UASB reactor

Generation of wastes is a riotous component of modern industrialized world. Dairy industries are one of the most considerable due to release of both solid and liquid wastes. Even though many technologies are trustworthy to adopt in dairy industry, anaerobic digestion is considered as best choice due to the better out comings. While construction of the suitable anaerobic digester is the most need to treat colossal amount of dairy waste. Objectives of the present study are physico-chemical characterization of dairy processing industrial effluent to assess it for their suitability in anaerobic treatment, designing two-phase Upflow Anaerobic Sludge Blanket (UASB) reactor with internal packing column for treating dairy waste water and to examine the maximum COD removal of dairy effluent, the reactor operated with different organic loading rate at different phases. The collected dairy water samples were analysed following the standard methods of water and waste water analysis by American Public Health Association. The UASB reactor used in this experiment was designed having the following specifications. Height: 1m, breadth: 16cm, width: 16cm, feed inlet points (sample port): 4, diameter of sample port: 4mm, aperture area: 5cm, volume of the UASB reactor: 25 l, volume of the gas separator zone: 5lt, peristaltic pump: 4-40ml/min, effective volume of the reactor: 20 l. With this reactor the dairy waste water was treated and all the physico chemical and biomass characters were observed.

The effect of reactor process configuration on anaerobic production of useful energy (hydrogen and methane) from a complex substrate was investigated for the following reactor systems: suspended growth, two-phase mixed, two-stage mixed, upflow anaerobic sludge blanket (UASB) reactor, and two-phase UASB. The mixed two-phase and two-stage configurations yielded the highest specific energy productions of 13.3 and 13.4 kJ/g COD fed, respectively. Reactor process configuration influenced microbial pathways in acidogenic reactors in that butyrate was the predominant volatile acid in phased configurations, whereas acetate was predominant in the staged configuration. The UASB reactor achieved the highest average daily energy production per reactor volume of 101 kJ/L reactor-d. All reactor configurations achieved high COD removals on the order of 99%. However, hydrogen represented only 3% of the total energy produced by the two-phase mixed and two-phase UASB configurations. Theoretical analy...

Three UASB reactors were operated at different salinity levels in order to assess the effects on the granular sludge properties. High levels of activity inhibition were observed at sodium concentrations over 7 g Na+/L, which resulted in low applicable organic loading rates and VFA accumulation in reactor effluents. However, either sludge adaptation or selection for saline resistant microorganisms occurred, which could be concluded from the observed increase in the 50% activity inhibitory concentrations of sodium during continuous flow experiments. Changes in Na+ susceptibility in time are likely to be expected when treating saline wastewaters. The latter was evidenced by the high sodium tolerance of granular methanogenic sludge coming from a full-scale industrial reactor treating such wastewater. High salinity conditions resulted in a reduced granule strength, predicting process instabilities during long term reactor operation. Batch tests showed that high sodium concentrations seem...

Most of developing countries often suffer from the absence of efficient institutions; lack of technological knowledge and empirical Know-How of wastewater treatment processes and their implementation; also inappropriate management practices. Trying to get some solutions of the wastewater problems in those countries, Natural Oriented municipal Wastewater Treatment and Reuse concept (NOWTR) will be implemented as a naturally oriented low cost

Life Cycle Assessment (LCA) was applied to estimate and analyze the environmental impacts from the construction and operation phases of a full-scale wastewater treatment plant (WWTP) located in the municipality of Lauro de Freitas, Bahia, Brazil. The WWTP process consists of the association of an Upflow Anaerobic Sludge Blanket (UASB) reactor followed by four constructed wetlands (CWL) and a disinfection step. The functional unit was defined as one cubic meter of treated effluent during the useful life of this WWTP (20 years). The LCA was carried out using SimaPro ® software and the Centre of Environmental Science (CML) assessment method. The environmental impacts during construction phase were mainly from the wooden forms for concrete and the use of reinforcing steel. During the operation phase, the chlorine used as effluent disinfectant caused the greatest impacts in the abiotic depletion and acidification categories. Macronutrient concentrations present in the treated effluent and the methane generated also caused significant environmental impacts during the WWTP's useful life. The results obtained highlight the importance of the application of a methodology like LCA to assist in decision-making with regard to the implementation, construction and operation of a WWTP.

