Orientador: Roberto Alves de Oliveira / Banca: Wanderley José de Melo / Banca: Marco Antonio Penalva Reali / Resumo: Nas estações de tratamento de água (ETA), as impurezas retiradas da água juntamente com os produtos hidrolisados dos coagulantes dão origem aos resíduos dos decantadores e das águas de lavagem dos filtros, denominados lodo de ETA. Neste experimento, foi avaliado a disposição de lodo de ETA em reatores anaeróbios de fluxo ascendente com manta de lodo (UASB), com volume de 18 L e 38 L, visando o tratamento para destinação adequada do efluente e do lodo excedente dos reatores. Tal experimento foi dividido em quatro ensaios, com tempo de detenção hidráulica de 24 h nos reatores UASB, previamente inoculados com lodo granulado e floculento. Foram observadas condições em que foram aplicadas ao reator UASB, lodo de ETA, com DQOtotal de 161 mg/L e ST de 1.948 mg/L, e misturas de lodo de ETA com esgoto sanitário nas seguintes proporções, em volume, de 1:1 (lodo de ETA : esgoto sanitário) com DQOtotal de 458 mg/L e ST de 3.039 mg/L; 1:3, com DQOtotal de 519 mg/L e ST de 1.562 mg/L e 1:7, com DQOtotal de 1.174 mg/L e ST de 3.502 mg/L. Os valores médios de eficiência de remoção da DQOtotal foram de 75 a 83% e de ST de 73 a 87%. A maior remoção de P foi de 90% e de N de 41%. As eficiências de remoção de Ca, Co, Fe, Mn, Ni, Cu, Pb, Cr e Zn foram superiores a 70%, confirmando a alta capacidade de bioadsorção de metais do lodo anaeróbio. As concentrações de N-am, Fe, Mn, Ni, Cd, Pb, Cu, Cr e Zn atenderam aos padrões de lançamento de efluentes da legislação federal. Ocorreram remoções de E. coli acima de 90%, resultando contagens do efluente de 1,5x10 UFC/100 mL, apresentando qualidade microbiológica correspondente à água doce de classe 1, conforme os padrões estabelecidos na Resolução CONAMA 357/2005 . O lodo do reator UASB apresentou valores de relação SV/ST e E. coli que permitiram o seu uso na agricultura. / Abstract: In water treatment plants (WTP), impurities removed from water mixed with coagulative hydrolytic product create waste of decanters and launderings water filters residues called WTP sludge. In this experiment the WTP sludge disposal in an Upflow Anaerobic Sludge Blanket Reactor (UASB) were evaluated, with a volume of 18 L and 38 L, aiming treatment for appropriate disposal of effluent and excess sludge reactors. Such experiment was divided into four assays, with hydraulic detention time of 24 h in UASB reactors by being inoculated previously with flocculent and granular sludge. It was observed conditions in wich it was added to the UASB reactor WTP sludge with CODtotal of 161 mg/L and TS of 1,948 mg/L, and mixtures of WTP sludge and wastewater in the following amounts, in volume, 1:1 (WTP sludge : wastewater) with CODtotal of 458 mg/L and TS of 3,039 mg/L; 1:3 with CODtotal of 519 mg/L and TS of 3,382 mg/L and 1:7 with CODtotal of 1,174 mg/L and TS 3,501 mg/L. The average values of removal efficiency of CODtotal were 75 the 83% and TS 73 the 87%. The highest P removal was 90% and the highest one of N was 41%. Removal efficiencies of Ca, Co, Fe, Mn, Ni, Cu, Pb, Cr and Zn were higher than 70% wich confirmed the high capacity of biosorption and bioaccumulation of metals from anaerobic sludge. Concentrations of Nam, Fe, Mn, Ni, Cd, Pb, Cu, Cr and Zn fit the quality standards of effluent discharge required by federal legislation. There were removals of E. coli higher than 90% which resulted in counts for effluent of 1.5x10 CFU/100 mL and it showed microbiological quality corresponding to freshwater class 1, according to the standards established in CONAMA Resolution 357/2005. Sludge from the reactor showed ratios of VS /TS and E. coli which allows agricultural use. / Mestre

>Magister Scientiae - MSc / Environmental pollution is a major threat to all life, which needs to be addressed. Heavy metals are well-known environmental pollutants due to their toxicity and, persistence in the environment toxicity for living organisms and having a bioaccumulative nature. Environmentally, the most common hazardous heavy metals are: Cr, Ni, Cu, Zn, Cd, Pb, Hg, and As. Remediation using conventional physical and chemical methods is uneconomical and generates waste chemicals in large quantities. This study focuses on the extraction and determination of heavy metals (Nickel, Copper and Cobalt) by chelating Schiff base ligands of the type [O,N,N,O] with these metal ions. Two Schiff base ligands [N,N’-ethylenebis(salicylimine)] (Salen) and ligand [1,3-bis(salicylideneamino)-2-propanol] (Sal-DAP) were synthesized and characterised using FTIR, 1H and 13C NMR spectrometry and GC-MS techniques. Electrochemical detection of heavy metal ions in this work was achieved via ligand-metal complexation via two approaches. The in-situ method in which the metal and ligands were added to the electrochemical cell and stirred to allow complexation to occur and monitored by square wave voltammetry. While the ex-situ approach involved modifying the electrode surface by depositing a thin film of Schiff base on the electrode surface and immersed into a heavy metal solution to allow the complexation. Three modified GCE were used viz. Salen coated GCE, reduced graphene oxide-Salen coated GCE and a nafion-Salen coated GCE. The two approaches used for the electrochemical detection were successful and effective. The ex-situ approach was selected for the modification of the electrode surface since it demonstrated a higher capacity for heavy metal ion extraction.

