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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Pilot-Scale Constructed Wetlands Combined with Phosphorus Removing Slag Filters for Treating Dairy Wastewater

Lee, Martin 02 October 2009 (has links)
Pilot-scale constructed wetlands (CW), with electric arc furnace steel slag phosphorus removing filters were built and implemented for treating dairy wastewater on the Paul Miller Dairy Farm at the University of Vermont. Two distinct CW types were used in the study, hybrid and integrated. Hybrid CWs consist of more than one CW in-series, and in this research three hybrid CW systems were tested. Two hybrid CWs used a vertical saturated flow (VF) CW followed in-series by a horizontal saturated flow (HF) CW. One hybrid CW used a HF CW followed in series by a second HF CW. In this study, three integrated CW systems were implemented which consisted of a CW followed by a phosphorus removing slag filter. Two integrated CW systems consisted of a VF CW followed in-series by a saturated horizontal flow slag filter. One integrated CW system consisted of a HF CW followed by a horizontal saturated flow slag filter. All individual CWs and slag filters had the same dimensions; a length, width, and height of 1.7m, 1.1 m, and 0.5 m, respectively. CWs were filled with 2 cm diameter gravel, topped with 3 cm of compost, and planted with river bulrush (Schoenoplectus fluviatilis). Slag filters were filled with 2-5 cm diameter slag, having a porosity of 0.42. From August to December of 2007 the six CW systems were fed with a pulse flow of dairy wastewater with a hydraulic loading rate of 1.9 cm/day. This gave a nominal retention time of ~10 days for each CW system. From May to September of 2008 the flow was changed to a continuous inflow, and resulted in a hydraulic loading rate of 3.9 cm/day. A nominal retention time of ~5 days for each CW system was calculated. Weekly monitoring was carried out for five-day biochemical oxygen demand (BOD5), total suspended solids (TSS), ammonium (NH4+), dissolved reactive phosphorus (DRP), and pH. Integrated CWs and hybrid CWs were monitored for their ability to treat dairy wastewater. The analyses focused on determining if there were important differences in pollutant treatment efficiencies between the two distinct systems. Time series temporal semivariogram analysis of the measured water parameters illustrated that different treatment efficiencies existed in the beginning of the 2008 summer (early summer) compared to the end of the 2008 summer (late summer). Furthermore, the CWs were found to have significantly different (p-value < 0.0001) treatment performances, in terms of TSS and BOD5 removal, from early to late summer 2008. Integrated CWs remove significantly more DRP than hybrid CWs (p-value < 0.05). During the late summer of 2008, the integrated CWs removed significantly more ammonium (p-value < 0.05) then all other CW systems. Hybrid and integrated CWs were both efficient in removing organics, but the hybrid systems were significantly (p-value < 0.05) more efficient during the period of highest macrophyte biomass. Mechanisms of pollutant removal in these CW systems were further analyzed. Ultimate BOD laboratory experiments were used to determine the maximum amount of biologically available organic matter and the corresponding rate constants for the removal kinetics of organic matter in the dairy wastewater. Geochemical modeling of the minerals that form on steel slag show that hydroxyapatite controls the activities of phosphate and calcium ions. The geochemical modeling results show a similar finding to field results, because as the wastewater:slag ratio decreases the pH increases (pH > 11) and phosphorus is removed.
2

Phosphorus reduction in dairy effluent through flocculation and precipitation

Bragg, Amanda Leann 17 February 2005 (has links)
Phosphorus (P) is a pollutant in freshwater systems because it promotes eutrophication. The dairies in the North Bosque and its water body segments import more P than they export. Dairies accumulate P-rich effluent in lagoons and use the wastewater for irrigation. As more P is applied as irrigation than is removed by crops, P accumulates in the soil. During intense rainfall events, P enters the river with stormwater runoff and can become bio-available. Reducing the P applied to the land would limit P build up in the soil and reduce the potential for P pollution. Since wastewater P is associated with suspended solids (SS), the flocculants, poly-DADMAC and PAM, were used to reduce SS. To precipitate soluble P from the effluent, NH4OH was added to raise the pH. Raw effluent was collected from a dairy in Comanche County, TX, and stored in 190-L barrels in a laboratory at Texas A&M University. Flocculant additions reduced effluent P content by as much as 66%. Addition of NH4OH to the flocculated effluent raised the pH from near 8 to near 9, inducing P precipitation, further reducing the P content. The total P reduction for the best combination of treatments was 97%, a decrease from 76 to 2 mg L-1. If this level of reduction were achieved in dairy operations, P pollution from effluent application would gradually disappear.
3

