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Análise energética, econômica e ambiental da biodigestão de resíduos agropecuários gerados por pequenos e médios produtores rurais da região sul do Espírito Santo; Energetic, economic and environmental analysis of anaerobic digestion of rural residues generated by small and medium farmers in southern Espirito Santo

Ribeiro, Claudio Moises
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/11/2013 PT
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66.71%
No Brasil, apesar do desenvolvimento mais acentuado na suinocultura, é na bovinocultura que se encontra o maior potencial para a digestão anaeróbia no tratamento de dejetos animais. O último Censo Agropecuário revelou uma tendência de concentração da criação de bovinos de leite e corte, além da migração para a região amazônica, resultando em maior pressão sobre a floresta nativa. Também evidenciou que a maior parte dos dejetos ainda é utilizada in natura. O aproveitamento em biodigestores dos dejetos coletáveis de um rebanho com aproximadamente 200 milhões de bovinos poderia resultar na auto-suficiência energética do setor agropecuário brasileiro. Os principais desafios encontram-se na dispersão destes resíduos e num entendimento limitado dos benefícios dos subprodutos da biodigestão, em especial o valor econômico e ambiental do biofertilizante. As ferramentas disponíveis costumam tratar separadamente as duas vertentes, uma energética associada ao biogás e a outra agronômica associada ao biofertilizante. Este trabalho apresenta uma abordagem original deste problema através do desenvolvimento de uma ferramenta que trata estas vertentes simultaneamente, através da simulação da dinâmica dos nutrientes no sistema solo-planta-animal. Partiu-se do modelo Century...

Anaerobic digestion of stillage to produce bioenergy in the sugarcane-to-ethanol industry

Fuess, Lucas Tadeu; Garcia, Marcelo Loureiro
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.67%
Stillage is the main wastewater from ethanol production, containing a high chemical oxygen demand in addition to acidic and corrosive characteristics. Though stillage may be used as a soil fertilizer, its land application may be considered problematic due its high polluting potential. Anaerobic digestion represents an effective alternative treatment to reduce the pollution load of stillage. In addition, the methane gas produced within the process may be converted to energy, which can be directly applied to the treatment plant. The objective of this paper was to investigate the energetic potential of anaerobic digestion applied to stillage in the sugarcane ethanol industry. An overall analysis of the results indicates energy recovery capacity (ERC) values for methane ranging from 3.5% to 10%, respectively, for sugarcane juice and molasses. The processes employed to obtain the fermentable broth, as well as the distillation step, represent the main limiting factors to the energetic potential feasibility. Considering financial aspects the annual savings could reach up to US$ 30 million due to anaerobic digestion of stillage in relatively large-scale distilleries (365,000 m3 of ethanol per year). The best scenarios were verified for the association between anaerobic digestion of stillage and combustion of bagasse. In this case...

A method to detect and quantify long chain fatty acids in liquid and solid samples and its relevance to understand anaerobic digestion of lipids

Neves, L.; Pereira, M. A.; Mota, M.; Alves, M. M.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2007 ENG
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66.43%
A method for long chain fatty acids (LCFA) extraction, identification and further quantification by capillary gas chromatography was developed and its application to liquid and solid samples demonstrated. Linear calibration curves (r² between 0.997 and 1.000) were constructed for C12 to C18 LCFA, in the range from 25 to 1270 mg/L. All the acids were quantified in a single run using pentadecanoic acid (C15:0) as internal standard with response factors ranging from 0.79 to 1.09. Relative standard deviation values lower than 15% and mean LCFA recoveries above 90% were obtained. After validation, the usefulness of this method was demonstrated in a cow manure digester receiving pulses of an industrial effluent containing high lipid content. The knowledge obtained with the application of this method can contribute to a better understanding of LCFA adsorption and degradation processes that occur during the anaerobic digestion of lipids.