El propósito de este estudio fue evaluar la aplicación de Tecnología Anaerobia en un reactor UASB a escala laboratorio, para la degradación biológica de los lixiviados provenientes de un sector del vertedero en que se disponen los residuos sólidos urbanos de una ciudad de ...

The enhancement of water quality by constructed wetland systems is increasingly being employed throughout the world. For this study two treatment schemes consisting of an Up-flow Anaerobic Sludge Blanket (UASB) reactor followed by either subsurface flow (SSF) or free surface flow (FSF) constructed wetlands have been investigated. The common macrophyte in Egypt Typha latifolia (cattail) was used at a planting density of three rhizomes/m2. To evaluate the role of plants in the treatment process, an unplanted gravel bed identical to the SSF unit was operated as control. During the study period, the wetlands were fed with the UASB effluent at an organic loading rate ranging from 17.3 to 46.8 kg BOD5/ha·d (55.1 to 134.6 kgCOD/ha·d). Effectiveness of the system for the removal of key constituents (COD, BOD, TSS, nutrients and FC) has been investigated. The results showed that, the level of CODtot, and TSS in the final effluent of SSF was lower than that of FWS. Subsurface flow wetland has...

This paper describes a new wastewater treatment concept which was assessed to be technically and economically feasible for suburban and rural areas in Mediterranean countries. The treatment consists of a two-step anaerobic high-rate reactor like UASB reactor followed by vertical flow constructed wetland (CW) and UV radiation. It fulfills the defined criteria, as meeting the standards for water reuse, costs especially for energy are low, sewage sludge production is limited and operation and maintenance are simple. Although there are much experience and data available about design and operation of CW and UV radiation, the knowledge about anaerobic treatment of municipal wastewater in UASB reactor at moderate temperature is limited. Therefore bench-scale experiments with pre-settled high-strength municipal wastewater were carried out in a one step UASB reactor of 55 liters. The results show a satisfactory effluent quality at fluctuating HRT. During 9 months of continuous operation, tot...

The use of an integrated treatment scheme consisting of wet hydrogen peroxide catalytic oxidation (WHPCO) followed by two-stage upflow anaerobic sludge blanket (UASB) reactor (10 l each) for the treatment of olive mill wastewater was the subject of this study. The diluted wastewater (1:1) was pre-treated using Fenton's reaction. Optimum operating conditions namely, pH, H2O2 dose, Fe+2, COD:H2O2 ratio and Fe+2:H2O2 ratio were determined. The UASB reactor was fed continuously with the pre-treated wastewater. The hydraulic retention time was kept constant at 48 h (24 h for each stage). The conventional parameters such as COD, BOD, TOC, TKN, TP, TSS, oil and grease, and total phenols were determined. The concentrations of polyphenolic compounds in raw wastewater and effluents of each treatment step were measured using HPLC. The results indicated a good quality final effluent. Residual concentrations of individual organic compounds ranged from 0.432 mg l−1 for ρ-hydroxy-benzaldhyde ...

Esse trabalho teve como objetivo avaliar a viabilidade técnica e econômica da regeneração de coagulantes pela acidificação de lodos de ETA's e a posterior aplicação dos coagulantes regenerados no tratamento de esgotos. Foram realizados ensaios em escala de bancada visando o estudo das condições de regeneração, da qualidade do coagulante produzido e do lodo resultante. O coagulante regenerado teve desempenho satisfatório no tratamento de efluentes de reator UASB e foi observado que ocorreram reduções significativas de sólidos em suspensão nos lodos das ETA's. Com respeito à avaliação econômica, foi verificado que considerando as reduções de custos decorrentes da diminuição de lodo a ser tratado e disposto, o custo de produção do coagulante regenerado é muito próximo ao custo do coagulante comercial. Portanto, concluiu-se que hoje em dia essa tecnologia deve ser considerada como uma alternativa potencialmente viável dos pontos de vista técnico e econômico para o tratamento e r...