Finite element(FE) method has been used to model cutting process since 1970s. However, it requires special techniques to cope with the difficulties in simulating extremely large strain when compare to static or small deformation problems. With the advancement of FE techniques, researchers can now have a deeper insight of the mechanism of material flow and chip formation of metal cutting process. Even the stagnation effect of the workpiece material in front of the cutting edge radius can be captured by using FE techniques such as Remeshing and Arbitrary Lagrangian Eulerian(ALE) formulation. However most of this models are limited to plane strain assumption which means they are 2-dimensional. Although 3D models are existing in the literatures, most of them employ Remeshing technique which is very computationally intensive and has many critics regarding its accuracy due to its frequent remeshing and mapping process. The rest of the 3D models employ Lagrangian formulation. The 3D models by Lagrangian formulation have the same limitations and drawbacks as in 2D models, as it requires failure criteria and in most of the cases predefined partition surfaces are also required. ALE technique on the other hand resolves all the drawbacks of the other formulations, it not only inherits the advantages of the other techniques but also has its own unique advantages such as it can simulate a longer time span up to couple seconds more economically by fixing the number of elements used. Although it's commonly accepted that ALE formulation is superior to other formulations of techniques in modeling metal cutting process, its usage is only limited to 2D models. Limited 3D ALE metal cutting models is available in the literature. Thus the main objective of this research is to explore the possibility of building a 3D metal cutting model with ALE formulation. The reliability and limitations will also be studied. Furthermore, Couple Eulerian-Lagrangian(CEL) formulation is a recent developed formulation that has a lot of potential in modeling metal cutting process in 3D. It will be compared with ALE models to study its potential and limitations in modeling metal cutting process. A new frictional model will also be proposed, which suggests that the frictional phenomenon in metal cutting is a consolidated effect of both friction between material interface and shear yield of the workpiece material. This idea provide a brand new perspective of viewing the friction phenomenon of metal cutting compared to those existed models. / Thesis / Master of Science (MSc)

Made available in DSpace on 2017-07-20T13:41:58Z (GMT). No. of bitstreams: 1 Elaine Carvalho da Paz.pdf: 5913998 bytes, checksum: 3abfb310351a148f2f4495951bcca8d2 (MD5) Previous issue date: 2016-05-25 / The present study evaluates the iron removal efficiency (Fe), manganese (Mn), apparent color and turbidity, using adsorptive filtration compared with conventional filtration, using a natural Zeolite as layer second material in a pilot unit with constructive and operational typology similar to the rapid downward filter, gravity and double layer. As adsorbent material was selected Zeolite WATERCELL-ZF-0410®, commercially available Clinoptilotite from Cuba, for having physical characteristics similar to the anthracite coal. Morphological characterization assays were performed (FEG-SEM) and elemental (EDS), physical characteristics (particle size, density, effective size and uniformity coefficient), lixiviation and filtration on a pilot scale. Morphological characterization analysis, it was found that the zeolite under consideration has a high adsorption capacity, prone to adsorption iron, manganese and sulfur in the upper range anthracite coal. The physical characterization analysis, it was verified that this Zeolite is a uniform material and graduated, has physical similarity to the coal and anthracite can be used as filtering material of the layer second. Leaching analysis showed that, possibly, there will be no release above the maximum value allowed in CONAMA Resolution n. ° 357/2005, metals detected in the leached extract for a backwashing of filter using this material as media filter, as well as probably not occur detachment of these metals in the final disposal of this waste system. The filtration analysis on a pilot scale concluded that designing a filter with downward filtration, with depth action and double layer using the Zeolite WATERCEL-ZF-0410 on the layer second, is viable. The conception of treatment proposed, in the conditions, parameters and settings studied, has average efficiency: 100.00% for the removal of manganese; 96.17% for the removal of iron; 99.90% for the removal of apparent color; and 98.96% for the removal of turbidity. / O presente trabalho avalia a eficiência de remoção de ferro (Fe), manganês (Mn), cor aparente e