. The biodegradability, acute toxicity (Microtox assay), embryo toxicity (Zebrafish assay), and metal binding capacity of the diastereomers was investigated and compared to natural monorhamnolipid. Biodegradability testing showed all the diastereomers were inherently biodegradable. By the Microtox assay, all of the monorhamnolipids were categorized as slightly toxic by Environmental Protection Agency ecotoxicity categories. Out of 22 parameters tested, the zebrafish toxicity assay showed only diastereomer toxicity for the mortality parameter, except for diastereomer R,R which showed no toxic effects. All the monorhamnolipids interacted with both Cd2+ and Pb2+. Ion flotation is one possible technology for metal recovery and remediation of metal contaminated waters. Ion flotation utilizes charged surfactants to collect and concentrate non-surface active ions at the surface of an aerated solution. Rhamnolipid's suitability as a collector in ion flotation was investigated. A flotation column was designed to test monorhamnolipid efficacy as a collector. Monorhamnolipids form foams and effectively remove Cs+, Cd2+, and La3+ from solution. The efficacy of the flotation process relies on the collector:colligend ratio and valency of the colligend. Flotation of metal solutions showed a removal order of Cd2+>La3+>>Cs+ when the metals were present individually and mixed at equimolar concentrations. When mixed at order of magnitude different concentrations, the flotation order was Cd2+>>Cs+>>La3+. These studies show rhamnolipid has potential to be used for environmentally-compatible metal recovery and metalliferous water remediation, especially for the rare earth elements.

Thesis (Ph.D.)--Chemical Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Hsieh, Jeffery; Committee Member: Breedveld, Victor; Committee Member: Empie, Jeff; Committee Member: Forney, Larry; Committee Member: Singh, Preet

The South African coal mining industry generates large volumes of coal ultrafine waste (< 150 microns) each year, with a significant amount being dumped in tailing slurry dams. These slurry dams have been associated with prolonged pollution and loss of valuable resources. In the two stage flotation process developed at the University of Cape Town, froth flotation is used to both recover coal (stage 1) and remove pyritic sulfur (stage 2) from ultrafine coal waste, resulting in three outputs streams: a saleable coal product, a small volume sulfide-rich stream, and a reduced volume sulfide lean tailings stream. Pre-disposal removal of sulfide sulfur and coal recovery by means of froth flotation is aimed at effectively removing the acid rock drainage (ARD) risk associated with sulfide bearing waste s and at recovering valuable resources respectively. Previous studies have demonstrated the technical feasibility of this process for a number of coal waste types on a laboratory-scale, with results indicating that it is possible to recover large quantities of useable coal whilst generating a tailings waste stream with a reduced sulfur content and negligible ARD risk. An order of magnitude financial model for a fictitious plant has also been developed, and applied to demonstrate the economic viability for s elected case studies. To date, however, studies on the environmental viability of the process have only focused on the ARD mitigating potential of the two-stage flotation process and little attention has been given to the systemic environmental implication s of the process such as the energy and reagent usage. The research study therefore aims to evaluate the environmental burdens and benefits of the two-stage flotation process, particularly from a South African context, and to compare the environmental performance to the conventional disposal of untreated coal ultrafines. Furthermore, this project aims to establish which stages along the process contribute the most to the environmental burdens of the process and how the variations of the input parameters affect the overall environmental performance of the proposed process. To this end, a life cycle inventory of inputs and outputs was compiled on the basis of the empirical results derived from a previous laboratory-scale case study conducted on a sample of an acid generating ultrafine coal waste from the Waterberg region. Experimental results from the case study, which entailed two-stage flotation (using Naflote 9858 as a coal collector and xanthate (SIBX) as a sulfide collector in stages 1 and 2), and detailed characterisation of the feed and desulfurised tailings, was supplemented with literature information and data from mass and energy balance calculations for a fictitious plant. An environmental impact analysis was subsequently conducted using a combination of Life Cycle Impact Assessment and risk-based impact assessment techniques and criteria. The impact categories selected included climate change, terrestrial acidification, fossil fuel depletion, natural land transformation, aquatic water pollution risk, drinking water quality risk, aqueous acidification, salinity and consumptive water footprint. Aquatic water pollution risk, drinking water quality risk and aqueous acidification impact indicators were calculated by summing up risk potential factors for the constituents of the final disposed waste streams. The rest of the impact categories were calculated by multiplying the inventory result with a characterisation factor developed from impact assessment models The case study results indicated that the simple mentation of the two-stage flotation process results in a notable decrease in eco-toxicity, salinity, consumptive water footprint, metal toxicity, aqueous acidification, fossil fuel depletion and natural land transformation impacts. However, the results al so indicated an increase in atmospheric related impacts (climate change and terrestrial acidification impacts), which has been attributed to the additional energy consumption associated with the two-stage flotation process and the production processes associated with the flotation reagents. Analyses of the process contributions to the individual impact categories for the two-stage flotation process revealed the climate change and terrestrial acidification impact categories to be dominated by the electricity production process and the flotation reagents production process. The sensitivity analyses revealed a higher dependence of the fossil fuel depletion impact category on the percentage coal yield than the electricity consumption of the foreground process. Furthermore the sensitivity analyses indicated a strong dependence of the climate change and terrestrial acidification impacts on the electricity consumption and the SIBX dosage in the foreground process. In the South African context, implementation the two-stage flotation process would result in a significant recovery of coal (approximately 1.2 million tonnes for every 4 million tonnes dry coal ultrafines lost per annum) and a sulfide-rich product which can be utilised for electricity production and sulfuric acid production respectively, hence promoting resource efficiency. Although higher than in the case of conventional land disposal, the energy used in the two-stage flotation process is infinitesimal compared to the energy recovered in the process through the generation of additional coal, and results in only a 0.025 % increase in the annual greenhouse gas emissions. The implementation of the two-stage flotation would also result in reduced water losses in comparison to conventional land disposal, which is beneficial in the South African context as South Africa is a water scarce region. Lastly whilst the implementation of the two-stage flotation process would result in the reduction of water related impacts associated with acidification, salinization and metal pollution, it might pose a further threat to aquatic life if the xanthate salt reagents are emitted to local water sources. The limitations of the study were mainly associated with the quality of the input and output data, the impact categories and the system boundary and scenario development. The multiple sources of information and the variations in literature of the energy input estimates were noted as a source of uncertainty. The lack of characterisation factors for some of the substances in the system as well as the exclusion of the possibility of utilization of the sulfide-lean stream were also part of the limitations associated with the study. Recommendations for future work include improving the environmental assessment by incorporating various case studies and by incorporating downstream processing as well as optimizing the two-stage flotation process by using less energy and by using less toxic flotation reagents.

