In recent decades, advances in low NOₓ coal combustion and increasingly strict CO₂ reduction mandates have changed power plant boiler operations quite significantly. As a result of these necessary efforts, the characteristics of fly ash generated at many power plants have also changed. In particular, increases in unburned carbon content have been observed with detrimental implications on the utility of these fly ashes in concrete applications. Over the same time period, the combustion of biomass for energy generation has received increased attention due to the potential benefits of reducing CO₂ emissions and improved sustainability when compared to fossil fuel combustion. Biomass is directly burned, gasified, or co-fired with coal to achieve this goal. Currently, close to 120 million metric tons of coal combustion by products are produced in the U.S. annually. As with coal combustion, production of energy from biomass combustion/gasification results in significant by-product generation that must either be productively reused or geologically disposed. While much research effort has been devoted to understanding the properties and potential productive reuse alternatives for coal combustion residuals, relatively little work has been done on the by-products of biomass combustion. This study investigated the properties and engineering behavior of sixteen ash samples that were produced in eleven different power plants. Specifically, three high carbon content Class F fly ashes, eight coal and biomass co-fired ashes, three pure biomass ash samples, and two high quality, low carbon content ash samples, one of which is commercially marketed (for reference) were chosen. The various ash samples were characterized by means of: electron microscopy; laser diffraction and dry sieve particle size analysis; loss on ignition and total organic carbon analysis; specific surface area analysis; as well as x-ray fluorescence and x-ray diffraction. The ash samples were also investigated for their potential engineering application in the fired clay brick industry, as low-cost adsorptive agents, and in alkali activated geopolymer synthesis for geotechnical and geoenvironmental applications. Results from physical and chemical characterization of the ash samples show no significant differences between pure coal ash and coal co-fired with biomass ash samples from the same power plant. However, there are significant morphological, chemical, and mineralogical differences between coal ash and pure biomass ash. Unlike pure coal ash, biomass ash is not composed primarily of aluminosilicate glass cenospheres but rather consists mainly of charred, fibrous woody remnants with elevated calcite content as compared to coal ash. Bench scale fired bricks produced by partial replacement of clay material with high carbon coal ash, co-fired ash, and pure biomass ash, respectively, was successful. Physical properties of a number of the mix designs exceeded the highest ASTM weathering grade requirements. As sorptive agents, high carbon concentrates from coal and co-fired ash samples, along with all the biomass ash samples, showed significant uptake of lead. The unaltered as- received ash samples (i.e. no acid or steam activation) showed only moderate arsenic (V) and selenium (VI) sorption capacity. Finally, solidification/stabilization by geopolymerization of high carbon content, co-fired ash with as little as 3 molar NaOH in the activator solution was successful, possibly paving the way for various geotechnical and geoenvironmental applications in ground improvement and soil/ash-pond stabilization.

Made available in DSpace on 2015-03-26T13:55:17Z (GMT). No. of bitstreams: 1 texto completo.pdf: 135161 bytes, checksum: ed8591d951d63626602e4249d36967ad (MD5) Previous issue date: 2011-04-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The study evaluated the production and composition of milk, intake and apparent digestibility of dry matters and nutrients, efficiency on the use of nitrogenous compounds, yield and efficiency of microbial protein synthesis in dairy cows fed with different substitution of soybean meal proportions for integral yeast of sugar cane ethanol. It was used 16 Holstein cows, in which 8 were primiparous and 8 multiparous, distributed in four 4x4 Latin squares, organized according to days and order of lactation. The treatments consisted in a basal diet, in which the soybean meal was the main protein source, and three diets with 33,3; 66,6 and 100% levels of soybean meal substitution for the yeast, based on DM. The experiment lasted 68 days, subdivided in four experimental periods of 17 days. The levels of yeast inclusion did not influence the intake of DM, OM, EE, NDFi and TDN (P>0,05), however, the CP and NDFcp (P>0,05) intake decreased lineally and the NFC (P>0,05) intake raised lineally with the growing levels of yeast in animal diets. There was no treatment effect on the digestibility coefficient of DM, OM, CP, NDFcp and NCF (P>0,05), nevertheless, the EE digestibility coefficient lineally decreased with the yeast inclusion in the experimental diets (P<0,05). The milk yield, 4% fat-correct milk yield, fat content, crude protein, lactose, total solids and SCC did not differ between treatments (P>0,05). It was not verified the effects on the sum of allantoin excretions in the urine and milk, uric acid, total purine, microbial protein and microbial efficiency (P>0,05). It was observed a decreased lineal effect for the urea nitrogen concentrations in plasma and milk (P<0,05), however, it was not verified the difference for daily excretion of total and urea nitrogen