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Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Desalination, by means of reverse osmosis (RO), in combination with other processes, can produce potable water at high recoveries. Antiscalants are generally used to reduce scaling on equipment surfaces and to improve water recovery during RO by slowing down the precipitation kinetics of sparingly soluble salts in the RO feed, thereby allowing concentration levels in the RO brine at several times the solubility limit of these salts. In addition, a fraction of the concentrate may be recycled back to the feed of the RO-membrane to improve the overall recovery, but only after the super saturated salts in the concentrate have been precipitated. The inhibitory character of the antiscalants (which are rejected into the concentrate stream) complicates the removal of salt from the concentrate and therefore prohibits such recycling. The focus of this study is aimed at properly understanding some of the parameters that influence the functionality or effectiveness of antiscalants used in high sulphate waters, with the purpose to override the effect of the antiscalant in the concentrate stream and force precipitation of the super saturated salts in solution. A batch crystallization technique, which considers the precipitation of calcium sulphate dehydrate (gypsum) from a solution of changing super saturation, was used to perform precipitation tests 1) on synthetically prepared solutions, super saturated with gypsum and 2) industrial concentrate, rich in sulphate (produced by concentrating acid mine drainage (AMD) by means of a lab scale RO unit). During batch crystallization, the precipitation process was observed by means of monitoring the depletion of calcium, using a calcium selective electrode (ISE). Deductions concerning the kinetics of precipitation were made from observing two kinetic variables (response variables) e.g. the induction time and the growth rate (tC80 – inferential variable). Two antiscalants have been evaluated in this study: a phosphonate based antiscalant (HYDREX) and a polyacrylate antiscalant (BULAB), at concentrations of 4 mg/l and 12 mg/l. The objective was to chemically and physically manipulate the antiscalant effectiveness, override its effect and force precipitation of gypsum by means of changing parameters in the system, such as the temperature (15°C- 25°C), pH (4-10), ferric chloride concentration (2-10 mg/l) or seeding the solution with gypsum seed at a concentration of 0-2000 mg/l. In addition, lime and a combination of gypsum and lime were also used for seeding at concentrations of 2000 mg/l. The induction time, prior to precipitation, was found to be most strongly affected by the change in seed concentration and pH at a given antiscalant concentration. Seed at a concentration of 2000 mg/l was sufficient in most cases to immediately override the effect of HYDREX and BULAB (at 4-12 mg/l) and produce ~ 0 minutes induction time. A pH of 10 increased the adsorption capacity of HYDREX and BULAB, leading to longer induction times (exceeding 24 hours in some cases). At a pH of 4 the adsorption capacity was very low for both HYDREX and BULAB (lower) leading to shorter induction times (zero to 100 minutes). It was especially in the ‘no-seed’ cases that the effect of pH on the induction time was prominent. The rate of precipitation (crystal growth rate) was increased at a temperature of 25°C, compared to 15°C (the rate increased two fold for an increase in 10°C). The addition of lime-seed, instead of gypsum, (at 2000 mg/l) produced growth rates, two times higher compared to when gypsum was used at the same conditions. In Addition, seeding with lime produced induction times (150 minutes for HYDREX and 50 minutes for BULAB) prior to precipitation, compared to zero induction time when gypsum was used at the same conditions. It was proven that an induction time could be eliminated by adding a combination of gypsum and lime both at a concentration of 2000 mg/l. with the added benefit of the higher growth rate. An increase in the calcium concentration increased the crystal growth rate in the presence of HYDREX. The presence of a high pH, however caused the effect of calcium on the growth (in the presence of BULAB) to be overshadowed. At a higher pH the growth rate of gypsum slowed down as a result of the increase in adsorption capacity of the polymer onto the crystal surface. The interaction of the antiscalant with FeCl3 seemed to be important with regard to crystal growth. Higher ferric concentrations (10 mg/l) were sufficient to limit the inhibitory effect of 12 mg/l antiscalant (HYDREX and BULAB) on the crystal growth rate. Conversely, low ferric concentration resulted in slower growth rates in the presence of an antiscalant. The best conditions (within the scope of the current study), sufficient 1) to override the inhibitory effect of antiscalants (HYDREX and BULAB) and 2) to produce rapid precipitation of gypsum, lie in the use