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017.
In the recent past, the poultry industry in South Africa has grown due to an increased demand of poultry products as a result of population growth and improved living standards. Furthermore, this has led to poultry slaughterhouses generating high strength wastewater which is laden with a high concentration of organic and inorganic pollutants from the slaughtering process and sanitation of equipment and facilities. As a result, South Africa has promulgated restrictions and a set of quality standards for effluent discharged into the environment to minimize ecological degradation and human health impact. Hence, there is a need for improved Poultry Slaughterhouse Wastewater (PSW) pre-treatment prior to either discharge into municipal wastewater treatment plants (WWTP) or on-site secondary treatment processes such as anaerobic digesters. Additionally, amongst the pre-treatment methods for Fats, Oil and Grease (FOG) laden wastewater, flotation remains the most popular with Dissolved Air Flotation (DAF) system being the most applied. However, modelling and optimization of a biological DAF system has never been attempted before in particular for a bioflocculant supported DAF (BioDAF) for PSW pre-treatment. Process modelling and optimization involves process adjustment to optimize influential parameters. In this study, Response Surface Methodology (RSM) was used to develop an empirical model of a BioDAF for pre-treatment of PSW, for which a bioflocculant producer including production conditions, flocculant type and its floc formation mechanism, were identified. Twenty-one (n = 21) microbial strains were isolated from the PSW and their flocculation activity using kaolin clay suspension (4g/L) was quantified, with a mutated Escherichia coli (mE.coli) [accession number LT906474.1], having the highest flocculation activity even in limited nutrient conditions; hence, it was used for further analysis in other experiments. Furthermore, the optimum conditions for bioflocculant production achieved using RSM were pH of 6.5 and 36°C conditions which induced instantaneous bioflocculant production with the highest flocculation activity. The bioflocculant produced by the mE.coli showed the presence of carboxyl/amine, alkyne and hydroxyl functional groups, which was indicative that the bioflocculant contained both polysaccharides and some amino acids.

Numerous organic reagents of diverse structural composition are employed in the froth flotation process for the beneficiation of non-metallic and sulphide ores. Alkyl xanthates are used as collectors for sulphide ores while amines and fatty acids are used for non-metallic ore beneficiation. Although these collector reagents react preferentially with the concerned minerals in the treated ore pulp, excess and unreacted concentration of these organic collectors end up in the mill process effluents. It has been known that even small concentrations of these organic reagents in water streams are toxic to water life, besides their deleterious influence on end stream processes during recycling. Bioremediation has long been recognised as an inexpensive, flexible and environmentally benign technique for waste water treatment. These organic flotation reagents are amenable to biological degradation. The major objective of this work is the degradation of solubilized collector reagents from aqueous solutions using a microbial technique. Bacillus polymyxa, a Gram-positive, neutrophilic, periflagellated heterotroph that occurs indigenously in soils and certain mineral deposits has been used in the bioremediation studies. Organic flotation reagents namely, dodecyl ammonium acetate (DAA), which is used as a collector for oxides and silicates, sodium isopropylxanthate which finds application in sulphide flotation and sodium oleate, mainly used for oxide and salt-type minerals, have been chosen for the degradation studies. Pure minerals of galena, pyrite, magnetite, quartz and calcite have been typically selected for these investigations. The growth of Bacillus polymyxa in the presence of these organic reagents at different concentrations has been assessed and the degradation of these reagents monitored. Attempts have been made to grow the bacterium in the presence of the organic reagents, both in the absence and presence of sucrose, by adaptation technique. Electrokinetic studies on the chosen minerals namely, galena, pyrite, quartz, calcite and magnetite have been carried out both in the presence of the organic reagents and Bacillus polymyxa cells or metabolite. Biological stripping of the adsorbed collector reagents from the mineral surfaces have been examined through FTIR spectroscopy. The progress of bioremoval of the organic reagents along with the generation of newer reaction products has also been monitored through uv-visible spectroscopic technique. The results of this study highlight that Bacillus polymyxa and its metabolic products bring about the degradation of the chosen organic flotation collectors. Further, the bacteria are able to utilise the collector reagents as carbon source for their growth, in the absence of added organic carbon (sucrose). Electrokinetic studies and examination by FTIR spectroscopy reveal that consequent to interaction with Bacillus polymyxa, significant surface modification on the mineral takes place. Probable mechanisms in the biodegradation processes are illustrated. Biological metabolic products responsible for bringing about the bio-deterioration have been analysed and characterised.

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016.
Poultry slaughterhouse wastewater (PSW) contains organic matter that can be degraded by microorganisms. Such matter can further be used by the microbial community as a nutrient source for growth. Moreover, this type of wastewater also contains a high quantity of particulate matter, lipids and proteins, including antimicrobial compounds such as triclosan (TCS) and trichlorocarbanilide (TCC) used during cleaning and sanitising of processing facilities. Lipids and particulate matter lead to clogging of pipes and fouling of diffusers in the wastewater treatment plants (WWTPs). To overcome this problem, a pre-treatment system such as a dissolved air flotation system (DAFs) in which synthetic flocculants are used, is commonly used prior to the biological treatment of the wastewater. Synthetic flocculants add to the environmental burden associated with the use of synthetic compounds, particularly when these compounds are used in WWTPs. This study focused on the reduction of suspended solids, lipids and proteinaceous matter using a bioflocculant- supported DAF for the treatment of PSW.

This paper is about the studies carried out to analyze the feasibility of using an innovative treatment system in the primary treatment process for municipal waste water. Furthermore, experiments are conducted to analyze the optimal parameters for utilizing the treated waters for irrigation purposes and for biogas production from the recovered sludge. The work is carried on the incoming municipal wastewater from Hammarby locality with around 30,000 inhabitants. Chemicals used in this process are, a metal salt namely polymerized aluminum chloride (PAX XL36) and two flocculation chemicals namely, a high molecular weight polymer (HM) (SNF Nordfloc C-192) and a low molecular weight polymer (LM) (Purfix 120). The choice of these chemicals was based on the recommendations made by previous studies on flocculation chemicals. These chemicals aid in flock formation and the DAF unit which provides compressed air, aids in flock flotation. The study is focused on optimizing parameters which implies minimal usage of chemicals and aimed to attain maximum sludge production with best possible treated water quality. All the experiments have been carried out on a pilot scale unit, designed with required specifications and with the foresight to scale up into a large scale unit based on the results. These are obtained by performing a series of analysis specifically formulated for this study. In laboratory experiments were carried out to analyze COD (chemical oxygen demand), Ammonium, Nitrate, Total nitrogen and phosphorus using Dr. Lange cuvettes. As the prime focus is on reuse of the treated water for irrigation purpose and biogas production, all the parameters are modulated in accordance with the standard water quality prescriptions for the water to be used for irrigation. In accordance with the climatic conditions of the region, various parameters are modulated in such a way that in summers the outcome water quality is emphasized and maximization of sludge/organic matter is emphasized during winter season.

The aim of this project is to investigate the feasibility of the use of a novel process of high liquid carryover (HLC) mode flotation to treat wastewater from a cardboard printing and coating plant. This is conducted by characterising the process conditions with the purpose of achieving a set condition that have a low susceptibility to variability in the wastewater composition. Information pertaining to the surface and physical characteristics of the solid contained in the wastewater sample were used to explain the flotation outcomes. Fe(II) was found to be more suited for industrial use as coagulant over the more commonly known coagulants, Al(III) and Fe(III), as it has the advantages of having a constant optimum flotation pH (6.5) regardless of wastewater characteristics, as well as having a much lower detrimental effect on the flotation outcome when present in excess of the minimum requirement for flocculation of wastewater solids. This allows the setting of a coagulant dose (5 mM) that will treat both high and low solids content wastewater samples. The use of cationic surfactant (CTAB) was found to require lower coagulant dosages compared to those required for anionic (SDS) or non-ionic (TericG12A8) surfactants in order to achieve good flotation outcomes. A CTAB concentration of 300 ppm was required to achieve a stable foam that can sustain for a prolonged period to allow solid (in foam)/liquid separation. The optimum batch mode conditions for HLC flotation were found to be pH 6.5, 5 mM Fe(II) and 300 ppm CTAB. This was found to correspond to a small and negative electrophoretic mobility at the wastewater solid surface and large floc size. Batch mode flotation of individual ink components under the optimum conditions for industrial wastewater treatment revealed that the presence of large quantities of either blue or yellow inks in the wastewater can lead to poor removal. Their combined presence, however, did not have detrimental effects. Continuous mode flotation at 5 mM Fe(II), 300 ppm CTAB and pH 6.5 was found to remove above 96% of contaminants at cell residence times of 6 minutes and 88% of contaminants at cell residence times of 1.5 minute. Greater than 87% of the initial wastewater volumes were recovered as treated effluent (i.e. < 13% disposed as waste foam sludge), yielding a waste foam sludge containing between 12 and 17% solids. The best flotation outcomes were achieved when all the wastewater volume entering the flotation cell leaves the cell with the foam.

