Komati Power Station has installed a membrane plant consisting of ultrafiltration, double pass reverse osmosis and continuous electro-deionisation to treat cooling tower blowdowns in order to produce demineralised water and to conduct sidestream chemistry control of the cooling water circuit. This plant has replaced the existing ion-exchange plant that was used for the production of demineralised water and thus serves to reduce the loading of mobile salts in the ash dam (90% reduction) by eliminating regeneration effluent from the ion-exchange plant. Due to oil contamination in the cooling water circuit (when oil from oil coolers leaks into the cooling water), the membrane plant was also designed to operate on raw water from either the Nooigdedacht or the Vygeboom Dam or a blend of both dams. This is considered to be an emergency intervention under abnormal conditions to prevent possible irreversible fouling of the membranes due to oil in the cooling water. The Nooigtedach Dam water contains high concentrations of organic matter and is also enriched with nutrients due to raw sewage influent into the Dam water. This poses a challenge with regard to treatment of the high fouling feed water on the membrane plant. Natural organic matter in water has the ability to foul reverse osmosis membranes. This adversely affects the operation of the reverse osmosis process. However, very little information is available regarding the fouling characteristics of natural organic material in the raw and cooling water at Komati Power Station for the reverse osmosis membranes. Therefore, a pilot study was undertaken to determine the influence of natural organic matter on membrane fouling, to optimise the process for the removal of natural organic matter and to assess the ability of two different reverse osmosis membranes to effectively treat the high fouling feed water at Komati Power Station. The ability of a polyethersulphone hollow-fibre ultrafiltration membrane system was first evaluated to remove natural organic matter in the feedwater, by conducting pilot tests, initially without coagulation of the raw water and thereafter with in-line coagulation for organics removal. Jar tests were conducted in the laboratory to determine the most suitable coagulant and dosage for turbidity and natural organic matter removal. Various coagulants were tested and, based on the results of the jar tests, a coagulant (U3000) was identified based on optimal removal of both total organic carbon and turbidity at a dosing level of 20 mg/L. During the operation of the ultrafiltration pilot plant, permeate flow; feed pressure and feed temperature were monitored. Performance of the ultrafiltration membrane was monitored in terms of flux versus time for operation with and without a coagulation process. The results indicated that there was very little total organic carbon removal (maximum removal of 4%) without coagulation and a slight decrease in flux. The flux declined as a result of fouling but could be recovered by performing hydraulic backwashes and CEB procedures. Permeate flux, however, could be maintained at about 90 Lmh (from 642 hours of operation). Since most of the organics passed through the ultrafiltration membrane, it was concluded that the loss in flux was due to colloidal fouling of the membrane. This was observed when the operation was carried out using raw water as feed as well as when cooling water was used. The total organic carbon removal increased to 30% when the plant was operated with inline coagulation. The flux remained relatively stable during the first 600 hours of operation and only decreased significantly during the last 200 hours of operation as a result of fouling. The reduction in flux prior to cleaning was less than the 15% (maximum flux decline of 9.9% during the test period) which is acceptable according to the industry norm of 15%. It appeared that flux could be maintained at around 90 Lmh which was about the same as when no coagulant was applied. The 30% total organic carbon reduction that was obtained was not sufficient to reduce the organics to the level of 6mg/L dissolved organic carbon that was specified by the membrane manufacturer for the standard brackish water reverse osmosis membrane. Two reverse osmosis membranes – the standard brackish water reverse osmosis membrane (BW30-2540) and the extra-low-fouling membrane (BW30XFR-2540) – were assessed in terms of their ability to remove dissolved organic carbon, ease of cleaning of the membrane and the ability to recover flux after cleaning. This was done to establish which membrane is more suited to Komati’s high-fouling feedwater. The evaluation of the performance of the two reverse osmosis membranes was conducted using pre-treated water (filtered water after in-line coagulation, anti-scalant and biocide dosing) as well as using water that was not pre-treated. During operation (under both conditions), the normalised permeate flux, conductivity, dissolved organic carbon and organics absorbing at UV254 were monitored. It was established that in terms of flux decline that the extra low-fouling membrane gave slightly superior performance to that of the standard membrane, achieving longer production runs (up to 5 days compared with 3 days achieved by the standard brackish water membrane) without requiring chemical cleaning. The low fouling membrane achieved better CWF recovery after the cleaning cycles (81.26% Lmh of the virgin membrane on the occasions when there was flux loss) compared to the standard membrane (restored to 77.35% of CWF of the virgin membrane) when using untreated feed water. This performance improved when pre-treated feed water was used and the low fouling membrane’s CWF regained after the CIP was 95.89% which was within the industry norm of a flux recovery of 95%, indicating that the CIP had been effective. It was determined that the TOC rejection of the low-fouling membrane was higher (average TOC rejection of 97%, maximum TOC rejection of 99%) than that of the standard membrane (average TOC rejection of 95.3%, maximum TOC rejection of 97%). Preliminary efforts to optimize the pre-treatment for organics removal in order to reduce organic loading for the RO membranes confirmed that the use of granular activated carbon and use of an organic scavenger resin might not be economically feasible due to the relatively quick TOC breakthrough (8910BV, approximately 18000BV and less than 18000BV for the Filtrasorb 300, Filtrasorb 400 and organic scavenger resin, respectively). Although further investigations should still be conducted, the preliminary results indicate that it would be beneficial to also identify other options that can be further investigated for optimization of organics removal at Komati Power Station. Decline in the normalised flux as well as the evidence of biofouling were witnessed during the pilot operation suggesting that the membranes were fouled. Autopsies were performed on both membranes to identify foulants responsible for the decline in flux that was observed during the pilot study. The results did not indicate an organic foulant on the membrane surface. Biofouling should however, be monitored in the main plant as this was suspected to have resulted in the flux decline during the pilot study. The low fouling membrane demonstrated a better capability to treat the Komati raw and cooling water and would be expected to achieve lower operating costs for the plant (CIP costs and membrane replacement costs) while achieving better organics removal and it is therefore recommended that the low-fouling membranes be used at Komati Power Station as they are superior to the standard membrane and the cost of the low-fouling membranes is comparable to that of the standard membrane. While this would provide somewhat better performance than that obtained with the standard brackish water membranes, it is proposed that further investigation into pre-treatment optimization for organics removal as well as more efficient cleaning solutions be investigated to improve the performance and economics of the main water treatment plant at Komati power Station. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Chemical Engineering / unrestricted