of seeding with gypsum and lime (2000 mg/l), adding ferric chloride (10 mg/l), lowering the pH to 4 or lower (which can only be obtained when lime is not added) and setting the solution temperature to a moderate value of 25°C or higher. These ‘best’ conditions were subsequently applied to a concentrate, produced from concentrating AMD in a RO unit, and proved to be even more successful in overriding the effect of HYDREX and BULAB than in synthetic aqueous solutions. The induction times of precipitation of AMD in all cases were ~ 0 minutes, whereas the growth rate increased threefold compared to the synthetic tests. The presence of additional foreign precipitates of aluminum, calcium and magnesium as well as an increased [SO4ª-] x [Caª+] product of 3.73 (AMD concentrate) vs. 3.46 (synthetic solutions) is thought to be responsible for the increase in precipitation kinetics when only gypsum seed was used. The addition of lime caused an increase in the precipitation potential of the brine by increasing the calcium concentration. Although the addition of lime caused an increase in the pH to 12.3 (at which point the antiscalant was most effective), the increase in pH is likely to cause an increase in the natural carbonate in the water, which would stimulate CaCO3 precipitation. The CaCO3 precipitate would be responsible for the adsorption of antiscalants, reducing their efficiency. / AFRIKAANSE OPSOMMING: Ontsouting by wyse van tru-osmose (TO), in samewerking met ander prosesse, kan help om drinkwater te lewer teen verhoogte herwinning. Tipies word antiskaalmiddels gebruik om bevuiling op die oppervlak van toerusting te verminder en terselfdetyd herwinning te verhoog deurdat dit die presipitasiekinetika van superversadigde soute in die TO voerwater vertraag. Dit lei daartoe dat water (superversadig met soute) deur die membraansisteem kan beweeg, sonder om bevuiling te veroorsaak. ‘n Breukdeel van die konsentraat kan herwin word na die TO voer om sodoende die algehele waterherwinning te verhoog. Dit kan egter eers gebeur nadat die soute in die konsentraat neergeslaan en verwyder is. Die inhirente ‘vertragingskarakter’ van antiskaalmiddels (wat ook in die konsentraat stroom beland) kompliseer die verwydering van sout vanuit die konsentraat en verhoed so herwinning. Die fokus van hierdie studie is daarop gemik om die parameters wat die funksionaliteit of effektiwiteit van antiskaalmiddels (wat in sulfaatryke waters gebruik word), beter te verstaan. Die doel is daarop gemik om die betrokke antiskaalmiddel se effek te kanselleer asook presipitasie van die superversadigde soute in oplossing aan te help. ‘n Lot (‘batch’) kristallisasietegniek wat die presipitasie van kalsiumsulfaatdehidraat (gips) beskou vanuit ‘n oplossing waar die konsentrasie verander soos presipitasie plaasvind, is gebruik om presipitasietoetse uit te voer 1) op oplossings wat sinteties versadig is met gips en 2) op sulfaatryke AMD (gekonsentreer met behulp van ‘n laboratoriumskaal TO eenheid). Die presipitasie proses is in elke geval waargeneem, deur die vermindering van die kalsium konsentrasie in die oplossing dop te hou, met die gebruik van ‘n kalsiumselektiewe elektrode. Afleidings rakende die kinetika van presipitasie is gemaak deur twee responsveranderlikes dop te hou: die induksietyd en die kristal groeitempo (tC80). Twee antiskaalmiddels by ‘n konsentrasies van 4 dpm (deetjies per miljoen) en 12 dpm is evalueer: ‘n fosfonaat (HYDREX) and poliakrilaat (BULAB). Die doel was om die antiskaalmiddel se werking chemies en fisies te manipuleer, hul werking teen te werk en presipitasie van gips te forseer. Die manipulasie het geskied deur die volgende parameters te verander: temperatuur (15°C-25°C), pH (4-10), FeCl3 (2-10 mg/l) of saad byvoeging (gips: 2000 mg/l). Kalsiumhidroksied (gebuste kalk) en ‘n kombinasie van gips en gebluste kalk is ook gebruik by konsentrasies van 2000 mg/l. Die induksietyd (by ‘n spesifieke antiskaalmiddel konsentrasie) is die sterkste beïnvloed deur ‘n verandering in saad konsentrasie en pH verandering. In die meeste gevalle was ‘n saad konsentrasie van 2000 mg/l voldoende om die induksie effek van beide HYDREX en BULAB te vernietig en nulminute induksietyd is verkry. ‘n pH van 10 het gelei tot die verhoging van die adsorpsiekapasiteit van HYDREX en BULAB wat gelei het tot langer induksietye (in sommige gevalle het dit 24 uur oorskry). By ‘n pH van 4 was die adsorpsie kapasiteit van beide antiskaalmiddels baie laag (laer vir BULAB) en induksie-tye is beperk tot 100 minute. Dit is veral wanneer geen saad toegevoeg is nie wat die effek van pH prominent was. Die tempo van presipitasie was verhoog by ‘n temperatuur van 25°C (2 keer hoër as by 15°C). Die byvoeging van gebluste kalk teen 2000 mg/l het ‘n kristal groeitempo, 2 keer hoër as in die teenwoordigheid van gips gelewer. Gebluste kalk saad byvoeging het egter gelei tot ‘n indukisetyd (150 minute vir HYDREX en 50 minute vir BULAB). Hierdie probleem is oorkom deur ‘n kombinasie van gips en gebluste kalk te