Phosphorus reduction in dairy effluent through flocculation and precipitation

Bragg, Amanda Leann 17 February 2005 (has links)
Phosphorus (P) is a pollutant in freshwater systems because it promotes eutrophication. The dairies in the North Bosque and its water body segments import more P than they export. Dairies accumulate P-rich effluent in lagoons and use the wastewater for irrigation. As more P is applied as irrigation than is removed by crops, P accumulates in the soil. During intense rainfall events, P enters the river with stormwater runoff and can become bio-available. Reducing the P applied to the land would limit P build up in the soil and reduce the potential for P pollution. Since wastewater P is associated with suspended solids (SS), the flocculants, poly-DADMAC and PAM, were used to reduce SS. To precipitate soluble P from the effluent, NH4OH was added to raise the pH. Raw effluent was collected from a dairy in Comanche County, TX, and stored in 190-L barrels in a laboratory at Texas A&M University. Flocculant additions reduced effluent P content by as much as 66%. Addition of NH4OH to the flocculated effluent raised the pH from near 8 to near 9, inducing P precipitation, further reducing the P content. The total P reduction for the best combination of treatments was 97%, a decrease from 76 to 2 mg L-1. If this level of reduction were achieved in dairy operations, P pollution from effluent application would gradually disappear.
4

Seawater/Wastewater Production of Microalgae-Based Biofuels in Closed Loop Tubular Photobioreactors

Lowrey, Joshua Bradley 01 June 2011 (has links) (PDF)
The push for alternatives to petroleum fuels has forced researchers to look for highly productive, renewable, non-food resources. The advantages of using microalgae instead of traditional oil crops for biofuel production include high oil yields, rapid reproductive rates, and versatile growing requirements. In order to reduce the cost of producing microalgae based biofuels, wastewater has been used as a nutrient source instead of specialized plant nutrients. The purpose of this study was to compare the relative effectiveness of different combinations of microalgae strain and dairy wastewater for increasing biomass. The methods for monitoring growth included optical density, cell counting, biomass estimation by chlorophyll-a, and volatile suspended solids. The analyses compared four concentrations of wastewater media as well as four strain treatments: Chlorella vulgaris, Tetraselmis sp., mixed freshwater culture and mixed saltwater culture. Optimum wastewater concentrations for microalgae growth were approximately 0% and 25% for most strain treatments. The results of the wastewater treatments concluded that dairy wastewater could serve as an effective nutrient substitute for plant food at concentrations approximately 25%. Chlorella vulgaris and Tetraselmis sp. prevailed over the mixed cultures for biomass production. Nitrate was the most limiting nutrient and exhibited the greatest reductions, sometimes in excess of 90%. The regression equations derived from the volatile suspended solids data achieved high R2 values and determined that total nitrogen, ammonium, and nitrate were significant in the model. In those equations, increasing either ammonium or nitrate yielded an increase in volatile suspended solids. With regards to comparing biomass quantification methods, the two most useful and reliable biomass quantification methods were optical density and volatile suspended solids.
5

Dairy Manure Flushwater Treatment by Algae Raceway Ponds and Aerated Biofilm Reactors