turbidez, utilizando a filtração adsortiva em relação à filtração convencional, com utilização uma Zeólita natural como material de segunda camada, em uma unidade piloto com tipologia construtiva e operacional semelhante de um filtro rápido descendente e a gravidade. Como material adsorvente foi selecionado a Zeólita WATERCELL-ZF-0410, comercialmente disponível, clinoptilotita proveniente de Cuba, por possuir características físicas semelhantes à do carvão antracito. Foram realizados ensaios de caracterização morfológica (MEV-FEG) e elementar (EDS), de caracterização física (granulometria, massa específica, tamanho efetivo e coeficiente de desuniformidade), de lixiviação e de filtração em escala piloto. Da análise de caracterização morfológica, verificou-se que a Zeólita em estudo tem alta capacidade de adsorção, com predisposição para adsorção de ferro, manganês e enxofre, em escala superior ao carvão antracito. Da análise de caracterização física, verificou-se que a Zeólita em estudo é um material uniforme, bem graduado, possui equivalência física com o carvão antracito e pode ser utilizada como material filtrante de segunda camada. Da análise de lixiviação, verificou-se que, possivelmente, não haverá desprendimento, acima do valor máximo permitido na Resolução Conama n.° 357/2005, dos metais detectados no extrato lixiviado para a água de lavagem de um filtro que utilize esse material como meio filtrante, bem como, possivelmente, não ocorrerá desprendimento destes metais no sistema de disposição final deste resíduo. Da análise da filtração em escala piloto, concluiu-se que é viável a concepção de um projeto de filtro a gravidade, com filtração descendente, ação de profundidade e dupla camada, utilizando a Zeólita WATERCEL-ZF-0410 como material de segunda camada e que, esta concepção de tratamento, nas condições, parâmetros e configurações estudadas, apresentou eficiência média de: 100,00% para remoção de manganês; 96,17% para remoção de ferro; 99,90% para remoção de cor aparente; e 98,96% para remoção de turbidez.

Zur selektiven Entfernung von Schwermetallen aus industriellen Abwässern und Prozesslösungen der metallverarbeitenden Industrie werden synthetische metallkomplexierende funktionelle Polymere – mit Iminodiessigsäure (IDE) als aktive Spezies – seit Jahren erfolgreich zur Eliminierung störender Kationen eingesetzt. Ständig steigende Anforderungen an die Qualität der aufzubereitenden Wässer verlangen nach leistungsfähigen Selektivaustauschern, die den Erhalt der Eigenschaften von Prozesslösungen (z. B. pH-Wert, Salzgehalt) ermöglichen. Ziel der Untersuchungen war es, die strukturellen Matrixeinflüsse auf Beladung, Kapazität, Selektivität und Kinetik durch Variation der Matrix und der experimentellen Bedingungen näher zu untersuchen. Auf Basis einer monodispersen Erstsubstitution eines Styren-Divinylbenzen-Copolymerisates wurde durch gezielten Einbau funktioneller Gruppen – Synthese mit differenziertem Substitutionsgrad (TK/N 1-2) – versucht, systematisch den Einfluss des Substitutionsgrades der Matrix auf die Eigenschaften der Ionenaustauscher zu analysieren. Methodisch geordnet wurden zunächst die Versuche nach dem Batch- und anschließend nach dem Säulenverfahren durchgeführt und parallel dazu die Matrix charakterisiert. Das Verhalten der funktionellen Ankergruppen in Abhängigkeit vom pH-Wert der Lösung (pH-Bereich 2 - 5) wurde untersucht, der optimale Anreicherungs-pH-Wert, die maximale Beladung (Kapazität) und Selektivität der unterschiedlich substituierten Proben für die Schwermetall-Ionen Cu, Zn, Ni, Cd, Pb und Co ermittelt. Den statischen Versuchen folgten dynamische Untersuchungen im Säulenverfahren. Ziel war die Ermittlung des Durchbruchverhaltens und der Durchbruchkapazität bei optimalem pH-Wert in Abhängigkeit vom Substitutionsgrad gegenüber den Einzelmetallionen (Cu, Ni, Zn) und ausgewählten Paaren (Cu/Ni, Cu/Zn, Ni/Zn). Alle Ionenaustauscher wurden ausschließlich in der Ca-Form eingesetzt. / Selective ion exchange offers a good solution for cleaning many waste streams. The aim of this study was to develop selective ion exchange materials for effective and economical applications in waste water treatment. The investigation of chelate resins is based on iminodiacetate with different secondary substitution (degree of substitution TK/N 1 - 2, from aminoacetic acid to iminodiacetate as functional group). As comparison the weak acid resin Lewatit TP 207 was used. The research focused on the application of selective ion exchange resins for waste effluents to ascertain the feasibility of a selective ion exchange process employing chelating cation exchangers for heavy metal removal. The metals of interest were copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), lead (Pb) and cadmium (Cd) and the resins appointed in the Ca-form. The batch operation was