Dissertations / Theses on the topic 'Agricultural wastes'

Anaerobic digestion technology has not gained widespread acceptance on UK farms due mainly to the long return on investment periods involved. It has been suggested that co-digestion of agricultural and industrial wastes may enhance the economic viability of such installations. Batch and continuous digestion of cattle slurry and organic industrial wastes was carried out in specially constructed pilot plant digesters, to determine optimum mixtures of waste and digester loading rates. A total of 10 different wastes were tested, on a batch digestion basis, for their potential to co-digest with cattle slurry. Of these, 3 were chosen for continuous pilot plant trials, due to either a need to provide a disposal route for the waste, or positive effects of the waste on methane productivity. Chicken manure was found to slightly enhance methane productivity, but ammonia inhibition of methanogenic bacteria was noted over time. The organic fraction of municipal household waste (OFMSW) significantly enhanced digester methane productivity, while fish offal (FO) slightly enhanced methane productivity when added to the digester in small quantities, but quickly caused digester failure when added in larger amounts. An economic model of a digestion facility was developed and used to show the financial benefits of co-digestion.

Global cement production is continuously increasing from 1990 till 2050 and growing particularly rapidly in developing countries, where it represents a crucial element for infrastructure development and industrialisation. Every tonne of ordinary Portland cement (OPC) produced releases, on average, about 800 kg of CO2 into the atmosphere, or, in total, the overall production of cement represents roughly 7% of all man-made carbon emissions. The present paper aims to deepen the re-use of agricultural solid waste materials as partial replacement of OPC, which can positively contribute to the sustainability of the concrete industry because of their availability and environmental friendliness. In particular, rice-husk ash (RHA) and oat-husk ash (OHA), burned under the right conditions, can have a high reactive silica content, representing very potential pozzolans. The mechanical and physical characteristics of both materials are investigated to evaluate the influence on concrete properties. Subsequently, using the environmental product declarations (EPDs) of the material used, a comparative environmental impact analysis between RHA concrete and ordinary concrete having the same resistance class, is presented. It is concluded that the use of RHA as supplementary cementitious material can serve a viable and sustainable partial replacement to OPC for the reduction of CO2 emissions and global warming potential.
Den globala cementproduktionen ökar från 1990 till 2050 och växer särskilt snabbt i utvecklingsländer, där den utgör en viktig del för infrastrukturutveckling och industrialisering. Varje ton vanligt portlandcement (OPC) släpper i genomsnitt ut cirka 800 kg koldioxid i atmosfären, och, totalt, representerar den totala cementproduktionen ungefär 7% av alla koldioxidutsläpp från mänsklig verksamhet. Det här examensarbetet syftar till att fördjupa kunskapen om och därmed i förlängningen återanvändningen av fasta avfallsmaterial från jordbruket som delvis ersättning av OPC, vilket kan bidra till hållbarheten i betongindustrin på grund av deras tillgänglighet och miljövänlighet. I synnerhet kan risskalaska (RHA) och havreskalaska (OHA), som bränns under rätt process, ha en hög reaktiv kiseldioxidhalt, vilket representerar mycket potentiella puzzolaner. De mekaniska och fysiska egenskaperna hos båda materialen har undersökts för att utvärdera deras inverkan på betongegenskaper. Därefter presenteras en jämförande miljökonsekvensanalys mellan RHA-betong och OPC-betong med samma motståndsklass med användning av miljövarudeklaration (EPD) för det använda materialet. Man drar slutsatsen att användningen av RHA som alternativt bindemedel (SCM) till OPC kan hjälpa till att minska koldioxidutsläppen och den globala uppvärmningspotentialen.

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The greatest management concern with animal wastes is the movement of nitrate into water supplies. Health problems in humans and livestock can result from excessive levels of nitrate in drinking water. This publication outlines the guidelines to minimizing the risk of contaminating your drinking water. It also lists a number of questions to check if your management practices in the collection and storage of animal wastes may pose a risk to your groundwater.

The spread of tetracyclines through agricultural systems is causing the present bacteria to develop antibiotic resistance. The spread of this bacteria, as well as the tetracycline antibiotics in the environment is dangerous because these antibiotics pose health hazards for humans. The overuse of antibiotics, which are added to livestock feed, results in the antibiotics being released into the environment via animal feces. In this research, we have attempted to design an analytical method to isolate antibiotics from agricultural wastes with subsequent detection using liquid chromatography and mass spectrometry (LC-MS). The antibiotics investigated in this study were tetracycline, chlortetracycline, and oxytetracycline. The analytical procedure involves mixing the agricultural samples with an organic solvent, such as methanol, which solubilizes these antibiotics. Next, samples are centrifuged to remove solid particulates. A polymeric weak cation cartridge was used to concentrate and separate the antibiotics from the unwanted organic chemical compounds found in the samples. The antibiotics were released with methanol with small amounts of acid and then detected and quantified using LC-MS and high performance liquid chromatography with a photodiode array detector (HPLC-PDA).

Aqueous solutions are becoming increasingly contaminated in all parts of the world (2015). Heavy metals are toxic contaminants that are mainly distributed in urban stormwater run-off and industrial wastewaters as a result of some mining operations, electronic assembly planting, battery manufacturing, and etching operations (Kadirvelu et al. 2001). Pb (II) is a heavy metal that causes significant damage in the human body. Drinking lead-contaminated water even at low concentrations may cause lifethreatening conditions such as cancer, kidney damage, brain damage, and liver problems (El-Said 2010). Therefore, it is necessary to remove lead from aqueous solutions. Several conventional physical, chemical, and biological systems have been used to eliminate Pb (II) ions from contaminated aqueous solutions, including membrane filtration (Song et al. 2011), electrolysis (Deng et al. 2010), chemical precipitation (Cort 2005), magnetic base methods (Ma et al. 2017), water filtration (Gohari et al. 2013, Magni et al. 2015), and adsorption techniques (Pehlivan et al. 2009). However, the cost of some of the cited techniques is prohibitively high, while others cannot remove low Pb (II) ion concentrations efficiently (Babel and Kurniawan 2003, Volesky and Holan 1995). Although adsorption is a reasonable process for removing dissolved lead from contaminated water, the cost of using conventional media (e.g. activated carbon and resin) make it cost inhibitive for the treatment of large quantities of wastewater (Cutillas-Barreiro et al. 2016, Demirbas 2008). It also takes a long time in some cases to achieve adsorption equilibrium (Czinkota et al. 2002). In recent decades, interest in the use of cost-effective adsorbents to reduce the expense of water treatment processes has intensified. Attention has been focused on natural agricultural waste materials such as seeds (Gilbert et al. 2011), fruit peel (Mallampati et al. 2015), nut shells (Taşar et al. 2014) , crop residues (El-Said 2010), and fruit shells (Zein et al. 2010) as low-cost and environmentally friendly adsorbents which are highly efficient and generally available in large quantities (Ibrahim et al. 2010). Against this backdrop, many agricultural residues are being produced every day, and they need to be managed. Using agricultural wastes to treat contaminated water is a low-cost and effective approach that deal with waste management and water treatment at the same time. This project describes an economically viable and practical way to utilize crop residues as adsorbents to remove toxic Pb (II) ions from lead-contaminated water. These agricultural waste adsorbents have a number of advantages; they are cheap and biodegradable, they have a porous surface, and are able to eliminate Pb (II) ions from contaminated water quickly and effectively. Therefore, in this research two Western Australian crop residues were used as adsorbents to eliminate lead ions from aqueous solutions. The study was carried out in four phases: the first phase involved the selection and preparation of different local Western Australian agricultural wastes. Lupin straw and canola stalk were collected from local farms and studied for their efficiency as two low-cost natural adsorbents that can remove dissolved Pb2+ ions from synthetic wastewater. In the second phase, experiments were carried out to understand the equilibria of Pb (II) adsorption onto adsorbents. The effect of various environmental conditions such as contact time, pH, initial adsorbent dosage and adsorbate concentration were investigated. The presence of different functional groups, chemical compositions, and the surface characteristics of the adsorbents were analysed in the third phase using energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) devices. In the final phase, the obtained experimental data were validated using different isotherm models developed by Langmuir, Freundlich, Harkins-Jura, Redlich- Peterson and Halsey to describe the adsorption process based on the homogeneity of the surfaces of the adsorbents. Pseudo-first-order, pseudo-second-order, intra-particle diffusion, Elovich, and fractional power kinetic models were utilized to investigate the dynamic mechanism of lead adsorption onto adsorbents over time.

To reinforce cement against the attack of supercritical CO2 in a storage site, agricultural wastes (POFA and RHA) and Nano particles (Nano Silica) were used. Post-carbonation tests of agricultural wastes and Nano Silica based cement were done according to the API standard and it was found that almost all samples have a lesser carbonated area then the neat cement except 5 wt% POFA. Nano Silica based cement seem to be the best choice.

The sugar refinery process used by Lantic Sugar Ltd generates three by-products having characteristics that give them potential as soil amendments or fertilizers, particularly as a phosphorous and calcium source. Laboratory and a field trials were conducted in order to examine the changes in agronomic properties of soil produced by the application of these residues.
During the laboratory experiment, the by-products examined were spend bone char (SBC), filter-press mud (FPM), clarification scum (SCU) and a compost (COM) produced using FPM and SCU, where as in a field experiment, COM, SBC and a mixture (MIX) made of FPM and SCU, were compared to a commercial fertilizer (TSP) and non-treated soils.
The orthic humic gleysol of clay texture and low pH soil conditions in which the field experiment was conducted resulted in high P fixation of all the applied residues. Contrasts analysis showed that TSP behaved as the soils unamended P for all nutrient concentrations in tissues over two cropping seasons (1993 and 1994), on two crops, namely wheat (Triticum aestivum, L.) and corn (Zea mays, L.). Treatments (residues at different rates of application) did not significantly increase the Ca levels in COM plots nor did they increase the wet aggregate stability of soil under either crop. (Abstract shortened by UMI.)