Son, Darin 01 September 2020 (has links) (PDF)
Nitrogen removal technologies can help dairy industries meet their nutrient management needs. This thesis investigated two separate treatment technologies for total ammonia nitrogen (TAN) removal: algae raceway ponds and aerated biofilm reactors. Six 1000- liter algae raceway ponds and four 1000-liter tote tanks, each equipped with 10 sheets of nonwoven geotextile (i.e., thermally bonded or needle-punched) biofilm substrate, were used to treat the effluent from a flush dairy in central coastal California (TAN = 251 mg/L, cBOD5 = 204 mg/L). For the algae raceway ponds (TAN loading rate = 7 - 35 g/m³-day among 7-, 10- and 14-day hydraulic residence times (HRT)), first-order removal rate constants (k) were ~0.2 day⁻¹ in the summer and 0.1 - 0.2 day⁻¹ in the winter. Removal rate constants had no correlations (R² < 0.1) with water temperature, weak to moderate (for 7-day ponds, R² = 0.55) correlations with insolation and weak to no correlations with biomass (i.e. volatile solids) concentration. During the winter, low insolation likely inhibited algal photosynthesis and biological TAN treatment. Ponds with 7-day HRT had distinct absence of nitrate and nitrite compared to 10- and 14-day ponds. Net productivities were ~20 g/m²-day in summer and 9 – 11 g/m²-day in winter; gross productivities were 120 – 160 g/m²-day in summer and 77 – 150 g/m²-day in winter. Productivities had no correlations (R² < 0.1) with water temperature and weak to moderate correlations (for 14-day ponds, net productivity R² = 0.56, gross productivity R² = 0.83) with insolation. Analysis of organic compounds in pond effluent showed dissolved volatile solids (~2300 mg/L) were mostly non-biodegradable (~98% of soluble oxygen demand). Dissolved organic nitrogen concentrations in the pond effluent were ~35 mg/L. For the aerated biofilm reactors, tanks with needle-punched geotextiles had greater first- order TAN removal rate constants (0.69 day⁻¹) than tanks with thermally bonded geotextiles (0.23 day⁻¹) while operating in batch mode. Needle-punched geotextile reactor also accumulated sludge faster and had higher attached to water column biomass (i.e. volatile solids) ratios (~0.08 g VS/g VS) than thermally bonded geotextile reactor (~0.04 g VS/g VS). Among the four tanks, mass of attached biomass was 150 – 340 g per tank while mass of biomass in the water column was 3290 – 5430 g per tank. Comparing the two treatment technologies, aerated biofilm reactors (removal = 64 – 77%, k = 0.2 – 0.3 day⁻¹, removal rate = 36 – 43 g-N/m²-day, 16 – 19 g-N/m³-day) had more removal and faster removal rates per square meter of land footprint compared to the algae raceway ponds (removal = 38 – 77%, k = 0.1 – 0.2 day⁻¹, removal rate = 4 – 5 g- N/m²-day, 13 – 17 g-N/m³-day), likely due to direct application of aerators in the reactors.
6

Recuperação de águas residuárias geradas na indústria de produtos lácteos por sistema híbrido para fins de reúso / Recovery of wastewaters generated by the dairy industry applying a hybrid system for reuse purposes