Modelling inhibitory effects of long chain fatty acids in the anaerobic digestion process

Zonta, Z.; Alves, M. M.; Flotats, X.; Palatsi, J.
Fonte: Elsevier; Elsevier BV Publicador: Elsevier; Elsevier BV
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
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Mathematical modelling of anaerobic digestion process has been used to give new insights regarding dynamics of the long chain fatty acids (LCFA) inhibition. Previously published experimental data, including batch tests with clay mineral bentonite additions, were used for parameter identification. New kinetics were considered to describe the bio-physics of the inhibitory process, including: i) adsorption of LCFA over granular biomass and ii) specific LCFA substrate (saturated/unsaturated) and LCFA-degrading populations. Furthermore, iii) a new variable was introduced to describe the state of damage of the acetoclastic methanogens in order to account for the loss of cell-functionality (inhibition) induced by the adsorbed LCFAs. The proposed model modifications are state compatible and easy to be integrated into the International Water Association’s Anaerobic Digestion Model N1 (ADM1) framework. Practical identifiability of model parameters was assessed with a global sensitivity analysis, while calibration and model structure validation were performed on independent data sets. A reliable simulation of the LCFA-inhibition process can be achieved, if the model includes the description of the adsorptive nature of the LCFAs and the LCFA-damage over specific biomass. The importance of microbial population structure (saturated/unsaturated LCFA-degraders) and the high sensitivity of acetoclastic population to LCFA are evidenced...

A survey system to present the status of anaerobic digestion in Europe in different sectors – Agriculture, industrial, urban waste and waste water sector

Körner, Ina; Amon, Barbara; Amon, Thomas; Balsari, Paolo; Bioteau, Thierry; Dach, jacek; De Buisomje, Fridtjof; Deipser, Anna; Fabbri, Claudio; Kupper, Thomas; Malico, Isabel; Paula Marques, Isabel; Mata, Joan; Roshani, Elaheh; Schnurer, Anna; Scholwin,
Fonte: RAMIRAN Publicador: RAMIRAN
Tipo: Artigo de Revista Científica
ENG
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The RAMIRAN Anaerobic Digestion (AD) Task Group has completed a second survey of the status of European biogas for the years 2010/12. The survey has been split into agricultural, industrial, urban waste and wastewater sectors and data has been collected from eleven countries for at least one of these sectors. The questions included driving forces, the number, type and size of plants, substrates, utilisation of digestate and energy production. AD was found to be well established in most participating countries. GE still remains predominant regarding the number of AD units. Feed-in tariffs remain the strongest driving force, and energy production the dominant goal. AD in GE is still dominated by maize digestion in small plants, whereas the opposite is true in DK and IT. There relatively large plants are preferred and manure is the dominant feedstock. Based on the findings of the first two surveys, the questionnaire is considered suitably short and concise.

Anaerobic digestion experiment using Cynara cardunculus L. stalks

Oliveira, I.D.B.; Diberardino, S.; Gominho, J.; Duarte, E.
Fonte: Cordovil, C. e Ferreira, L. Publicador: Cordovil, C. e Ferreira, L.
Tipo: Conferência ou Objeto de Conferência
Publicado em /09/2010 ENG
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RAMIRAN International Conference; Anaerobic digestion is an industrial process applied to organic wastes treatment with several environmental and energetic advantages over other forms of treatment and specially when is integrated in the agriculture sector (Möller, 2009; Prochnow, 2009; Chynoweth, 1987). In addition to the organic wastes treatment there is an emerging interest in the production of biomethane as a biocombustible through anaerobic digestion of biomass and / or energy crops (IEA, 2010; Chanakya, 2009; CONCAWE, 2008; Tilche, 2008; Yadvika, 2004; Gunaseelan, 1997; Chynoweth, 1987). Cynara cardunculus L. or commonly known as cardoon is a perennial herb or herbaceous crop native to Mediterranean region, grown since ancient times as a wild plant or as vegetable using intensive management techniques (Ortega, 2007; Fernández, 2006). The average biomass annual production varies from 15 to 20 tons of biomass/ha depending on soil and rainfall with 11% of moisture content and the following biomass partitioning: 40 % stalks, 25% leaves and 35 % capitula (Gominho, 2001 and 2008). Different studies have been shown the high potential of this plant as energy crop: the aerial biomass used as a solid biofuel and the oil from seeds used for the production of biodiesel (Fernández...

