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1.
Arq. bras. med. vet. zootec. (Online) ; 73(3): 675-683, May-June 2021. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1278351

ABSTRACT

The objective of the present study was to evaluate losses, production and polluting potential of the effluent, nutritional value and aerobic stability of silages of Brachiaria brizantha cv. Paiaguás grass, in different particle sizes and compaction density in silage. Three theoretical particle sizes (TTP 5; 8 and 12mm) and three compaction densities (DC 550; 600 and 650kg/m3) were evaluated, distributed in a factorial design (3 x 3), with four repetitions. The highest volume of effluent was found in silages with higher compaction densities (600 and 650kg/m3) and lower TTP (5 and 8mm). The highest chemical oxygen demand and biochemical oxygen demand were registered in the treatment with TTP of 5mm and higher DC (600 and 650kg/m3). Greater in vitro digestibility of DM was verified in the silage chopped at 5 and 8mm. There was no break in aerobic stability for 216 hours. Silage with a low compaction density 550kg/m3 and processing with a theoretical particle size of 12mm reduces effluent losses. In general, the nutritional value of Paiaguás grass was not influenced by the treatments. Different particle sizes and compaction density did not change the aerobic stability of silages.(AU)


Objetivou-se avaliar perdas, produção e potencial poluidor do efluente, valor nutricional e estabilidade aeróbia de silagens do capim Brachiaria brizantha cv. Paiaguás, em diferentes tamanhos de partícula e densidade de compactação na ensilagem. Foram avaliados três tamanhos teóricos de partícula (TTP 5; 8 e 12mm) e três densidades de compactação (DC 550; 600 e 650kg/m3), distribuídos em arranjo fatorial (3 x 3), com quatro repetições. O maior volume de efluente foi verificado nas silagens com maiores densidades de compactação (600 e 650kg/m3) e menores TTP (5 e 8mm). As maiores demanda química de oxigênio e demanda bioquímica de oxigênio foram registradas no tratamento com TTP de 5mm e nas maiores DC (600 e 650kg/m3). Maior digestibilidade in vitro da MS (média de 57,2%) foi verificada na silagem picada a 5 e 8mm. Não houve quebra da estabilidade aeróbia durante 216 horas. A ensilagem com baixa densidade de compactação (550kg/m3) e o processamento com tamanho teórico de partículas 12mm reduzem as perdas por efluente. O valor nutricional da silagem de capim-paiaguás, em geral, não foi influenciado pelos tratamentos. Diferentes tamanhos de partícula e densidade de compactação não alteraram a estabilidade aeróbia das silagens.(AU)


Subject(s)
Solid Waste Compaction/analysis , Waste Management/methods , Brachiaria , Environmental Pollution/prevention & control , Particulate Matter , Biological Oxygen Demand Analysis/methods
2.
São Paulo; s.n; 2021. 204 p.
Thesis in Portuguese | LILACS | ID: biblio-1362253

ABSTRACT

O Programa Córrego Limpo é parte de um conjunto de políticas públicas que buscam despoluir os principais rios da cidade de São Paulo através da recuperação de seus afluentes. O programa atua no controle de cargas pontuais, e adota parceria com as lideranças locais das bacias. O objetivo deste estudo é identificar os principais conflitos socioambientais na manutenção da limpeza do córrego Tenente Rocha. O curso d'água em questão está localizado na Zona Norte de São Paulo e tem sido beneficiado pelas ações do Programa Córrego Limpo desde o ano de 2007. Desenvolveu-se uma pesquisa exploratória de caráter quali e quantitativo, focando o envolvimento social na gestão da qualidade de cursos d'água urbanos, mediante aplicação de entrevistas estruturadas aos moradores do entorno do córrego. A análise da qualidade das águas, através do parâmetro Demanda Bioquímica de Oxigênio, apontou uma redução nos índices de carga orgânica após as ações iniciais de intervenção na bacia do córrego, mantendo-se em valores abaixo de 30 mg/L na média. Em contraponto, fatores associados à reincidência de cargas pontuais e difusas tem causado alterações significativas na qualidade das águas. Na opinião de 95% dos residentes, o curso d'água em questão encontra-se poluído, o que causa o afastamento dos moradores da linha d'água. Concluiu-se que a comunicação e o compartilhamento das informações entre os residentes e as instituições gestoras exercem papel relevante, porém não são os únicos fatores que limitam os resultados no processo de despoluição do córrego Tenente Rocha.