Os principais impactos ambientais causados pelas indústrias de laticínios estão relacionados ao lançamento dos efluentes líquidos, geralmente sem nenhum tipo de controle ou tratamento. O efluente lácteo é caracterizado pelo elevado teor de matéria orgânica, sendo de fundamental importância a implementação de técnicas de tratamento eficazes e de baixo custo. O presente trabalho tem como objetivo avaliar o desempenho de uma coluna de flotação operando em batelada para o pré-tratamento de um efluente lácteo. A primeira etapa consistiu em investigar os processos de floculação/sedimentação e flotação de um efluente lácteo sintético em seu ponto isoelétrico. Este foi preparado pela adição de leite em pó à água, sob agitação mecânica, de maneira a obter-se uma suspensão homogênea. Foi utilizada uma concentração de leite de 6,5% (p/v), visando simular as características de um efluente real. A condição ótima de floculação foi determinada através do teste de jarro pela adição de uma solução aquosa de HCl na proporção de 1:10 (v/v). Testes de sedimentação da suspensão na condição ótima de floculação foram realizados em duplicata por meio da observação do deslocamento da altura de flocos em função do tempo. A densidade dos flocos foi avaliada por meio da técnica de centrifugação e o diâmetro dos flocos foi determinado de acordo com equações que descrevem a fluidodinâmica de sistemas floculentos. O ensaio de flotação foi realizado em uma coluna operando em batelada. A condição ótima de floculação foi observada a pH 4,0, sendo obtida uma eficiência de recuperação dos flocos de 88% no teste de jarro. Os ensaios de sedimentação demonstraram que após cerca de 15 minutos os flocos já atingiam a região de compactação, sendo observada uma estabilização da altura do sedimento. A velocidade máxima de sedimentação observada foi semelhante para ambos os experimentos, com valores de 0,97 cm/min e 0,84 cm/min. A densidade e o diâmetro médio dos flocos foram de 1,0160,012 g/cm3 e 275 mm, respectivamente, e o percentual de recuperação dos sólidos foi de 93%, demonstrando a eficiência do processo de floculação/sedimentação para o tratamento primário de efluente lácteo sintético floculado. Por outro lado, a flotação não foi satisfatória, sendo observada a sedimentação dos flocos na coluna de flotação. Na segunda etapa do trabalho foi utilizado um efluente lácteo industrial (soro de queijo), obtido de uma pequena indústria localizada no Agreste pernambucano. A caracterização físico-química do efluente foi realizada em termos do teor de proteínas, cinzas, lipídios, carboidratos e pH. O efluente apresentou aproximadamente 5 g/100mL de carboidratos, 0,8 g/100mL de proteínas e 0,6 g/100mL de lipídios e um pH igual a 5,0. Não foi possível a observação visual de formação de flocos variando-se o pH da suspensão entre 2,5 e 5,5. Um Vilar, A.C. Utilização da flotação em coluna para o tratamento de efluente da indústria Láctea planejamento fatorial foi empregado para avaliar a eficiência da coluna de flotação na remoção da DQO do efluente, tendo como variáveis o pH e a vazão de ar do sistema. A máxima remoção de DQO (70%) foi atingida para uma vazão de ar de 1.362 mL/min, enquanto que o pH não apresentou-se como uma variável significativa. A eficiência de flotação atinge 76% na presença de um floculante catiônico a uma concentração de 0,1%. O efluente apresentou baixa hidrofobicidade, ponto isoelétrico a pH 4,0 e diâmetro médio de partícula de 0,43 mm. Os dados experimentais foram ajustados de maneira satisfatória a um modelo cinético de primeira ordem
The main environmental impacts caused by the dairy industries are related to discharge of liquid effluents, usually without any kind of control or treatment. The dairy effluent is characterized by high content of organic matter, being important the implementation of techniques for its effective treatment and low cost. This study aims to evaluate the performance of a flotation column operating in batch for the pre-treatment of a dairy effluent. The first step was to investigate the processes of flocculation / sedimentation and flotation of a synthetic dairy effluent in the isoelectric point. This was prepared by the addition of milk powder to water under mechanical stirring, to obtain a homogeneous suspension. It was used a milk concentration of 6.5% (w/v), aiming simulate the characteristics of a real effluent. The optimal condition of flocculation was determined using a jar test by the addition of an aqueous solution of HCl 1:10 (v/v). Settling tests using the flocculated suspension were performed in duplicate through the observation of the displacement of flocs along the time. Flocs density was evaluated through centrifugal technique and the flocs diameter was determined according equations that describe the flocculent systems fluidodynamic. Flotation test was carried out in a column operating in batch. The optimal condition of flocculation was observed at pH 4.0, with a flocs recovery efficiency of 88% in the jar test. Settling tests showed that after 15 minutes flocs had already reached the compactation region, being observed a stabilization of the sediment height. Settling maximum velocity was similar for both experiments, with values of 0.97 cm/min and 0.84 cm/min. Density and flocs diameter were 1,0160,012 g/cm3 and 275 mm, respectively, and the solids recovery efficiency was 93%, demonstrating the efficiency of the flocculation/sedimentation process for primary treatment of a flocculated synthetic dairy effluent. Moreover, flotation was not satisfactory, with a effluent sedimentation in the flotation column. In the second stage of work was used an industrial dairy effluent (obtained from cheese processing) from a small industry located in the agreste region of Pernambuco State. Physical-chemical characterization of effluent was made to determine the contents of protein, ash, lipids, carbohydrates and pH. The effluent had approximately 5 g/100mL carbohydrates, 0.8 g/100mL of proteins and lipids of 0.6 g/100mL and pH 5.0. The visual observation of flocs formation in the range pH 2,5 to pH 5,5 was not possible. A factorial design was used to evaluate the efficiency of the flotation column to remove the COD content, and the variables investigated were pH and air flow. The maximum removal of COD (70%) was achieved for an air flow of 1.362 mL/min, while pH was not statistically significant. Flotation efficiency reaches 76% in the presence of a flocculating agent in a concentration of 0.1%. The effluent showed low hydrophobicity, isoelectric point at pH 4.0 and mean particle diameter of 0.43mm. Experimental data were fitted satisfactorily to a first-order kinetic model