Anaerobic digestion of organic matter. Biogas production from energy crop residues (Maize stalks)

Santos, André Manuel Simóes dos
Fonte: ISA/UTL Publicador: ISA/UTL
Tipo: Dissertação de Mestrado
Publicado em //2011 ENG
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Mestrado em Engenharia do Ambiente - Instituto Superior de Agronomia; The agricultural sector is one of the most interesting for effective dissemination of large-scale use of renewable energy, especially anaerobic digestion of feedstock from plant and animal origin. Laboratory-scale experiments were carried out with maize stalks, by apply-ing some pretreatments to enhance its specific biogas yield in anaerobic digestion, due to its methane content. Feedstock were pretreated chemically (different ammonia concentrations), mechanically (particles size reduction) and/or thermally (pressure cooking). The methane percentage in biogas was between 51-72.5% and it was evident that methane yield had the same trend as biogas yield. The highest value of biogas and methane were found on maize stalks just pretreated with 2% NH3 (467.570 LN/kgVS and 280.265 LN/kgVS, respectively) and the lowest were found on maize stalks unwrapped pretreated mechanically (180.81 LN/kgVS and 82.764 LN/kgVS, respectively). The results show that all the pretreatments done were effective in enhancing methane yield, being the best feedstock the one pretreated with 2% NH3 and the best pre-treatment, the one where it was not preformed any other pretreatment. Based on the value of the biogas yield obtained in this experiment...

Anaerobic digestion of a fish processing industry sludge

Carvalho, L.; Di Berardino, Santino; Duarte, E.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2011 ENG
Relevância na Pesquisa
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Due to the fact that all fish processing plants operating in Portugal send their sludge from the wastewater treatment process to landfill, and because it is a costly management policy, the aim of this work was to assess the potential use of this substrate for the production of biogas through the anaerobic process technology. Anaerobic digestion has long proven to be an efficient way for the production of a renewable fuel – Biogas - that can be used as a source of energy to produce electricity and heat. This renewable energy resource can be used to reduce the plant processing costs, reducing also the industry carbon footprint. So, the produced sludge becomes a valuable sub-product of the wastewater treatment process instead of being considered a waste, with disposal costs associated. In this study we performed mesophilic (35 ± 1°C) batch assays during 51 days. The inoculum used was from an anaerobic digester operating in a municipal WWTP, also at mesophilic conditions. The anaerobic digestion of the fish sludge produced 700 m3 of CH4/ton SV, which is a really promising result.

Phenolic compouds with antiradical activity from the cork boiling wastewater anaerobic digestion

Marques, Isabel Paula Ramos; Gil, Luís; La Cara, F.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 ENG
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66.43%
This work aims to develop a procedure that explores the different types of valorization that can be obtained by integrating a biological process, such as the anaerobic digestion, to promote the bioconversion of the industrial cork effluents (cork boiling wastewater, CBW).

Cork boiling wastewater anaerobic digestion process leads to biogas and valuable enzymes production

Marques, Isabel Paula Ramos; Gil, Luís; La Cara, F.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 ENG
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66.69%
Cork is the outer bark of the cork-tree (Quercus suber L.) and it is a very important industrial sector in western Mediterranean region, being Portugal the world-leading producer and exporter (1). The anaerobic digestion has never been applied to the treatment and valorization of the industrial cork effluents (cork boiling wastewater, CBW). The goal of the present work is evaluate the role of this biological process in providing valuable biomolecules, i.e. enzymes, during the conversion of CBW. Anaerobic experiments were conducted under mesophilic conditions of temperature and the obtained results suggest that CBW is an interesting substrate to be treated and valorised through the anaerobic digestion. Besides the energy recovery through biogas production by anaerobic digestion of CBW, the increase in the reactor effluent of valuable biomolecules is an aspect of great industrial interest. The identification and characterization of such products of high added value creates a supplementary prospect of effluent valorisation, contributing to the cork sector profits. During the CBW anaerobic digestion process several important alterations on the enzymatic capacity of the digested flow were observed. For instance, the laccase activity contained in the CBW was implemented by anaerobiosis and the xilanase was formed during the process. Laccases exhibit low substrate specificity and can be used in different industrial sectors (i.e. paper manufacturing...

Energetic and biochemical valorization of cork boiling wastewater by anaerobic digestion

Marques, Isabel Paula Ramos; Gil, Luís; La Cara, F.
Fonte: BioMed Central Ltd Publicador: BioMed Central Ltd
Tipo: Artigo de Revista Científica
Publicado em //2014 ENG
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66.58%
In addition to energy benefits, anaerobic digestion offers other interesting advantages. The cork industry is of great environmental, economic and social significance in the western Mediterranean region, with Portugal being the world-leading producer and exporter. Cork boiling wastewater (CBW) is a toxic and recalcitrant organic effluent produced by this sector, which constitutes a serious environmental hazard. However, there is no documented research on anaerobic treatment/valorization performed with this effluent. The work presented here was developed with the aim to use the anaerobic digestion process to convert the CBW polluting organic load into an energy carrier gas and valuable molecules for industry.