gebuik teen ‘n konsentrasie van 2000 mg/l. Geen induksie tyd is waargeneem met die voordeel van ‘n hoër presipitasietempo (kristal groei). ‘n Verhoging van kalsium konsentrasie verhoog die kristal groei tempo in die teenwoordigheid van HYDREX. Nietemin, die invloed van pH oorskadu die invloed van kalsium op die groei tempo (in die teenwoordigheid van BULAB). By ‘n hoë pH word die kristal groei tempo vertraag as gevolg van die verhoging van die adsorpsiekapasiteit van die antiskaalmiddel. Die interaksie van FeCl3 met die antiskaalmiddel blyk van belang te wees. By hoë FeCl3 konsentrasies (10 dpm), is die werking van beide HYDREX en BULAB (12 dpm) beperk. Die ‘beste’ kondisies (verkry binne die konteks van hierdie studie), 1) om die vertragingseffek van HYDREX en BULAB teen te werk en 2) spoedige presipitasie van gips te bewerk, lê in die gebruik van saad (gips en gebluste kalk teen 2000 mg/l), die byvoeging van FeCl3 (10 mg/l), ‘n lae pH (4 of laer, wat natuurlik net tersprake is wanneer slegs gips as saad gebruik word aangesien geluste kalk die pH sal lig) asook ‘n relatiewe hoë temperatuur (25°C). Hierdie ‘beste’ kondisies is toegepas in AMD konsentraat om die effek van HYDREX en BULAB te vernietg en gips te presipiteer en die gevolg was dat dit selfs meer suksesvol was as in sintetiese oplossings. In elke geval is die induksietyd na nul minute toe verminder, terwyl die kristal groei tempo 3 maal verhoog het in vergelyking met die sintetiese toetse. Die teenwoordigheid van onsuiwerhede insluitende aluminium, kalsium, magnesium sowel as ‘n verhoging in die [SO4ª-]x[Caª+] produk (3.73 teenoor 3.46 vir sintetiese toetse), blyk verantwoordelik te wees vir die versnelling van die kinetika. Met die byvoeging van gebluste kalk is dit waarskynlik dat die verhoging van die pH (12.3) lei tot die verhoging van natuurlike karbonate in die water wat weer CaCO3 stimlueer. Die teenwoordigheid van CaCO3 kan verantwoordelik gehou word vir bykomende nukleasie en groei, sowel as die deaktivering van antiskaal effektiwiteit.

Thesis (MScAgric (Soil Science))--Stellenbosch University, 2005. / Soil acidity is one of the greatest limitations to crop production in most soils of the world. The increasing high costs of conventional liming materials have made it necessary to explore the possibilities of using cheaper substitutes. In South Africa, 16 million hectares of land are naturally acid while on the other hand, the country’s coalfired power plants generate 28 million tons of mostly alkaline coal ash per year, disposal of which is increasingly becoming difficult. The use of coal ash as an agricultural soil amendment while solving the liming needs of local farmers, may also present a safe and more economical disposal option. This study was carried out to evaluate the effectiveness of coal ash as an agricultural liming material. A greenhouse experiment was conducted using maize as test crop. A field experiment was also established on Beestepan Farm in Middelburg, Mpumalanga Province using dry beans as test crop for the first season. In both experiments, fresh unweathered coal ash from Duvha power station (CCE 10%), dolomitic lime (CCE 77%) and calmasil (calcium silicate slag, CCE 99%) were applied to acidic sandy loam soils in the presence or absence of gypsum. Both calmasil and dolomitic lime were applied at equivalent rates of 0, 1, 2, and 4 tons/ha, and rates of 0, 7, 14 and 28 tons/ha were used for ash. Gypsum was applied at a rate of 4 tons/ha. All treatments were applied in three replications. Results showed that liming increased soil pH, improved soil nutrient status and plant uptake of base cations, and enhanced yield. In the greenhouse, coal ash decreased exchangeable acidity from 13.0 mmolc/kg to 6.67 mmolc/kg, increased Ca levels from 200 mg/kg to 379 mg/kg, and increased Mg levels from 25.9 mg/kg to 42.0 mg/kg. Nitrate levels were also raised from 4.4 mg/kg to 14.8 mg/kg hypothetically as a result of the increase in the activity of nitrifying bacteria following a decrease in soil acidity after ash application. Maize yield in the greenhouse was not significantly affected by ash or by other liming materials, and the sufficient watering and consequent elimination of aluminium-induced drought stress is put forward as having masked crop responses to acidity. In the field, coal ash reduced exchangeable acidity from 10.0 mmolc/kg to 5.88 mmolc/kg, increased Ca levels from 71 mg/kg to 132 mg/kg, and increased Mg levels from 7.3 mg/kg to 17 mg/kg. The increase in bean yield from 958 kg/ha to 1724 kg/ha by ash was similar to that realized by dolomitic lime and calmasil. Gypsum had little effect on soil acidity, but it substantially improved soil Ca and sulfate levels, and enhanced bean yield in the field experiment. The study demonstrated that coal ash could be effective as a liming material, and underscores the need for a cost-benefit assessment of ash use necessitated by the relatively higher rates of ash required to obtain significant soil and plant responses.