in milk, total and urea nitrogen in urine, and nitrogen balance (P>0,05). It was concluded that the integral yeast can totally replace the soybean meal in the diet for dairy cows with a daily average milk yield of 25kg. / Objetivou-se avaliar a produção e composição do leite, consumo e digestibilidade aparente da matéria seca e dos nutrientes, eficiência de utilização dos compostos nitrogenados, produção e eficiência da síntese de proteína microbiana de vacas leiteiras alimentadas com diferentes proporções de substituição do farelo de soja pela levedura seca de cana-de-açúcar. Foram utilizadas 16 vacas holandesas, destas 8 eram primíparas e 8 multíparas, distribuídas em quatro quadrados latinos 4x4, organizados de acordo com os dias e ordem de lactação. Os tratamentos consistiram de uma dieta basal, onde o farelo de soja foi a principal fonte de proteína, e três dietas com os níveis de 33,3; 66,6 e 100% de substituição do farelo de soja pela levedura, com base na MS. O experimento teve duração total de 68 dias, subdividido em quatro períodos experimentais de 17 dias. Os níveis de substituição do farelo de soja pela levedura não influenciaram os consumos de MS, MO, EE, FDNi e NDT (P>0,05), porém os consumos de PB e FDNcp decresceram e o consumo de CNF (P<0,05) aumentou linearmente. Não houve efeito de tratamento sobre os coeficientes de digestibilidade da MS, MO, PB, CNF e no teor de NDT (P>0,05), porém o coeficiente de digestibilidade do EE decresceu linearmente com a inclusão de levedura nas dietas experimentais (P<0,05). A produção leite, produção de leite corrigida para 3,5% de gordura, teor de gordura, proteína bruta, lactose, sólidos totais e CCS não diferiram entre os tratamentos (P>0,05). Não foi verificado efeito dos tratamentos sobre a soma das excreções de alantoína na urina e no leite, ácido úrico, purinas totais, proteína microbiana e eficiência microbiana (P>0,05). Observou-se efeito linear decrescente para as concentrações de nitrogênio uréico no plasma e no leite e excreção diária de nitrogênio uréico no leite (P<0,05), porém não foi verificado diferença para excreção diária de compostos nitrogenados no leite, nitrogênio total e uréico na urina e balanço de nitrogênio (P>0,05). Conclui-se que a levedura seca de cana-de-açúcar pode substituir totalmente o farelo de soja na dieta de vacas leiteiras com média diária de produção de 25 kg de leite.

No description available.

Doctor of Philosophy / Department of Civil Engineering / Kyle A. Riding / The cement industry is an important component in the quest to reduce global greenhouse gas emissions because of vast amounts of cement used annually. Incorporating supplementary cementitious materials (SCMs) into concrete is one alternative to reduce cement production and thereby reduce greenhouse gas emissions. This study investigated three types of agricultural residues, namely corn stover, wheat straw, and rice straw, in addition to bioethanol byproducts as potential resources for SCM production for concrete applications. Pretreatments, commonly used in bioethanol production, were used to improve pozzolanic reactivity of corn stover ash (CSA), wheat straw ash (WSA), and rice straw ash (RSA) in cementitious systems. In the first part of this research, the impact of distilled water and dilute hydrochloric acid pretreatments on pozzolanic reactivity of WSA, RSA, and CSA were studied. Results showed that pretreatments, particularly dilute acid, improved pozzolanic properties of CSA, WSA, and RSA by removing potassium and phosphorous from the biomass prior to ashing. In addition, WSA and RSA were shown to have similar pozzolanic reactivity to that of silica fume. In the second part of this study, suitability of high lignin residue (HLR), a bioethanol byproduct, for SCM production was investigated. It was shown that burning high lignin residue produces HLR ash that is very reactive in cementitious materials and can be used as a reactive SCM in concrete. The impact of each step in the production of bioethanol on the quality of bioethanol byproduct for subsequent burning and use in concrete was also studied. Sodium hydroxide and sulfuric acid pretreatments and enzymatic hydrolysis were used. Results revealed that sodium hydroxide pretreatment of the biomass have negative impact on biomass ash properties for concrete use because sodium hydroxide pretreatment did not remove phosphorous and other crystalline phases out of the biomass. However, sulfuric acid pretreatment of biomass greatly improved ash properties. It was also shown that enzymatic hydrolysis could have beneficial impact on ash properties because, during enzymatic hydrolysis, some phosphorous was leached out of the biomass.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Published Article / The waste management practices used at red-meat abattoirs in the Free State province for disposal of condemned products generated in abattoirs and the problems associated with the different waste disposal methods were investigated. Problems caused by various products generated at abattoirs. such as abattoir waste water, blood, stomach contents, manure, whole carcasses, fetuses and all products unsuitable for human consumption requiring disposal were identified. Recommended solutions took into account the most effective handling manner, causing minimum environmental pollution, reducing any health risks to communities, and converting condemned products into value-added by-products by changing certain waste management processes / strategies. The handling of waste, specifically of condemned products, at 78 red meat abattoirs was analysed.

