scholarly journals The effect of operational conditions on the hydrodynamic characteristics of the sludge bed in UASB reactors

2011 ◽  
Vol 64 (9) ◽  
pp. 1935-1941 ◽  
Author(s):  
R. C. Leitão ◽  
S. T. Santaellla ◽  
A. C. van Haandel ◽  
G. Zeeman ◽  
G. Lettinga
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Hydrodynamic Characteristics ◽  
Anaerobic Sludge ◽  
Fluidised Bed ◽  
Operational Conditions ◽  
Uasb Reactors

This work aims to evaluate the hydrodynamic properties of the sludge bed of Upflow Anaerobic Sludge Blanket (UASB) reactors based on its settleability and expansion characteristics. The methodologies used for the evaluation of the settleability of aerobic activated sludge, and for the expansibility of a sludge bed of Expanded Granular Sludge Bed reactors and Fluidised Bed Reactors were adapted and applied to the particular characteristics of the sludge of UASB reactors. An easy-to-build experimental set-up was developed to assess the parameters necessary for the equations of settleability and of expansibility. The results obtained from the sludges of seven differently operated reactors show that, for the treatment of low strength wastewater, settleability increased and expansibility decreased at decreased hydraulic retention time, from 6 to 1 h, and/or increased influent concentrations, from 136 to approximately 800 mg chemical oxygen demand/L. The results also show that it is useless to design an UASB reactor with a longer hydraulic retention time to cope with hydraulic shock loads, as a more expansible sludge will develop at such condition.

Grey water treatment in upflow anaerobic sludge blanket (UASB) reactor at different temperatures

2011 ◽  
Vol 64 (3) ◽  
pp. 610-617 ◽  
Author(s):  
Tarek Elmitwalli ◽  
Ralf Otterpohl
Keyword(s):  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Septic Tank ◽  
Anaerobic Sludge ◽  
Grey Water ◽  
Methanogenic Activity ◽  
Operational Conditions ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors

The treatment of grey water in two upflow anaerobic sludge blanket (UASB) reactors, operated at different hydraulic retention times (HRTs) and temperatures, was investigated. The first reactor (UASB-A) was operated at ambient temperature (14–25 °C) and HRT of 20, 12 and 8 h, while the second reactor (UASB-30) was operated at controlled temperature of 30 °C and HRT of 16, 10 and 6 h. The two reactors were fed with grey water from ‘Flintenbreite’ settlement in Luebeck, Germany. When the grey water was treated in the UASB reactor at 30 °C, total chemical oxygen demand (CODt) removal of 52–64% was achieved at HRT between 6 and 16 h, while at lower temperature lower removal (31–41%) was obtained at HRT between 8 and 20 h. Total nitrogen and phosphorous removal in the UASB reactors were limited (22–36 and 10–24%, respectively) at all operational conditions. The results showed that at increasing temperature or decreasing HRT of the reactors, maximum specific methanogenic activity of the sludge in the reactors improved. As the UASB reactor showed a significantly higher COD removal (31–64%) than the septic tank (11–14%) even at low temperature, it is recommended to use UASB reactor instead of septic tank (the most common system) for grey water pre-treatment. Based on the achieved results and due to high peak flow factor, a HRT between 8 and 12 h can be considered the suitable HRT for the UASB reactor treating grey water at temperature 20–30 °C, while a HRT of 12–24 h can be applied at temperature lower than 20 °C.

scholarly journals Hydrodynamic behavior of a lab-scale upflow anaerobic sludge blanket reactor (UASB) operated with an adopted hydraulic retention time (HRT) of 12 hours

2009 ◽  
Vol 33 (4) ◽  
pp. 1139-1144 ◽  
Author(s):  
Aguinaldo Menegassi Pereira Lourenço ◽  
Cláudio Milton Montenegro Campos
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Physical Analysis ◽  
Hydrodynamic Behavior ◽  
Operational Conditions ◽  
Hydrodynamic Parameters ◽  
Anaerobic Sludge Blanket