The effects of sulfur-containing amendments (H₂SO₄,Al₂(SO₄)₃ and gypsum) or crust formation, soil chemical properties, seedling emergence and yields of onions (Allium cepa), tomatoes (Lycopersicum esculentum) and chili peppers (Capsicum sp.) were studied on a Pima clay loam soil. Treatments were surface applied on a strip above the seeds. The chemicals influenced the penetrometer index, soil-pH, electrical conductivity, DPTA-extractable soil Fe, Cu, Zn, Mu and seedling emergence in two greenhouse experiments. Gypsum and H₂SO₄ increased seedling emergence while Al₂(SO₄)₃ reduced the soil-pH and EC more than H₂SO₄ and gypsum. Based upon penetrometer readings, H₂SO₄ was the best anti-crusting agent tested followed by gypsum and Al₂(SO₄)₃. At the end of the study, all soil samples were very low in KCl extractable Al, showing that Al toxicity was not responsible for seedling damage. Gypsum decreased levels of Mn and Zn but did not affect Fe and Cu. Al₂(SO₄)₃ increased Fe and Zn, decreased Cu but did not affect Mn. H₂SO₄ did not affect extractable Mn, Cu, Zn and Fe levels. In a field study using two water qualities at Safford, gypsum produced the most tomato seedlings whereas Al₂(SO₄)₃ and H₂SO₄ produced the least. Onion stand counts were not affected by the chemicals with either water. Gypsum, H₂SO₄ and Al₂(SO₄)₃ polymer produced the highest pepper stand counts with the saltier water but there were no differences with lower salt water. Tomatoes produced the highest yield with gypsum and lowest with H₂SO₄ and Al₂(SO₄)₃ with saltier water. With lower salt water, gypsum produced highest yield, followed by the H₂SO₄. Both H₂SO₄ treatments produce low yields. Onions showed no treatment response under lower salt water, while with saltier water, gypsum and H₂SO₄ produced the highest yields. Pepper yields were not affected by amendments with the lower salt water. Al₂(SO₄)₃ polymer, H₂SO₄ and gypsum increased yields with the saltier water. Varieties of peppers and tomatoes produced different yields in response to water quality in a supplementary field study.

Synthesebedingt fällt die DTPMP als dunkelbraune, zähflüssige Lösung mit zahlreichen Verunreinigungen an. Diese Arbeit beschäftigt sich mit der Herstellung einer hochreinen, festen DTPMP. Hierfür wurden zwei unterschiedliche Reinigungsmethoden untersucht. Durch Umkristallisation und anschließendes Rühren in Ethanol konnte mit 95 % eine höhere Reinheit als bisher veröffentlicht erzielt werden. Eine alternative Reinigungsmethode stellt die Ausfällung als Erdalkali-DTPMP-Salz und anschließende Auflösung in Schwefelsäure und Abtrennung des entstehenden Erdalkalisulfats dar, wobei eine Reinheit > 99 % erzielt wurde. Zur strukturellen Charakterisierung wurden zahlreiche Kristallisationsexperimente zur Züchtung von Kristallen der DTPMP als Säure und deren Alkali- und Erdalkalisalzen durchgeführt. Weiterhin wurde das thermische Verhalten der DTPMP und deren Salzen charakterisiert. Unter den zahlreichen möglichen Anwendungen der DTPMP wurde beispielhaft die Wirksamkeit auf die Gipskristallisation untersucht.