Arctic rivers transport 31-42 Tg organic carbon (OC) each year to the Arctic Ocean, which is equal to 10% of the global riverine OC discharge. Since the Arctic Ocean only holds approximately 1% of the global ocean volume, the influence of terrestrially derived organic carbon (OCter) in the Arctic Ocean is relatively high. Despite the global importance of this region the behavior of the, by far largest fraction of the OCter, the dissolved organic carbon (DOC) in Arctic and sub-arctic estuaries is still a matter of debate. This thesis describes data originating from field cruises in Arctic and sub-arctic estuaries and coastal areas with the aim to improve the understanding of the fate of OCter in these areas, with specific focus on DOC. All presented studies indicate that DOCter and terrestrially derived particulate organic carbon (POCter) are subjected to substantial degradation in high-latitude estuaries, as shown by the non-conservative behavior of DOC in the East Siberian Arctic Shelf Seas (ESAS) (paper I) and the even more rapid degradation of POC in the same region (paper II). The removals of OCter in Arctic shelf seas were further supported by multiple isotope studies (paper III and IV), which showed that a use of 13C/12C in both OC and DIC, together with 34S/32S is a powerful tool to describe the sources and fate of OCter in estuaries and coastal seas. High-latitude estuaries play a key role in the coupling between terrestrial and marine carbon pools. In contrast to the general perception, this thesis shows that they are not only transportation areas for DOCter from rivers to the ocean, but are also active sites for transformation, degradation and sedimentation of DOCter, as well as for POCter. In a rapidly changing climate, the importance of these areas for the coupling between inorganic and organic carbon pools cannot be underestimated. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: In press. Paper 2: Submitted. Paper 4: Manuscript.</p>

Le TOC des sédiments du système Gange-Brahmapoutre croît linéairement avec la proportion de phylosilicates et de particules fines. La proportion de Corg fossile est ~ 20 % dans les MES et > 50 % dans les sédiments de fond. Plus de 50 % du Corg dérivé de l'Himalaya est oxydé et remplacé lors du transport dans la plaine du Gange. La charge en Corg est similaire dans les sédiments du Cône et dans les sédiments de rivière. L'abondance et le d13C des biomarqueurs indique que le Corg est dominé par les apports terrigènes. Par conséquent, l'efficacité d'enfouissement du Corg terrigène est proche de 100 %. Dans le système himalayen, nous estimons les flux d'enfouissement de Corg récent et fossile à respectivement 3.1±0.3 × 1011 mol/an et 0.9±0.4 × 1011 mol/an. L'enfouissement de Corg représente donc ~ 80 % de la consommation de CO2 engendrée par l'érosion de l'Himalaya. De manière générale, les orogènes actifs se caractérisent probablement par un enfouissement efficace de Corg / In the Ganga-Brahmaputra system, TOC linearly increases with the relative proportion of philosilicates and fine grain minerals. The proportion of fossil Corg in the suspended and bed sediments is respectively ~ 20 % and > 50 % of the TOC. During the Gangetic floodplain transit, more than 50 % of recent Corg derived from the Himalaya is oxidised and is replaced by Corg derived from the floodplain. The Corg loadings of river and recent Bengal Fan sediments are comparable. Biomarker abundance and ð13C show that Corg is dominated by terrestrial inputs. Consequently, the terrestrial Corg burial efficiency must be around 100 %. In the Himalayan basin, we estimate the burial fluxes or recent and fossil Corg to be respectively 3.1±0.3 × 1011 mol/yr and 0.9±0.4 × 1011 mol/yr. Corg burial therefore account for ~ 80 % of atmospheric CO2 consumption generated by Himalayan erosion. Efficient burial of Corg is likely a characteristic of high physical erosion typical of active orogenic systems