The present research was carried out in the Laboratory of Water Analysis at the Engineering Department at Federal University of Lavras (LWAED-UFLA), in order to evaluate the hydrodynamic behavior of a lab-scale upflow anaerobic sludge blanket reactor (UASB) that was continuously fed with liquid effluent from swine manure with solid separation over 2mm. The hydrodynamic parameters were determined by a tracer study, under hydraulic retention time (HRT) of 12 hours, using Lithium Chloride (LiCl) as a tracer. The system was monitored periodically through physical analysis of samples collected at UASB, during the steady-state operational conditions. The physical-chemical analyses were accomplished using a flame photometry. The operational average temperature in the UASB reactor was 23.9ºC .The UASB hydrodynamic parameters determined were: average residence time (<img src="/img/revistas/cagro/v33n4/t4_barra.gif" align="absmiddle">) of 38.3 h, number of dispersion d= 0.27, and the flow type was characterized as dispersed flow of great intensity. This research is of great importance due to the fact that the scaling-up of biological reactors is based on the hydrodynamic behavior, through which the bacterial kinetic is directly influenced, as reported by Saleh (2004).

Diversity and dynamics of ammonia-oxidizing bacterial communities in a sponge-based trickling filter treating effluent from a UASB reactor

2013 ◽  
Vol 68 (3) ◽  
pp. 650-657 ◽  
Author(s):  
E. F. A. Mac Conell ◽  
P. G. S. Almeida ◽  
A. M. Zerbini ◽  
E. M. F. Brandt ◽  
J. C. Araújo ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Trickling Filter ◽  
Strong Concentration ◽  
Operational Conditions ◽  
N Removal

Changes in ammonia-oxidizing bacterial (AOB) population dynamics were examined in a new sponge-based trickling filter (TF) post-upflow anaerobic sludge blanket (UASB) reactor by denaturating gradient gel electrophoresis (DGGE), and these changes were linked to relevant components influencing nitrification (chemical oxygen demand (COD), nitrogen (N)). The sponge-based packing media caused strong concentration gradients along the TF, providing an ecological selection of AOB within the system. The organic loading rate (OLR) affected the population dynamics, and under higher OLR or low ammonium-nitrogen (NH4+-N) concentrations some AOB bands disappeared, but maintaining the overall community function for NH4+-N removal. The dominant bands present in the upper portions of the TF were closely related to Nitrosomonas europaea and distantly affiliated to Nitrosomonas eutropha, and thus were adapted to higher NH4+-N and organic matter concentrations. In the lower portions of the TF, the dominant bands were related to Nitrosomonas oligotropha, commonly found in environments with low levels of NH4+-N. From a technology point of view, changes in AOB structure at OLR around 0.40–0.60 kgCOD m−3 d−1 did not affect TF performance for NH4+-N removal, but AOB diversity may have been correlated with the noticeable stability of the sponge-based TF for NH4+-N removal at low OLR. This study is relevant because molecular biology was used to observe important features of a bioreactor, considering realistic operational conditions applied to UASB/sponge-based TF systems.

Degradation of 3-Nitrophenol with Sodium Acetate as Co-Substrate in an Upflow Anaerobic Sludge Blanket Reactor

2011 ◽  
Vol 393-395 ◽  
pp. 1153-1156
Author(s):  
Zong Lian She ◽  
Lei Lei Li ◽  
Ying Jie Zhu ◽  
Tian Xie ◽  
Li Na Jiang ◽  
...  
Keyword(s):  
Treatment Effect ◽  
Retention Time ◽  
Conversion Rate ◽  
Sodium Acetate ◽  
Hydraulic Retention Time ◽  
Operating Temperature ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Anaerobic Sludge Blanket

The effects on degrading 3-nitrophenol (3-NP) with sodium acetate as co-substrate under the conditions of laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was investigated at an operating temperature of 35±1°C in this study. The results showed that the optimum influent 3-NP concentration was 71.6mg/L when keeping influent COD concentration for 2500 mg/L and hydraulic retention time (HRT) for 30 h. At the stage of reducing influent COD concentration, all of the 3-NP removal rates were more than 95%; while the conversion rate of 3-aminophenol (3-AP) decreased from 61.4% to 0.2%. Meanwhile, the reduction of HRT also had significantly effects on the treatment effect of 3-NP. With the decreases of HRT, COD removal dropped to 49.7% from 82.7%.

scholarly journals Performance of UASB reactors in two stages under different HRT and OLR treating residual waters of swine farming