O presente estudo investigou a participação do H2S04, como agente corrosivo no carste do Grupo Una, na bacia de Irecê e na bacia do rio Salitre, tendo como base o monitoramento hidroquímico e a determinação de fácies hidroquímicas. A fácies escoamento superficial alogênico é caracterizada por baixos valores de pH (\'X BARRA\'=4,79 ; CV=3,15%) e dos principais cátions e ânions, com destaque para S\'O IND. 4 POT. 2-\' (x=0,57 mg/L ; CV10,32%); A fácies fluxo freático profundo carbonático representa a maior concentração de HC\'O IND. 3 POT. -\' de todo conjunto amostrado, com média igual a 359,08 mg/L. Na média as águas desta fácies encontram-se saturadas para calcita (S\'l IND. c\' = 0,02) e insaturadas para gipsita (S\'l IND. g\' = -1,51). A concentração de S\'O IND. 4 POT. 2-\' também é alta (\'X BARRA\'=204,50 mg/L ; CV 135,00%), destacando-se um ponto de amostragem que exibe elevado valor médio para \'SO IND. 4 POT. 2-\' (\'X BARRA\'= 746,07 ; CV = 13,79%); Na fácies percolação vadosa a concentração de S\'O IND. 4 POT. 2-\' é expressiva, com média igual a 305,09mg/L; Nos reservatórios subterrâneos destaca-se a alta concentração de HC\'O IND. 3\'(média - 305,10 mg/L), Índice de Saturação para calcita muito próximo do equilíbrio (S\'l IND. c\'=-0,02) e concentração média para S\'O IND. 4 POT. 2-\' (\'X BARRA\'=17,79 mg/L; CV = 52,03%); Nas nascentes cársticas observou-se alto teor de HC\'O IND. 3 POT. -\' (\'X BARRA\'=246,96 mg/L ; CV = 11,0%), S\'l IND. c\'=0,00 (0,28 a -0,37), em equilíbrio de saturação para o mineral calcita e concentração de S\'O IND. 4 POT. 2-\' (\'X BARRA\'= 19,30mg/L ; CV = 31,47%). As águas meteóricas são caracterizadas por baixas concentrações dos principais cátions e ânions, com médias inferiores a 0,5mg/L. Cálculos estequiométricos foram aplicados aos dados hidroquímicos e conclui-se que no balanço molar as águas não seguem as razões clássicas para dissolução exclusiva por ácido carbônico, mas sim, adequam-se ao sistema \'H IND. 2\'S\'O IND. 4\' - CaMgC\'O IND. 3\'. Minerais secundários de cavernas foram analisados e detectou-se ocorrências expressivas de gipsita, sob a forma de crostas, estalactites e filamentos, que, vinculadas ao ambiente de formação, indicam a participação de soluções ricas em sulfato em seus processos. O evento principal de deposição de gipsita foi associado ao rebaixamento do NA após fase de ampliação paragenética dos condutos. Análises isotópicas de \'\'delta\' POT. 13\'CHC\'O IND. 3 POT. -\' em amostras de águas subterrâneas indicam valores enriquecidos (-10,4%o PDB-V) em relação ao esperado para a reação de dissolução da rocha carbonática por ácido carbônico (-17,1%o), condição relacionada à influência de \'ANTPOT. 13 C\' oriundo da rocha por ação do ácido sulfúrico. O \'delta\' POT. 34\'S de sulfato em água subterrânea (\'X BARRA\'=17,7%o CDT) é levemente empobrecido em relação à pirita (\'X BARRA\'=21,3%o), com valores na faixa de amplitude prevista para o processo de oxidação, condição que atesta a participação de ácido sulfúrico na dissolução da rocha carbonática. Análises microbiológicas na água subterrânea do aqüífero cárstico indicaram a presença de bactérias do gênero Acidithiobacillus e bactérias redutoras de sulfato (BRS), ambas presentes no ciclo do enxofre e responsáveis pela produção de ácido sulfúrico. Neste sentido, as variáveis estudadas possibilitam a confirmação da participação do ácido sulfúrico na dinâmica do sistema cárstico do Grupo Una no Estado da Bahia. / The main goal of this study is to determine the effectiveness of sulfuric acid as a corrosive agent in the karst system of the Una Group (lrecê geological basin and Salitre river basin), based on hydrochemical monitoring and the respective hydrochemical facies. The allogenic surface runoff is characterized by low ion concentrations and pH (ph=4,79 ; CV=3,15%). Sulfate is also low for this facies (\'X BARRA\'=0,57 mg/L ; CV 10,32%). With respect to the HC\'O IND. 3 POT. -\' content, the deep phreatic flux in the carbonate aquifer has the highest concentration compared to the other facies, with a mean of 359,08 mg/L. This deep phreatic flux is saturated with respect to calcite and undersaturated with respect to gypsum, showing average concentrations of 204,5 mg/L (CV 135,00%) for S\'O IND. 4 POT. 2-\', including one sampling site with average concentration of 746,07 mg/L (CV = 13,79%). Expressive sulfate concentration was also detected in the vadose seepage, with a mean of 305,09 mg/L. Underground reservoirs have high HC\'O IND. 3 POT. -\' content (\'X BARRA\'=305,10 mg/L) together with calcite