L'évolution de la législation en matière de valorisation des déchets organiques incite au développement de filières de valorisation, parmi lesquelles le compostage présente un intérêt d'amendement pour les sols, lié notamment à la présence de substances humiques. La matière organique (MO) est une composante importante du sol en raison de son rôle dans les équilibres physiques, chimiques et biologiques, ainsi que par son implication dans le comportement des métaux et métaux traces (MMT). Les objectifs de cette thèse étaient de développer une approche méthodologique afin de caractériser la MO du sol (MOS) et étudier son évolution spatio-temporelle suite à l’apport d’un compost sur une année et 2 profondeurs, et d'approcher son impact sur le comportement des MMT. Une procédure d’extraction séquentielle en 4 étapes (eau, acide, soude, pyrophosphate) a été réalisée afin de fractionner la MOS. Des analyses quantitatives et qualitatives, ont été effectuées sur les extraits. La procédure de fractionnent chimique a permis de distinguer plusieurs catégories de composés organiques (labiles, fulviques et humiques plus ou moins aromatiques). Les analyses quantitatives et les réponses spectrales sur les extraits ont révélé un effet compost essentiellement les trois premiers mois après l’épandage et en été, avec un impact des paramètres climatiques au cours de l'année, mais pas au-delà de 15 cm. Le compost peut apporter au sol une charge supplémentaire en MMT, notamment potentiellement mobilisables, avec un risque de contamination modéré, mais non négligeable lié aux effets potentiels d’accumulation et de concentration sur le long terme. / The evolution of the legislation regarding the valorization of biowaste (green manure) induces the development of valorization chains, among which amending soils with compost is of particular interest, due to the presence of humic substances. Organic matter (OM) is an important component of the soil due to its physical, chemical and biological participation, and its implication in the behaviour of metals and trace metals (MTM).The aims of this thesis were to develop a methodological approach to characterize OM of soil (SOM) and to study its spatiotemporal evolution over one year at two different depths following the addition of compost, and its impact on the behaviour of MTM. A 4-step sequential extraction procedure (water, acid, sodium hydroxide, pyrophosphate) was used to the SOM fractionation. Quantitative and qualitative analysis were applied on extracts. Solubilization kinetics of MTM was also carried out to refine the study of their mobility.The chemical fractionation procedure allowed distinguishing several classes of organic compounds (labile, fulvic and humic with various aromaticity). Quantitative analyzes and spectral responses of the extracts revealed an effect of the compost (organic carbon, metals, aromaticity and molecular weight compounds) essentially during the first three months after spreading and during the summer period, with a climate parameter effect during the year, but not beyond 15 cm of depth. Compost can bring to the soil an additional load of MTM, including potentially mobilized forms, with a moderate, but not negligible risk of contamination, due to the potential effects of accumulation and concentration over the long term.