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Neste trabalho foram efetuados estudos de depressores na flotação de uma amostra de finos de minério sílico-carbonatado de manganês (estocados como rejeito) da Unidade Morro da Mina / RDM, localizada em Conselheiro Lafaiete-MG. Foram realizados testes de microflotação em tudo de Hallimond modificado, curvas de potencial zeta dos minerais puros na presença e ausência de reagentes e ensaios de flotação em bancada com amostra do resíduo do minério deslamado. Os reagentes estudados foram: fluorsilicato de sódio, metasilicato de sódio, amido de milho, dextrina branca e alguns tipos de quebracho (Floatans T0, T1, T5 e M3) utilizando-se oleato de sódio como coletor. A eficiência dos depressores testados na microflotação em relação à seletividade para a separação do quartzo dos minerais de manganês foi: floatan M3 > floatan T1> fluorsilicato de sódio > metassilicato de sódio > amido de milho > floatan T0 > dextrina > floatan T5. Os pontos isoelétricos dos principais minerais de Mn e ganga presentes neste minério foram determinados: rodonita (pH 2,8), rodocrosita (pH 10,5) e quartzo (pH 1,8). O estudo da adsorção que caracteriza a interação dos reagentes com as superfícies dos minerais mostrou ser de caráter específico. Os depressores mais eficientes na flotação em bancada entre os minerais de Mn e de ganga foram: floatan M3, floatan T1 e fluorsilicato de sódio, onde foram obtidos concentrados com teores de Mn, SiO2 e Al2O3 de aproximadamente 30, 17 e 10 %, respectivamente, para os três depressores testados. No entanto, a recuperação metalúrgica de Mn foi de 72,5 % para o floatan M3, 51 % para o floatan T1 e 45,2 % para o fluorsilicato de sódio. Posteriormente, efetuaram-se estudos preliminares de calcinação desse minério deslamado. O mais alto teor de Mn encontrado foi de aproximadamente 30 % com perda de massa de 11,2 % para temperatura de 1000 °C. ____________________________________________________________________________________________________
ABSTRACT: Flotation depressants were studied from silicate-carbonate manganese ore samples (waste) at RDM – Morro da Mina, in Conselheiro Lafaiete – MG, Brazil. Micro-flotation tests were conducted in a modified Hallimond cell, also zeta potential curves for pure minerals in the presence or lack of reagents and bench-scale flotation tests for deslimed ore waste sample. The following reagents were studied: sodium fluorosilicate, waterglass, starch, white dextrin, some quebracho kinds (Floatans T0, T1, T5 e M3) and sodium oleate as a collector. The efficiency of the depressants during the micro-flotation regarding the selection for separation of quartzo from manganese mineral was as it follows: floatan M3> floatan T1> sodium fluorosilicate > waterglass > starch > floatan T0 > dextrin > floatan T5. The isolectric points (pl) of the main ore were also determined as rhodonite (pH 2.8), rhodochrosite (pH 10.5) and quartz (pH 1.8). The adsorption test, characterized by the interaction of reagents and mineral surfaces, indicates its specific nature. The most efficient depressants in bench-scale flotation test among Mn ore and ganga were floatan M3, floatan T1 and sodium fluorosilicate containing Mn, SiO2 and Al2O3 concentrations of approximately 30, 17 and 10%, respectively, for all depressants herein mentioned. However, the metallurgical recovery for Mn was 72,5 % when using floatan M3, 51 % for floatan T1 and 45,2% for sodium fluorosilicate. Furthermore, calcination preliminary studies were conducted and the highest concentration of Mn found was approximately 30%, with an 11.2% weight loss for a 1000°C temperature.

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The high productivity in the breeding of shrimp makes it necessary to approach some aspects to their sustainability, particularly the aquatic environment of the nursery. Thus, the treatment of effluents originating from the shrimp becomes of fundamental importance, considering the need to minimize the environmental impacts generated by this productive activity. This study investigates the uses of flotation types of column and dissolved air to the treatment of shrimp effluent. The effluent used was from the farm Tabatinga, located on the north coast of Pernambuco State. Was performed physical-chemical and microbiological characterization of effluent being obtained parameters consistent with those found in the literature. A column flotation bench was used in experimental trials, being employed an experimental design with two variables (pH and air flow) to evaluate the removal of turbidity of the effluent. The effect of adding a flocculant was also investigated. The FAD cell experiments were performed with pressure values of 3 and 6 bar, and a pH of 5.8 and 9.8, and additional experiments were performed using an anionic collector. The results of column flotation for the effluent from the beginning of culture showed that the turbidity decreases with increasing air flow and the decrease in pH after 40 minutes of the proceedings, was obtained as best fit a linear model with interaction. The presence of flocculant concentration of 0.1% (p / v) at pH 7.8 showed a removal of turbidity of only 25% for the condition of lower air flow. For the treatment of effluent from the end of cultivation, the turbidity removal also increased with increasing air flow and with decreasing pH, reaching a maximum removal of about 40% after 35 minutes of the proceedings, with an adjustment quadratic model. In dissolved air flotation effluent end of the cultivation, the highest percentage of turbidity removal were obtained at pH 5.8, reaching values of 52 and 47% for operating pressures of 3 and 6 bar, respectively. In the presence of an anionic collector, there was an increase in the removal of turbidity values between 56 and 65%.
A elevada produtividade nos criadouros de camarão torna necessária a abordagem de alguns aspectos para sua sustentabilidade, principalmente do ambiente aquático dos viveiros. Dessa forma, o tratamento de efluentes originados da carcinicultura torna-se de fundamental importância, considerando a necessidade de minimizar os impactos ambientais gerados por essa atividade produtiva. O presente trabalho investiga os usos das flotações dos tipos por coluna e ar dissolvido para o tratamento de efluentes da carcinicultura. O efluente utilizado foi proveniente da fazenda Tabatinga, localizada no litoral norte do Estado de Pernambuco. Foi realizada a caracterização físico-química e microbiológica dos efluentes, sendo obtidos parâmetros condizentes com os encontrados na literatura. Uma coluna de flotação de bancada foi utilizada nos ensaios experimentais, sendo empregado um planejamento experimental com duas variáveis (pH e vazão de ar) visando avaliar a remoção de turbidez do efluente. O efeito da adição de um floculante(Bozefloc CE 340 líquido) também foi investigado. Os experimentos em célula FAD foram realizados com valores de pressão de 3 e 6 bar, e pH de 5,8 e 9,8, e experimentos adicionais foram realizados utilizando um coletor aniônico. Os resultados de flotação em coluna para o efluente do início do cultivo demonstraram que a turbidez diminui com o aumento da vazão e com a diminuição do pH após 40 minutos de processo, sendo obtido como melhor ajuste um modelo linear com interação. A presença do floculante na concentração de 0,1% (p/v) a pH 7,8 demonstrou uma remoção de turbidez de apenas 25% para a condição de menor vazão de ar. Para o tratamento do efluente do fim do cultivo, a remoção de turbidez também aumentou com o aumento da vazão de ar e com a diminuição do pH, atingindo um valor máximo de remoção de cerca de 40% após 35 minutos de processo, com um ajuste quadrático do modelo. Na flotação por ar dissolvido do efluente do fim do cultivo, os maiores percentuais de remoção de turbidez foram obtidos a pH 5,8, atingindo valores de 52 e 47% para pressões de operação de 3 e 6 bar, respectivamente. Na presença de um coletor aniônico(Flomin-C-5435), observou-se um aumento na remoção da turbidez para valores entre 56 e 65%.