Thesis (MScIng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The fine ash produced at the Sasol Secunda Petrochemical Plant is disposed of through a wet ash disposal system. Other process waste streams with high salt concentrations are co-disposed of in the Sasol Secunda ash disposal system. This has led to a steady rise in the salt concentrations of the recycled clear ash effluent (CAE) over the past 17 years. To combat this increase in salt concentrations, the capability of the Sasol Secunda ash disposal system to act as a salt sink, needs to be enhanced. This investigation focussed on ways to enhance the salt removal/retention capabilities of the Sasol Secunda ash disposal system and consisted of the following: • A literature survey of relevant information. • The mixing of different combinations of fine ash, brine and CAE. • Adding CO2 to the fine ash and CAE mixtures. • Investigation to enhance salt precipitation in the CAE and Evaporation dams. • Salt balances and a residence time calculation over the CAE and Evaporation dams. From these investigations it were concluded that the Sasol Secunda ash disposal system could be used as a salt sink for SO4 ions. Up to 43% of the SO4 is removed from the brines after the initial ash/water contact. It was also found that the tubular reverse osmosis (TRO) brine could be used as a carrier medium for the ash. The large amounts of Ca that is leached into the ash water during the mixing of the CAE and fine ash can be prevented by the addition of CO2 to the mixing point. There is usually an increase of 240% in the Ca concentration and this is reduced to only an 8% increase with the CO2 addition. The most feasible precipitation enhancement for the CAE and Evaporation dams is an increase in evaporation. This enhances CaCO3 precipitation, which is the main mechanism for salt removal in the CAE and Evaporation dams. Ca, Na and Cl are retained in the evaporation and CAE dams. SO4 is leached from solid phases in the dams. There is however an overall decrease in the total dissolved solids (TDS) of the ash water. The salt removal of the CAE and Evaporation dams is approximately 57 tons per day. The capability of the Sasol Secunda ash disposal system to act as a salt sink can be enhanced by the addition of CO2 at the mixing point and by increasing the evaporation rate in the CAE and Evaporation dams. Using the TRO brine as carrier medium may also increase the SO4 precipitation capabilities of the Sasol Secunda ash disposal system. / AFRIKAANSE OPSOMMING: Die fynas wat by die Sasol Secunda Petrochemiese Aanleg geproduseer word, word verwyder deur ‘n geslote nat asstelsel. Ander afvalstrome wat hoë konsentrasies soute bevat word ook in die Sasol Secunda asstelsel gestort. Dit het tot gevolg dat daar oor die afgelope 17 jaar ‘n volgehoue styging in die sout konsentrasies van die hergebruikte aswater (genoem CAE – “clear ash effluent”) was. ‘n Manier om hierdie styging in die sout konsentrasies teen te werk, is om die sout verwyderingsvermoë van die Sasol Secunda asstelsel te verbeter. Hierdie ondersoek het gefokus op maniere om die sout verwyderings- /terughoudingsvermoë van die Sasol Secunda asstelsel te verbeter en het die volgende ingesluit: • ‘n Literatuur oorsig van toepaslike inligting. • Die meng van verskillende kombinasies van fynas, soutstrome en CAE. • Toediening van CO2 by die fynas en CAE mengsels. • ‘n Ondersoek na metodes om die soutverwydering in die CAE en Verdampingsdamme te verbeter. • Soutbalanse en ‘n residensie tyd berekening vir die CAE en Verdampingsdamme. Na hierdie ondersoeke kon die gevolgtrekking gemaak word dat die Sasol Secunda asstelsel ‘n sout sink vir SO4 ione is. Tot 43% van die SO4 word verwyder na die aanvanklike as/water kontak. Daar is ook gevind dat die TRO (“tubular reverse osmosis”) soutstroom gebruik kan word as ‘n draer vir die fynas. Die groot hoeveelhede Ca wat in die aswater in loog, kan voorkom word deur die toediening van CO2 by die mengpunt van die fynas en aswater. Daar is normaalweg ‘n verhoging van 240% in die Ca konsentrasie van die aswater en dit word verminder na ‘n skrale 8% met die toediening van CO2. Die mees praktiese metode om die soutverwydering in die CAE en Verdampingsdamme te verbeter, is met die verhoging van die verdamping. Dit sal die neerslag van CaCO3, wat die meeste soutverwydering tot gevolg het, verhoog. Ca, Na en Cl word teruggehou in die Verdampings en CAE damme. SO4 loog uit soliede fases in die damme. Daar is wel ‘n afname in die algehele opgeloste spesies (“TDS”) van die aswater. Die soutverwydering van die Verdampings en CAE damme is ongeveer 57 ton per dag. Die vermoë van die Sasol Secunda asstelsel om as ‘n sout sink gebruik te word, kan verbeter word deur CO2 by die mengpunt by te voeg en die verdampingstempo in die Verdampings en CAE damme te verhoog. Die gebruik van die TRO pekelstroom as draer van die as kan die SO4 neerslag in die Sasol Secunda asstelsel ook verhoog.