conducted to determine the equilibrium data and the operating resin capacity, one of the most important properties. The main equilibrium parameter affecting the ion exchange was the pH value (array 2-5). The best accumulation pH value was obtained using pH 5 for all metals. The only exception was lead with pH 3. After determining the viability of the different resins with batch systems, this study has focused on the column mode experiments. They were generated for the selected resins in the continuous ion exchange process which are essentially reserved for industrial applications. A practical application of the breakthrough curves is the determination of the breakthrough time which helps to find the best operating conditions.

Effect of ionic strength on the efficiency of heavy metal removal and recovery from aqueous solutions via continuous mode polymer enhanced ultrafiltration (PEUF) method was examined. Application of PEUF to divalent ions of cadmium, nickel and zinc after their prior linking with polyethylenimine (PEI) results in complete removal of metal ions from single component aqueous solutions at high pHs. Binding ability and hence the extent of metal retention in high ionic strength medium exhibits differences between solutions containing single and multicomponent metal mixtures. In single component metal solutions, extent of retention decreases but binding order of metals remains unaffected both in low and high ionic strength medium. But, in binary component metal mixtures, with increase in ionic strength the binding order of metals changes. Fractional separation of Cd, Ni and Zn ions from equimolar binary and ternary mixtures of these metals and effect of ionic strength on fractional separation efficiency were investigated. Depending on pH and salt concentration and metal pairs present in the solution fractional separation can be achieved.Dynamic and static light scattering experiments were performed in order to gain insight about the conformational changes in PEI structure due to the pH and ionic strength alternations in solution. It was found that, the increase in ionic strength reduces the size of the macromolecules. A chemical equilibrium model was developed in order to estimate the apparent binding constants of metal-PEI complexes. Based on the data obtained from continuous and batch mode PEUF experiments apparent binding constants were estimated and compared to reveal the performance differences between these operational modes.

Orientador: Silvana Moreira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-16T10:36:10Z (GMT). No. of bitstreams: 1 AvelinoNeto_Sebastiao_D.pdf: 6321049 bytes, checksum: a54827db20bdd0eedb9943b48ef60d17 (MD5) Previous issue date: 2008 / Resumo: O presente trabalho teve como objetivo avaliar a operação e o desempenho de seis Leitos Cultivados de Fluxo Subsuperficial que operaram como pós-tratamento de um Tanque Séptico Modificado, instalados na Faculdade de Engenharia Agrícola da Universidade Estadual de Campinas. O sistema em estudo é composto por três leitos retangulares e três quadrados, dispostos em paralelo. Como meio suporte utilizou-se brita e foram cultivadas duas espécies de macrófitas emergentes (Typha sp. e Eleocharis sp.). Foi estudado o desempenho do leito cultivado para diferentes tempos de detenção hidráulicos e para isto foram coletadas amostras das folhas das macrófitas, do perfil do meio suporte em diferentes profundidades, da água residuária no afluente e no efluente de cada leito cultivado. Para a análise quantitativa foi empregada a técnica de Fluorescência de Raios X por Reflexão Total com Radiação Síncrotron. Para a avaliação do desempenho dos leitos estudados as concentrações de Cr, Mn, Fe, Cu, Zn e Pb foram avaliadas nas folhas das macrófitas, no meio suporte, no afluente e no efluente. Foi verificado que o desempenho do leito quadrado cultivado com Eleocharis foi superior ao retangular para os seguintes elementos: Mn, Fe, Cu e Zn. Para os elementos Cr e Pb o leito retangular cultivado com Eleocharis teve um melhor desempenho. Verificou-se que tanto no leito quadrado quanto no retangular as folhas de Eleocharis e Typha apresentaram eficiência de remoção superior a do meio suporte. Assim como no leito cultivado com Eleocharis, foi observado um melhor desempenho do leito cultivado com Typha quadrado para Mn, Fe, Cu e Zn, enquanto que para Cr e Pb o leito cultivado com Typha retangular apresentou melhor desempenho. No sistema de leito cultivado de geometria quadrada com Typha e Eleocharis e Controle removeram os metais Fe, Cu e Zn a limites permitidos pela legislação em qualquer dos tempos de detenção hidráulico empregado. No entanto para a remoção de Cr a níveis estabelecidos pela legislação é recomendado a operação do sistema com tempo de detenção hidráulico de 4 dias, e para Pb os tempos de