Liquid film and diffusional resistances of brewery granules during acetate, propionate, and ethanol utilization were investigated. Substrate utilization rate increased with decreased granule size. Effectiveness factors for acetate, propionate, and ethanol were calculated by comparing the maximum rates of substrate utilization of whole granules (1.8 to 3.0 mm) and fine flocs (20 to 75 mum) derived by disrupting whole granules. For acetate, propionate, and ethanol, maximum specific substrate utilization rates (k(m') g/g VS . d) for the flocs, were 5.11, 6.25, and 5.49, respectively, and half-velocity coefficients (K(g') mM) were 0.45, 0.40, and 3.37, respectively. Calculated effectiveness factors were 0.32, 0.41, and 0.75 for acetate, propionate, and ethanol, respectively. The effect of temperature on substrate utilization was examined at 26 degrees C, 31 degrees C, and 37 degrees C using acetate as sole carbon source. Utilization rates increased with temperature. Flocs were most sensitive to temperature, and whole granules were least affected. The behavior of flocs was well described by the Van't Hoff-Arrhenius equation. Effectiveness factors for acetate utilization by the granules were 0.36, 0.35, and 0.32 at 26 degrees C, 31 degrees C, and 37 degrees C, respectively, indicating little effect of temperature. Based on these results, we conclude that both liquid film and diffusional resistances influenced the rate of substrate utilization in a UASB reactor with granular sludge. Temperature effects were much less important than diffusional limitations within the granules. (c) 1995 John Wiley & Sons, Inc.

The biodegradation route of the octylphenol ethoxylates (OPEOs) by denitrification in an upflow anoxic sludge blanket (UASB) reactor was studied. An anaerobic sludge adapted to denitrifying conditions with acetate was adapted with increasing amounts of OPEOs and diminishing amounts of acetate until only 300 mg x L(-1) of OPEOs were fed. Only 70% of stoichiometric NO3- was fed so partial removal was expected. The total OPEOs fed was transformed with 70% COD removal. HPLC and GC-MS analyses showed that octylphenol (OP) was immediately formed but disappeared while other intermediates, the ethoxylated moieties; mono and diethoxylate (OPEO1 and OPEO2 respectively) led to the cleavage of the alkyl chain to form propylphenol triethoxylate (PPEO3) and heptylphenol diethoxylated (HPEO2). These last two compounds are produced due to an attack to both sides of the molecule; the hydrophilic and the hydrophobic. These findings suggest three simultaneous routes of OPEO degradation.

Cattle manure from farms in the autonomous community of Asturias, Spain, was characterised and subsequently treated, after filtration through a 1 mm sieve, in upflow anaerobic sludge blanket laboratory reactors. The volume generated per cow and day ...

The primary goal of this work was to evaluate the technical and economical feasibility of coagulant recovery from acidification of water treatment plant sludges, and the use of recovered coagulants in wastewater treatment. Acidification bench tests were conducted in order to study the regeneration conditions, the recovered coagulant quality and the remaining sludge. The recovered coagulant had a satisfactory behavior in the treatment of UASB reactor effluent and was observed significantly suspended solids reductions in the water treatment plant sludges. On the economical evaluation it was verified that considering the costs decrease due to the sludge reduction, the recovered coagulant production cost was very similar to commercial coagulants cost. Thus, it was concluded that nowadays this technology must be considered as a potential alternative for the treatment and reuse for water treatment plant sludges, regarding to technical and economical aspects.

Comparative investigation of the components and characteristics of three types of fully developed granular sludges operating in full-scale and laboratory upflow anaerobic sludge blanket reactors under different conditions was qualitatively and quantitatively carried out. Extracellular polymeric material of granular sludges contained 1.7–2.7% carbohydrates, 2.5–5.1% nucleic acids and 8.3–16.3% proteins of total suspended solids (TSS). The ash content of the granular

Revista de Biologia e Ciencias da Terra Universidade Estadual da Paraíba revbiocieter@yahoo.com.br ISSN (Versión impresa): 1519-5228 BRASIL ... 2006 José Tavares de Sousa / Israel Nunes Henrique / Valderí Leite Duarte / Wilton Silva Lopes ...

Constructed wetlands have been recognized as offering a removal treatment option for high concentrations removal of chemical and biological contaminants in domestic wastewater. The enteric protozoan parasite Cryptosporidium is considered one of the highly resistant to treatment and highly infectious organisms to humans and animals. Moreover, some species of Cryptosporidium are known to have a zoonotic nature. In this investigation

The paper presents the monitoring results of a pilot UASB reactor followed by a baffled polishing pond treating domestic sewage in Brazil. Longitudinal profiles of E coli and helminth eggs along the baffled pond have been undertaken. The experimental results have been compared with von Sperling's model for coliform removal and Ayres' model for helminth eggs removal, and the fitting was considered satisfactory in both cases. The distribution of the helminth species along the system is also presented.