Capes
A indústria de laticínios utiliza grande quantidade de água para sua produção, em consequência deste fato, gera proporcionalmente elevadas quantidades de efluentes em suas atividades. As águas residuárias dos processos envolvidos em laticínios, possuem alta carga de matéria orgânica e de nutrientes como nitrogênio e fósforo. Os Sistemas Alagados Construídos (SAC) são uma opção de baixo custo de manutenção e operação, além de serem eficazes em sistemas de tratamento de efluentes. Desta forma, foi construído um sistema alagado construído de fluxo vertical, com fundo saturado em escala piloto em uma indústria de laticínios no município de Londrina. As dimensões do SAC foram de 0,6 x 1,7 x 2,6 m, preenchido com substrato de brita 0 (perfil de 0,20 m), 1 (perfil de 0,25 m) e 2 (perfil de 0,15 m) de forma descendente. O tempo de detenção hidráulico utilizado para dimensionamento de 3 dias com taxa de irrigação média de 60 L.d-1.m-2. Utilizou-se a planta Cyperus papyrus para realizar o tratamento do efluente de laticínio proveniente do flotador por ar dissolvido (FAD) da indústria, que removia a alta carga orgânica presente no efluente. As variáveis estabelecidas para este trabalho foram cor aparente, turbidez, demanda química de oxigênio (DQO), pH, condutividade elétrica, alcalinidade, série de sólidos, nitrogênio total (NTK) e fósforo total. Cartas de controle foram utilizadas para verificar se o processo estava sob controle estatístico. No FAD, as variáveis que estiveram sob controle foram o fóforo, sólidos totais, sólidos dissolvidos e sólidos suspensos; no SAC foram a condutividade elétrica, turbidez, DQO, e sólidos suspensos. O índice de capacidade de processo (Cp) foi aplicado aos parâmetros de pH, DQO, fósforo total, NTK e sólidos suspensos para verificar se o tratamento foi capaz de atender aos padrões de lançamento especificados pela legislação ambiental. As variáveis capazes de atender a legislação foram o pH e os sólidos suspensos. Ensaios hidrodinâmicos do SAC foram realizados ao longo do processo de tratamento para avaliar a vazão e a colmatação durante o experimento. Não foi constatada colmatação no SAC. Também foi avaliado o crescimento das plantas no meio filtrante como efluente tratado advindo do FAD. Pode-se averiguar que as macrófitas se adaptaram ao sistema com um crescimento adequado. Os resultados obtidos de eficiência do SAC permitem concluir que o sistema é capaz de remover a matéria orgânica após o FAD, porém não apresenta controle de processo nas demais variáveis analisadas.
The dairy industry uses a large amount of water for its production. As a consequence, it generates proportionally high amounts of effluent in its activities. Wastewater from processes involved in dairy products has high organic matter and nutrients such as nitrogen and phosphorus. Constructed Alachate Systems (SACs) are a low-cost option for maintenance and operation, as well as being effective in effluent treatment systems. In this way, a flood system was installed, built with a vertical flow, with a saturated bottom on a pilot scale in a dairy industry in the city of Londrina. SAC dimensions were 0.6 x 1.7 x 2.6 m, filled with substrate gravel 0 (profile of 0.20 m), 1 (profile of 0.25 m) and 2 (profile of 0, 15 m) in descending order. The hydraulic detention time used for 3-day sizing with an average irrigation rate of 60 L.d-1.m-2. The Cyperus papyrus plant was used for the treatment of the dairy effluent from the float by dissolved air (FAD) of the industry, in order to remove the high organic load present in the effluent. The variables established for this work were apparent color, turbidity, chemical oxygen demand (COD), pH, electrical conductivity, alkalinity, solids series, total nitrogen (NTK) and total phosphorus. Control charts were used to verify if the process was under statistical control. In the FAD, the variables that were under control were the phosphorus, total solids, dissolved solids and suspended solids; In SAC were the electrical conductivity, turbidity, COD, and suspended solids. The process capacity index (Cp) was applied to the pH, COD, total phosphorus, NTK and suspended solids parameters to verify if the treatment is able to meet the release standards specified by the environmental legislation. The variables capable of complying with the legislation were pH and suspended solids. SAC hydrograph tests were carried out along the treatment process to evaluate the flow and the filling during the experiment, without verification of the sealing process in the SAC. The growth of the plants in the filter medium as treated effluent from FAD was also evaluated. It can be verified that macrophytes have adapted to the system with adequate growth. The results of SAC efficiency allow to conclude that the system is able to remove organic matter after FAD, but does not present process control in the other analyzed variables.