Schmitt, Dalila Maria Formentini 05 March 2018 (has links)
Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2018-05-10T00:06:25Z No. of bitstreams: 1 Dalila_Schmitt_2018.pdf: 2548931 bytes, checksum: 5ee22f914bbdcce603c158d7a45f4786 (MD5) / Made available in DSpace on 2018-05-10T00:06:26Z (GMT). No. of bitstreams: 1 Dalila_Schmitt_2018.pdf: 2548931 bytes, checksum: 5ee22f914bbdcce603c158d7a45f4786 (MD5) Previous issue date: 2018-03-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The whey industrialization process generates effluents that need a special attention regarding treatment and final disposal. Currently, many advanced treatment techniques have been studied in order to provide a treated water with high quality for reuse purposes. In this context, this work aimed at evaluating the efficiency of a hybrid system based on coagulation/flocculation/sedimentation (C/F/S) and nanofiltration (NF) for industrial reuse purposes. In the C/F/S process, the use of Moringa oleifera Lam (Moringa) seeds as a natural coagulant was evaluated. Different methods and saline solutions (KCl, MgCl2.6H2O, and CaCl2.2H2O) were studied when extracting the active components from the seeds. Nanofiltration was performed with polyamide membranes based on the tangential flow filtration principle. The extraction method that utilized the whole Moringa, ground directly with the saline solution, was highlighted among the evaluated ones, by using a smaller number of steps. The extraction with calcium chloride dehydrated demonstrated the best efficiency, compared to the magnesium chloride hexahydrate and potassium chloride. The C/F/S step was optimized through serial factorial designs, in which the turbidity removal was the response variable. It was obtained a turbidity removal of 91.52% when using 300 mg L-1 of the Moringa coagulant (MC), extracted with a saline CaCl2.2H2O solution (0.9 mol L-1) and a pH value of 10.0. The empirical quadratic model obtained, validated by the ANOVA and F-test, in conjunction with the desirability function, demonstrated the possibility to obtain turbidity removals of 92.04 % ( 9.13%) with the following conditions: MC = 300 mg L-1, CCaCl2 = 0.9 mol L-1 e pH = 11.0. The sedimentation time was reduced from 40 to 25 minutes. The MC performance concerning the turbidity removal proved to be dependent on the alkaline pH (8.0 to 11.0). In the nanofiltration process, it was evaluated the influence of the C/F/S optimized as a pre-treatment, comparing the hybrid C/F/S/NF and the direct NF at 4 bar. High removals of apparent color (99.7%), turbidity (99.1%), COD (88.9%), total hardness (66.3%), and calcium (63.7%) were obtained using the hybrid treatment system, providing a removal of 81.2% in the membrane fouling, compared to the raw NF treatment. The proposed hybrid system allows the reuse of this wastewater in the industry. / O processo de industrialização do soro de leite gera águas residuárias que necessitam de atenção especial, quanto ao seu tratamento e disposição final. Atualmente, muitas técnicas de tratamento avançadas são estudadas com o objetivo de produzir águas tratadas de elevada qualidade, para fins de reuso. Dentro deste contexto, o presente trabalho teve como objetivo avaliar a eficiência de um sistema de tratamento híbrido, composto por coagulação/floculação/sedimentação (C/F/S) e nanofiltração (NF), para fins de reuso industrial. No processo de C/F/S, foi avaliado o uso das sementes de Moringa oleífera Lam (Moringa) como coagulante natural. Foram avaliados diferentes métodos e soluções salinas (KCl, MgCl2.6H2O e CaCl2.2H2O) na extração dos componentes ativos das sementes. A nanofiltração foi realizada com membranas planas de poliamida pelo princípio de filtração tangencial. O método de extração no qual a Moringa integral foi triturada diretamente com a solução salina destacou-se dentre os avaliados, por utilizar um número menor de etapas. A extração com o cloreto de cálcio dihidratado, demonstrou ser mais eficiente, em comparação aos sais cloreto de magnésio hexahidratado e cloreto de potássio. A etapa de C/F/S foi otimizada através de planejamentos fatoriais em série, nos quais, utilizou-se a remoção de turbidez como variável resposta. Foi obtida uma remoção de turbidez de 91,52 %, ao utilizar 300 mg L-1 de coagulante de Moringa (CM), extraído com solução salina de CaCl2.2H2O (0,9 mol L-1) e pH 10,0. O modelo quadrático empírico obtido, validado pela ANOVA e teste “F”, juntamente com a função desejabilidade, demonstraram ser possível obter remoção de turbidez de 92,04 % ( 9,13 %), nas seguintes condições: CM = 300 mg L-1; CCaCl2= 0,9 mol L-1 e pH = 11,0. O tempo de sedimentação foi reduzido de 40 para 25 minutos. O desempenho de CM para remoção de turbidez demonstrou ser dependente do pH alcalino (8,0 a 11,0). No processo de nanofiltração avaliou-se a influência de C/F/S otimizado como pré-tratamento, compondo o tratamento híbrido C/F/S/NF, em comparação ao tratamento por NF direto (Bruto-NF), na pressão de 4 bar. Elevadas remoções de cor aparente (99,7 %), turbidez (99,1 %), DQO (88,9%), dureza total (66,3 %) e cálcio (63,7 %) foram obtidas utilizando o sistema de tratamento híbrido, que proporcionou redução de 81,2% no fouling da membrana, em comparação ao tratamento Bruto-NF. O sistema híbrido proposto possibilita o reuso desta água dentro da indústria.
7