A compost-bioremediation approach was adopted in this study to explore more sustainable and economically viable methods of degrading pollutant hydrocarbons in oil-field drill cuttings and coal tar impacted soils (CTIS). The compost amendments used were agricultural waste products including grass cuttings, spent mushroom compost and straw. Laboratory-scale compost experiments were conducted to test the performance of different compost blends comprised of each contaminated medium and organic amendments in different mix ratios for 53 days. The compost mix type which produced the greatest reduction in pollutant hydrocarbon concentrations was further scaled-up and tested in an outdoor pilot scale compost treatment for 56 days. At the end of the lab-scale treatments, degradations in total petroleum hydrocarbon (TPH) concentrations of 85.1% and 90.6% were recorded for the drill cuttings and CTIS, compared to 36.7% and 28.4% that was achieved in the control experiments, respectively. The concentrations of total n-alkanes and polycyclic aromatic hydrocarbons (PAHs) were significantly decreased in the best performing compost mix types, however most of the 5 and 6-ring PAH compounds in the CTIS treatment compost mix exhibited recalcitrance to degradation and some even appeared to increase in concentration which is ascribed to increased PAH availability to solvent extraction and reduction in the compost mass during the composting-biodegradation process. The best performing compost mix type for treatment of CTIS was subsequently tested in outdoor tumbler compost bins after being scaled-up by a factor of 600; this was found to produce 78% degradation of TPH concentration at the end of the treatment period. Concentrations of total nalkanes and PAHs were also significantly lowered by biodegradation. Low molecular weight (2 and 3-ring) PAHs were almost completely removed and 4-ring PAHs from the coal tar, including fluoranthene, pyrene, benzo[a]anthracene and chrysene were significantly degraded but not the 5 and 6-ring PAH compounds. Phytotoxicity assays showed that the seed germination in the treated matrix was 70% and 20% more, for corn and pea, respectively, 5 days after planting and 78% more for mustard 3 days after planting. Phosphatase enzyme activity was found to decrease in the treated matrices possibly due to the short time between end of composting and testing. The results generated from the chemical and toxicity assays of this study showed the efficacy of the composting treatment for hydrocarbon removal from these contaminated matrices and identified the best performing compost mix types (DGMSt3 and SGSt3) which can be further tested in field scale trials.

In this work, adsorption of cadmium and lead from waste solutions by activated carbon was investigated. The activated carbons were produced from ion exchange resins and agricultural wastes in previous thesis studies under different conditions. BET surface areas of the activated carbons were given in previous studies. They were further characterized in this study. Slurry pH was measured by change in pH of water in which activated carbon was added. Methylene blue numbers were determined by adsorption of methylene blue onto activated carbons. Isoelectric points were determined by measuring zeta potential of activated carbons at different equilibrium pH. Results of the first part of sorption experiments showed a strong dependency of adsorption on pH since adsorption mechanism was exchange of heavy metal ions with H+ ions on the surface. Activated carbon produced from hazelnut shell had the highest removal efficiency with 95% Pb removal and 50% Cd removal at pH 6. However, activated carbon produced from apricot stone removed only 25% and 80% of Cd and Pb, respectively at the same pH. Initial concentration had positive effect on percent removal as shown by the second part of sorption experiments. This can be explained with saturation of available active sites as initial concentration increased. Activated carbon produced from hazelnut shell could remove 42% of Cd and 85% of Pb, but the one produced from synthetic resin couldn&
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t remove Cd and Pb more than 20% and 35%, respectively at initial concentration of 100 mg/l. Langmuir and Freundlich isotherms were plotted and both isotherms were in good agreement with experimental data.

Thesis ( MTech (Business Administration))--Cape Peninsula University of Technology, 2016.
Capital investment in bioethanol production requires sound economic feasibility studies. This study investigated the economic feasibility of using maize as a feedstock to produce bioethanol in South Africa. There is a huge opportunity to use dedicated underutilised arable land to grow maize which can be used for both consumption and bioethanol production. The study used 200 000 ton/year of maize that could have been exported to SADC countries to size a plant that produces 80 million litres per year of bioethanol. An advanced bioethanol processing technology that separates the fibre/bran which is burnt in a steam boiler to produce process steam was selected owing to advantages such as low energy consumption and capital expenditure on fermentation and distillation equipment. This study employed a combination of qualitative and quantitative methods to gather data. The findings from a qualitative instrument indicated that a majority of respondents were in favour of the decision of excluding maize made by the South African government. Putting security of food at risk and uncertainty in the profitability of a maize-fed bioethanol plant in the South African context, were two of the primary reasons the respondents opted for an explicit exclusion of maize as a feedstock. Findings from quantitative analysis revealed that the profitability of the bioethanol plant was largely influenced by the prices of feedstock and bioethanol. The 2016 fiscal year indicated the worst case scenario in terms of economic viability of the bioethanol. The astronomically high price of maize due to drought (R5000/ton) rendered the project unprofitable as all of the economic indicators were negative. In the same marketing year, however, the trade balance of maize was positive, indicating a surplus. The study recommended that all of the surplus maize should be exported because it is not economically viable to build a bioethanol plant. The 2011 fiscal year indicated the best case scenario in terms of the economics of the project. This was due to the decrease in price of maize (R1726/ton) and a slight increase in the price of bioethanol. All of the economic indicators were positive, suggesting the benefits of investing in bioethanol production. It was recommended that under normal conditions of maize production in South Africa, a bioethanol plant can be operated simultaneous to maize exportation to other countries without compromising food security, because a maize-fed bioethanol plant uses only a small proportion of maize (14.3%) from the total volume of maize that is exported. Furthermore, it generates more revenue (99.9%) compared to the maize export revenue. It was recommended that sensitivity analysis should be conducted in a holistic manner whereby all variables in the economic model must be adjusted to assess the impact of each on the overall project profitability.

Environmentally sound treatment of by-products in a value-adding process is an ongoing challenge in animal agriculture. Thermophilic anaerobic digestion of wastes originating from agricultural production and animal processing represents a potential waste treatment technology to address environmental concerns such as odor emissions and removal of pathogenic microorganisms, while at the same time producing renewable energy (biogas) as a by-product. However, thermophilic digestion is subject to inhibition by ammonia and long chain fatty acids (LCFA), both of which are prevalent in manure and animal processing wastewater. Several swine manure collection methods under development separate the urine from the feces, which creates the opportunity to operate a digester on feces only, greatly reducing the ammonia load to the digester. One objective of this study was to determine whether operation on feces only would yield significant performance improvements for a thermophilic anaerobic digester operating on swine waste. Effluent from a continuously stirred tank reactor (CSTR) was used as the inoculum for batch tests in which the substrate contained three different concentrations of urine (urine-free, as-excreted urine:feces ratio and double the as-excreted urine:feces ratio). Inocula were acclimated to these same urine:feces ratios to determine methane production. Results show that both urine-free and as-excreted substrates were not inhibitory to anaerobic inocula. Anaerobic microorganisms can be readily acclimated to substrate with double the as-excreted urine concentration, which contained TKN concentrations up to 7.20 g-N liter-1. The sludge collected from the dissolved air flotation (DAF) wastewater treatment process in swine processing facilities is an example of a high-lipid substrate containing potentially inhibitory levels of LCFA. A second objective of this study was to determine the fundamental performance parameters for thermophilic anaerobic digestion of DAF sludge. Testing in a semi-continuous stirred tank reactor and in batch reactors was conducted to determine substrate degradation rates and biogas yield. Stable operation could not be achieved using pure DAF sludge as a substrate, possibly due to inhibition by long chain fatty acids or to nutrient deficiencies. However, a 1:1 ratio (w/w, dry basis) of DAF sludge and swine manure (feces only), resulted in stable and productive digester operation. In the semi-continuous stirred reactor at 54.5ï°C, a hydraulic residence time of 10 days, and an organic loading rate of 4.68 gVS/day/L, the methane production rate was 2.19 L/L/day and the specific methane production rate was 0.47 L/gVS (fed). Maximum specific methanogenic activity (SMA) in batch testing was 0.15 mmolesCH4 hr-1 gVS-1 at a manure/DAF substrate concentration of 6.9 gVS liter-1. Higher substrate concentrations cause an initial lag in methane production, possibly due to long chain fatty acid or nitrogen inhibition.