Enhancement of anaerobic digestion of microcrystalline cellulose (MCC) using natural micronutrient sources

Suárez,A. G.; Nielsen,K.; Köhler,S.; Merencio,D. O.; Reyes,I. P.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
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66.48%
The effect of adding four minerals as micronutrient sources to stimulate the anaerobic process of microcrystalline cellulose (MCC) was investigated. Three mineral doses (5, 10 and 15 mg/L) were evaluated and the response to trace metal addition was monitored by the methane yield (Y CH4) and specific methanogenic activity (SMA). A clear stimulation of the Y CH4 and SMA on MCC due to the presence of minerals with a high content of trace elements was observed, respectively: the Y CH4 and SMA of the sludge with 5 mg/L of high-Fe-Mg mineral increased to 397 NmLCH4/gVSsubstrate and 0.267 gCOD NmLCH4/gVSinoculum/d compared to 303 NmLCH4/gVSsubstrate and 0.205 gCOD NmLCH4/gVSinoculum/d in a medium without adding mineral. An increase in the doses of high-Ca mineral highly decreased methane production and process stability, due to a possible inhibition of the anaerobic digestion by calcium ions.

Anaerobic digestion of the liquid fraction of dairy manure in pilot plant for biogas production: Residual methane yield of digestate

Rico de la Hera, Carlos; Rico Gutiérrez, José Luis; Tejero Monzón, Juan Ignacio; Muñoz Soler, Noelia; Gómez Ruiz, Beatriz
Fonte: Elsevier Publicador: Elsevier
Tipo: info:eu-repo/semantics/article; acceptedVersion
ENG
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The performance of the only dairy manure biogas plant in Cantabria (Northern coast of Spain) was evaluated in terms of liquid–solid separation and anaerobic digestion of the liquid fraction. Screened liquid fraction was satisfactorily treated in a CSTR digester at HRTs from 20 to 10 days with organic loading rates ranging from 2.0 to 4.5 kg VS/(m3 d). Stable biogas productions from 0.66 to 1.47 m3/(m3 d) were achieved. Four anaerobic effluents collected from the digester at different HRTs were analyzed to measure their residual methane potentials, which ranged from 12.7 to 102.4 L/g VS. These methane potentials were highly influenced by the feed quality and HRT of the previous CSTR anaerobic digestion process. Biomethanization of the screened liquid fraction of dairy manure from intensive farming has the potential to provide up to 2% of total electrical power in the region of Cantabria.

Comparison of various microbial inocula for the efficient anaerobic digestion of Laminaria hyperborea

Sutherland, Alastair D.; Varela, J.
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 23/01/2014 ENG
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66.52%
Background: The hydrolysis of seaweed polysaccharides is the rate limiting step in anaerobic digestion (AD) of seaweeds. Seven different microbial inocula and a mixture of these (inoculum 8) were therefore compared in triplicate, each grown over four weeks in static culture for the ability to degrade Laminaria hyperborea seaweed and produce methane through AD. Results: All the inocula could degrade L. hyperborea and produce methane to some extent. However, an inoculum of slurry from a human sewage anaerobic digester, one of rumen contents from seaweed-eating North Ronaldsay sheep and inoculum 8 used most seaweed volatile solids (VS) (means ranged between 59 and 68% used), suggesting that these each had efficient seaweed polysaccharide digesting bacteria. The human sewage inoculum, an inoculum of anaerobic marine mud mixed with rotting seaweed and inoculum 8 all developed to give higher volumes of methane (means between 41 and 62.5 ml g-1 of seaweed VS by week four) ,compared to other inocula (means between 3.5 and 27.5 ml g-1 VS). Inoculum 8 also gave the highest acetate production (6.5 mmol g-1 VS) in a single-stage fermenter AD system and produced most methane (8.4 mL mmol acetate-1) in phase II of a two-stage AD system. Conclusions: Overall inoculum 8 was found to be the most efficient inoculum for AD of seaweed. The study therefore showed that selection and inclusion of efficient polysaccharide hydrolysing bacteria and methanogenic archaea in an inoculum offer increased methane productivity in AD of L. hyperborea. This inoculum will now being tested in larger scale (10L) continuously stirred reactors optimised for feed rate and retention time to determine maximum methane production under single-stage and two-stage AD systems.; Marie Curie Senior Researcher Fellowship (SEAWEED AD)