detenção hidráulico recomendados são os de 4 e 6 dias. Para o leito retangular cultivado com Eleocharis e Typha, assim como no leito controle podemos observar que para os elementos Fe, Cu e Zn, as concentrações estão abaixo dos valores máximos permitidos pela legislação de lançamento de efluentes, para todos os tempos de detenção hidráulico. Entretanto para uma remoção eficiente de Cr, Mn e Pb os tempos de detenção de 4 e 6 dias são os mais recomendados para a operação do sistema. Os leitos controles quadrado e retangular tiveram eficiência de remoção inferior ao dos leitos cultivados com as macrófitas. O meio suporte nas profundidades de 10, 30 e 50 cm do leito cultivado de geometria quadrado e retangular cultivados com as macrófitas Typha sp. e Eleocharis sp., removeu os metais Cr, Mn, Fe, Cu, Zn e Pb de forma semelhante, ou seja, não houve uma profundidade que tivesse eficiência de remoção superior as demais / Abstract: The purpose of this work was evaluated the operation and performance of six constructed wetland of subsuperface flow, operating as post-treatment of a septic tank, installed on Agricultural Engineering College at University of Campinas. The system in study containing three square units, disposed in parallel. The substrate used was gravel and two emergent macrophytes species were cultivated (Typha sp. and Eleocharis sp.). The performance of the units were studied for different hydraulic residence times (2, 3, 4 and 6 days) and for this leaf of the macrophytes, substrate in different depths, wastewater in all units were collected. For quantitative analysis Synchrotron Radiation Total Reflection X-ray Fluorescence technique was employed. For evaluation of the performance in the constructed wetlands concentrations of Cr, Mn, Fe, Cu, Zn e Pb in leaf macrophytes, substrate, entrance and exit of the system were determined. The performance of the square unit with Eleocharis was higher than rectangular shape for Mn, Fe, Cu and Zn elements. For Cr and Pb the rectangular unit with Eleocharis presented better performance. Leaf of Eleocharis and Typha showed removal efficiency higher than substrate for square and rectangular units. As in the unit with Eleocharis a better perfomance was observed in a square unit cultivated with Typha for Mn, Fe, Cu and Zn, while for Cr and Pb the rectangular shape with Typha presented better performance. In the square system cultivated with Typha, Eleocharis and the control removed Fe, Cu and Zn to levels permitted by the legislation for all hydraulic residence times. Moreover for Cr removal to levels established by the legislation the operation with 4 days of hydraulic residence time was indicated and for Pb the recommended times were 4 and 6 days. For rectangular systems cultivated with Eleocharis and Typha, as the control unit, Fe, Cu and Zn, concentrations were smaller than the permissive values established by the legislation for all hydraulic residence times. By the order hand for a efficient removal of Cr, Mn and Pb the residence times of 4 and 6 days were most recommended for the system operation. Square and rectangular control units showed efficiency removal smaller than units containing the macrophytes. The removal of Cr, Mn, Fe, Cu, Zn and Pb metals by the substrate in 10, 30 and 50 cm depths of square and rectangular shapes cultivated with the two macrophytes showed no significative difference / Doutorado / Recursos Hidricos / Doutor em Engenharia Civil

Dagvatten från urbana områden för med sig metaller och andra föroreningar orsakat av bl. a. fordonstrafik och korrosion av metallbärande konstruktioner. Sedan 90-talet har det varit vanligt med dagvattenbehandling för högtrafikerade vägar. Vissa kommuner har även utvecklat riktvärden som begränsar hur höga metallkoncentrationerna som tillförs dess recipienter får vara. Metaller i dagvattnet kan förekomma antingen i löst form eller i partikulär form. För att avlägsna den partikulära formen används konventionellt sett sedimentering men då den lösta formen är mer biologiskt upptagbar är det viktigt att även den avskiljs. Användningen av reaktiva filter som behandlingsmetod är ett sätt att fastlägga både metallpartiklar och lösta metaller, genom fysisk avskiljning respektive kemisk fastläggning. I denna studie undersöktes i en pilotanläggning förmågan att avskilja metaller från vägdagvatten hos ett referensmaterial (filtersand) samt fyra reaktiva filter. Resultaten visade att det var möjligt att uppnå god fastläggning av de 11 metaller som studerades. Inkommande vatten visade höga koncentrationer av Cu och Zn relativt till utvalda riktvärden. Lägst genomsnittlig avskiljning av dessa, sett över provperioden, hade Råda filtersand (62%), referensmaterialet, medan högst uppnåddes av Petrit T-S (99%), en filterprodukt från Höganäs AB. Fortsatta försök behövs för att få en uppfattning