Tratamento de águas residuárias da indústria de laticínios pelos processos combinados coagulação/floculação/adsorção/ultrafiltração utilizando semente de Moringa oleífera como coagulante / Wastewater treatment of dairy industry by combined process coagulation/flocculation/adsorption/ultrafiltration using Moringa oleífera seed as coagulant

Schmitt, Dalila Maria Formentini 16 February 2011 (has links)
Made available in DSpace on 2017-07-10T18:08:18Z (GMT). No. of bitstreams: 1 Dalila M Formentini Schmitt.pdf: 1687104 bytes, checksum: d5ea17cddd5fa8a48f15d9203dd84077 (MD5) Previous issue date: 2011-02-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In Brazil, the dairy industry are mostly small and medium-sized and using conventional processing techniques coupled with the use of inorganic coagulants. Therefore, this sector needs special attention with regard to advanced techniques for treating their wastewater, in order to meet new environmental regulations and seek alternatives for reuse of treated water. Within this context, this study evaluated the effectiveness of treatment techniques based on principles of coagulation / flocculation using coagulant extracted from Moringa oleifera seed with salt solutions of KCl and NaCl 1.0 Molar, adsorption with Moringa oleífera seed as biosorbent and ultrafiltration with tubular ceramic membrane. The different techniques were evaluated individually and in combination, the efficiency of processes was assessed in terms of removal of parameters: apparent color, turbidity and COD. Among the techniques evaluated the best results were obtained with the combination of technique and the coagulation / flocculation / sedimentation for 60 min using 1500 ppm of coagulant extracted from Moringa oleífera with 1.0 Molar KCl solution combined with ultrafiltration technique at a pressure of 2 bar. This combination of techniques has achieved a 99.9% removal of apparent color and turbidity, and 98.5% of COD. Based on the results of Moringa oleífera was presented as a promising natural coagulant for the treatment of wastewater from the dairy industry. This technique combined with ultrafiltration can enable the reuse of water within the industry. / No Brasil, as indústrias de laticínios na sua maioria são de pequeno e médio porte e utilizam técnicas de tratamento convencionais somadas ao uso de coagulantes inorgânicos. Por isso, este setor precisa de atenção especial no que se refere a técnicas avançadas para o tratamento de suas águas residuárias, com objetivo de atender as novas regulamentações ambientais e buscar alternativas de reúso desta água tratada. Dentro deste contexto, o presente trabalho avaliou a eficiência das técnicas de tratamento baseadas nos princípios de coagulação/ floculação utilizando coagulante extraído da semente de Moringa oleífera com soluções salinas de KCl e NaCl 1,0 Molar, adsorção com semente de Moringa oleífera como biossorvente e ultrafiltração com membrana tubular cerâmica. As diferentes técnicas foram avaliadas individualmente e de forma combinada, a eficiência dos processos foi avaliada em termos de remoção dos parâmetros: cor aparente, turbidez e DQO. Dentre as técnicas avaliadas os melhores resultados foram obtidos com a combinação da técnica de coagulação/ floculação/ sedimentação de 60 min utilizando 1500 ppm do coagulante de Moringa oleífera extraído com solução de KCl 1,0 Molar combinada à técnica de ultrafiltração na pressão de 2 bar. Esta combinação de técnicas alcançou uma remoção de 99,9% de cor aparente e turbidez e 98,5% de DQO. Com base nos resultados obtidos a Moringa oleífera apresentou-se como um coagulante natural promissor para o tratamento das águas residuárias da indústria de laticínios. Esta técnica combinada à ultrafiltração pode possibilitar o reúso desta água dentro da indústria.

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