Caixas de gordura são dispositivos para retenção de material gorduroso, de origem animal e vegetal, proveniente de pias de cozinha. Sua instalação é exigida por muitos municípios para liberação de ligações de esgoto, visando reduzir as concentrações de óleos e graxas (OG) lançadas no sistema público de coleta e tratamento. Um fator primordial para que estas caixas cumpram suas funções é o estabelecimento de rotinas de manutenção envolvendo inspeção e limpeza periódica. A instalação de locais para recebimento e pré-tratamento dos resíduos retirados das caixas de gordura pode incentivar boas práticas de operação e manutenção destes dispositivos. Diante disso, os objetivos desta pesquisa contemplam a caracterização de resíduos acumulados em caixas de gordura e a avaliação da flotação como alternativa para o seu pré- tratamento, seguido de caracterização do óleo extraído da escuma produzida no flotador. Para tanto, materiais acumulados em caixas de gorduras de fontes distintas foram caracterizados, possibilitando observar grande variação em sua composição, e elevadas concentrações de DBO, DQO, SST e OG. Para verificar o desempenho da flotação visando à redução de OG no efluente pré-tratado, foram realizados ensaios em bancadas e testados quatro produtos químicos coagulantes, sendo eles o PAC, o cloreto férrico, o tanino e o polímero catiônico. Todos apresentaram eficiências elevadas na remoção de OG, porém o produto que apresentou mais vantagens na aplicação foi o polímero. Utilizando o polímero, foram realizados ensaios para verificação do desempenho de várias dosagens associadas a três pH de coagulação diferentes e o melhor desempenho se deu com a aplicação de 30 mg/L de polímero combinada ao pH 4,3, natural da amostra. Foram também realizados ensaios utilizando diferentes relações A/S (7,5/1000, 15/1000 e 22/1000 gar/gsólidos),obtendo-se melhores remoções de OG com a utilização da relação 22/1000 gar/gsólidos. Os materiais flotados obtidos nos ensaios de avaliação da relação A/S foram caracterizados e apresentaram concentrações de ST entre 9,7 e 10,6% e de OG entre 6,1 e 6,7%. Baseado nos resultados obtidos a flotação mostra-se como alternativa com bom desempenho para o pré- tratamento dos resíduos estudados. Para avaliar a dificuldade do manuseio dos resíduos provenientes de caixas de gordura, uma planta piloto foi operada, e entre as principias dificuldades observadas estão o odor intenso, a necessidade de remoção de sólidos grosseiros e de homogeneização do resíduo no tanque de equalização. Visando reaproveitamento do resíduo flotado, foi realizada a extração do óleo com solvente de uma amostra deste material (com teor de sólidos de 8,86%), obtendo a recuperação de 30g óleo/L resíduo com acidez de 13,76 mg KOH/L. A elevada acidez indica a necessidade de purificação, se o objetivo for a produção de biodiesel.
Grease traps are devices that retain animal and vegetal fatty material from kitchen sinks. Many municipalities demand its installation in order to connect house wastewater to the public network, aiming to reduce fat, oil and grease concentration in the collecting and treatment systems. The establishment of maintenance schedule involving inspection and periodic cleaning is a key factor to the right functioning of the device. The existence of appropriated sites to receive and pretreat grease trap wastes may stimulate good practices on maintenance and operation of these devices. In this direction, the objectives of this research are the characterization of grease trap wastes and the evaluation of flotation as an alternative for its pretreatment, followed by characterization of the oil extracted from the scum formed at flotator. Therefore, grease trap wastes from different sources were collected and characterized. It could be observed a wide variation on its composition and high concentrations of BOD, COD, TSS and FOG. Lab scale tests were performed to assess flotation performance to reduce pretreated effluent FOG using four chemical coagulants: PAC, ferric chloride, tannin and cationic polymer. All of them achieved high efficiency on FOG removal, however the product that presented more advantages on application was polymer. More tests were performed using several dosages of polymer associated to three pH coagulation conditions. The combination that resulted in the best efficiency was 30 mg/L of polymer combined to pH 4.3, samples natural pH. Different A/S ratios were also tested (7.5/1000, 15/1000, 22/1000 gair/gsolids), the ratio 22/1000 gair/gsolids presented the best FOG removal efficiencies. Floated material from A/S ratio tests were characterized and presented TS concentrations between 9.7% and 10.6% and FOG was from 6.1% to 6.7%. Based on the obtained results, flotation appears as a high performance alternative for the pretreatment of studied wastes. A pilot plant was operated to evaluate problems related to grease trap waste handling. The main problems were: bad odor, the need of screening and waste homogenization in equalization tank. Aiming to reuse the floated waste, oil was extracted from a sample (8.86% solid content) using solvent, achieving the recovery of 30g oil/L waste with 13.76 mgKOH/L acidity. The high acidity points to the need of purification if biodiesel production is intended.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A primeira etapa do presente trabalho consistiu em caracterizar um efluente lácteo industrial (soro de queijo) em termos microbiológicos e físico-químicos visando à obtenção de um consórcio de microrganismos para a sua biodegradação. Foram determinadas a contagem padrão de bactérias heterotróficas e a contagem de fungos filamentosos e leveduras de acordo com as metodologias oficiais, e a caracterização físico-química foi realizada em termos do teor de proteínas, cinzas, lipídios, carboidratos, pH e demanda química de oxigênio (DQO). O consórcio microbiano foi obtido em biorreator operando em batelada e contendo 1,5L do efluente, a 200rpm, aeração de 1vvm e temperatura de 28 - 30oC. Os cultivos foram realizados em duplicata durante onze dias, sendo realizado um pulso de 150mL do efluente (10% do volume útil do biorreator) no sétimo dia do cultivo. Foram obtidas concentrações iniciais de 3x109UFC/mL e 8x104UFC/mL para contagem total de bactérias e de fungos e leveduras, respectivamente. O efluente apresentou uma DQO inicial de 64.000mgO2/L, pH 5,0, e concentrações correspondentes a 5g/100mL de carboidratos, 0,8g/100 mL de proteínas e 0,6g/100 mL de lipídios. Os cultivos do efluente no biorreator demonstraram um aumento da concentração de bactérias ao longo do tempo, atingindo 1x1013UFC/mL após oito dias, enquanto que as concentrações de fungos filamentosos e de leveduras foram inibidas. Foi observada uma redução da DQO de 47 a 63,5% após 11 dias de cultivo, demonstrando a potencialidade da utilização do consórcio microbiano no tratamento do efluente. Ensaios qualitativos demonstraram a presença das enzimas: lipase, amilase, protease e celulase no extrato metabólito do consórcio microbiano. No entanto, foram obtidos baixos valores de atividade lipolítica quando comparados com a atividade da enzima comercial, sendo observado ainda que a atividade decresce ao longo do tempo. Na segunda etapa do trabalho foi avaliada a hidrólise enzimática de material flotado, obtido a partir do processo de flotação em coluna do efluente, utilizando a técnica de planejamento de experimentos. Inicialmente, foi avaliado o desempenho de uma lipase comercial (lipolase), sendo investigados os efeitos da agitação e da concentração de enzima sobre a hidrólise. Foi realizada a análise estatística considerando os efeitos significativos para um nível de confiança de 95%. Concentrações maiores de enzima dentro da faixa investigada (1 a 7%) maximizam a hidrólise de óleos e gorduras do material flotado, bem como para níveis de agitação entre 100 e 150rpm. Em todos os experimentos houve a liberação de ácidos graxos no meio em percentuais próximos a 100% apenas após 4 horas de reação. Vale salientar ainda que percentuais de liberação de ácidos graxos superiores a 92% foram obtidos para toda a faixa de concentração testada. Uma agitação de 150rpm foi utilizada em um segundo planejamento experimental, avaliando-se a concentração da enzima comercial associada a um consórcio microbiano, sendo verificado que a adição do consórcio não influenciou de maneira positiva o aumento do teor de ácidos graxos livres no meio.
The first step of the present work was characterizing a dairy effluent in terms microbiological and physical-chemical used to obtain a microbial consortium for its biodegradation. Microbiological characterization was performed by total heterotrophic bacteria, filamentous fungi and yeasts count according to the official methodologies. Physical-chemical characterization was accomplished by content of protein, ash, lipids, carbohydrates, pH and chemical oxygen demand (COD). Microbial consortium was obtained in batch using a bioreactor containing 1,5L of dairy effluent, at 200 rpm, 1vvm, at 28 - 30oC. Cultivations were performed in duplicate for eleven days, being applied a pulse of 10% (v/v) of effluent on the seventh day of the experiment. Cellular growth kinetics, chemical oxygen demand concentration and lipolytic activity were determined. Initial concentrations of bacteria and fungi and yeasts were equal to 3x109CFU/mL and 8x104CFU/mL, respectively. Effluent presented a COD of 64.000mgO2/L, pH 5,0 and concentrations of 5g/100mL of carbohydrates, 0,8g/100mL of protein and 0,6g/100mL of lipids. Cultivations showed an increase on the bacteria concentration, reaching 1x1013CFU/mL after eight days, while filamentous fungi and yeast concentrations were inhibited. An reduction of COD concentration in the range of 47 to 63,5% was observed after eleven days of cultivation, demonstrating the potentiality of use of microbial consortium for effluent treatment. Qualitative assays showed the presence of the enzymes lipase, amylase, protease and cellulase in the metabolic extract of the microbial consortium. However, low values of lipolytic activity were obtained as compared to the commercial enzyme, being observed that activity decreases along time. In the second step of this study, was evaluated the enzymatic hydrolysis of floated material, obtained from the column flotation of a dairy industry, using the technique of experimental design. Initially, performance was evaluated by a commercial lipase (lipolase), being investigated the effects of agitation and enzyme concentration on hydrolysis. A statistical analysis was performed considering the significance of effects to a confidence level of 95%. Higher enzyme concentrations in the range investigated (1 to 7%) maximize the hydrolysis of oils and fats in the floated material, and to agitation levels between 100 and 150rpm. In all experiments, fatty acids were released in rates near to 100% only after 4 hours of reaction. Moreover, rates of released fatty acids were greater than 92% in all the concentration range tested. An agitation of 150rpm was used in a second experimental design, evaluating the concentration of commercial enzyme associated with a microbial consortium. The kinetic monitoring of the process showed that the addition of the consortium did not influence in a positive manner the increase the content of free fatty acids.