Determinação e análise do efeito da trituração de FORSU como pré-tratamento para a digestão anaeróbia; Determination and analysis of the effect of grinding OFMSW as pre-treatment for anaerobic digestion

Coelho, Fábio David Pereira
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Trabalho de Conclusão de Curso
Publicado em //2014 POR
Relevância na Pesquisa
66.74%
Dissertação de mestrado integrado em Engenharia Biológica (área de especialização em Tecnologia do Ambiente); O presente estudo pretende avaliar o potencial da digestão anaeróbia da fração orgânica de resíduos sólidos urbanos (FORSU) e a influência da redução de tamanho da FORSU (de 8cm para 1cm de tamanho), em termos de produção de biogás e degradação orgânica. Como caso de estudo, foi considerada a empresa multimunicipal BRAVAL e o tratamento anaeróbio implementado na sua unidade de tratamento mecânico e biológico (TMB). Os RSU utilizados no ensaio experimental são provenientes da cidade de Braga. Apesar de não simular identicamente as condições e modo de operação do sistema real de tratamento de digestão anaeróbia do TMB, este ensaio experimental permitiu distinguir algumas das vantagens e limitações que podem surgir à escala industrial. Foram operados em sistema batch (com 30% ST) dois digestores anaeróbios, um deles contendo uma mistura de FORSU e outro uma mistura de FORSU triturada. A operação dos reatores decorreu durante 83 dias, sendo monitorizados os teores de CQO solúvel, AGV's, azoto amoniacal e produção de biogás. No final da operação foi determinado o conteúdo de metano no biogás e a remoção de sólidos. Os resultados monstraram que ambos os digestores foram afetados pela inibição por azoto amoniacal...

Influence of organic loading rate and hydraulic retention time on the performance, stability and microbial communities of one-stage anaerobic digestion of two-phase olive mill solid residue

Rincón, Bárbara; Borja Padilla, Rafael; Portillo Guisado, María del Carmen; Sáiz-Jiménez, Cesáreo
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
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A study of the effect of organic loading rate (OLR) and hydraulic retention time (HRT) on the performance, stability and microbial communities of a laboratory-scale completely stirred tank anaerobic reactor treating two-phase olive mill solid residue (OMSR) was carried out at mesophilic temperature (35 °C). The reactor operated at a fixed influent substrate concentration of 162 g total chemical oxygen demand (COD)/L and 126 g volatile solids (VS)/L. The OLR and HRT varied in the ranges of 0.8–11.0 g COD/L day and 108–15 days, respectively. COD removal efficiencies in the range of 97–77% were achieved for OLRs and HRTs in the ranges of 1.5–9.2 g COD/L day and 108–17 days, respectively. The maximum methane production rate was found to be 1.7 L CH4 STP/L day and it was achieved for an OLR of 9.2 g COD/L day and HRT of 17 days. The methane yield coefficient was 0.244 ± 0.005 L methane at STP conditions/g COD removed. The results obtained demonstrated that an OLR of 11.0 g COD/L day and a HRT of 15 days brought about a decrease in the pH and total volatile fatty acids (TVFA)/alkalinity ratios up to values of 5.3 and 1.5 (mequiv. acetic acid/mequiv. CaCO3), respectively, causing the destabilization of the reactor and process failure. Microbial communities...

Effect of linear alkylbenzene sulphonates (LAS) on the anaerobic digestion of sewage sludge

Garcia Ramón, María Teresa; Campos, Encarna; Sánchez-Leal, Joaquim; Ribosa Fornovi, Isabel
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 19968 bytes; application/msword
ENG
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7 pages, 4 figures, 1 table.; Batch anaerobic biodegradation tests with different alkylbenzene sulphonates (LAS) at increasing concentrations were performed in order to investigate the effect of LAS homologues on the anaerobic digestion process of sewage sludge. Addition of LAS homologues to the anaerobic digesters increased the biogas production at surfactant concentrations 5–10 g/kg dry sludge and gave rise to a partial or total inhibition of the methanogenic activity at higher surfactant loads. Therefore, at the usual LAS concentration range in sewage sludge, no adverse effects on the anaerobic digesters functioning of a wastewater treatment plant (WWTP) can be expected. The increase of biogas production at low surfactant concentrations was attributed to an increase of the bioavailability and subsequent biodegradation of organic pollutants associated with the sludge, promoted by the surfactant adsorption at the solid/liquid interface. When the available surfactant fraction in the aqueous phase instead of the nominal surfactant concentration was used to evaluate the toxicity of LAS homologues, a highly significant relationship between toxicity and alkyl chain length was obtained. Taking into account the homologue distribution of commercial LAS in the liquid phase of the anaerobic digesters of a WWTP...