The Clean Stream Program is part of a set of public policies that seek to clean up the main rivers in the city of São Paulo through the recovery of their tributaries. The program acts in the control of punctual loads, and adopts a partnership with local leaders of the basins. The aim of this study is to identify the main social-environmental conflicts in maintaining the cleanliness of the Tenente Rocha stream. The refered stream water is located in the north of São Paulo, and has been benefited from the actions of the Clean Stream Program since 2007. An exploratory qualitative and quantitative research was developed, focusing on social involvement in the quality management of urban watercourses, through the application of a structured choice to the inhabitants of the surroundings of the stream. The analysis of water quality, through the Biochemical Oxygen Demand parameter, showed a reduction in the organic load indices after the initial intervention actions in the stream basin, remaining at values below 30 mg/L on average. In contrast, factors associated with the recurrence of punctual and diffuse loads have caused significant changes in water quality. In the opinion of 95% of residents, the watercourse in question is polluted, which causes the residents to stay away from the waterline. It was concluded that communication and information sharing between residents and management institutions play a relevant role, but they are not the only factors that limit the results of the depollution process of the Tenente Rocha stream.


Subject(s)
Public Policy , Water Quality , Water Purification , Biological Oxygen Demand Analysis
3.
Electron. j. biotechnol ; 39: 98-106, may. 2019. tab, graf, ilus
Article in English | LILACS | ID: biblio-1052269

ABSTRACT

BACKGROUND: The amount of municipal solid waste (MSW) gradually increased along with the rapid development of modern cities. A large amount of landfill leachate are generated with excessive chemical oxygen demand (COD), which create a great deal of pressure on the environment-friendly treatment process. Anaerobic digestion is an ideal technique to solve the above problem. RESULTS: A thermophilic granular sludge was successfully adapted for anaerobic digestion of MSW leachate (from an aging large-scale landfill) for methane production. The COD degradation efficiency improved by 81.8%, while the methane production rate reached 117.3 mL CH4/(g VS d), which was 2.34-fold more than the control condition. The bacterial and archaeal communities involved in the process were revealed by 16S rRNA gene high-throughput pyrosequencing. The richness of the bacterial community decreased in the process of thermophilic granular sludge, while the archaeal community structure presented a reverse phenomenon. The bacterial genus, Methanosaeta was the most abundant during the mesophilic process, while Methanobacterium, Methanoculleus, Methanosaeta and Methanosarcina were more evenly distributed. The more balanced community distribution between hydrogenotrophic and acetotrophic methanogens implied a closer interaction between the microbes, which further contributed to higher methane productivity. The detailed relationship between the key functional communities and anaerobic digestion performances were demonstrated via the multivariate canonical correspondence analysis. Conclusions: With the assistance of adaptive thermophilic granular sludge, microbial community structure was more evenly distributed, while both of COD degradation rate and methane production was improved during anaerobic digestion of MSW landfill leachate.


Subject(s)
Bacteria, Anaerobic/metabolism , Solid Waste , Anaerobic Digestion , Sludge Treatment , Methane/metabolism , Sewage/microbiology , Bacteria, Anaerobic/isolation & purification , Water Pollutants, Chemical , Polymerase Chain Reaction , Urban Area , Biofuels , Biological Oxygen Demand Analysis , Hot Temperature , Anaerobiosis
4.
Biosci. j. (Online) ; 34(3): 587-594, mai/jun. 2018. tab, graf
Article in English | LILACS | ID: biblio-966904

ABSTRACT

This study evaluated the adjustment of four kinetic models and their respective parameters on data of dairy wastewater treatment by the physico-chemical process of flotation and ozonation. The experiment was implemented during the year 2014, with all the tests in triplicate. The treatments were carried out at different pH levels (3.6, 7.0 and 10.4), and flotation/ozonation was catalyzed by manganese (Mn2+) in neutral level (pH 7.0). Best removal efficiencies for chemical oxygen demand (COD) were obtained in acidic medium, with removals greater than 75% after 20 min of treatment. There was no significant difference with regards to addition of Mn2+ on COD removal by the physicochemical process. The kinetic models that best fit to the experimental data, for all treatments, were the asymptotic (residual) model and that of Chan and Chu. Treatment in acidic medium showed the highest values of the kinetic parameters for the adjusted model, obtaining a k coefficient equal to 0.2394 min-1 for the asymptotic model and kinetic coefficient 1/ of 0.4816 min-1 for the Chan and Chu model, both presenting a determination coefficient greater than 99%.