Thesis (MEng)--University of Stellenbosch, 2000.
ENGLISH ABSTRACT: Peach and apricot shells are agricultural waste products. These waste products accumulate around canneries and food-processing plants in South Africa. No effort is being made to utilise these waste products. This study is the first part of the product development from these products i.e. peach shell activated carbon and apricot shell activated carbon. By producing activated carbon from peach and apricot shells the solid waste problem is addressed, but most of all a profit can be made. But why activated carbon? Activated carbons are unique and versatile adsorbent with a vast amount of adsorption applications. It can be produced via a simple oxidation reaction with steam and the nature of peach and apricot shells are such that it is expected that activated carbons with good adsorption properties can be produced from it. The single largest consumer of activated carbon in South Africa is the gold mining industry that uses imported coconut shell activated carbon for gold adsorption in the gold recovery process. Activated carbon is also used as water purification adsorbents. During this study activated carbons were produced in a fluidized bed reactor at various activation conditions: 700 - 900°C, 0.0425 - 0.0629 g steamlg char.min and 30 - 60 min. This was done in order to find the optimum activation conditions within the activation parameter range. The optimal activated carbons were defined as peach and apricot shell activated carbons that showed good microporous as well as mesoporous character. The optimal activated carbons produced are: peach shell activated at 875°C, 0.0533 g stearnlg char. min, 60 min and apricot shell activated carbon at 850°C, 0.0533 g steamlg char.min, 60min. The possible use of these optimal activated carbons and two other activated carbons produced (Peach shell activated carbon 900°C, 0.0425 g steamlg char. min, 60 min and apricot shell activated carbon 900°C, 0.0425 g steamlg char.min, 60min) were tested in gold recovery and water purification. The gold adsorption properties of peach and apricot shell activated carbons were found to be better than two commercial coconut shell activated carbons (Chemquest 650 and GRC 22). No definite conclusions could, however, be drawn about the replacement of coconut shell activated carbon with peach or apricot shell activated carbon, because abrasion test work and thermal regeneration of the experimental carbons still have to be performed. The experimental activated carbons displayed good phenol adsorption characteristic, although further test work is required.
AFRIKAANSE OPSOMMING: Perske- en appelkoospitte is landbouafvalprodukte. Hierdie afvalprodukte versamel rondom inmaakfabrieke en voedselververkingsaanlegte. Tans word daar geen poging in Suid-Afrika aangewend om hierdie afvalprodukte te benut nie. Hierdie studie is die eerste deel van die ontwikkeling van die produkte: Perskepitdop-geaktiveerde koolstof en appelkoospitdop-geaktiveerde koolstof. Deur geaktiveerde koolstof van die perske- en appelkoospitdoppe te maak, word nie net 'n antwoord op die vastestofafvalsprobleem gevind nie, maar daar kan ook geld gemaak word. Hoekom geaktiveerde koolstof? Aktiveerde koolstowwe is veelsydige en unieke adsorbente met 'n groot verskeidenheid adsorpsie toepassings. Dit kan vervaardig word via 'n eenvoudige oksidasie reaksie met stoom en die aard van die perske- en appelkoospitdoppe is sodanig, dat verwag kan word om geaktiveerde koolstowwe met goeie adsorpsie eienskappe daarvan te kry. Die grootste enkelverbruiker van geaktiveerde koolstof in Suid-Afrika is die goudmynbedryf, wat kokosneutdop geaktiveerde koolstof invoer om goud te herwin. Geaktiveerde koolstof word ook gebruik vir watersuiwering. Tydens hierdie studie IS geaktiveerde koolstowwe by verskillende aktiveeringskondisies in 'n gevloeïdiseerde bed vervaardig: 700 - 900oe, 0.0425 - 0.0629g stoornlg gepiroliseerde pitdoppe.min en 30 - 60 mm. Die aktiveringskondisies is gevarieer om sodoende die optimale aktiveringskondisies binne die aktiveringsparameterreeks te kry. 'n Geaktiveerde koolstof is as optimaal geklassifiseer as dit 'n goeie mikro- sowel as mesostruktuur getoon het. Die optimaal geaktiveerde koolstowwe is: geaktiveerde koolstof vervaardig van perskepitdoppe by 875°e, 0.0533 g stoornlg gepiroliseerde pitdoppe.min, 60 mm en geaktiveerde koolstof vervaardig van appelkoospitdoppe by 850oe, 0.0533 g stoornlg gepiroliseerde pitdoppe.min, 60min. Die gebruik van die twee optimale geaktiveerde koolstowwe sowel as twee ander geaktiveerde koolstowwe (perskepitdop-geaktiveerde koolstof, 900oe, 0.0425 g stoornlg gepiroliseerde pitdoppe.min, 60 min en appelkoospitdop-geaktiveerde koolstof, 850°C, 0.0533 g stoom/g gepiroliseerde pitdoppe.min, 60min) is VIr goudadsorpsie en watersuiwering ondersoek. Die goudadsorpsie eienskappe van die perske-en appelkoospitdop-geaktiveerde koolstowwe was beter as die van twee kommersiële kokosneutdop-geaktiveerde koolstowwe (Chemquest 650 and GRC 22). Daar kan egter geen definitiewe gevolgtrekkings gemaak word oor die vervanging van kokosneutdop geaktiveerde koolstowwe met dié van perske of appelkoospitdoppe nie, aangesien daar nog toetsresultate oor die slytweerstand en reaktiverings eienskappe van die eksperimentele geaktiveerde koolstowwe uitstaande is. Die eksperimentele geaktiveerde koolstowwe toon goeie adsorpie ten opsigte van fenol, maar verdere toetswerk is egter nodig.

In order to integrate organic fertilisers into mainstream agriculture, it is necessary to be able to predict with reasonable accuracy the supply of nutrients from a given product. This will allow organic fertilisers to be applied to the soil at correct rates (on their own and in combination with inorganic fertilisers) to meet the crop nutrient requirements and avoid any excess supply that might harm the environment. The focus of the research within this thesis was on the supply of plant available nitrogen (PAN) from recycled organic (RO) wastes and its prediction. The research documented in this thesis addressed the following four hypotheses; • Hypothesis 1 – The NLBAR (i.e. Nitrogen Limited Biosolids Application Rate) formula (New South Wales biosolid guidelines) and its percentage organic N mineralisation assumptions provide an accurate prediction of the mineral N supply from biosolids in the first year of a crop. • Hypothesis 2 – RO waste composition affects the proportion of its organic N mineralised in the soil. • Hypothesis 3 – Certain composition characteristics of RO wastes can provide a reliable prediction of the mineral N supply from RO wastes under controlled conditions. • Hypothesis 4 – Near-infrared spectrometry can be used to accurately predict the mineral N supply and recalcitrant C pools from RO wastes applied to the soil, under controlled conditions.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Thesis (Masters of Environmental Health)--Cape Peninsula University of Technology, 2018.
In the Western Cape, South Africa and other regions globally, grape pomace (GP) is one of the abundant agro-waste from the winery industry. This study reports on the hyper-extraction of fermentable sugars from GP treated with white rot fungi (WRF) Phanerochaete chrysosporium BKMF 1767 to facilitate improved biovalorisation for total reducing sugars (TRS) extraction in conjunction with Nepenthes mirabilis digestive fluids. TRS were quantified using the 3,5-dinitrosalicylic acid (DNS) reagent method. The free readily dissolvable sugars from the GP recorded for the bio-treated (BT) samples was 206.39 ± 0.06 mg/L and for the untreated (UT) samples was 271.05 ± 0.02 mg/L. Overall, the TRS yield for the Bio-treated (BT) and untreated (UT) samples was recorded as 205.68 ± 0.09 and 380.93 ± 0.14 mg/L, respectively, using hot water pretreatment (HWP) with 2266.00 ± 0.73 (BT) and 2850.68 ± 0.31 mg/L (UT), respectively, for dilute acid pretreatment (DAP); with 2068.49 ± 6.02 (BT) and 2969.61 ± 8.054 mg/L (UT) respectively, using the cellulase pretreatment (CP) method. Using the HWP as a reference, the relative increases imparted by the biotreatment was higher (51%) for DAP and low (33%) for CP. The combination of conventional used pre-treatment methods (hot water pretreatment, dilute acid pre-treatment, and cellulase pre-treatment) in a single pot system was also done while monitoring the total residual phenolics (TRPCs) in the samples. Furthermore, powder X-ray diffraction (pXRD) were used to measure the crystallinity index (CrI) and functional groups of pre- and post-pretreated GP to ascertain the efficiency of the pre-treatment methods, with quantification of lignin, holocellulose, and ash. Overall, the TRS yield for N. mirabilis pre-treated agro-waste was 951 mg/L ± 4.666 mg/L, with biomass having a lower CrI of 33%, and 62% residual lignin content. Furthermore, reduced TRPCs were observed in hydrolysate, suggesting limited inhibitory by-product formation during N. mirabilis pre-treatment

Agricultural activities produce a large quantity of waste each year in the Mekong Delta. For example, appropriately 26.86 million tons of rice straw, 5.37 million tons of rice husks, 1.33 million tons of bagasse and 0.59 million tons of corn straw were produced in 2016. Despite such a huge quantity of agricultural waste, the waste has been rarely used effectively. Around 54.1 - 98.0% of rice straw is normally burnt on the field; only 20 - 50% of rice husk is used for pellet or energy purposes; a few sugar-cane factories apply bagasse feeding to steam cookers, and a small quantity of corn straw is used as livestock feeding. If this biomass source is used for electricity generation, in theory, for the period of 2006 - 2020, it is estimated that this source can potentially generate 1203 million MWh/year from rice straw, 236 million MWh/year from rice husk, 45 million MWh/year from bagasse, and 40 million MWh/year from corn straw. Electricity generation of biomass source will not only solve the problem of environmental pollution caused by agricultural waste but also meet increasing energy demands for socio-economic development in this region.
Hàng năm lượng chất thải phát sinh từ một số loại hình canh tác nông nghiệp chính ở ĐBSCL rất lớn. Chỉ tính riêng năm 2016 ghi nhận thải ra khoảng 26,86 triệu tấn rơm rạ; 5,37 triệu tấn vỏ trấu; 1,33 triệu tấn bã mía và 0,59 triệu tấn thân cây bắp. Lượng chất thải phát sinh lớn nhưng các biện pháp sử dụng những nguồn sinh khối này chưa đa dạng, rơm rạ phần lớn được người dân đốt trực tiếp ngay trên đồng ruộng chiếm 54,1 - 98,0% lượng rơm rạ thải ra; chỉ có khoảng 20 - 50% lượng vỏ trấu được sử dụng; bã mía chỉ được một số nhà máy sử dụng để đốt cho lò hơi; một lượng nhỏ thân cây bắp được người dân sử dụng cho chăn nuôi. Nếu có thể tận dụng các nguồn sinh khối này để sản xuất điện thì tiềm năng lý thuyết ước tính từ năm 2005 đến 2020 của rơm rạ là 1203 triệu MWh/năm; vỏ trấu là 236 triệu MWh/năm; bã mía là 45 triệu MWh/năm; và thân cây bắp là 40 triệu MWh/năm. Sản xuất điện từ các nguồn sinh khối này không chỉ giải quyết lượng phế phẩm nông nghiệp phát sinh, giảm thiểu ô nhiễm môi trường mà còn có thể tạo ra nguồn điện cung cấp cho nhu cầu phát triển của vùng.