ANAEROBIC DIGESTION AND THE DENITRIFICATION IN UASB REACTOR (doi: 10.4090/juee.2008.v2n2.063067)

de Sousa, José Tavares
Fonte: JUEE Press Publicador: JUEE Press
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 29/07/2009 ENG
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The environmental conditions in Brazil have been contributing to the development of anaerobic systems in the treatment of wastewaters, especially UASB reactors – Up flow Anaerobic Sludge Blanket. The classic biological process, for removal of nutrients, use three reactors - Bardenpho System, therefore, this work intends an alternative system, where the anaerobic digestion and the denitrification happen in the same reactor, in this system, is reduced for two, the number of reactors. The experimental system was constituted by two units: first was a nitrification reactor with 35L volume and 15 days of sludge age. This system was feed with raw sanitary waste. Second unit was an Up flow Anaerobic Sludge Blanket (UASB), with 7.8 L and 6 hours of hydraulic detention time, feed with ¾ of effluent nitrification reactor and ¼ of raw sanitary waste. This work had as objective evaluates the performance of the UASB reactor, in terms of removal efficiency, of bath COD and nitrogen. It was verified that the anaerobic digestion process was not affected, the removal efficiency of organic material expressed in COD, was 71%, removal already expected for a reactor of this type. It was also observed that the denitrification process happened; the removal nitrate efficiency was 90%. Therefore...

Behavior of the mesophilic and termophilic anaerobic digestion in the stabilization of municipal wastewater sludge (Part 1)

Méndez-Contreras,J.M.; Rendón-Sagardi,J.A.; Ruiz-Espinoza,J.E.; Alvarado-Lassman,A.; Martínez-Delgadillo,S.A.
Fonte: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería Publicador: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2009 EN
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The objective of this study was to evaluate the performance of the mesophilic and thermophilic anaerobic digestion process as an alternative for the biosolids production. Biological sludge from a municipal and industrial (brewery and pulp and paper) wastewater treatment plant using a UASB reactor was used. During the operation of the mesophilic batch system, the volatile solids (VS) were reduced from 60.3% (15.67 g/L) up to 37.5% (9.67 g/L) with 31 d of treatment time. The mesophilic process presented a stable operation reducing 38% of VS with 1.76 Kg VS m-3 d-1 of organic load feed fulfilling with the criterion of vectors attraction reduction. However, in mesophilic conditions, the digested sludge must be post-treated with a process of pathogenic microorganism inactivation because only remove low concentrations of pathogenic microorganism. The obtained results demonstrated that the process in thermophilic conditions (55°C) is capable to stabilize 3.9 Kg VS m-3 d-1 and to inactive the totality of fecal coliforms, Salmonella spp. and helminth ova fulfilling with the permissible limits for class A biosolids.

The use of hydrodynamic disintegration as a means to improve anaerobic digestion of activated sludge

Machnicka,A; Grűbel,K; Suschka,J
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
66.61%
Disintegration by hydrodynamic cavitation has a positive effect on the degree and rate of sludge anaerobic digestion. By applying hydrodynamic disintegration the lysis of cells occurs in minutes instead of days. The intracellular and extracellular components are set free and are immediately available for biological degradation which leads to an improvement of the subsequent anaerobic process. Hydrodynamic disintegration of the activated sludge results in organic matter and a polymer transfer from the solid phase to the liquid phase, and an increase in COD value of 284 mg∙ℓ-1 was observed, i.e. from 42 mg∙ℓ-1 to 326 mg∙ℓ-1. In addition the degree of disintegration changed from 14% after 15 min disintegration to 54% after 90 min of disintegration. A disruption of bacterial cells by hydrodynamic cavitation has a positive effect on the degree and rate of excess sludge anaerobic digestion. The cells of the activated sludge micro-organisms rupture and addition to the digestion process leads to increased biogas production. The hydrodynamic disintegration of activated sludge leads to a higher degree of degradation and higher biogas production. Adding the disintegrated sludge (10%, 20% and 30% of volume) to fermentation processes resulted in an improvement in biogas production of about 22%...