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Both liquid and solid wastes from Pacific whiting surimi manufacturing were characterized and value-added products were recovered. A proteinase in surimi wash water (SWW) was determined to be cathepsin L with Mr 54,200 on SDS-substrate gel. Heat treatment and acidification shifted the activity zone to M [subscript r] 39,500. No evidence of calpain, cathepsin B or H activity was found. Cathepsin L from SWW was recovered by ohmic heating (55°C for 3 min), ultrafiltration, and freeze-drying with overall yield of 0.83 g protein/L SWW and 78% recovery of activity. A 5.9 purification fold was achieved by these processes. The recovered enzyme had an optimum activity at pH 4.0 and showed preferable hydrolytic activity towards casein, acid-denatured hemoglobin and myofibrils. β-Mercaptoethanol, dithiothreitol and urea enhanced the enzyme activity. The recovered proteinase showed 18.5% residual activity after 7 wk storage at 4°C. Proteolytic activity in solid waste and digestive organs from Pacific whiting was investigated. Pepsin-like proteinase predominated in solid waste, while trypsin-like proteinase was predominant in viscera. Carboxypeptidase b was found in both viscera and solid waste. Protein hydrolysate was produced from Pacific whiting solid waste (PWSW) using commercial proteinase, Alcalase, under optimum hydrolysis conditions. Enzyme concentration, reaction time and waste/buffer ratio affected the hydrolysis and nitrogen recovery (NR). Correlation between the degree of hydrolysis (DH) and NR was high (R₂=0.978). Freeze-dried hydrolysate contained 79.97% protein and showed similar amino acid composition to PWSW and Pacific whiting muscle but tryptophan was reduced. With different DH (20, 30, 40, 50, 60%), surface hydrophobicity, total and surface sulfhydryl content decreased as the DH increased. The hydrolysate showed a high solubility over a wide pH range. Fat adsorption and fat binding capacity were reduced, while foam expansion was enhanced with an increased DH. Hydrolysate with DH of 30% showed highest emulsifying activity. Low emulsion stability and high foam stability were obtained in all hydrolysates tested. Hydrolysate showed antioxidant activity, but no obvious differences in activity were found with varying DH and hydrolysate concentrations. / Graduation date: 1997

A method of solubilizing and extracting proteins from by-products was tested. The raw materials used were finely homogenized and digested at 60(DEGREES)C and pH 10.5 for 30 to 120 minutes in the presence of 0.5% alkaline nonspecific bacterial proteases from Bacillus subtillis. The protein in solution was separated from nonsoluble and organic solvent soluble components by filtration or centrifugation. When desired, the proteinaceous solution was dried (preferably by spray drying). Raw materials that were test digested included keratin from turkey feathers, bovine skin collagen, shark waste, shrimp heads, whole squid, inedible chicken carcass, bovine blood plasma, slaughterhouse waste, cotton gin waste, Enteromorpha sp. (a marine alga), Batis sp. and Distycilus sp. (two halophytes), soybean meal, casein, and fibrinogen. With this method, plant proteins were 57.4% to 59.9% extractable and animal proteins were 75.8% to 93.0% extractable. The native protein hydrolyzed by the procedure was reduced to an average molecular weight of 10,000-15,000 daltons. Other changes characteristic of the digestion process were increased protein concentration and decreased ash concentration. Complementation of by-product proteins in Tetrahymena medium resulted in increased growth compared to Tetrahymena cultures using soy or casein as the sole protein source up to 1.25 times. Decreasing protein molecular weight resulted in decreased growth in Tetrahymena (up to 4 times). Shrimp fed hydrolyzed animal proteins grew only 37.6% to 54.8% as much as squid-fed shrimp controls. White leghorn chicks fed 40% protein as hydrolyzed by-product proteins grew as much as chicks fed a commercial-type milo-soy diet supplemented with methionine. Amino acids from smaller peptides were more rapidly absorbed and more completely incorporated into muscle mass by chicks than were larger peptides.