Hydrogen production by means of anaerobic fermentation was researched utilizing three different substrates. Synthetic wastewater, dairy manure, and cheese whey were combined together at different concentrations under batch anaerobic conditions to determine the optimal hydrogen producing potential and waste treatment of each. Cheese whey at a concentration of 55% was combined with dairy manure at a concentration of 45% to produce 1.53 liters of hydrogen per liter of substrate. These results are significant because the control, synthetic wastewater, which was a glucose-based substrate, produced less hydrogen, 1.34 liters per liter of substrate, than the mixture of cheese whey and dairy manure. These findings indicate that cheese whey and dairy manure, which are of little value, have potential to produce clean combusting hydrogen fuel. The effluent from the anaerobic hydrogen fermentations was then placed into a second continuous-fed reactor as part of a two-phase anaerobic digestion system. This system was designed to produce hydrogen and methane for a mixture of approximately 10% hydrogen. The two-stage process also further treated the synthetic wastewater, dairy manure, and cheese whey. The two-phase anaerobic methanogenic reactor was shown to produce more methane in the second phase (56 L IBR anaerobic digester), 1.36 mL per minute per liter substrate, as compared to the single-phase anaerobic reactor (56 L IBR), which produced 1.22 mL per minute per liter substrate. In general, this research has suggested that agricultural and food processing wastes provide the needed nutrients for hydrogen production and that a two-phase anaerobic digestion system is ideally set up to produce hydrogen-methane mixtures while treating wastes for discharge into the environment.

The entrainment of microbes from agricultural land into overland flow during rainfall events is recognised as an important source of pathogenic microbes to surface water bodies and yet this transport process is poorly understood. In this study, a method has been developed to separate bacteria into the forms in which they have been postulated to exist in overland flow. Then Escherichia coli was used as a model organism to investigate the transported state of bacteria eroded from cowpats and their subsequent transport in overland flow. Simulated rainfall experiments were used to generate runoff direct from cowpats. Concentrations of E. coli in the runoff direct from cowpats were found to be directly proportional to the concentration in the cowpat, regardless of the age of the cowpat. It was also observed that E. coli were predominantly eroded from cowpats as individual cells. The interactions between E. coli and soil particles in overland flow were then examined in a small laboratory scale model system and showed that E. coli attached to large (>45 [mu]m) soil particles were transported significantly less than unattached cells. However, in the runoff from the model system, E. coli were found to be attached mainly to clay particles that were similar in size to the bacterial cells. Furthermore, the transport of E. coli through the model system appeared to follow the transport of a conservative chemical tracer implying that (a) the cells were being transported as a solute with the bulk of the water flow, and (b) that E. coli attached to small clay particles were as mobile in the overland flow as unattached cells. These observations imply that E. coli predominantly interact with small clay particles that are also being carried along in the overland flow. The transport of E. coli at a larger scale was then investigated using 5-metre long, 1-metre wide buffer strips operated under saturation excess conditions. In buffer strips using intact soils and existing pasture cover, E. coli removal was very poor (26 % removal) at the low flow rate of 2 L min⁻� with no removal observed at the higher flow rates of 6 and 20 L min⁻�. E. coli removal rates were increased to 41 % removal at 2 L min⁻� by cultivating the soils, with the removal rate again decreasing with increasing flow rate. E. coli in the overland flow from the buffer strips did not form into large flocs or attach to large soil particles, but were transported in small neutrally buoyant particles that remain entrained in the overland flow. Under saturation excess runoff conditions, E. coli in overland flow were not effectively removed by buffer strips as the small particles are transported either over the soil surface or, through large pores in the soil. This Thesis has shown that E. coli is transported in overland flow in small particle sizes that are difficult to trap or remove from overland flow thereby explaining the high fluxes of faecal bacteria observed in overland flow from agricultural land.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed Mar. 19, 2009). Vita. Includes bibliographical references.

Thesis (Doctor of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018.
Lignocellulosic biomass (agro-waste) has been recommended as the most promising feedstock for the production of bioalcohols, in the biofuel industry. Furthermore, agro-waste is well-known as the most abundant organic matter in the agricultural and forestry product processing industry. However, the challenge with utilizing agro-waste as a feedstock is its highly recalcitrant structure, which limits hydrolysis to convert the holocelluloses into fermentable sugars. Conventional pre-treatment methods such as dilute acid, alkaline, thermal, hot water and enzymatic, have been used in previous studies. The challenge with these conventional methods is the generation of residual toxicants during the pretreatment process, which inhibits a high bioalcohol yield, by reducing the microbial populations’ (fermenter) ability to be metabolically proficient during fermentation. Numerous studies have been developed to improve the engineered strains, which have shown to have an ability to reduce the inhibition and toxicity of the bioalcohols produced or by-products produced during pre-treatment, while enhancing the bioalcohol production. In the present study (chapter 5), evaluation of common conventional methods for the pretreatment of the mixed agro-waste, i.e. (˃45µm to <100µm) constituted by Citrus sinensis, Malus domestica peels, corn cobs from Zea mays and Quercus robur (oak) yard waste without a pre-rinsing step at a ratio of 1:1 at 25% (w/w) for each waste material, was undertaken, focusing on hot water pre treatment followed by dilute acid (H2SO4) pre-treatment. To further pretreat the mixed agro-waste residue, cellulases were used to further hydrolyse the pre-treated agro-waste in a single pot (batch) multi-reaction process. The TRS concentration of 0.12, 1.43 and 3.22 g/L was achieved with hot water, dilute acid and cellulases hydrolysis as sequential pretreatment steps, respectively, in a single pot multi-reaction system. Furthermore, a commercial strain was used to ascertain low (C1 to C3) and high carbon content (C4+) bioalcohol production under aerobic conditions. Multiple bioproducts were obtained within 48 to 72 h, including bioethanol and 1-Butanol, 3-methyl, which were major products for this study. However, undesirable bio-compounds such as phenolics, were detected post fermentation. Since multiple process units characterised by chemical usage and high energy intensivity have been utilized to overcome delignification and cellulolysis, a sustainable, environmental benign pretreatment process was proposed using N. mirabilis “monkey cup” fluids (extracts) to also reduce fermenter inhibitors from the delignification of mixed agrowaste; a process with minimal thermo physical chemical inputs for which a single pot multi-reaction system strategy was used. Nepenthes mirabilis extracts shown to have ligninolytic, cellulolytic and xylanolytic activities, were used as an enzyme cocktail to pretreat mixed agro-waste, subsequent to the furtherance of TRS production from the agro-waste, by further using cellulase for further hydrolysis. N. mirabilis pod extracts were determined to contained carboxylesterases (529.41±30.50 U/L), β-glucosidases (251.94±11.48 U/L) and xylanases (36.09±18.04 U/L), constituting an enzymatic cocktail with a significant potential for the reduction in total residual phenolic compounds (TRPCs). Furthermore, the results indicated that maximum concentration of TRS obtainable was 310±5.19 mg/L within 168 h, while the TRPCs were reduced from 6.25±0.18 to 4.26 ±0.09 mg/L, which was lower than that observed when conventional methods were used. Overall N. mirabilis extracts were demonstrated to have an ability to support biocatalytic processes for the conversion of agro-waste to produce fermentable TRS in a single unit facilitating multiple reactions with minimised interference with cellulase hydrolysis. Therefore, the digestive enzymes in N. mirabilis pods can be used in an integrated system for a second generation biorefinery.

Thesis (DTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017.
The process of anaerobic digestion (AD) is one of the most cost-effective and environmentally sustainable technologies to treat wastewater in the agricultural sector. In South Africa, in some industries in the agricultural sector, such as the poultry industry in particular, slaughterhouses have the highest consumption of potable water, culminating in the production of a large quantity of high strength wastewater. This high consumption of potable water has become a concern in South Africa due to water scarcity and reduced rainfall attributed to global warming, including weather changes. Furthermore, the generation of a large volume of wastewater poses environmental pollution concerns. The wastewater from poultry slaughterhouses can be quite easily treated to a suitable quality for reuse, using various bioreactor systems that utilise low cost anaerobic digestion processes. However, as this wastewater contains a high quantity of biodegradable organic matter – with the primary pollutants being proteins, blood, fats, oil and grease (FOG) – selecting a suitable anaerobic reactor configuration (up-flow vs down-flow) plays an important role in achieving high reactor performance. In this study, both the up-flow, (i.e. Expanded Granular Sludge Bed Reactor) and the down-flow (i.e. Static Granular Static Granular Bed Reactor), were studied to quantitatively determine their performance in treating poultry slaughterhouse wastewater. Firstly, the feasibility of treating poultry slaughterhouse wastewater with an up-flow Expanded Granular Sludge Bed Reactor (EGSB) coupled with anoxic and aerobic bioreactors was investigated at an HRT of 7 (168 hr), 4 (96 hr) and 3 (72 hr) days using organic loading rates of 0.5, 0.7 and 1.0 gCOD/L.day. The averaged tCOD removal for the EGSB reactor was 40%, 57% and 55%, respectively, at the various OLRs and HRTs investigated. The overall tCOD removal of the system (EGSB-anoxic/aerobic) at high OLR of 1.0 gCOD/L.day was increased to 65%. The redundant performance of the up-flow EGSB reactor was attributed to the periodical sludge washout experienced during its operation due to high FOG and TSS concentrations in the influent. Due to the periodic sludge washout, the reactor required continuous re-inoculation resulting in the EGSB being operated for a short period (i.e. 26 days). As a result of such system deficiency, it was recommended that to improve the performance of the up-flow EGSB reactor in treating poultry slaughterhouse wastewater, a pre-treatment system – such as a Dissolved Air Floatation system (DAFs) or a FOG skimmer – is required to reduce the FOG and total suspended solids (TSS) load prior to the wastewater fed to the EGSB. This will minimise system failure and the need for a continuous re-inoculation of the system (see Appendix C for improved operation strategy of the EGSB reactor). Furthermore, a system redesign was recommended, thus the use of the SGBR. Secondly, after the EGSB system evaluation, the performance of a down-flow system (i.e. SGBR) for the new design, the following were deemed appropriate for improved system (SGBR) design: 1) reduced HRT for high wastewater treatment through-put rates; 2) the ability to adequately treat the wastewater with higher organic loading rates; and 3) reduction of the plant footprint by using a membrane filtration system (i.e. a single process unit) to effectively reduce process requirements needed for the anoxic/aerobic bioreactors (i.e. n=2 process unit) used with the EGSB. Similarly, for large-scale operations, it is advisable to have a backwash system to adequately handle declogging processes (i.e. these systems modifications were evaluated in the SGBR). The SGBR, coupled with an ultra-filtration (UF) membrane system, was then investigated for treating the poultry slaughterhouse wastewater at an HRT of 55 hrs and 40 hrs, including average OLRs of 1.01 and 3.14 gCOD/L.day, respectively. The average maximum performance of the SGBR in terms of tCOD, TSS and FOG removal was > 90% at the OLRs and HRTs investigated. The UF membrane system used as a post-treatment system further yielded a system performance improvement for tCOD, TSS and FOG of 64%, 88% and 60%, respectively. The overall performance of the combined system (SGBR and UF membrane system) in terms of tCOD, TSS and FOG removal was 98%, 99.8% and 92.4%, respectively. The highest performance for the down-flow SGBR was attributed to its ability to retain granulated sludge in the reactor while maximizing the digestion of the organic matter fed into the reactor, even at higher OLRs. Furthermore, for effective declogging, the implementation of a periodic backwash system to effectively remove dispersed fine sludge particles in the underdrain and excessive suspended solids entrapment was observed to ease the system operational deficiencies.