saturation index close to equilibrium (S\'l IND. c\'=-0,02) and lower sulfate concentration (mean of 17,79 mg/L; CV = 52.03%). The karst springs revealed similar chemistry to the underground reservoirs, with high HC\'O IND. 3 POT. -\' content (\'X BARRA\'=246,96 mg/L ; CV = 11,0%), saturated with respect to calcite (mean of S\'l IND. c\' = 0,00; varying between 0,28 and -0,37) and mean sulfate concentration of 19,30mg/L (CV = 31.47%). The meteoric recharge has a very low solute load, with means of all ions lower than 0.5 mg/L. Stoichiometric balance calculations applied to the hydrochemical results showed that the molar balances of the various water facies do not follow the classical ratios of carbonate dissolution only due to carbonic acid, but on the contrary, they follow better the chemical system of \'H IND. 2\'S\'O IND. 4\' - CaMgC\'O IND. 3\'. The study of the expressive secondary gypsum deposits in caves, represented by crusts, stalactites and filaments, showed that their origin is related to the deep phreatic water and that the major deposition event of these deposits occurred during the water table lowering after the high water table period related to the paragenetic conduit enlargement. Isotopic composition of dissolved inorganic carbon in groundwater samples showed values of \'\'delta\' POT. 13\'CHC\'O IND. 3 POT. -\' around -10,4%o PDB-V, which are relatively enriched with respect to the predicted \'\'delta\' POT. 13\'CHC\'O IND. 3 POT. -\' of -17,1%o, if the system would be affected only by carbonic acid. This enrichment is attributed to the \'ANTPOT. 13 C\' originated by the reaction between carbonate rock and sulfuric acid. The \'delta\' POT. 34\'S of sulfate in water (\'X BARRA\'=17,7%o CDT) is slightly depleted than that of pyrite disseminated in carbonate rock (\'X BARRA\'=21,3%o), but still in the range predicted for the fractionation due to pyrite oxidation, indicating that carbonate rock is dissolved by sulfuric acid. Microbiological analysis of groundwater in the karstic aquifer revealed the presence of bacteria of the genera Acidithiobacillus and sulfate reducing bacteria (SRB). Both are typical of the sulfur cycle and produce sulfuric acid. Finally, it can be stated, based on the above described results, that sulfuric acid is an important agent in the dynamics of the studied karst.

Made available in DSpace on 2017-07-24T19:38:04Z (GMT). No. of bitstreams: 1 Elayne Cristina da Silva.pdf: 1345009 bytes, checksum: f392911201026a5ccd75d0704508a00a (MD5) Previous issue date: 2010-09-01 / Many soils in the state of Parana are acidic in their natural state, with levels of aluminum in the shape and levels that are toxic to plants, this leads to the need for use of agricultural lime in the soil. Limestone is the most used corrective, but has slow mobility in the soil profile, but is slow its correctness beyond the layer of incorporation. In this sense, the use of gypsum now has in recent years, a special interest, because this has important chemical and physical characteristics necessary to be used as conditioner subsurface layers. This study was conducted to evaluate the vertical mobility of cations through soil columns after application of limestone, gypsum and a mixture of gypsum and limestone, submitted to percolation of water from a Cambissol Haplic Aluminic Irati municipality of in Parana State, this soil has a high amount of aluminum, and is widely used for growing crops, but little studied. The experiment was conducted in the in the laboratory, we used PVC columns with 8 cm diameter and 35 cm tall, sectioned and applied to water, simulating the average annual rainfall of 1245 mm in the region, split applications, three of percolations 450 mL, one every 15 days. After the soils were analyzed: pH, C, Ca, Mg, Al3+, concentration extractable P and K, H + Al (potential acidity), S (sum of bases) and CTC (capacity cation exchange) , base saturation (V), aluminum saturation (Al) and by atomic absorption was analyzed metals (Cu, Cr, Ni, Zn, Pb, Fe and Mn) easily exchangeable through leaching. Observe that, for the Cambisol study, the setting meets the needs of correction of pH, neutralization, Al3+, retention of bases and nutrients just for the treated layer, but with very slow process of leaching. The mixture with gypsum in lime facilitates this process by increasing the amount of copper, but increasing the mobility of metals. / Muitos solos paranaenses são ácidos em seu estado natural, com teores de alumínio em forma e níveis que são tóxicos às plantas, isto leva a necessidade de uso de corretivos no