om filtermaterialens långsiktiga avskiljningseffektivitet och funktionella livslängd. / Stormwater from urban areas contains metals and other pollutants released from for example vehicle traffic, wearing of the road surface, and corrosion of metallic construction. Treatment of storm water from highly trafficked roads has been common since the nineties. Some municipalities have also developed regulations to control the concentrations of metal discharges to their recipient waters. Metals in stormwater can be in either particulate form or in dissolved form. Sedimentation has conventionally been employed to remove particulate metals. However, it’s important to also remove dissolved metals since these are more bioavailable. One way of removing both particulate and dissolved metals is by using reactive filters, since these can physically trap particulates and chemically bind dissolved matter. In this study, that took place in a stormwater treatment pilot plant, the abilities to remove metals from stormwater by one reference material (filter sand) and four reactive filter materials were studied. The results showed that it was possible to achieve a high percentual removal of the 11 metals studied. The incoming water contained high concentrations of Cu and Zn, compared to the municipal guideline concentrations considered. The lowest removal efficiency of these two metals (calculated by averaging the removal efficiency across the test period) was seen in the reference material Råda filter sand (62%), while Petrit T-S, an electric arc furnace slag, showed the highest average removal efficiency (99%). Further studies are needed to gain better understanding of the long-term removal efficiency and functional life span of the analyzed filter materials.

M. Tech. (Department of Biotechnology, Faculty of Applied and Computer Sciences) Vaal University of Technology. / Pollution of aquatic systems by wastewater containing pathogens, heavy metals and high concentrations of nutrients is of great concern due the ecological risks they impose. The toxic effects of metals may occur even at low concentrations because of potential bio magnification in the food chain. Excessive nutrients cause algal blooms which depletes oxygen and prevents sunlight from penetrating into the water, thereby killing fish and other aquatic organisms. This study investigated the pollutant removal efficiency of a riparian wetland located in Sebokeng, Emfuleni local municipality, South Africa. The study was carried out to assess the water quality of a wetland located downstream of the Sebokeng wastewater treatment plant by monitoring and analysing the physico-chemical parameters which included pH, temperature, electrical conductivity, nutrient levels (nitrates, phosphates, nitrites) and heavy metals. The water samples were collected from the effluent discharge of the treatment plant, upstream and downstream of the wetland. Plant uptake of heavy metals in a riparian wetland, nitrification as well as denitrification processes have been historically recorded as the main processes that contribute to the high removal of pollutants in a wetland. The contaminant concentrations of the influent and the effluent were used to estimate the wetland efficiency in improving the water quality that passes through it and its potential effects on improving the quality of irrigation waters. The heavy metals of interest included Al, Cd, Cr, Cu, Fe, Pb, Mn and Zn. Most heavy metals within the wetland occurred at low concentrations (lower than detectable limits and within the discharge limits for irrigation purposes). The results indicate that the average removal efficiencies for Electrical Conductivity (EC), Total coliforms (TC), E. coli, BOD5, COD, TSS, carbonate hardness, aluminium, iron, manganese, copper, nitrite, nitrate, sulfate and ortho-phosphate were 43 %, 51%, 85%, 60%, 61%, 61%, 21%, 67%, 52%, 51%, 83%, 56%, 89%, 49% and 54% respectively. The study showed that this wetland can provide up to 89% removal efficiency of pollutants. Of particular significance was the high pathogen and nutrient removal efficiency. A t-test was performed in order to determine the statistical significance of the wetland pollutant removal efficiencies. All p-values calculated were well below 0.05 and the removal efficiencies are therefore considered statistically significant. For this particular ecosystem the findings show that there is no great concern about metal pollution since most of the metals tested for were below the minimum limit for irrigation stipulated by the South African water regulation department (DWAF 1996a). Therefore, the wetland effluent water qualifies for both agriculture and landscape irrigation. Future considerations in choosing to use wetlands as a polishing facility for wastewater treatment systems are highlighted in the study.