Nowadays, lot of attention is devoted both to the application of bio-based polymers as promising alternative to the currently used petro-based polymers, and to the recycling of waste materials coming from agriculture industry. However, a series of economic barriers hinder the application of bio-based polymers in large scale. The aim of this study was to evaluate the application of PLA composites containing up to a 30 %wt of wastes deriving from coffee production. The waste was coffee silverskin which is the main byproduct of coffee roasting process. The composites were formulated in three different proportions of waste including 10 %wt, 20 %wt, and 30 %wt of the composites. The mechanical properties, microstructure, and crystallinity of the composites, as well as thermal stability, water uptake, and contact angle have been evaluated. The results show that coffee silverskin did not compromise the thermal stability and degree of crystallinity of the composites, while it changed the mechanical properties. Specifically, tensile strength gradually decreased on addition of coffee silverskin, while the Young’s modulus slightly increased. The distribution of filler throughout the matrix was almost homogeneous without porosities in the composites. An increase in the value of water uptake was obtained, but the water absorption behavior was not modified. Furthermore, the values of contact angle were constant for all the composites. Due to the production conditions of this study, in order to obtain acceptable properties for the composites, the amount of waste should be limited up to 20 %wt. The simple and low cost operations performed on the waste for obtaining the filler, lead to a decrease in material price on account of PLA reduction. Moreover, using coffee waste as filler in production of green composites, in addition to adding value to agricultural waste, would results in minimizing the dependency on petro-based polymers.

Thesis (MBA)--Stellenbosch University, 2008.
ENGLISH ABSTRACT: The goal of this study was to investigate the feasibility of a small-scale biomass gasification system within the context of a cooperative wine cellar operation in the Western Cape of South Africa. Central to this goal was the questions whether the time for the implementation of such small-scale renewable energy technologies in South Africa has arrived, in light of the status quo which has changed drastically from the days of abundant and cheap coal-based electricity, and whether the new opportunities afforded by the CDM can help foster financial feasibility. There are various macro-drivers contributing to the current-day emphasis on renewable energy and cogeneration projects. The first and most pressing driver is the global climate change imperative, while the others include the increased aspiration of countries towards energy security, the realization of the importance of sustainable development and the subsequent renewable energy policies that falls within the ambit of sustainable development. Small-scale biomass gasification technology still poses some challenges, particularly when it comes to the gasification of agricultural residues, as with grape residues in the case of this project. The most important technical feasibility problem to overcome is the low ash agglomeration temperature of grape residues reported in the literature. Although the local equipment manufacturer foresees no problem in this regard with their system design - since they have conducted tests on sunflower seed residues, which have similar ash properties, without experiencing any agglomeration problems - the seriousness of this aspect will be confirmed during pilot trials. In order to be eligible for emissions reduction trading under the CDM, the project must adequately demonstrate that the emissions reductions are additional to the business-as-usual scenario, in both the environmental and financial sense. The project will satisfy the environmental additionality requirement, since in its absence the wine cellar will continue its full reliance on coal-based electricity from the grid. Financial additionality, in its strictest sense, requires for the project to be infeasible if it does not pursue CDM participation, which the financial feasibility modeling results indicated to be true in this case. A feasibility model was developed to - subject to the input parameter values assumed and basic assumptions made - be able to assess the financial viability of the project. The main assumptions were that the private feed-in into the national electricity grid was available to all IPPs, in spite of the fact that in its Medium Term Power Purchase Program me (MTPPP) of May 2008 Eskom had only requested expressions of interest from IPPs that had a generating capacity of 5MW and higher to install private base load capacity. This assumption is commensurate with the country's renewable energy targets and the official government aim of achieving a 30% contribution from IPPs to the national electricity mix. The second assumption was that the 65 to lOOclkWh offered by Eskom in its MTPPP will be applicable to sub-SMWe IPPs as well (Creamer, 2008), and that this lower bound electricity price of 65clkWh can be applied over the whole project lifetime. Inherent to this assumption is the further supposition that the progressive decline of electricity prices to an eventual level of 35clkWh by 2018 foreseen by Eskom will not materialize, due both to the sustained pressure an expanding South African economy will put on the considerable but time-consuming supply-side initiatives launched by Eskom, and the likelihood for price premiums to be introduced for clean electricity in order to meet the country's renewable energy targets. From the assumed input parameter values the initial capital and COM expenditures, operating revenues and costs over the project lifetime were determined, and then used to calculate the net cash flows, where after the NPV was computed to serve as the deciding criterion on financial feasibility. A discount rate of 18% was assumed, corresponding with the subjectively judged risks that the project posed as a small-scale renewable energy system within the wine cellar operations. In the case where the project excluded all CDM aspects, the NPV was negative at - ZAR342 573, but this improved to ZAR325 193 if the project participated in the CDM. Thus it was concluded that the project will only be financially feasible if it includes CDM participation, and that this positive contribution can be leveraged by pursuing a programmatic CDM approach. This entails the development of this project as part of a larger program in which similar projects are implemented as they arise, up to the official UN limit of 15MWe in total to still qualify as a small-scale program. The nature of the assumptions that form the backbone of this study indicate that the positive financial feasibility result in the case where the project includes COM participation will become practically relevant only over the short- to medium-term as these assumptions become reality in South Africa. Therefore, although the time for such small-scale renewable energy projects has clearly not arrived as yet, it would seem that it is indeed around the corner.
AFRIKAANSE OPSOMMING: Die mikpunt van die navorsing was om die lewensvatbaarheid van 'n klein-skaal biomassa vergassing sisteem binne die konteks van 'n kooperatiewe wynkelder in die Wes-Kaap van Suid-Afrika te ondersoek. 'n Sentrale aspek was die vrae of die tyd aangebreek het om klein-skaal volhouhare energie projekte in Suid-Afrika tot uitvoering te bring, gesien in die lig van 'n status quo wat drasties weg beweeg het van die tydperk toe elektrisiteit volop en goedkoop was, en of die geleentheid wat die CDM bied sulke projekte finansieel lewensvatbaar kan maak. Daar is verskeie eksterne makro-drywers wat bydrae tot die huidige fokus op sulke volhoubare energie projekte. Hieronder tel globale klimaatsverandering as die dringendste drywer, terwyl die res onder andere die hernuwe strewe van lande tot verbeterde energie-sekuriteit, die besef van die belangrikheid van volhoubare ontwikkeling en die daaropvolgende volhoubare energie beleid stappe insluit. Daar bestaan nog etlike tegniese uitdagings tot die toepassing van klein-skaal biomassa vergassing tegnologie, spesifiek met betrekking tot die vergassing van afval landbou byprodukte, soos wat die geval is met druiwe afval in hierdie projek. Die belangrikste tegniese uitvoerbaarheids-aspek wat aandag verg is die lae smeltpunt van druifafval-as wat in die literatuur rapporteer word. Alhoewel die plaaslike toerustings-vervaardiger nie enige probleme in hierdie verhand voorsien nie, aangesien toetse met sonneblom afval - met as-eienskappe rofweg identies aan die van druiwe-afval - geen smelting van die as getoon het nie, sal dit tog nogsteeds aan verdere toetse onderwerp word. Vir die projek om te kwalifiseer as geskik vir verhandeling in kweekhuisgas vermindering deur middel van die COM, moet dit voldoende bewys kan word dat alle uitlaatgas vermindering addisioneel is tot wat die geval sou wees in die gewone gang van besigheid. Hierdie addisionaliteit is relevant in beide 'n omgewings- en finansiele sin. Hierdie projek sal orngewings-addisionaliteit bevredig deurdat die wynkelder in sy afwesigheid volkome afhanklik van die steenkool-gebaseerde elektrisiteit vanaf die nasionale netwerk sou bly, terwyl finansiele addisionaliteit bewys is deur die finansiele lewensvatbaarheids-model wat getoon het dat die projek slegs ekonomies uitvoerbaar sal wees indien dit CDM deelname insluit. Die lewensvatbaarheids-model is ontwikkel om die ekonomiese uitvoerbaarheid van die projek te evalueer, onderworpe aan die aangenome inset parameter waardes en basiese aannames in die studie. Die hoof-aanname was naamlik dat privaat terugvoer in die nasionale elektrisiteits-netwerk vir alle grootte IPPs moontlik is, ten spyte van die feit dat Eskom se MTPPP van Mei 2008 slegs kapasiteite van 5MW en groter aanvaar bet. Hierdie aanname is gebaseer op Suid-Afrika se volhoubare energie teikens en die regering se offisiele mikpunt om 30% van alle krag-voorsiening vanaf IPPs te bekom. Die tweede hoof-aanname was dat die 65 tot 100clkWh wat Eskom in sy MTPPP aangebied het, ook van toepassing sal wees op sub-SMW IPPs (Creamer, 2008), en dat die laer prys-limiet van 65c/kWb oor die hele projek-leeftyd toegepas kon word. Inherent tot hierdie aanname is die verdere veronderstelling dat die progressiewe daling in elektrisiteits-pryse tot 'n eventuele vlak van 35clkWh voorsien deur Eskom nie sal realiseer nie, beide as gevolg van die volgehoue druk wat die groeiende Suid-Afrikaanse ekonomie op die aansieniike, maar tydrowende, opwekkings-kapasiteit uitbreidings van Eskom behoort te plaas, en ook die hoe waarskynlikheid dat prys premiums vir skoon elektrisiteit ingestel word sodat Suid-Afrika sy volboubare energie telkens kan bereik. Die aanvanklike kapitaal en CDM uitgawes, en bedryfsuitgawes en - inkomstes oor die projekleeftyd is vanaf die aangenome inset parameter waardes afgelei, waarop die NPV van die projek uitgewerk is om te dien as die beslissende maatstaf van ekonomiese haalbaarheid. 'n Diskontokoers van 18% is gebruik, ooreenstemmend met die subjektief beraamde risikos wat die projek inhou as 'n klein-skaal volhoubare energie sisteem. Die resultate van die finansiele lewensvatbaarheids-model het getoon dat in die geval waar die projek geen CDM aspekte bevat nie, die NPV hoogs negatief sou wees met 'n waarde van -ZAR342 573, terwyl dit verbeter na ZAR325 193 as die projek CDM deelname insluit. Die gevolgtrekking is dus gemaak dat die spesifieke projek slegs ekonomies haalbaar sal wees indien dit wel CDM deelname insluit, en dat hierdie positiewe finansiele bydrae van die CDM geoptimaliseer kan word deur 'n programmatiese CDM benadering te volg. Dit behels die ontwikkeling van die projek as deel van 'n groter program waarin soortgelyke projekte mettertyd geimplementeer word soos hulle ontstaan, tot by die offisiele VN limiet van 15MWe om sodoende nog te kwalifiseer as 'n algehele klein-skaalse program. Die aard van die hoof-aannames in hierdie studie is indikatief dat die positiewe finansiele lewensvatbaarheid in die geval waar die projek CDM deelname insluit, eers oor die kort- tot medium-termyn prakties relevant sal word soos die aannames bevredig word. Dus, alhoewel die era van klein-skaalse volhoubare energie projekte nog nie aangebreek het in Suid-Afrika nie, lyk dit tog asof dit om die draai is.