2013 ◽  
Vol 33 (2) ◽  
pp. 367-378 ◽  
Author(s):  
Estevão Urbinati ◽  
Rose M. Duda ◽  
Roberto A. de Oliveira
Keyword(s):  
Oxygen Demand ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
In Series ◽  
Two Stages ◽  
Uasb Reactors

In this study it was evaluated the effects of hydraulic retention time (HRT) and Organic Loading Rate (OLR) on the performance of UASB (Upflow Anaerobic Sludge Blanket) reactors in two stages treating residual waters of swine farming. The system consisted of two UASB reactors in pilot scale, installed in series, with volumes of 908 and 188 L, for the first and second stages (R1 and R2), respectively. The HRT applied in the system of anaerobic treatment in two stages (R1 + R2) was of 19.3, 29.0 and 57.9 h. The OLR applied in the R1 ranged from 5.5 to 40.1 kg CODtotal (m³ d)-1. The average removal efficiencies of chemical oxygen demand (COD) and total suspended solids (TSS) ranged, respectively, from 66.3 to 88.2% and 62.5 to 89.3% in the R1, and from 85.5 to 95.5% and 76.4 to 96.1% in the system (R1 + R2). The volumetric production of methane in the system (R1 + R2) ranged from 0.295 to 0.721 m³CH4 (m³ reactor d)-1. It was found that the OLR applied were not limiting to obtain high efficiencies of CODtotal and TSS removal and methane production. The inclusion of the UASB reactor in the second stage contributed to increase the efficiencies of CODtotal and TSS removal, especially, when the treatment system was submitted to the lowest HRT and the highest OLR.

Alternative biological systems for the treatment of vinasse from wine

2010 ◽  
Vol 62 (12) ◽  
pp. 2899-2904 ◽  
Author(s):  
A. Vlyssides ◽  
E. M. Barampouti ◽  
S. Mai ◽  
A. Stamatoglou ◽  
E. Tsimas
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Environmental Technology ◽  
Ferrous Sulfide ◽  
System 2 ◽  
Anaerobic Sludge Blanket ◽  
System 1

This work studied alternative treatment schemes for the vinasse wastewater from wine distilleries aiming at overcoming the problems caused by the high nitrogen and sulfur concentrations. A plexiglas laboratory-scale upflow anaerobic sludge blanket (UASB) reactor of 20 L volume that was operated at 45°C and hydraulic retention time 1 d, was included in all the examined systems. System 1 was the conventional UASB reactor, system 2 was the UASB reactor supplemented with iron. System 3 consisted of the UASB reactor supplemented with iron and a CSTR reactor that operated under the following conditions: Diluted Oxygen 1.2 mg/L, Hydraulic Retention Time 1 d, pH 6.7 and Temperature 45°C. System 3 aimed at converting ammonium directly to dinitrogen gas under anaerobic conditions but it needed to be preceeded by a first partial nitrification step. All systems had high COD efficiencies over 75%. Ferrous iron addition apart from enhancing the performance of systems 2 and 3, it was able to retain all sulphur content of the wastewater as ferrous sulfide stripping the biogas from hydrogen sulfide. System 3 also managed to meet its goal, since it achieved an 86% nitrogen reduction. Conclusively, system 3 seems to be a very promising environmental technology for the treatment of distillery and winery byproducts, as well as industrial wastewater with high sulfur and nitrogen content.

scholarly journals Performance Comparison of Conventional and Modified Upflow Anaerobic Sludge Blanket (UASB) Reactors Treating High-Strength Cattle Slaughterhouse Wastewater

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 806 ◽  
Author(s):  
Mohammed Ali Musa ◽  
Syazwani Idrus ◽  
Hasfalina Che Man ◽  
Nik Norsyahariati Nik Daud
Keyword(s):  
Oxygen Demand ◽  
High Strength ◽  
Performance Comparison ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Slaughterhouse Wastewater ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors

Cattle slaughterhouse wastewater (CSWW) with an average chemical oxygen demand (COD) and biochemical oxygen demand of 32,000 mg/L and 17,000 mg/L, respectively, can cause a severe environmental hazard if discharged untreated. Conventional upflow anaerobic sludge blanket (UASB) reactor is used in the treatment of slaughterhouse wastewater to meet the discharge standard limit of wastewater discharge set by the Department of Environment Malaysia (DOE). However, at higher loading rates the conventional systems are characterized by slow-growing microorganism resulting in long startup period, surface scum formation, and sludge washout. In this work, the performance of two laboratory scale (12 L) conventional (R1) and modified (R2) UASB reactors treating CSWW at mesophilic (36 ± 1 °C) condition were investigated. Both reactors were subjected to increasing organic loading rate (OLR) from 1.75 to 32 g L−1 day−1. The average COD, BOD5, and TSS removal efficiencies were ˃90%, at an OLR between 1.75 to 5 g L−1 day−1. The study revealed that R1 drastically reduced to 50, 53, and 43% with increasing OLR until 16 g L−1 day−1, whereas R2 maintained 76, 77, and 88% respectively, under the same OLR. Sign of reactor instability was very much pronounced in R1, showing poorly active Methanosaeta spp., whereas R2 showed a predominantly active Methanosarcina spp.

scholarly journals Assessment of the Treatment of Textile Mill Effluent Using UASB Reactor

2011 ◽  
Vol 28 (2) ◽  
pp. 139
Author(s):  
A Arshad ◽  
N.H Hashim ◽  
A.K Kashif ◽  
A Bashir
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Operating Conditions ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Optimum Operating ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Textile Mill ◽  
Volatile Fatty Acid Concentration

This study was designed to evaluate the feasibility of the treatment of actual textile mill effluent using a upflow anaerobic sludge blanket (UASB) reactor. The main objective of this study was to generate design aids; in terms of organic loading rate (OLR), hydraulic retention time (HRT) versus chemical oxygen demand (COD) and colour removal in the textile effluent using a UASB reactor at neutral pH and constant mesophilic temperature. The COD, colour and total suspended solids concentration of the textile wastes used in the study were analyzed as 5440 mg/l, 3280 mg/l, 2320 units and 955 mg/l, respectively. The UASB reactor was started up by gradually increasing the OLR from 0.2 kg-COD/m3-day to 2.6 kg-COD/m3-day in order to prevent an organic shock to the reactor. Similarly, the hydraulic retention time (HRT) was slowly reduced from 58 h to 8 h to prevent the wash-out of sludge from the reactor. It was observed that more than 80% of COD and colour could be effectively removed at an OLR of 2.2 kg-m3/d and HRT of 20 h. At optimum operating conditions, the effluent volatile fatty acid concentration was observed to be 430 mg/l. The average biogas production observed during this study was 0.34 l/g-CODremoved and it was composed of 58% methane. During the course of maturity of granular sludge, its effective size and settling velocity were observed to increase exponentially as 0.261e0.051x and 1.91e0.017x respectively. The overall observed biomass yield (Yobs) for the experimental period was calculated as 0.049 g-VSS/g-CODrem. This study suggests that the use of a UASB reactor for textile mill effluent is a fairly feasible and viable option. 

Influence of temperature and pH on nitrogen removal in a series of maturation ponds treating anaerobic effluent

2013 ◽  
Vol 67 (10) ◽  
pp. 2241-2248 ◽  
Author(s):  
Fernando Augusto Lopes de Assunção ◽  
Marcos von Sperling
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Hydraulic Retention Time ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Influence Of Temperature ◽  
Operational Conditions ◽  
Anaerobic Sludge Blanket ◽  
Influence Of Ph

This paper presents an evaluation of the influence of pH and temperature on nitrogen removal in a series of three shallow maturation ponds serving as post-treatment of upflow anaerobic sludge blanket (UASB) reactor effluent (approximately 200 population equivalent). Monitoring was from January 2007 to May 2009. Throughout this period, the ponds maintained relatively stable operational conditions in terms of depth and hydraulic retention time, thus enabling the evaluation of the influence of variations in temperature and pH on the performance in terms of nitrogen removal. In general, as expected, the removal of nitrogen was more effective when the temperature and pH of the ponds were higher, implying that these variables are relevant in the removal of nitrogen. Due to the fact that these parameters are included in the prediction equations for effluent ammonia and total nitrogen found in traditional models from the literature, fitting of the models to the experimental data was investigated. The models gave acceptable fittings in the estimation of effluent concentrations of ammonia and total nitrogen from maturation ponds treating UASB reactor effluent.

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