Neste estudo, avaliou-se o ajuste de quatro modelos cinéticos (modelo de escoamento pistonado, mistura completa, assintótico ou residual e de Chan e Chu e seus respectivos parâmetros, na degradação da matéria orgânica presente no efluente de laticínios pelo processo físico-químico de flotação e ozonização. O experimento foi implementado durante o ano de 2014, com todos os testes em triplicata, os s tratamentos foram realizados sob diferentes pHs (3,6; 7,0 e 10,4), além da flotação/ozonização catalisada pelo manganês (Mn2+) em meio neutro. Observando que em meio ácido ocorreram as melhores eficiências de remoção da demanda química de oxigênio (DQO), tendo sido obtida uma remoção superior a 75% em 20 min de tratamento. Não houve diferença significativa em relação à adição de Mn2+ ao processo físico-químico. Os modelos que mais se ajustaram aos dados experimentais, para todos os tratamentos realizados, foram o modelo assintótico e o de Chan e Chu. O tratamento em meio ácido foi o que apresentou os maiores valores dos parâmetros cinéticos para os modelos ajustados, obtendo-se para o modelo assintótico, coeficiente k igual a 0,2394 min-1, e para o modelo de Chan e Chu, coeficiente cinético 1/ de 0,4816 min-1, apresentando para ambos os modelos um coeficiente de determinação superior a 99%.


Subject(s)
Kinetics , Flotation , Ozonation , Organic Matter , Waste Water , Chemical Waste Degradation , Dairying , Biological Oxygen Demand Analysis , Manganese
5.
Braz. j. microbiol ; 47(3): 628-639, July-Sept. 2016. tab, graf
Article in English | LILACS | ID: lil-788957

ABSTRACT

ABSTRACT The main objective of this study was to evaluate the anaerobic conversion of vinasse into biomethane with gradual increase in organic loading rate (OLR) in two upflow anaerobic sludge blanket (UASB) reactors, R1 and R2, with volumes of 40.5 and 21.5 L in the mesophilic temperature range. The UASB reactors were operated for 230 days with a hydraulic detection time (HDT) of 2.8 d (R1) and 2.8-1.8 d (R2). The OLR values applied in the reactors were 0.2-7.5 g totalCOD (L d)−1 in R1 and 0.2-11.5 g totalCOD (L d)−1 in R2. The average total chemical oxygen demand (totalCOD) removal efficiencies ranged from 49% to 82% and the average conversion efficiencies of the removed totalCOD into methane were 48-58% in R1 and 39-65% in R2. The effluent recirculation was used for an OLR above 6 g totalCOD (L d)−1 in R1 and 8 gtotalCOD (L d)−1 in R2 and was able to maintain the pH of the influent in R1 and R2 in the range from 6.5 to 6.8. However, this caused a decrease for 53-39% in the conversion efficiency of the removed totalCOD into methane in R2 because of the increase in the recalcitrant COD in the influent. The largest methane yield values were 0.181 and 0.185 (L) CH4 (gtotal COD removed)−1 in R1 and R2, respectively. These values were attained after 140 days of operation with an OLR of 5.0-7.5 g totalCOD (L d)−1 and total COD removal efficiencies around 70 and 80%.


Subject(s)
Sewage/microbiology , Fermentation , Methane/biosynthesis , Phosphorus/metabolism , Bioreactors , Volatile Organic Compounds , Biological Oxygen Demand Analysis , Hydrogen-Ion Concentration , Anaerobiosis , Nitrogen/metabolism
6.
Mycobiology ; : 260-268, 2016.
Article in English | WPRIM | ID: wpr-729715