Metallspridning via dagvatten är ett problem, vilket fo ̈rväntas växa i framtiden. Det finns dock en problematik i att många metoder för dagvattenrening inte är tillräckligt effektiva gällande avskiljning av lösta metalljoner. Detta har medfört ett ökat intresse för reaktiva filtermaterial vilka avskiljer lösta metalljoner.  I dagsläget finns en begränsad kunskap om funktionen av reaktiva filter speciellt under nordiska förhållanden med kalla vintrar där dubbdäck är regel och halkbekämpning med vägsalt är vanligt.  Detta arbete är genomfört i ett fullskaleförsök under vinterförhållanden med höga salthalter och låga temperaturer i vägdagvattnet.  I undersökningen har inverkan av pH och vägsalt på avskiljningen av metaller och igensättning studerats för det reaktiva filtermaterialet Filtralitea® P. Undersökningen har genomförst vid Lilla Essingens dagvattenreningsanläggning som behandlar dagvatten från ett avrinningsomr ̊ade med en yta på 17 600 m2, varav Essingeleden med en årsdygnstrafik ( ̊ADT) på 140 000 fordon, utgör en större del av avrinningsområdet. Undersökningen genomfördes under perioden 28/01-2021 till 16/04-2021. Efter sedimente- ring pumpades vägdagvatten till två parallella filterbrunnar (Filter 1 och Filter 2) laddade med Filtralite P. Uppehållstiden i Filter 1 var fyra timmar medan uppehållstiden i Filter 2 varierade mellan 9 till 24 timmar. Den hydrauliska belastningen på Filter 1 var således avsevärt högre än för Filter 2. Turbiditeten hos det inkommande vattnet till brunnarna var väldigt låg (<46,5 FNU) och igensättning kom inte att påverka drifttiden för filtermaterialet i denna anläggning i någon större utsträckning, då tendenser till igensättning endast påvisades i Filter 1. Kloridkoncentrationen i vägdagvattnet varierade mellan 119 - 4 990 mg L−1 och temperaturen i vattnet som pumpades till de reaktiva filtren varierade mellan 0 – 6 °C. Det reaktiva filtret visade goda förmågor att avskilja partikulärt och löst zink och koppar. Järn- mangan- och kalciumkoncentrationerna avskiljdes i Filter 2, men i Filter 1 ökade ofiltrerade halten järn samt mangan- och kalciumkoncentrationerna. Detta tros bero på att den högre belastningen på Filter 1 orsakade en kraftigare pH-reduktion som i sin tur minskade adsoptionsförmågan och därmed ökade saltets påverkan. En viss avskiljning av krom observerades med undantag fär den filtrerade fraktionen efter Filter 2. Nickelkoncentrationen i utgående vatten var förhöjd i bägge filter (Filter 1: totalhalt max 9,48 μg L−1, löst halt 10,8 μg L−1, Filter 2: totalhalt max 4,08 μg L−1, löst halt 4,13 μg L−1). Koncentrationerna av magnesium och molybden var högre efter båda reaktiva filtren. Metallerna bly, kadmium och kvicksilver förekom endast i låga koncentrationer under försöken. Filter 1 påvisade i regel sämre avskiljning än Filter 2, vilket kan innebära att en lägre hydraulisk belastning resulterar i effektivare rening. Salthalten korrelerade med koncentrationerna av kalcium, järn, mangan, magnesium och zink efter filterbrunnarna och det är därmed möjligt att salthalten kan mobilisera bundna metaller. Ett tröskelvärde för mobilisering av metaller kan vara en salthalt av 2 500 mg L−1. / The growing infrastructure creates more impermeable surfaces, causing an increase in stormwater that brings contaminants from surfaces such as roofs and roads, spreading these in the environment. There are a number of different stormwater treatment methods but many lack the ability to remove metal ions. One promising method is the use of reactive filter materials. However, there is a limited amount of research conducted on how these reactive filter systems perform in natural conditions, especially in nordic environments with cold winters, de-icing salt application and usage of studded tyres. This study aims at in- vestigating how de-icing salt (NaCl), pH, temperature, clogging and water flow affect the treatment efficiency of the reactive filter material Filtralite® P in a real-life application. The catchment area that contributed water to the studied system had a total area of 17,600 m2, including parts of Essingeleden, one of the most trafficked roads in Sweden with an annual average daily traffic load of 140,000 vehicles. The studied system consisted of a stormwater pond fed with water from the catchment area. The pond connected to a measuring well which in turn was connected to a pumping well. From there, water was pumped upwards through two parallel wells (Filter 1 and Filter 2) containing Filtralite P and was then discharged into lake Ma ̈laren. Filter 1 was subjected to a higher hydraulic load compared to Filter 2, resulting i a residence time of four hours