The trophic state of lakes is commonly defined by the concentration of nutrients in the water column. High nutrient concentrations generate high phytoplankton production, and lakes with low nutrient concentrations are considered low-productive. This simplified view of lake productivity ignores the fact that benthic primary producers and heterotrophic bacteria can be important basal producers in lake ecosystems. In this thesis I have studied clear-water and brown-water lakes with respect to primary production, respiration and bacterial production based on allochthonous organic carbon. These processes were quantified in pelagic and benthic habitats on temporal and spatial scales. I also calculated the net ecosystem production of the lakes, defined as the difference between gross primary production (GPP) and respiration (R). The net ecosystem production indicates whether a lake is net heterotrophic (GPP &lt; R), net autotrophic (GPP &gt; R) or in metabolic balance (GPP = R). Net heterotrophic lakes are sources of carbon dioxide (CO2) to the atmosphere since respiration in these lakes, by definition, is subsidized by an external organic carbon source. External organic carbon is transported to lakes from the terrestrial environment via inlets, and can serve as a carbon source for bacteria but it also limits light availability for primary producers by absorbing light. On a seasonal scale, four of the clear-water lakes studied in this thesis were dominated by primary production in the soft-bottom benthic habitat and by respiration in the pelagic habitat. Concentrations of dissolved organic carbon (DOC) were low in the lakes, but still high enough to cause the lakes to be net heterotrophic. However, the lakes were not low-productive due to the high production in the benthic habitat. One of the clear-water lakes was studied also during the winter and much of the respiration under ice was supported by the benthic primary production from the previous summer. This is in contrast to brown-water lakes where winter respiration is suggested to be supported by allochthonous organic carbon. By studying lakes in a DOC gradient (i.e. from clear-water to brown-water lakes) I could draw two major conclusions. The lakes became less productive since benthic primary production decreased with increasing light extinction, and the lakes became larger sources of CO2 to the atmosphere since pelagic respiration was subsidized by allochthonous organic carbon. Thus, lake carbon metabolism can have an important role in the global carbon cycle due to their processing of terrestrial organic carbon and to their possible feedback effects on the climate system.

One of the modern times worst environmental problem are polluted water resources. An example of source of pollution to water resources are, heavy metal leached from acid sulfate soils (ASS). When these soils are stable, which they are if they are left underwater in an anoxic environment (for example below the water table), they are often sought after since they consist of high amount of nutrients which farmers use as farmlands. ASS is therefore created when farmers drain their land and the sulfide soil gets exposed to air, resulting in its oxidation and therefore formation of sulfuric acid. In a previous study performed by scientists from Linnaeus University, it was concluded that a natural reserve located in Vattenriket, Kristianstad was possibly damaged by the drainage discharge of an adjacent acid sulfate soil. For remediation of acid sulfate soil, notably removal of metals from drainage waters, grounded coffee has been suggested to be able to perform well as an adsorbent. This study was performed to investigate how well grounded coffee could be used as an adsorbent, for calcium (Ca) and zinc (Zn), from water samples collected in Vattenriket, Kristianstad. It was also studied to see if grounded coffee could be cleaned using a sodium hydroxide solution to increase its adsorption capacity. To be able to evaluate how well it could be used as an adsorbent, it went through two different cleaning procedures and total organic carbon and pH readings was performed. The used method for this paper was to clean the grounded coffee in two different stages. The first stage consisted of using distilled water and letting it run through the residues until the water came out as transparent. Cleaning using a NaOH solution consisted of suspending the residues in a NaOH solution for 45 minutes and swapping the solution 6-8 times. After the grounded coffee had dried in an oven at 30o for 48 hours, it was put into different fraction sizes, weighed and bagged. The water samples then had to be filtered using a pump and Filtropur S 0.45 filters. Lastly, 45 falcon tubes containing 15 different amounts of grounded coffee had 50 ml of filtered water sample added to them. For analysis, atomic absorption spectroscopy was used. The results showed that the maximum amount of adsorbed calcium was achieved at 1.5g of grounded coffee in a 50 ml water solution which managed to adsorb 99.53% of calcium. The maximum amount of adsorbed zinc was achieved at 1.25g of grounded coffee in a 50 ml solution which resulted in 99.16% of adsorbed zinc. The study also showed that when the total organic carbon-content was decreasing, due to excessive cleaning, the pH was increasing. This was further proof that the grounded coffee still had residues onto its surface that could inhibit its adsorption capabilities.