ABSTRACT

Regulation of alkaline-resistant laccase from Perenniporia tephropora KU-Alk4 was proved to be controlled by several factors. One important factor was the initial pH, which drove the fungus to produce different kinds of ligninolytic enzymes. P. tephropora KU-Alk4 could grow at pH 4.5, 7.0, and 8.0. The fungus produced laccase and MnP at pH 7.0, but only laccase at pH 8.0. The specific activity of laccase in the pH 8.0 culture was higher than that in the pH 7.0 culture. At pH 8.0, glucose was the best carbon source for laccase production but growth was better with lactose. Low concentrations of glucose at 0.1% to 1.0% enhanced laccase production, while concentrations over 1% gave contradictory results. Veratryl alcohol induced the production of laccase. A trace concentration of copper ions was required for laccase production. Biomass increased with an increasing rate of aeration of shaking flasks from 100 to 140 rpm; however, shaking at over 120 rpm decreased laccase quantity. Highest amount of laccase produced by KU-Alk4, 360 U/mL, was at pH 8.0 with 1% glucose and 0.2 mM copper sulfate, unshaken for the first 3 days, followed by addition of 0.85 mM veratryl alcohol and shaking at 120 rpm. The crude enzyme was significantly stable in alkaline pH 8.0~10.0 for 24 hr. After treating the pulp mill effluent with the KU-Alk4 system for 3 days, pH decreased from 9.6 to 6.8, with reduction of color and chemical oxygen demand at 83.2% and 81%, respectively. Laccase was detectable during the biotreatment process.


Subject(s)
Biological Oxygen Demand Analysis , Biomass , Carbon , Copper , Copper Sulfate , Fungi , Glucose , Hydrogen-Ion Concentration , Ions , Laccase , Lactose , Physiology
7.
Electron. j. biotechnol ; 18(6): 428-432, Nov. 2015. graf, tab
Article in English | LILACS | ID: lil-772286

ABSTRACT

Background Deproteinized potato wastewater and glycerol are two by-products which are difficult to dispose. The objective of this study was to determine the ability of Rhodotorula glutinis to use glycerol and nitrogen compounds present in deproteinized potato wastewater and to evaluate the ability of simultaneous biodegradation of potato wastewater and glycerol via microbiological methods. Results It has been found that R. glutinis used glycerol and potato wastewater as a source of carbon and nitrogen, respectively. The highest degree of glycerol content (70.6%) reduction was found after cultivation of the investigated strain using a medium with 5% glycerol. In this medium, a significant reduction in the total protein content, estimated at 61%, was observed. The process of 72 h cultivation of yeast in a medium containing potato wastewater and 5% glycerol reduced the chemical oxygen demand (COD) more than 77%. Supplementation of media with high doses of glycerol (i.e. 20 and 25%) led to decreased metabolic activity in the yeast strain tested. Conclusion It has been found that there is a possibility of simultaneous biodegradation of potato wastewater and glycerol during the cultivation of R. glutinis.


Subject(s)
Rhodotorula , Biodegradation, Environmental , Waste Water , Glycerol , Yeasts , Solanum tuberosum , Biological Oxygen Demand Analysis , Industrial Waste
8.
Rev. argent. microbiol ; 47(3): 229-235, set. 2015. ilus, tab
Article in Spanish | LILACS | ID: biblio-843130

ABSTRACT

Las toneladas de residuos orgánicos que se generan anualmente en la agroindustria pueden aprovecharse como materia prima para la producción de metano. Para que los residuos orgánicos se puedan convertir a metano a gran escala, es importante que previamente se realicen sobre ellos pruebas de biodegradabilidad; un parámetro importante que conviene establecer es su potencial bioquímico de metano. En el presente trabajo se estudió la biodegradabilidad, la producción de metano y el comportamiento de poblaciones de eubacterias y arqueobacterias durante la digestión anaerobia de residuos de plátano, mango y papaya provenientes de la agroindustria, adicionando un inóculo microbiano. Los residuos de mango y plátano tenían mayor contenido de materia orgánica (94 y 75 %, respectivamente) que el residuo de papaya con base en su relación sólidos volátiles/sólidos totales. Después de 63 días de tratamiento, la mayor producción de metano se observó en la digestión anaerobia del residuo de plátano: 63,89 ml de metano por g de demanda química de oxígeno del residuo. Los resultados del potencial bioquímico de metano demostraron que el residuo de plátano tiene el mejor potencial para ser usado como materia prima en la producción de metano. A través de un análisis por PCR-DGGE con oligonucleótidos específicos se logró evaluar el tamaño y la composición de las poblaciones de eubacterias y arqueobacterias presentes en la digestión anaerobia de residuos agroindustriales a lo largo del proceso.