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017.
An increase in the demand for poultry products coupled with the potable water shortages currently experienced in South Africa (SA), attributed to climate change among other factors, makes it crucial for SA to develop water conservation strategies to minimize potable water consumption by water-intensive industries, such as the poultry industry. The development of innovative wastewater treatment processes is therefore paramount in attempting to counteract the large quantity of wastewater generated as well as to manage the environmental health concerns arising from poultry slaughterhouse wastewater (PSW) discharge into the environment. Moreover, increasing wastewater treatment costs and the implementation of increasingly stringent government legislation to mitigate environmental pollution whilst minimizing fresh water source contamination, requires that wastewater such as PSW, be adequately treated prior to discharge. This study, investigated the feasibility of treating PSW from a poultry slaughterhouse to: 1) a water quality standard compliant with industrial wastewater discharge standards and 2) for possible re-use purposes. The performance of a lab-scale PSW treatment system consisting of an anaerobic static granular bed reactor (SGBR) followed by single stage nitrificationdenitrification (SSND) bioreactor and sidestream ultrafiltration membrane module (ufMM) post-treatment systems, were evaluated, with the objective being to: assess the treatment efficiency of the individual treatment systems namely; the SGBR, SSND bioreactor, and ufMM, under varying operational conditions, as well as to determine the performance of the overall designed PSW treatment system. The down-flow SGBR (2 L) was used to reduce the organic matter (COD, BOD5, and FOG) and total suspended solids (TSS) in the PSW. Anaerobic granules from a full-scale mesophilic anaerobic reactor treating brewery wastewater were used to inoculate the SGBR, and the PSW used as feed was obtained from a local poultry slaughterhouse (Western Cape, South Africa). The SGBR was operated continuously at mesophilic temperature (35-37 °C) without pH modification and under varying HRTs (24, 36, 48, 55, and 96 h) and OLRs (0.73 to 12.49 g COD/Lday), for a period of 138 days. The optimization of the SGBR, with regard to a suitable HRT and OLR, was determined using response surface methodology (RSM) and Design Expert® 10.0.3 statistical software. Periodic backwashing of the SGBR system was performed using stored effluent, i.e. treated PSW.

Thesis (M.Sc.) -- Hawkesbury Agricultural College, 1985.
"A thesis submitted to Hawkesbury Agricultural College in partial fulfilment of the requirements for the degree of Master of Applied Science."

Ao abordar o tema contaminação ambiental, logo se recorda a quantidade de resíduos domésticos e urbanos, que são gerados nas cidades e metrópoles, os quais muitas vezes não recebem nenhum tipo de tratamento. Porém, problemas de contaminação ambiental também estão vinculados à agricultura, onde são gerados resíduos orgânicos com elevados potenciais poluidores. Dessa forma, o projeto objetivou estudar o processo de codigestão anaeróbia de dejetos bovinos e suínos oriundos de sistemas de produção de suínos e atividade pecuária leiteira, como alternativa para tratamento destes tipos de matrizes, além de investigar a eficiência do biofertilizante produzido a partir das matrizes de resíduos em cultura de milho. Para isso, se coletaram amostras de dejetos de bovinos e suínos para caracterização e posterior utilização nos ensaios com tratamentos diferentes. Na sequência se fez a preparação das amostras para os ensaios utilizando-se de inoculos diferenciados (in natura, inoculo da rede de saneamento básico e inoculo isolado de dejeto bovino) com o propósito de avaliar a degradação dos dejetos via codigestão anaeróbia. Em cada ensaio citado se fizeram vinte tratamentos, via planejamento fatorial 2³, com seis pontos centrais, sendo as variáveis de entrada: tempo, fração de sólidos e razão de mistura; e as variáveis respostas (dependentes): pH, razão AV/AL, umidade, série de sólidos, razão SV/ST, redução de sólidos totais, DQO, redução de DQO, nitrogênio total, fósforo e potássio. Fez-se depois o estudo cinético do processo, se utilizando do ensaio in natura com proporção de mistura de 75% em dejeto suíno e 25% em dejeto bovino, com fração de sólidos de 8,9%, mediante Teste de Tukey. Após a estabilização da biomassa utilizada, fez-se a aplicação do biofertilizante em cultura de milho, comparando-se com fertilizante comercial (ureia), verificando-se o crescimento e desenvolvimento desta cultura. No planejamento fatorial se concluiu mediante análise de Tukey e considerando a importância de cada variável resposta que o ensaio in natura apresentou as melhores condições operacionais, pois se teve o maior número de variáveis respostas sendo consideradas satisfatórias, como razão AV/AL, razão SV/ST e redução da DQO. Observou-se durante o estudo cinético que a biomassa apresentou estabilização próxima aos vinte dias de tratamento, indicando a degradação orgânica dos dejetos em codigestão e produção de biofertilizante, o qual é mais estável e menos poluente ao ambiente, sendo utilizado como opção no processo de fertilização de culturas agrícolas como o milho. No que diz respeito à utilização do biofertilizante (40 kg.ha-1), notou-se semelhança deste se comparado à ureia (40 kg.ha-1) para o cultivo de milho, podendo ser uma alternativa interessante de destinação dos dejetos, diminuindo a poluição ambiental causada pelo manejo inadequado.
When discussing environmental contamination, just remember the amount of domestic and urban waste that are generated in towns and cities, which often do not receive any treatment. However, problems of environmental contamination are linked to agriculture, where organic waste with high potential polluters is generated. This way, the project had the objective of studying the anaerobic codigestion process of cattle and pig waste from the swine production systems and dairy farming activity, as an alternative to the treatment of these kinds of matrices, as well as to investigate the efficiency of biofertilizer matrices produced from the waste in cultured maize. For this, samples of manure from cattle and pigs were collected for characterization and subsequent use in the tests with different treatments. Then, the preparation of samples for the tests using the different inocula were made (in natura, inoculum of sanitation and inoculum isolated from bovine manure), in order to evaluate the degradation of waste via anaerobic codigestão. In each test mentioned twenty treatments were made, via 2³ factorial design with six central points, where the input variables: time, fraction of solids and mixing ratio; and the response variables (dependent): pH, ratio AV/AL, moisture, solids, ratio SV/ST, reduction of total solids, COD, reduction of COD, total nitrogen, phosphorus and potassium. It was made after the kinetic study of the process, using the test in natura mix ratio of 75% in swine manure and 25% in cattle manure with solid fraction of 8.9% by the Tukey test. After stabilization of the biomass used, there was the application of biofertilizers in crop maize compared with commercial fertilizer (urea), verifying the growth and development of this culture. In factorial design was completed by Tukey analysis and considering the importance of each variable response that the test in natura presented the best operating conditions, because it had the largest number of variable responses being considered satisfactory ratio as AV / AL, ratio SV / ST and COD reduction. It was observed during the kinetic study that biomass showed stabilization next to twenty days of treatment, indicating the degradation of organic waste in codigestão and biofertilizer production, which is more stable and less polluting to the environment, being used as an option in process fertilization of agricultural crops such as maize. Regarding the use of biofertilizers (40 kg.ha-1), this similarity was noted compared to urea (40 kg.ha-1) for the cultivation of maize and it may be an interesting alternative for allocation of waste, reducing environmental pollution caused by improper handling.

Title from PDF of title page (University of Missouri--Columbia, viewed on March 2, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dr. Sunggyu Lee, Dissertation Advisor. Vita. Includes bibliographical references.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on January 26, 2010). Thesis advisor: Dr. Wyatt Thompson. Includes bibliographical references.