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Universidade Federal do Paraná. Campus de Palotina
Nowadays, much has been said about global warming and its possible causes, but the scientific consensus identifies increased levels of greenhouse gases produced by human activity as the main influence. One alternative to reduce emissions of greenhouse gases is to replace fossil fuels with renewable sources such as biodiesel. The process of biodiesel production is composed of the following steps: preparation of raw material, the transesterification reaction, phase separation, recovery and dehydration of alcohol, glycerine distillation and purification of this renewable fuel, with the byproduct glycerin and water as waste purification. Since, for each 100 liters of biodiesel, 10 kg of crude glycerin are produced, generating on average 60 liters of wastewater. Therefore, studying alternatives to the use of glycerin and economically viable treatment of wastewater has become an important aspect of this production chain. In order to meet these assumptions, this thesis is structured in two chapters. In Chapter 1, we tackle the treatment of wastewater from biodiesel production system in dissolved air flotation (DAF), which was tested in two coagulants (aluminum sulfate and ferric chloride) and two auxiliary of flocculation (polifloc and tanfloc). The experiment was conducted at the Laboratory of Environmental Sanitation of the State University of Paraná, using a Jar Test adapted for testing of flotation. The combination showed better efficiency in the clarification of the effluent to remove color and turbidity and also better efficiency in removing oil and grease and COD was combined with aluminum sulfate polifloc synthetic polymer at pH 6 and recirculation rates of 15%. In Chapter 2 we studied the production of methane in anaerobic co-digestion of glycerin and swine wastewater. During the process tested the increment in biogas production and methane with increasing initial organic load, performed by the addition of glycerol as substrate. The experiment was conducted at the Technical University of Lisbon/ Institute of Agronomy, in a complete mix anaerobic reactor of laboratory scale. The addition of glycerol in the ratio of 3% v / v proved effective in increasing the production of methane.
Nos dias atuais, muito se tem falado sobre o aquecimento global e suas possíveis causas, mas o consenso científico identifica os níveis aumentados de gases de efeito estufa produzidos pela atividade humana como a principal influência. Uma das alternativas para se reduzir as emissões de gases-estufa é substituir os combustíveis fósseis por fontes renováveis, como o biodiesel. O processo de produção de biodiesel é composto das seguintes etapas: preparação da matéria-prima, reação de transesterificação, separação de fases, recuperação e desidratação do álcool, destilação da glicerina e purificação desse combustível renovável, tendo como subproduto a glicerina e como resíduo água de purificação. Uma vez que, para cada 100 L de biodiesel são produzidos 10 kg de glicerina bruta e gera em média 60 L de água residuária, estudar alternativas para o aproveitamento economicamente viável da glicerina e tratamento da água residuária tornou-se um aspecto importante nessa cadeia produtora. Com o intuito de atender estes pressupostos, esta tese estruturouse em dois capítulos. No Capítulo 1 foi abordado o Tratamento da água residuária da produção de biodiesel em sistema de flotação por ar dissolvido (FAD), no qual foram testados dois coagulantes (sulfato de alumínio e cloreto férrico) e dois auxiliares de floculação (polifloc e tanfloc). O experimento foi realizado no Laboratório de Saneamento Ambiental da Universidade Estadual do Oeste do Paraná, utilizando-se um Jar Test adaptado para realização dos ensaios de flotação. A combinação que mostrou melhor eficiência na clarificação do efluente com remoção de cor e turbidez e também melhor eficiência na remoção de óleos e graxas e DQO foi sulfato de alumínio combinado ao polímero sintético polifloc em pH 6 e taxas de recirculação de 15%. No Capítulo 2 foi estudada a produção de metano na co-digestão anaeróbia de glicerina e água residuária da suinocultura. Durante o processo foi testado o incremento na produção de biogás e metano com o aumento da carga orgânica inicial, efetuada pela adição de glicerol como substrato. O experimento foi realizado na Universidade Técnica de Lisboa/Instituto Superior de Agronomia, num reator anaeróbio de mistura completa de escala laboratorial. A adição de glicerol na razão 3% v/v se mostrou eficiente no incremento da produção de metano.

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This research work was aimed towards the geotechnical characterization of samples from iron ore rejects coming from flotation and magnetic separation processes, together with the addition of LD steel slag, in order to use these materials as components for base of paved roads. In order to reach such goal, this research work was also concentrated in studying techniques for the utilization of such materials considered as rejects of the iron ore industry, considering the use of mixtures from flotation and magnetic separation rejects combined with LD steel slag and local granular soils, in order to reduce environmental effects caused by conventional methods of storage of these rejects in tailing dams and pile rejects, generally disposed at the mine environment.The findings of the experimental program carried out through this research were based on the following geotechnical testes: characterization; compaction and CBR performed at normal, intermediary and modified compaction efforts; triaxial drained tests; resilient modulus tests; and sand equivalent test. Test results from granulometric stabilization techniques as well as those obtained from CBR and expansion tests, showed that the studied iron ore rejects are suitable for being used as subbase layers of flexible pavements, according to the "Design method of flexible pavements" from DNIT. Also, the laboratory testing program consisted of performing repeated load triaxial resilient modulus tests for these rejects and their mixtures. The best constitutive relationship was the one relating the resilient modulus and the bulk stress, M R = K 1θ K 2 . Finally, laboratory test results showed that these rejects and their mixtures are potentially suitable for application in pavement structures.
Este trabalho teve como objetivo a investigação em laboratório das características e propriedades geotécnicas (físicas e mecânicas) de rejeitos de minério de ferro (oriundos dos processos de flotação e concentração magnéticas) e escória de aciaria LD, com o propósito de inseri-los como material de construção em pavimentos rodoviários. Para tanto, nesta dissertação buscou-se encontrar técnicas de aproveitamento de materiais considerados como rejeitos dos processos do beneficiamento de minério de ferro, fazendo uso de misturas entre os rejeitos de flotação, de concentração magnética, escória de aciaria e cascalho, de forma a reduzir os impactos ambientais oriundos do seu armazenamento dentro da circunscrição da mina. Os resultados encontrados através do programa experimental realizado para a formulação desta dissertação basearam-se em um programa experimental com a seguintes ensaios geotécnicos: caracterização; compactação e CBR (Califórnia Bearing Ratio), nas energias de Proctor normal, intermediário e modificado; ensaios triaxiais drenados e triaxiais de cargas repetidas (módulo de resiliência); e, por ultimo, equivalente de areia. Os resultados da composição granulométrica assim como os resultados de CBR bem como suas expansões, indicaram que os rejeitos estudados são compatíveis para utilização como materiais de sub- base de pavimentos flexíveis, segundo o "Método de Projetos de Pavimentos Flexíveis" do DNIT. O melhor ajuste dos resultados de módulo de resiliência em termos de R2 foi o modelo que utiliza a primeira invariante de tensões, M R= K1 θ K2. Logo as misturas desses materiais apresentam potencial para serem utilizados em camadas de pavimento.

The hydrometallurgical refining of platinum group metals results in large volumes of liquid waste that requires suitable treatment before any disposal can be contemplated. The wastewater streams are characterized by extremes of pH, high inorganic ion content (such as chloride), significant residual metal loads and small amounts of entrained organic compounds. Historically these effluents were housed in evaporation reservoirs, however lack of space and growing water demands have led Anglo Platinum to consider treatment of these effluents. The aim of this study was to investigate whether biological wastewater treatment could produce water suitable for onsite reuse. Bench-scale activated sludge and anaerobic digestion for co-treatment of an acidic refinery waste stream with domestic wastewater were used to give preliminary data. Activated sludge showed better water treatment at lab scale in terms of removal efficiencies of ammonia (approximately 25%, cf. 20% in anaerobic digestion) and COD (70% cf. 43% in digestion) and greater robustness when biomass health was compared. Activated sludge was consequently selected for a pilot plant trial. The pilot plant was operated on-site and performed comparably with the bench-scale system, however challenges in the clarifier design led to losses of biomass and poor effluent quality (suspended solids washout). The pilot plant was unable to alter the pH of the feed, but a two week maturation period resulted in the pH increasing from 5.3 to 7.0. Tests on algal treatment as an alternative or follow-on unit operation to activated sludge showed it not to be a viable process. The activated sludge effluent was assessed for onsite reuse in flotation and it was found that there was no significant difference between its flotation performance and that of the process water currently used, indicating the effluent generated by the biological treatment system can be used successfully for flotation. Flotation is the method whereby minerals refining operations recover minerals of interest from ore through the addition of chemicals and aeration of the ore slurry. Target minerals adhere to the bubbles and can be removed from the process.

This dissertation presents the results of an investigation to develop a two-stage flotation process to produce: (i) a low-volume sulfide-rich concentrate that can be treated chemically or biologically or disposed of in a contained manner; (ii) a high-volume (low sulfur) benign tailings, with low ARD potential compared to conventional tailings; and (iii) a coal concentrate that has added value on account of its low sulfur and ash content. Success requires integration of flotation, aqueous chemistry and mineral bioleaching expertise. The approach adopted in this exploratory study entails coal flotation in the first stage, which takes advantage of its natural hydrophobicity.