The tons of organic waste that are annually generated by agro-industry, can be used as raw material for methane production. For this reason, it is important to previously perform biodegradability tests to organic wastes for their full scale methanization. This paper addresses biodegradability, methane production and the behavior of populations of eubacteria and archaeabacteria during anaerobic digestion of banana, mango and papaya agroindustrial wastes. Mango and banana wastes had higher organic matter content than papaya in terms of their volatile solids and total solid rate (94 and 75 % respectively). After 63 days of treatment, the highest methane production was observed in banana waste anaerobic digestion: 63.89 ml CH4/per gram of chemical oxygen demand of the waste. In the PCR-DGGE molecular analysis, different genomic footprints with oligonucleotides for eubacteria and archeobacteria were found. Biochemical methane potential results proved that banana wastes have the best potential to be used as raw material for methane production. The result of a PCR- DGGE analysis using specific oligonucleotides enabled to identify the behavior of populations of eubacteria and archaeabacteria present during the anaerobic digestion of agroindustrial wastes throughout the process.


Subject(s)
Anaerobic Digestion/methods , Waste Management/methods , Methane/biosynthesis , Biodegradation, Environmental , Solid Waste Use , Agribusiness/prevention & control , Recycling/methods , Biological Oxygen Demand Analysis/methods , Garbage
9.
Braz. j. microbiol ; 45(4): 1153-1160, Oct.-Dec. 2014. ilus, tab
Article in English | LILACS | ID: lil-741264

ABSTRACT

The present work aimed to investigate the microbial dynamics during the anaerobic treatment of the azo dye blue HRFL in bench scale upflow anaerobic sludge bed (UASB) reactor operated at ambient temperature. Sludge samples were collected under distinct operational phases, when the reactor were stable (low variation of color removal), to assess the effect of glucose and yeast extract as source of carbon and redox mediators, respectively. Reactors performance was evaluated based on COD (chemical oxygen demand) and color removal. The microbial dynamics were investigated by PCR-DGGE (Polimerase Chain Reaction - Denaturing Gradient of Gel Electrophoresis) technique by comparing the 16S rDNA profiles among samples. The results suggest that the composition of microorganisms changed from the beginning to the end of the reactor operation, probably in response to the presence of azo dye and/or its degradation byproducts. Despite the highest efficiency of color removal was observed in the presence of 500 mg/L of yeast extract (up to 93%), there were no differences regarding the microbial profiles that could indicate a microbial selection by the yeast extract addition. On the other hand Methosarcina barkeri was detected only in the end of operation when the best efficiencies on color removal occurred. Nevertheless the biomass selection observed in the last stages of UASB operation is probably a result of the washout of the sludge in response of accumulation of aromatic amines which led to tolerant and very active biomass that contributed to high efficiencies on color removal.


Subject(s)
Azo Compounds/metabolism , Biota , Biological Oxygen Demand Analysis , Biotransformation , Bioreactors/microbiology , Cluster Analysis , Color , Denaturing Gradient Gel Electrophoresis , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction , /genetics , Sequence Analysis, DNA , Sewage/microbiology
10.
Chinese Journal of Biotechnology ; (12): 1835-1844, 2014.
Article in Chinese | WPRIM | ID: wpr-345538

ABSTRACT

In order to simultaneously remove carbon and nitrogen from organic-rich wastewater, we used an up-flow anaerobic sludge bed/blanket (UASB) reactor that was started up with anammox with high concentration of carbon and nitrogen by gradually raising the organic loading of influent. We optimized the removal of nitrogen and carbon when the chemical oxygen demand (COD) concentration varied from 172 to 620 mg/L. During the entire experiment, the ammonium and total nitrogen removal efficiency was higher than 85%, while the average COD removal efficiency was 56.6%. The high concentration of organic matter did not restrain the activity of anammox bacteria. Based on polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and tapping sequencing analyses, the Planctomycete, Proteobacteria, Chloroflexi, Chlorobi bacteria are detected in the UASB reactor, which indicated complex removal pathway of carbon and nitrogen coexisted in the reactor. However, a part of Planctomycete which referred to anammox bacteria could tolerate a high content of organic carbon, and it provided help for high performance of nitrogen removal in UASB reactor.