Orientador: Rafael Montanari / Resumo: A qualidade do solo não é algo que se pode medir diretamente, no entanto, pode ser avaliada pelos atributos que caracterizam seu estado físico, químico e biológico. A escolha de atributos mais relevantes e a interpretação das medidas obtidas não é algo simples, devido aos efeitos da mudança de uso da terra e as interações entre eles e as condições climáticas e serviços ecossistêmicos de cada região. O objetivo desse estudo foi fornecer uma visão geral de alguns indicadores de qualidade física e química do solo no contexto de restauração de pastagens do Cerrado Brasileiro. A tese é disposta em capítulos, compondo além das considerações gerais apresentadas no Capítulo 1, os Capítulos 2 e 3, que são estudos científicos de avaliação da qualidade física e química do solo. Os experimentos foram desenvolvidos no município de Selvíria – MS em duas áreas destinadas à pecuária extensiva de corte, subsidiadas pela planta forrageira Urochloa brizantha cv. Marandu. Malhas experimentais de 2,7 e 1,4 hectares, com 70 e 65 pontos, respectivamente, foram instaladas nas áreas e amostras de solo de estrutura deformada e indeformada foram tomadas para avaliação dos atributos físicos e químicos. Também se avaliou os estoques de carbono orgânico total, suas frações granulométricas e a emissão de CO2 nas áreas, visando enxergar os efeitos da reforma sob o aporte de carbono e as emissões de gases de efeito estufa. Em uma das áreas avaliou-se a curva de retenção de água do solo e índice S em todos os... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Soil quality is not something that can be directly measured; however, it can be assessed by the attributes that characterize its physical, chemical and biological state. The choice of more relevant attributes and the interpretation of the measures obtained is not a simple matter, due to the effects of land use change and the interactions between them, the climatic conditions and ecosystem services of each region. The aim of this study was to provide an overview of some indicators of physical and chemical quality of the soil in the context of pasture restoration in the Brazilian Cerrado. The thesis is laid out in chapters, composing in addition to the general considerations presented in Chapter 1, Chapters 2 and 3, which are scientific studies to assess the physical and chemical quality of the soil. The experiments were carried out in the municipality of Selvíria – MS in two areas for extensive beef cattle, subsidized by the forage plant Urochloa brizantha cv. Marandu. Experimental meshes of 2.7 and 1.4 hectares, with 70 and 65 points, respectively, were installed in the areas and soil samples of deformed and undeformed structure were taken to assess the physical and chemical attributes. The total organic carbon stocks, their particle size fractions and the CO2 emission in the areas were also evaluated, aiming to see the effects of the reform under the carbon input and the greenhouse gas emissions. In one of the areas, the soil water retention curve and S index were evaluated ... (Complete abstract click electronic access below) / Doutor

The drive of the EU countries and most of the world towards a circular economy and togenerate zero waste raised a need to study more efficient and less costly treatment processes. The treatment of secondary and by-product fractions to convert them from what is considered waste to a resource will contribute to the movement towards zero waste and circular economy. The fines fraction of construction and demolition waste (CDW) contains high organic materials measured as total organic carbon TOC above the allowed landfilling levels that are allowed for landfilling in Sweden, yet lower organic matter than is required for energy recovery by incineration. The need for new processes to reuse and recycle materials have emphasized the work of thisstudy, this thesis research aims to develop viable, simple treatment methods and pathways ofrecycling systems to convert by-products that are considered waste to reusable and treatable fractions by reducing the total organic carbon TOC. Which have been defined in the researchquestion of this study “How can functional recycling become more effective through the development of innovative treatment pathways for by-products of the recycling system”? and its sub-questions. This study examined a fines fraction from the CDW sorting in Norway using mechanicalseparation methods including single and combined sequential processes of air classificationand float/sink density separation. Using single process batch separation of float/sink had produced a 73.80% weight of the original fines fraction, with reduced TOC from originally 35.54% DM to 4.09% DM which can be considered to be landfilled as non-hazardous provided that it meets all other leachateanalysis criterion, on the other hand, the process produced concentrated the organic carbon inthe float fraction giving a TOC of 40.14% DM to consider treating it with energy recovery. Using a single separation process of high air velocity with the zigzag air classification has lowered the TOC of 19.49% weight of the treated fraction to 1.8% DM from 35.54% DM of the original fines fraction, which can be considered to be landfilled as inert waste if it meetsall other leachate analysis criterion, or can be considered to be used in road base layers, and concentrated the organic carbon in the other fraction to TOC of 19.90% DM that which need further treatment. Using sequential air classification followed by float/sink sequentialseparation produced different low TOC fractions suitable for landfilling in the categoriesinert, non-hazardous, and hazardous waste in Sweden and concentrated the organic content toTOC levels of 20-48% DM TOC which can be considered for energy recovery recycling. The use of sequential density separation processes can lead to better results and can be controlled more to produced better fractions. The conclusion of this study, using float/sink and airclassification separation methods as single or combined sequential processes had successfully produced two fractions firstly the reduced the total organic carbon separated fraction to be suitable the landfilling requirements in Sweden at the same time concentrated the organicmaterial of the other fraction to be suitable for incineration.

No description available.

This thesis is focused on technological processes during drinking water treatment. The emphasis is put on monitoring indicators of organic substances present in water and indicators of the biological stability of treated water. The experimental part is focused on the comparison of separation efficiency of drinking water treatment technological processes by monitoring of chemical oxygen demand, absorbance measured at 254 nm, bioseston, culturable microorganisms and assimilable organic carbon.