solo. O calcário é o corretivo mais utilizado, porém tem lenta mobilidade no perfil do solo, sendo lenta a correção além da camada de incorporação. Nesse sentido, a utilização de gesso passou a ter nos últimos anos, um interesse especial, pois este possui importantes características químicas e físicas necessárias para ser usado como condicionador de camadas subsuperficiais dos solos. O presente trabalho foi conduzido com o objetivo de avaliar a mobilidade vertical de cátions ao longo de colunas de solo, após a aplicação de calcário agrícola, gesso agrícola, e uma mistura de gesso e calcário agrícola, submetidas à percolação com água de um Cambissolo Háplico Alumínico da região do município de Irati no Estado do Paraná, esse solo apresenta alto teor de alumínio, e é muito usado para plantio de lavouras, porém pouco estudado. O experimento foi realizado em laboratório, utilizaram-se colunas de PVC, com 8 cm de diâmetro e 35 cm de altura, seccionadas e aplicaram-se água, simulando a recipitação média anual de 1245 mm da região, aplicados parceladamente, em três percolações de 450 mL, uma a cada 15 dias. Após foram realizadas nos solos as seguintes análises: pH, C,Ca, Mg, Al3+ trocáveis, teores extraíveis de P e K, H + Al (acidez potencial), S (soma de bases) e CTC (capacidade de troca de cátions) ,saturação por bases (V), saturação por alumínio (Al), e através de absorção atômica analisou-se metais (Cu,Cr, Ni, Zn, Pb, Fe e Mn) facilmente trocáveis através de lixiviações. Observa-se que, para o Cambissolo Háplico Alumínico estudado, a calagem atende as necessidades de correção de pH, neutralização de Al3+ , retenção de bases e nutrientes apenas para a camada tratada, porém, com processo de lixiviação muito lento. A mistura com o gesso agrícola na calagem facilita este processo, aumentando a quantidade de cobre, mas aumentando a mobilidade do metais.

Made available in DSpace on 2017-07-25T19:31:00Z (GMT). No. of bitstreams: 1 Roberto De Carli.pdf: 2079271 bytes, checksum: 6ef44a2405637e03f847a58547e5b604 (MD5) Previous issue date: 2016-06-29 / Nitrogen is a nutrient with such a high contribution for agriculture, that various strategies are studied every year looking for enhancements of its use efficiency and reduction of its environmental impacts. This study hypothesis is that, the use of gypsum can change the soil’s nitrogen dynamic in the no-tillage system. So, the main objective of this study was to relate the dynamic of the labile compartments of C and N as indicators of fewer losses or lower efficiency of Nitrogen by the use of gypsum under a well-established no-till system. The objective was to relate the dynamics of labile compartments C and N as loss of reduction or efficiency indicators of N due to the use of gypsum in no-tillage system. The experiment was established in September 2012 on clay Oxisol in Ponta Grossa – PR, in a split-split plot completely randomized block design, with three replications. The sources of variation were used gypsum (plots), nitrogen (split-plots) and time (split-split plots). The corn sowing was done in September 2014. The treatments used in the plots were gypsum rates: a) absence of gypsum and b) 2.7 Mg ha-1 of gypsum applied surface. Treatments of subplots were: a) 0 kg ha-1 N; b) 80 kg ha-1 N; c) 160 kg ha-1 N and d) 240 kg ha-1 applied on corn at the V4 stage phenological (four leaves expanded). The time factor was inserted as split-split plots: a) 0 days after sowing (DAS); b) 34 DAS; c) 52 DAS; d) 87 DAS and e) 117 DAS. Within the first and the fifth time layers were sampled 0-5 cm, 5-10 cm, 10-20 cm, 20-40 cm and 40-60 cm. For intermediate times were sampled layers up to 20 cm. The variables analyzed were: a) Nitrate; b) hot water extractable organic carbon (HWEOC); c) permanganate oxidizable organic carbon (POXC); d) Total Organic Carbon (TOC) and e) Total Nitrogen (TN). It was also held for sampling density in the layers referred to only in the first season. Straw samples were collected for reading C and Total N was also evaluated the decomposition of crop residues. The corn production was studied in function of the treatments employed. The use of gypsum become an important tool to minimize the environmental impact nitrate leaching. In high fertility areas and therefore no chemical deterrents in depth to achieve high production ceilings, low doses of plaster do not provide increases in corn yields, but changes in labile compartments C are observed. In long term experiments changes should be seen in TOC and NT and consequently grain production in responses can be observed. / O