Subject(s)
Ammonia , Chemistry , Biological Oxygen Demand Analysis , Bioreactors , Carbon , Chemistry , Nitrogen , Chemistry , Sewage , Waste Disposal, Fluid , Methods , Waste Water , Chemistry
11.
International Journal of Environmental Research. 2013; 7 (3): 817-826
in English | IMEMR | ID: emr-130733

ABSTRACT

The aim of this work was to optimize the coagulation-flocculation [CF] process applied to municipal wastewaters [WW]. Optimization of CF was performed to minimize chemical oxygen demand [COD], turbidity, sludge produced, and some metals in sludge. A Box-Behnken design was used to evaluate the effects and interactions of three factors such as type of biopolymer [guar, mesquite seed gum and Opuntia mucilage], dose of biopolymer [25, 50 and 75 mg/L] and initial organic load of wastewaters WW [725, 1,425 and 1,325 mg COD/L]. Regarding the statistical analysis, Results were assessed with various descriptive statistics such as p value, lack of fit [F-test], coefficient of R2 determination and adequate precision [AP] values. p values 0.05 show that the F-statistics was insignificant implying significant model correlation between the variables and process responses. Regarding the fit of the model, the obtained R2 values were up to 0.98 for sludge produced, 0.94 for COD removal, 0.91 for Cd, 0.90 for turbidity removal, and 0.75 for sludge density. It is noteworthy that response surface methodology [RSM] also allowed optimizing de CF process. Employing this methodology it is feasible to determine COD, turbidity, and salts removals, as well as the amount and quality of the produced sludges under hypothetical conditions within predetermined parameter ranges, without the need of carrying out experimental runs


Subject(s)
Biopolymers , Flocculation , Sewage , Biological Oxygen Demand Analysis
12.
International Journal of Environmental Research. 2013; 7 (3): 827-834
in English | IMEMR | ID: emr-130734

ABSTRACT

Since treatment of landfill leachate is quite complicated, there is a need to develop a system that is capable of providing high treatment efficiencies. In this study, the treatment performance of a jet - loop membrane bioreactor [JLMB] operated at different organic loading rates was investigated by observing the changes in Chemical Oxygen Demand [COD], Total Kjehldahl Nitrogen [TKN] and Total Ammonia [NH[3]] concentrations. The same COD removal rates [83%] were observed at all the studied loading rates, and it should be noted that the biodegradable part of the leachate was removed completely. It was also observed that the NH[4] - N / TKN ratios, which were found to be approximately 0.9, did not change throughout the study. However, further treatment technologies, such as reverse osmosis, nanofiltration or ion - exchange, should be employed for the complete removal of inert COD and NH3 in order to meet related discharge limits


Subject(s)
Bioreactors , Biological Oxygen Demand Analysis , Nitrogen , Ammonia
13.
International Journal of Environmental Research. 2013; 7 (3): 859-866
in English | IMEMR | ID: emr-130737

ABSTRACT

The effect of hydraulic retention time in a range from 1.0-5.5 days was evaluated in a laboratory scale anaerobic fixed bed reactor packed with a hybrid material composed of tire rubber and zeolite. Under these conditions, COD removal efficiencies varied from 28.3% to 82.1%, respectively. Over the more than 6 months of operation, no clogging was observed. The results obtained demonstrated that this type of reactor was capable of operating with dairy waste at a hydraulic retention time 5 times lower than that used in a conventional digester. Based on the laboratory-scale experimental results obtained, a pilot-scale plant was designed. The pilot plant was installed in "Cot de Oreamuno" near the city of Cartago, Costa Rica. Biogas produced in the pilot-scale anaerobic plant was used for the generation of electricity on the farm. In this case, a COD removal efficiency of 63.6% was achieved in the full-scale anaerobic plant at a hydraulic retention time of 3 days, this value being comparable with that obtained at laboratory-scale


Subject(s)
Dairy Products , Temperature , Biological Oxygen Demand Analysis
14.
Iranian Journal of Public Health. 2013; 42 (8): 860-867
in English | IMEMR | ID: emr-140832

ABSTRACT

Anaerobic treatment methods are more suitable for the treatment of concentrated wastewater streams, offer lower operating costs, the production of usable biogas product. The aim of this study was to investigate the performance of an Anaerobic Fluidized Bed Reactor [AFBR] - Aerobic Moving Bed Bio Reactor [MBBR] in series arrangement to treat Currant wastewater. The bed materials of AFBR were cylindrical particles made of PVC with a diameter of 2-2.3 mm, particle density of 1250 kg/m[3]. The volume of all bed materials was 1.7 liter which expanded to 2.46 liters in fluidized situation. In MBBR, support media was composed of 1.5 liters Bee-Cell 2000 having porosity of 87% and specific surface area of 650m[2]/ m[3]. When system operated at 35 [degree sign] C, chemical oxygen demand [COD] removal efficiencies were achieved to 98% and 81.6% for organic loading rates [OLR] of 9.4 and 24.2 g COD/ l.d, and hydraulic retention times [HRT] of 48 and 18 h, in average COD concentration feeding of 18.4 g/l, respectively. The contribution of AFBR in total COD removal efficiency at an organic loading rate [OLR] of 9.4 g COD/ l.d was 95%, and gradually decreased to 76.5% in OLR of 24.2 g COD/ l.d. Also with increasing in organic loading rate the contribution of aerobic reactor in removing COD gradually decreased. In this system, the anaerobic reactor played the most important role in the removal of COD, and the aerobic MBBR was actually needed to polish the anaerobic treated wastewater