Bitumen recovery by the water-based extraction process produces waste streams known as tailings. When discharged into the tailing ponds, the coarse solids in the tailings stream settle out quickly, while the fine solids accumulate over years of settling to a solids content of 30-35% by weight. The formed fluid fine solids sludge, known as mature fine tailings (MFT), traps 1-3% by weight hydrocarbons within its stable slurry structure. The remediation of these mature fine tailings is one of the major challenges facing the oil sands industry. This study was intended to investigate the recovery of residual hydrocarbons in the MFT by froth flotation process. Using a laboratory Denver flotation cell operated in a batch mode, the effect of MFT dilution ratio by process water or tap water, the flotation hydrodynamics and aeration rate on hydrocarbon recovery kinetics was studied. It was found that at 1:2 dilution by weight of the MFT with process water, increasing aeration rate has a more favourable effect on recovering more than 85% of the hydrocarbons from the MFT. The hydrocarbon-rich froth produced was treated by naphtha and was found to produce a hydrocarbon product similar to diluted bitumen obtained in bitumen extraction process, suitable for upgrading. Similar approach was applied to the hydrocarbon-rich tailings from the Tailings Solvent Recovery Unit of paraffinic froth treatment. Satisfactory recovery of hydrocarbons from the MFT was obtained using a flotation column operated in a continuous mode, confirmed the results obtained from the batch tests. The tailings produced from the continuous flotation experiments were treated with polymer flocculants such as Magnafloc-1011 and Al-PAM to study the effect of hydrocarbon recovery on the remediation of the MFT. The results from initial tests showed that both flocculants were not as effective on flocculating MFT solids following the recovery of hydrocarbons by froth flotation.
in Chemical Engineering

An important industrial problem is the production of wastewater containing a large amount of heavy metal ions. The study described in this thesis is trying to use precipitate flotation technology to explore techniques for not only removing heavy metal ions from the solution, but also selectively separating them to recycle of the recoyered metal value from industry wastewater. Zinc and copper hydroxide precipitation and flotation behaviour have been studied. lt shows that it is almost impossible to separate copper and zinc ion using hydroxide precipitate flotation when the solution contains Fe3+ or Al3+ ions. The influence of additional ions such as Ca2+ and Mg2+, and other electrolytes on the flotation and separation have been studied. DLVO theory has been used to explain the mechanisms occurring in the process. A new process, named "self-carrier" precipitate flotation us~g anionic surfactants, has been developed to improve the flotation recovery and reduce the consumption of collector. The mechanism of the process is discussed in detail with reference to data collected from Optical Microscopy, Scanning Electron Microscopy and Zeta Potential Measurement. The xanthates are the most commonly used class of sulphide mineral collectors. This study investigated the copper sulphide precipitate reactions and the aggregation behaviour, the influence of oxidation, additional ions etc., and successfully used xanthate to float the sulphide precipitates. The mechanisms occurring in this process have been discussed. The investigation of the sulphide precipitate flotation behavior using a cationic collector has also been carried out to discover the possibility of copper and zinc separation. An important application of this study is the flotation and separation of copper and zinc ions from industry wastewater. The tailing wastewater from a mineral processing plant, Woodlawn Mines (N.S.W., Australia), which contains high concentrations of harmful heavy metal ions was used to test the flotation and separation of the heavy metal ions. Both xanthate and cationic collectors have been investigated for the flotation separation. Effective separation has been achieved .
Doctor of Philosophy

In the absence of any significant legislation, paper recycling in South Africa has grown to a respectable recovery rate of 43% in 2008, driven mainly by the major paper manufacturers. Recently introduced legislation will further boost the recovery rate of recycled paper. Domestic household waste represents the major remaining source of recycled paper. This source will introduce greater variability into the paper streams entering the recycling mills, which will result in greater process variability and operating difficulties. This process variability manifests itself as lower average brightness or increased bleaching costs. Deinking plants will require new techniques to adapt to the increasingly uncertain composition of incoming recycled paper streams. As a developing country, South Africa is still showing growth in the publication paper and hygiene paper markets, for which recycled fibre is an important source of raw material. General deinking conditions pertaining to the South African tissue and newsprint deinking industry were obtained through field surveys of the local industry and assessment of the current and future requirements for deinking of differing quality materials. A large number of operating parameters ranging from waste mixes, process variables and process chemical additions, typically affect the recycled paper deinking process. In this study, typical newsprint and fine paper deinking processes were investigated using the techniques of experimental design to determine the relative effects of process chemical additions, pH, pulping and flotation times, pulping and flotation consistencies and pulping and flotation temperatures on the final deinked pulp properties. Samples of recycled newsprint, magazines and fine papers were pulped and deinked by flotation in the laboratory. Handsheets were formed and the brightness, residual ink concentration and the yield were measured. It was determined that the type of recycled paper had the greatest influence on final brightness, followed by bleaching conditions, flotation cell residence time and flotation consistency. The residual ink concentration and yield were largely determined by residence time and consistency in the flotation cell. The laboratory data generated was used to train artificial neural networks which described the laboratory data as a multi-dimensional mathematical model. It was found that regressions of approximately 0.95, 0.84 and 0.72 were obtained for brightness, residual ink concentration and yield respectively. Actual process data from three different deinking plants manufacturing seven different grades of recycled pulp was gathered. The data was aligned to the laboratory conditions to take into account the different process layouts and efficiencies and to compensate for the differences between laboratory and plant performance. This data was used to validate the neural networks and select the models which best described the overall deinking performances across all of the plants. It was found that the brightness and residual ink concentration could be predicted in a commercial operation with correlations in excess of 0.9. Lower correlations of ca. 0.5 were obtained for yield. It is intended to use the data and models to develop a predictive model to facilitate the management and optimization of a commercial flotation deinking processes with respect to waste input and process conditions.
Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2011.

The focus of this investigation was the determination of air flotation parameters to perform solid liquid separation treatment in an activated sludge treating grease waste by promoting filamentous bacteria. The treatment was intended to achieve a pretreatment level, previous to the application of the typical activated sludge process. Generally solid liquid separation in activated sludge is performed by gravitational settling, but it is been demonstrated that the presence of an overgrowth population of filamentous microorganism in activated sludges hinder the settling properties of it. For this reason, gravitational settling may result in an inefficient treatment. Therefore, an alternative treatment has to be applied. The treated waste in this project has a density lighter than water; additionally filamentous microorganisms tend to trap fine bubbles therefore causes floating. These specific conditions make air flotation a suitable alternative technology. The ranges of minimum operation for Dissolve Air Flotation (DAF) controlling parameters (air pressure, recycle rate, rise rate, air to solid ratio, and solids recovery) were determined. For this purpose a descriptive model for the treatment was developed. The research determined that the traditional gravitational settling was not adequate for separating the biomass from the liquid phase. In contrast dissolve air flotation showed that it was possible to achieve the pretreatment level (300 mg/L in the final effluent). In the analysis the correlations between the parameters under study (air pressure and recycle rate) and the response variables (rise rate, air to solid ratio, suspended solids in the subnatant, and solids recovery) were determined. With the relationships defined, the minimum ranges for the parameters of operation of a DAF unit were determined. The results showed that in order to achieve the pretreatment level air pressure should range between 45-70 psi and the recycle rate between 30-35%. All the values for the rest of the response variables were determined to be within the ranges of the typical application of DAF, therefore the same equipment used for the typical application can be used to apply this treatment under these specific conditions.