nitrogênio é um nutriente de grande contribuição para a atividade agrícola, desta forma várias estratégias são estudadas cujo intuito é a maximização da eficiência associada à minimização dos impactos ambientais. O presente trabalho parte da hipótese que o uso do gesso agrícola altera a dinâmica do nitrogênio no solo em sistema plantio direto. Dessa forma o objetivo geral foi relacionar a dinâmica dos compartimentos lábeis de C e N como indicadores da redução de perda ou eficiência do N devido ao uso do gesso agrícola em sistema plantio direto de longa duração. O experimento foi implantado em setembro de 2012 em um Latossolo Vermelho distrófico argiloso em Ponta Grossa – PR. O delineamento experimental foi em parcelas sub-subdivididas com três repetições. As fontes de variação empregadas foram gesso agrícola (parcelas), doses de nitrogênio (sub-parcelas) e o tempo (sub-subparcelas). A semeadura do milho ocorreu em setembro de 2014. Os tratamentos empregados nas parcelas foram doses de gesso: a) ausência de gesso e b) 2,7 Mg ha-1 de gesso, aplicados em superfície. Os tratamentos que compuseram as subparcelas foram: a) ausência de N; b) 80 kg ha-1 de N; c) 160 kg ha-1 de N e d) 240 kg ha-1 aplicados no milho no estágio fenológico de V4 (quatro folhas verdadeiras expandidas). O fator tempo foi inserido como sub-subparcela, sendo que as avaliações foram realizadas em a) 0 dias após semeadura (DAS); b) 34 DAS; c) 52 DAS; d) 87 DAS e e) 117 DAS. Dentro da primeira e da quinta época foram amostradas as camadas 0-5 cm, 5-10 cm, 10-20 cm, 20-40 cm e 40-60 cm. Para as épocas intermediárias foram amostradas as camadas até 20 cm. As variáveis analisadas foram: a) Nitrato; b) Carbono extraído em água quente (C-AQ); c) carbono oxidado por permanganato (C-OXP); d) Carbono Orgânico Total (COT) e e) Nitrogênio Total (NT). Também foi realizada amostragem para densidade nas camadas referidas apenas na primeira época. Amostras de palha foram coletadas para leitura de C e N total, também foi avaliada a decomposição dos resíduos culturais. A produtividade do milho foi estudada em função dos tratamentos empregados. O uso do gesso se torna uma ferramenta importante para minimizar o impacto ambiental pela lixiviação de nitrato. Em áreas de alta fertilidade e consequentemente sem impedimentos químicos em profundidade para alcançar altos tetos produtivos, doses baixas de gesso não proporcionam incrementos na produtividade do milho, porém alterações nos compartimentos lábeis do C são observadas. Em experimentos que contemplem maior tempo, mudanças devem ser observadas nos estoques de COT e NT e consequentemente respostas em produção de grãos poderão ser observadas.

A indústria de cerâmica branca de objetos decorativos e utilitários, produz diariamente um contingente significativo de resíduo de gesso, oriundo do descarte dos moldes, cuja vida útil é extremamente curta. A deposição desse material via de regra é feita em aterros sanitários, sem qualquer tipo de isolamento em células e sem observar as recomendações da Lei da Política Nacional de Resíduos Sólidos. De acordo com a hierarquia estabelecida pela lei, a supressão da geração dos resíduos sólidos aparece como alternativa prioritária do ponto de vista das boas práticas ambientais. É nessa perspectiva que a tecnologia de produção industrial computadorizada de objetos tridimensionais por deposição de matéria prima, surge como alternativa. A intenção desse trabalho é apresentar conceitos de produtos que potencializem o uso dessa tecnologia através de configurações formais inovadoras para o setor, eliminando a utilização do gesso em seu processo de fabricação além de avaliar os resultados obtidos através da análise dos protótipos fabricados. / White ceramic industry of decorative and utilitarian objects, produces daily a significant contingent of waste gypsum, originated from the disposal of moulds, whose lifespan is extremely short. Deposition of this material usually is made in landfills without any type of isolation cells and without observing the recommendations of the Law of the Brazilian solid waste Policy. According to the ranking established by law, the elimination of solid waste generation appears as a priority alternative in terms of good environmental practices. In this perspective, the technology of computerized industrial production of three-dimensional objects by deposition of raw material, is an alternative. The aim of this paper is to present product concepts that enhance the use of this technology through innovative formal settings for the sector and make an analysis about the results.