Subject(s)
Bioreactors , Biological Oxygen Demand Analysis
15.
International Journal of Environmental Research. 2012; 6 (1): 119-128
in English | IMEMR | ID: emr-122452

ABSTRACT

Leachate treatment from municipal landfills has been always a major anxiety in waste management due to its high level of various contaminations. In this paper the effect of Nanosized Zero Valent Iron particles [NZVI] in Fenton process for the treatment of high COD strength landfill leachate was scrutinized. The results corroborated this procedure was fast and efficient. In fact, about 87% of initial COD [38 g/L] was reduced in an hour. The various operation conditions such as pH, initial H[2]O[2] concentration, H[2]O[2]/Fe molar ratio and temperature in a batch reactor were investigated. The optimum condition was obtained at pH value of 2, temperature of 40°C and H[2]O[2] to Fe molar ratio equal to 39 by using only 0.07 M of NZVI. In such conditions, 0.08 M H[2]O[2] for the removal of 1 g/L of COD was needed. Furthermore, hydrogen peroxide consumption after Fenton process was evaluated and it was found that it had a direct relationship with COD removal efficiency


Subject(s)
Hydrogen Peroxide , Iron , Biological Oxygen Demand Analysis , Waste Management
16.
International Journal of Environmental Research. 2012; 6 (1): 129-138
in English | IMEMR | ID: emr-122453

ABSTRACT

One of the most important concerns in Tehran municipal landfill is the production of leachate and its potential for water resources pollution, this study was undertaken to examine feasibility of biological and physico/chemical treating of high-strength landfill leachate that was collected from Tehran municipal landfill. Average COD of the leachate in aerobic submerged membrane bioreactor is 68000 mg/L. The reactor with a working volume of 175 L, having membrane module [Hollow fiber] with pore size of 0.1 microm coupled with reverse osmosis with pore size of 0.001 micron was used in this study. The dissolved oxygen [DO] concentration was maintained at 3.2 mg/L and solid retention times [SRTs] and hydraulic retention times [HRT] were controlled at 55 and 15 days respectively, the average Membrane Bioreactor effluent COD was 1733 mg/L with average removal efficiency of 97.46%. The average NH4 -N removal efficiencies was 99%. On the other hand, an almost complete nitrification was achieved during this period. PO[4] -P concentration in the effluent was low and its average removal efficiency was as high as 90%; especially during the operation period. The averages reverse osmosis [RO] effluent COD was 335 mg/L with average removal efficiency of 99.13%. PO[4]-P concentration in the RO effluent was 0.86 mg/L and its average removal efficiency was 99.33%. The use of Membrane technologies, more especially reverse osmosis offers the best solution of achieving full purification with average COD removal efficiency of 99% and solving the problem of water resources pollution


Subject(s)
Bioreactors , Osmosis , Biological Oxygen Demand Analysis
17.
International Journal of Environmental Research. 2012; 6 (1): 235-244
in English | IMEMR | ID: emr-122463

ABSTRACT

In this paper, startup performance of Upflow Anaerobic Hybrid Reactor and Upflow Anaerobic Sludge Blanket reactors in anaerobic treatment of distillery spentwash has been studied under identical conditions of operation. Various effluent characteristics like pH, Electrical Conductivity, Chemical Oxygen Demand, Biochemical Oxygen Demand and Total Solids and other process parameters like biogas production and methane per cent in biogas were studied until the attainment of steady state. The startup of the reactors has been completed and steady state condition attained on 25[th] day of reactor operation in UAHR and 34[th] day in UASB reactor. The treated effluent characteristics of both reactors were fairly steady after attaining the steady state condition. The pH of treated effluent during steady state condition was almost neutral for both reactors even though the influent had an acidic pH. The maximum COD, BOD and TS removal efficiencies were as high as 79.60%, 87.39% and 69.96% in UAHR as compared with UASB of 72.98%, 81.34% and 66.23%, respectively during the steady state period. The maximum volumetric gas production of 149 L nr3 produced more in UAHR than in UASB reactor during steady state condition. The population of total anaerobic bacteria and methanogenic bacteria also more as that of the other parameters in UAHR than in UASB reactor and it were 55.2 x 10[3] ml[-1] and 40.0 x 10[2] ml[-1] respectively in UAHR. It is found that from an overall assessment the UAHR has proved superior in its performance compared to the UASB reactor during the startup process