CNPq
A indústria têxtil tem grande impacto ambiental devido ao seu amplo consumo de água e da utilização de diferentes produtos químicos orgânicos como os corantes. Existem diferentes métodos utilizados no tratamento de efluentes têxteis, sendo um deles, a adsorção. A utilização de resíduos agroindustriais como adsorventes é uma alternativa para a descontaminação de efluentes com corantes. Desta forma, este trabalho teve por objetivo avaliar o resíduo agroindustrial de Bagaço de Maçã da variedade Fuji, proveniente da produção de sucos, como adsorvente alternativo na remoção de corantes têxteis C.I. Reactive Blue 203 e C.I. Reactive Red 195 em meio aquoso sintético. As características do adsorvente mostraram que o bagaço de maçã apresenta 89,36% de umidade, 35,64% de fibra bruta e a 52,72% de carbono. O pH(pcz) é de 3,5 e em sua superfície predomina sítios ácidos. Na espectroscopia do infravermelho observou-se a presença dos principais grupos funcionais (–OH), (–NH), (CH2), (–CO), (–C–O–), na microscopia eletrônica de varredura a morfologia da superfície do bagaço de maçã mostrou-se porosa e a determinação das características texturais indicaram uma área superficial de 2,088 (m2.g-1) para o tamanho de partícula de 0,125 mm. A partir dos resultados do planejamento experimental - 23, pode-se otimizar o processo de adsorção para os dois corantes pelo bagaço de maçã fixando as variáveis independentes com influência significativa (pH de 2,0 e granulometria do adsorvente em 0,125 mm). No estudo cinético o tempo de equilíbrio para o Reactive Blue 203 foi de 420 minutos e para Reactive Red 195 de 180 minutos e o ajuste matemático para ambos corantes foi para o modelo de pseudo-segunda ordem. As isotermas de equilíbrio foram testadas pelos modelos das isotermas de adsorção de Langmuir, Freundlich, Dubinin-Raduskevich e BET, sendo este último mais adequado para a descrição do processo. Os parâmetros termodinâmicos foram determinados em diferentes faixas de temperatura, em que valores negativos de ΔG° indicam a espontaneidade do processo de adsorção para os dois corantes e valores negativos para ΔH° no processo de adsorção do corante Reactive Blue 203 indicam natureza exotérmica no entanto para adsorção do corante Reactive Red 195 valores positivos de ΔH° sugerem a sua natureza endotérmica. Os valores de ΔH e Ea para a adsorção dos dois corantes em bagaço de maçã mostram que são da mesma ordem de grandeza que o calor e a energia de ativação da quimissorção. O bagaço de maçã mostrou-se altamente favorável para o processo de adsorção dos corantes Reactive Blue 203 e Reactive Red 195.
The textile industry has a big environmental impact because consume a lot of water, and use different chemical organic products like dyes. There are different methods for treatment of textile effluents one of those is adsorption. Using agroindustrial residues like adsorbents is an alternative for decontamination effluents by dyes. Therefore, this present work aimed to evaluate agroindustrial residue apple pomace of Fuji variety, that proceed of production of juices, like alternative adsorbent for the removal textile dyes C.I. Reactive Blue 203 and C.I. Reactive Red 195 in aqueous synthetic medium. The adsorbent characteristics showed that apple pomace present 89.36% of humidity and 35,64% of crude fiber. and 52,72% of C. The pH (pzc) is 3,5, and its surface prevails sites acids. In infrared spectroscopy it was observed the presence of the major functional groups (–OH), (–NH), (CH2), (–CO), (–C–O–). In scanning electron microscopy of the surface morphology of the apple pomace was found to be porous and determining the textural features indicated a surface area of 2,088 (m2.g-1) to 0,125 mm particle size. From the results of the experimental design 23 can optimize the process of adsorption of for both dyes by apple pomace, setting the independent variables with significant influence (pH of 2.0 and particle size of the adsorbent 0.125 mm). In the kinetic study the equilibrium time for Reactive Blue 203 was 420 minutes and for Reactive Red 195 was 180 minutes and for both dyes mathematical adjustment was to model the pseudo-second order. The equilibrium isotherms were tested by the models adsorption isotherms of Langmuir, Freundlich, Dubinin-Raduskevich and BET, the last being more suitable for the description of the process. The thermodynamic parameters were determined at different ranges of temperature, in which negative values of ΔG° means the spontaneity in the adsorption process for both dyes and negative values for ΔH° for adsorption process of Reactive Blue 203 suggest the exothermic nature However the adsorption to the dye Reactive Red 195 ΔH° positive values suggest its endothermic nature. The values for ΔH° and the Ea for the adsorption of the two dyes in apple pomace show that they are of the same order of magnitude as the heat and the activation energy of chemisorption. The apple pomace was highly favorable for the adsorption of the dye Reactive Blue 203 and Reactive Red 195.

Concerns about energy security, fossil fuel prices, and climate change issues, are leading to increasing renewable energy demand. Hydrogen is considered as one of the main possible energy carriers in future, due to its environmental (it can be converted to energy with the solely emission of water) and energetic (energy content of 120 MJ/kg, three times higher of the gasoline content of 44 MJ/kg) unique properties. If hydrogen is currently being produced mainly by fossil sources, its production from renewable sources answers to the demand of more environment-friendly exploiting alternatives, possibly leading to a renewable-based hydrogen economy. Biomasses are an important renewable source ranging from energy-dedicated crops to livestock waste effluents, agro-industrial wastewaters, food-processing industry residues and organic fractions of the municipal solid waste (OFMSW). Thus the agricultural sector may acquire a renewed importance in the mid-term as a producer of energy sources for renewable biohydrogen production. Among the biological ways to exploit biomasses for hydrogen production, this thesis focused its interest on anaerobic dark fermentation, which can simultaneously guarantee the production of an high-value product (H2) at high evolution rates and the treatment of wastes, thus transformed from an environmental pollution and greenhouse gases emissions source into a valuable resource. If on the one hand this process has lots in common with anaerobic digestion, which already is a well-established technology for treating different biomass types in real-scale plants, on the other hand it is a relatively new approach, which needs to be further studied for improving its performances and being concretely applicable. As a matter of fact, the main disadvantage of dark fermentation is its relatively low yield, compared to other bio-hydrogen production methods, which typically are between 2.4 and 3 mol H2/mol glucose. This represents just the 20-25% of the 12 mol of H2 theoretically obtainable by glucose fermentation. Therefore, generally two different (but not mutually exclusive) options could be chosen for improving the process and making it ready for full-scale applications: the optimization of the biological, biochemical, chemical-physical operative parameters that regulate process; or the coupling of this bioprocess with other technologies capable of exploiting the organic matter not fully used by the dark fermentative approach. For example, Microbial Electrolysis Cells (MECs) are able to biologically oxidize the organic matter (from simple substrates like volatile fatty acids, lactic acid, glucose, cellulose, to actual wastewaters) releasing electrons from an anode to a cathode where potentially pure hydrogen can be formed from protons in the water. Papers I and II basically belong to the first strategy. In Paper I indeed, two waste biomasses were co-digested: in consideration that in the Po Valley area (Italy) swine manures (SM) are yearly produced at high waste density levels and could be a cause of environmental problems, this waste was used as a co-substrate for biohydrogen production by the thermophilic fermentation of easily degradable and carbohydrate-rich materials, such as fruit and vegetable market waste (FVMW). Biohydrogen production rates and process stability were thus simultaneously maximized, thanks to the endogenous buffer capacity of manure, through the combination of a suitable composition (as FVMW/SM) of the feeding material and the hydraulic retention time (HRT) of the process. Thus, livestock manure represented not only a renewable source for supplying the production of biohydrogen, but also a source of alkali to be used for avoiding the addition of exogenous chemicals (alkali) to maintain the pH, and so the metabolic pathways and bacterial communities, into an optimal domain for biohydrogen production. To further study and optimize the bio-H2 production in laboratory-scale processes, but also to find applicable tools for favoring dark fermentation application in full-scale biogas plants, Paper II succeeded in obtaining mixed microbial cultures from natural sources (soil-inocula and anaerobically digested materials) which reached high hydrogen yields with glucose and were used to explore the potential of bio-hydrogen production from four organic substrates of possible interest for full-scale plants (market bio-wastes, maize silage, swine manure, OFMSW). In direct prosecution of the positive co-digestion results shown in Paper I and looking for future transfer of this bioprocess technical solutions to full-scale systems, Paper II used the enriched mixed microflora for evaluating the co-fermentation of a mixture of OFMSW and swine manure in a lab-scale continuously-fed CSTR (continuously stirred tank reactor) digester. Despite the good results obtained, our study suggested that further efforts are needed for future applications of effective biohydrogen fermentation in full-scale plants. Paper III and IV are more focused on the second scientific strategy. Paper III joins the interest toward implementation of bio-H2 in full-scale plants and the strategy of improving the overall recovery of the energy contained in the biomass associating hydrogen production to other bioprocesses. Many authors report that the two-stage anaerobic digestion (AD) process, if compared to traditional and extensively real-scale applied single-stage AD, has also other advantages, such as differentiating the biofuel production (bio-hydrogen and bio-methane), potentially reducing the plant dimensions and costs, improving the overall biogas production yields and allowing higher CH4 concentrations in the biogas produced in the second stage, thus decreasing the biogas purification costs. Therefore, a two-stage laboratory-scale CSTR anaerobic digester, fed with a mixture of agricultural and livestock residues, was monitored for a long run (approximately 700 hours) and compared to a similar one-stage reactor. This study obtained a good hydrogen yield per kg of biomass treated and partially confirmed the advantages previously illustrated, even if it reached almost the same overall energy recovery of the single stage process. Aiming at other possible biological strategies to improve the energy and hydrogen recovery efficiency with the use of effluents from a first dark fermentative stage, a relatively new electrohydrogenesis device (MEC) was studied. Paper IV explores the rate and the yield of biogas (a mixture of H2, CH4 and CO2) produced by MEC exploiting an actual industrial wastewater with high methanol content, a compound never before reported to be used in a MEC device. The energetic recovery and treatment performance of the process was evaluated and also compared with a simulation of anaerobic digestion of the same wastewater, revealing the economical competitiveness of the MEC technology with the AD process. This leads to future research perspectives aiming to realize a laboratory-scale two-stage reactor with a MEC using the volatile-rich effluent of a first dark fermentative stage.