in Filter 1 and 9 - 24 hours in Filter 2. Water samples were collected in the measuring well and above the filter media in both reactive filter wells. This allowed for examination of the metal concentrations before and after the reactive filters. Measurements of pH, temperature, conductivity and turbidity were conducted in the measuring well and in both filter wells. In addition, measurements of head loss and water flow were also taken in the filter wells. The samples and measurements of this study were taken between 28/01-2021 and 16/04- 2021. Before that, the reactive filter material had been in use from June to December of 2020. The turbidity in the measuring well varied between 2 and 50 FNU. A decrease in turbidity was observed after the reactive filter media, with an average of 3.3 FNU in Filter 1 and 0.9 FNU in Filter 2. The amount of suspended solids in the water was estimated to not exceed 16 mg L−1 and in total, approximately 1.4 kg of suspended solids was removed in Filter 1 and 0.3 kg in Filter 2. The head loss through Filter 2 was highly correlated with the hydraulic load due to the drastic variations in flow. The head loss in Filter 1 was observed to increase slightly over time, indicating that clogging might start to take place. However, clogging of the filter media did not seem to be an issue for the system, a theory strengthened by the low turbidity and low increase in head loss. The temperature in the measuring well varied between 0 and 6 °C and in the filter wells between 1.1 and 7.4 °C. The low temperature might have negatively affected the efficiency of the reactive filter. An increase in pH was observed after the water passed through the reactive filters, with Filter 1 raising the pH to around 9 and Filter 2 to around 10 in the beginning of the testing period. This increase in pH would diminish over the period in Filter 1 to approximately 8, while Filter 2 maintained a stable pH increase. The conductivity increased over the measuring period and reached a peak in February to then decrease during March, most likely caused by increased and decreased use of de-icing salts. Chloride concentrations in the incoming stormwater varied between 119 - 4 990 mg L−1. The treated water after the reactive filters exhibited a reduced concentration of filtered copper and zink. Meanwhile, the concentrations of calcium, iron, manganese and nickel increased in Filter 1, but decreased in Filter 2. Filtered chromium decreased in Filter 1 but no statistically significant reduction was observed in Filter 2. However, the reduction of chromium might have been more efficient, due to a majority of measurements showing concentrations below the detection limit after the reactive fitlers. There was an increased concentration of filtered molybdenum and magnesium after the reactive filters. The metals cadmium, lead and mercury were merely present in very low concentrations or below the de- tection limit of laboratory instruments. Futher investigations of these metals were therefore not conducted. In general, Filter 2 achieved a higher metal treatment efficiency compared to Filter 1. This is believed to be caused by the higher hydraulic load in Filter 1. This caused a pH reduction in the filter material which in turn led to a reduced adsorption efficiency and possibly enhanced the competition effect between the dissolved metals and the sodium ions from the de-icing salts. A correlation was found between chloride and calcium, manganese and iron in Filter 1. In Filter 2 there was a correlation between chloride and calcium, unfiltered magnesium and zink. The chloride concentrations are related to the de-icing salts and it is believed that the salts could have an impact on the efficiency of metal reduction in Filtralite P. At chloride concentrations of around 2 500 mg L−1 the concentrations of zink, magnesium, iron, copper and calcium seemed to increase in the effluent water, meaning that there might also be a threshold value, which if passed, leads to increased metal mobilization. The higher performance of Filter 2 might also be due to longer residence times. This increa- sed residence time might have allowed for a greater reduction of metals due to an increased contact time. It is important to note that more bed volumes had passed Filter 1 compared to Filter 2, with a total of 321 bed volumes through Filter 1 and 53 bed volumes through Filter 2 during the period of this study. However, if previous bed volumes are also taken into account, a total of 1,157 bed volumes have passed Filter 1 and 559 have passed Filter 2. This could also have caused the reduced efficiency observed in Filter 1 compared to Filter 2.