Subject(s)
Biofuels , Methane , Hydrogen-Ion Concentration , Electric Conductivity , Biological Oxygen Demand Analysis
18.
International Journal of Environmental Research. 2012; 6 (1): 285-296
in English | IMEMR | ID: emr-122468

ABSTRACT

A lab-scale cross flow membrane bioreactor [CF-MBR] was operated to determine the biokinetic coefficients under MLSS concentrations of 5000 and 3000 mg/L. The investigation showed that the yield [Y], the endogenous decay coefficient [k[d], the maximum specific growth rate [micro[m]] and the saturation constant [K[s]] were 0.276 mg/mg, 0.07 /day, 0.653 /day, and 396.62 mg COD/L respectively for MLSS 5000 mg/L, and 0.222 mg/mg, 0.09 /day, 1.2 /day, and 659.45 mg COD/L for MLSS 3000 mg/L. The values of kinetic coefficients were within the normal range of the activated sludge process found in the literature, except the values of Y. However, value of Y increased with the increase of MLSS. Kinetic parameters determined from CF-MBR process were used to simulate the effluent COD. The simulation study showed good agreement between model prediction and experimental data. Sensitivity analysis was carried out to determine influence of biokinetic parameters on the effluent substrate concentration. From the analysis, it was evident that k[d] and K[s] were directly proportional to the effluent substrate concentration, while micro[m] was inversely proportional


Subject(s)
Bioreactors , Sewage , Biological Oxygen Demand Analysis
20.
Rev. téc. (ITCA-FEPADE. En línea) ; 4(4): 46-50, 2011. ^c28 cm.tab., graf.
Article in Spanish | LILACS, BISSAL | ID: biblio-1151308

ABSTRACT

En la actualidad el Río Sucio es uno de los ríos más contaminados en El Salvador, catalogándose la calidad de su agua como de pésima calidad, esta calificación se determina mediante la medición de parámetros como Oxigeno Disuelto, Recuento Microbiológico, Demanda Bioquímica de Oxígeno, Demanda Química de Oxígeno, Sólidos Totales Disueltos y Sólidos Suspendidos, Turbidez, Nitrógeno y Fósforo, encontrándose la mayoría de ellos arriba de los limites establecidos en las normas oficiales, tal y como se logró determinar en el monitoreo realizado por la Escuela de Ingeniería Química de ITCA-FEPADE durante once meses, en la zona media del Río Sucio, donde operan al menos 15 empresas agroindustriales. Se logró identificar que gran parte de la carga contaminante del río proviene de los desechos domésticos, industriales, agroindustriales y agrícolas que se han vertido en él durante las ultimas décadas.


Currently, Río Sucio is one of the most contaminated rivers in El Salvador, cataloging his water quality as bad quality. This tag is determinated by the measuring parameters like Dissolved Oxigen, Microbiological Count, Biochemical Oxygen Demand, Chemical Oxygen Demand, Total Dissolved Solids and Suspended Solids, Turbidity, Nitrogen and Phosphorus, most of them being above the limits established in the official norms, as it will seek to determine in the monitoring carried out by the Escuela de Ingeniería Química ITCA-FEPADE for once months, in the middle area of ​​the Sucio River, where at least 15 agro-industrial companies operate. It was possible to identify that a large part of the river's pollutant load comes from domestic, industrial, agro-industrial and agricultural wastes that have been dumped into it during the last decades.


Subject(s)
Water Pollution, Chemical/analysis , Water Quality , Ocean Disposal of Hazardous Waste , Dissolved Oxygen , Dissolved Solids , Suspended Solids , Water Purification , Environmental Monitoring , Rivers , Environmental Pollutants , Biological Oxygen Demand Analysis
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