CAPES
O okara é uma biomassa gerada no processamento do extrato hidrossolúvel de soja e do tofu. Tal biomassa tem elevada qualidade nutricional em função do conteúdo de proteínas, fibras e compostos bioativos como as isoflavonas. É gerado em grandes quantidades pela indústria processadora de soja como um subproduto e embora se trate de um material de baixo valor comercial possui em sua composição moléculas com potencial nutricional e funcional. As isoflavonas estão presentes na soja principalmente nas formas conjugadas (β-glicosídicas, acetil e malonil) e, em menor proporção, nas formas livres (agliconas). Diversos estudos comprovam a eficiência das isoflavonas agliconas na prevenção de doenças crônicas. Algumas tecnologias têm sido empregadas para a bioconversão das isoflavonas β-glicosídicas em agliconas baseadas na ação de enzimas β-glicosidases sintetizadas por micro-organismos. Neste contexto, o presente trabalho objetivou a bioconversão de isoflavonas presentes no okara através de fermentação semissólida por Saccharomyces cerevisiae r. f. bayanus, buscando melhorar a qualidade nutricional e propriedades biológicas do okara para uso como ingrediente em produtos alimentícios. A fermentação semissólida foi conduzida a 28 °C durante 72 horas. O processo contribuiu para o aumento dos teores de proteínas e redução do conteúdo de fibra bruta o que pode contribuir para melhorar a digestibilidade do produto. A fermentação proporcionou a biotransformação de isoflavonas conjugadas em agliconas, o que levou ao aumento da quantidade de compostos fenólicos, capacidade antioxidante da biomassa e consequente melhoria da qualidade nutricional. A biotransformação das isoflavonas do okara por processo fermentativo mostrou ser uma estratégia promissora para agregação de valor e melhor aproveitamento da biomassa.
Okara is a biomass generated by the soybean and tofu water soluble extract process. Such biomass has a very important nutritional quality because of the protein content, fibres and bioactive compounds as the isoflavons. It is produced in great amounts by the soybean processing industry as a by-product, although it is a product of low commercial value, it possess on its composition molecules with nutritional and functional potential. The isoflavons are present in the soybean mainly in the combined forms (B-glycosidics, acetyl and molonic) and, in a minor proportion, in the free forms (aglycons). Several studies prove the efficiency of aglycons isoflavons preventing cronicle diseases. Some technologies have been employed for the bioconversion of β-glycosidic isoflavon in aglycons based in the action of enzymes β-glycoside hydrolase synthesized by microorganisms. In this context, the current work has aimed the bioconversion by Saccharomyces cerevisiae r. f. bayanus, trying to improve the okara nutritional quality and biological properties in order to use it as an ingredient in food. The semisolid fermentation has been lead under 28° C per 72 hours. The process was conduction at increase protein and reduction of crude fiber content improving the product digestibility. The fermentation provided a biotransformation of isoflavonscombining aglycons, what has taken to the raise of amount of phenolic compounds, biomasa antioxidant capacity and consequently improving of nutritional quality. The biotransformation of okara isoflavons by fermentation process has should to be a promising strategy for adding value and better use of biomass.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

碩士
大葉大學
食品工程研究所
90
The study focused on the production of deodorant and ethylene absorber by fermenting tea leaves and chitin with Monascus ruber 31535. In the study of the optimal culture conditions, it was found that the cultivation of Monascus ruber 31535 with tea leaves(4g), lemon residue(1g), at 30℃ for 6days will give the best result. The fermented product was tested on ammomia(NH3), and its deodorizing ratio was found to be 82%. The deodorant produced above slowed better deodorizing ratio (78%) at cooler temperature(4℃) than it was at room temperature. The deodorizing ratio reached to a plateau after 48h. When compared with two commercial deodorants, the fermented deodorant displayed much better results. The deodorizing ratio for commercial deodorants is 23% and 15%, respectively. Monascus ruber 31535 were also used to ferment chitin for production of deodorant. The ferment product from chitin was found to be a good absorber for ethylene. When ethylene produced by decomposed of ethephon was exposed to the above absorber, 91% of ethylene was absorbed after 24h of exposure at room temperature. The ethylene absorbed-ability of the fermented product was much better than those of commercial absorber.

博士
逢甲大學
環境工程與科學所
100
In Taiwan, approximately 1.4 million ton rice straw and 0.7 million ton fruit waste are produced annually. This study aimed to develop feasible technology to covert the agricultural waste into bio-energy to solve the problems with the treatment of the mass amount of rice straw or fruit waste with the benefit of more energy production. In this study, 3 kinds carbohydrate-rich agricultural wastes (namely, watermelon, papaya and pineapple) were used as the substrate to conduct anaerobic fermentation under mesotrophic (35 ℃) and thermophilic (55℃) conditions. The seed culture used was sewage sludge from Chunghsing Hsintsun, Nantou in Taiwan. The initial pH value was controlled at 6.7. The results show without inoculation of the seed sludge and without nutrient addition, the metabolic pathway was dominated by ethanol fermentation. After thermophilic fermentation with agricultural waste containing high carbohydrate content, the culture contained a residual carbohydrate concentration of 25-36 g/L. This is well suited to serve as the substrate for biohydrogen fermentation or composting. However, during mesotrophic fermentation, more hydrogen production was observed. It was found that pineapple is the better substrate for biohydrogen production, producing bioenergy with a heat value of 0.572 J/g and 0.374 J/g fermentation at 35 and 55℃, respectively. The agricultural waste with high cellulose content (i.e., rice straw and banana leaf) are non-food substrates for biomass energy production. In this study, cellulolytic enzymes were used to hydrolyze banana leaf for 24 hours at an initial pH value of 5.5、6.0、6.5 and 7.0, respectively. Using the supernatant of the hydrolysate of banana leaf as feedstock, the pick hydrogen production rate (53.9 ml/gVSS) occurred at initial pH 6.5. A full factorial experimental design was used to investigate the effects of enzyme hydrolysis time (12-48 hr) and pH value (5.5~7.0) on the hydrolysis efficiency. The results show that the maximum TCOD and total carbohydrate concentration both occurred at an enzyme hydrolysis time of 48 hr, while hydrolysis at an initial pH of 6.0 for 12 hr resulted in the highest cumulative hydrogen production (56.5ml) with a specific hydrogen production rate of 31.4 ml/gVSS. The mixed culture contained bacterial populations that were either directly involved or assisted in biohydrogen production and grew symbiotically. The co-fermentation substrates used were papaya and rice straw at a mixed rate of 5:0-0:5 (TCOD basis). The results show that co-fermentation can increase biohydrogen production. Using a mixed ratio of 4:1 (Papaya: rice straw, COD basis) was increase 18% hydrogen production. Using the mixed ratio 1:1 (agricultural waste : food factory wastewater, TCOD basis) can increased 40% hydrogen production. The enzymatic hydrolysate of rice straw could serve as the index to assess the feasibility of using cellulose-rich agricultural wastes as feedstock for biohydrogen production. Therefore, in this study 27 g COD/L of rice straw hydrolysate was used as substrate for biohydrogen fermentation with a controlled pH 6.0 and a HRT of 12、8、6 and 4 hr. The average hydrogen concentration was 30.5-37.4% and the peak hydrogen production rate is 133 mmol H2/L/d (at HRT=4 hr). The co-fermentation of agricultural waste and food factory wastewater with a mixed ratio 1:4 ratios was also used as the feedstock to improve the biohydrogen production efficiency. With a substrate concentration of 30 g COD/L, a controlled pH of 6.7, and a HRT of 12、8、6 and 4 hr. The average hydrogen concentration was 29.9-37.0% and the peak hydrogen production rate was 125 mmol H2/L/d (at HRT=4 hr). The energy recovery from hydrogen was calculated as 4.4-15.0%. Thus, connecting methane-forming reactor with hydrogen fermenter could be a more effective bioenergy production system.

碩士
國立成功大學
化學工程學系
102
In order to use lignocellulose of plant effectively rather than increasing carbon dioxide gas emissions by incineration.In the study, agricultural wastes were used for fabricating nano silicon carbide through carbothermal reduction method .The surface morphologies of nano silicon carbide materials were characterized by scanning electron microscopy (SEM), the results show that there are many flaky and linear part,further through X-ray diffraction (XRD) ,the results indicate successfully synthesis of silicon carbide. Moreover, extra Fumed silica could be added to increase the yield of nano silicon carbide,the study concluded that adding 10wt.% Fumed silica has the highest conversion rate.Through the way, the agricultural waste could effectively reuse and further produce the high value silicon carbide.From high-resolution transmission electron microscopy(HRTEM) results,the growth of silicon carbide structure can be divided into whiskers,nanofiber and particle.The silicon carbide particles were embedded in the amorphous carbon.As a result, The morphology of nano silicon carbide can be separated by characteristic of hydrophilic and hydrophobic.

碩士
明志科技大學
化學工程系生化工程碩士班
102
High energy lithium ion batteries are in demand for consumer electronics, electric-drive vehicles and grid-scale stationary energy storage. Silicon is of great interest since it has 10 times higher specific capacity than traditional carbon anodes. However, the poor cycling ability due to the large volume change of silicon upon insertion and extraction of lithium has been an impediment to its deployment. Rice is one of the most widespread food crops for human sustenance. Rice husks are the hard protecting coverings of grains of rice and its silica accounts for ~15-20 wt% of the entire rice husks. In this research, rice husks silica will be applied in lithium ion battery anodes by reducing the silica to silicon. Lithium ion battery performance, electrical capacity and cyclic stability, will also be determined by coin-type half cells. As the result, silicon was made from agricultural wastes that compared to commercial with more performance. In the first cyclic, reversible capacity and the coulomb efficiency of bio-silicon were 1500 mAh/g and 64.64% Respectively. However, the commercial materials capacity rapidly declined and only had 30 mAh/g. Therefore, Silicon from rice husks has great potential for lithium ion battery.