Kinetic Studies on a UASB Reactor Subjected to Increasing COD Concentration

1992 ◽  
Vol 25 (7) ◽  
pp. 103-111 ◽  
Author(s):  
D. R. Paula ◽  
E. Foresti
Keyword(s):  
Vertical Profile ◽  
Ammonium Acetate ◽  
Hydraulic Retention Time ◽  
Kinetic Studies ◽  
Uasb Reactor ◽  
Reactor Performance ◽  
Loading Rates ◽  
Overall Efficiency ◽  
Operation Parameters ◽  
Volumetric Loading

This paper shows the response of a UASB reactor subjected to increasing influent COD concentrations. The study was carried out using a 10.5 1 UASB reactor continuously operated during ten months, and fed with synthetic wastes prepared daily using glucose, ammonium acetate, methanol and nutrient solution. The. flow rate of 16 l.d−1 was held constant throughout the experiment, corresponding to a hydraulic retention time (θ) of 15.6 h. Four intermediate sampling ports besides the influent and effluent ones allowed a study of the reactor behaviour along its vertical profile. For average values of the initial COD concentrations ranging from 1780 to 9700 mg.l−1, corresponding to volumetric loading rates (BV) of 2.7 to 14.8 kg COD.m−3. d−1, COD removal efficiencies varying from 98 to 80% were achieved. It could be concluded that the step-increase of the influent COD affected the reactor performance in two different ways. First, the reactor could assimilate the shock loads due to the step-increase of the influent COD and BV beyond the transient periods following changes in the operation parameters. Second, the overall efficiency decreased gradually with the step-increase of the initial COD and BV. Kinetic studies indicate that the overall kinetic parameters are probably affected by the step-increase of influent COD concentrations.

Microbial community composition and reactor performance during hydrogen production in a UASB reactor fed with raw cheese whey inoculated with compost

2011 ◽  
Vol 64 (11) ◽  
pp. 2265-2273 ◽  
Author(s):  
E. Castelló ◽  
V. Perna ◽  
J. Wenzel ◽  
L. Borzacconi ◽  
C. Etchebehere
Keyword(s):  
Microbial Community ◽  
Hydrogen Production ◽  
Cheese Whey ◽  
Microbial Community Composition ◽  
Uasb Reactor ◽  
Hydrogen Yield ◽  
Reactor Performance ◽  
Loading Rates ◽  
Streptococcus A ◽  
Selection Of

This study investigated the microbial community developed in a UASB reactor for hydrogen production and correlated it to reactor performance. The reactor was inoculated with kitchen waste compost and fed with raw cheese whey at two organic loading rates, 20 gCOD/Ld and 30 gCOD/Ld. Hydrogen production was very variable, using an OLR of 30 gCOD/Ld averaged 1.0 LH2/Ld with no methane produced under these conditions. The hydrogen yield was also very variable and far from the theoretical. This low yield could be explained by selection of a mixed fermentative population with presence of hydrogen producing organisms (Clostridium, Ruminococcus and Enterobacter) and other non-hydrogen producing fermenters (Lactobacillus, Dialister and Prevotella). The molecular analysis of the raw cheese whey used for feeding revealed the presence of three predominant organisms that are affiliated with the genera Buttiauxella (a low-yield hydrogen producer) and Streptococcus (a lactic acid-producing fermenter). Although these organisms did not persist in the reactor, the continuous addition of these fermenters could decrease the reactor's hydrogen yield.

Denitrification in submerged biofilters of concentrated-nitrate wastewater

2001 ◽  
Vol 43 (1) ◽  
pp. 217-223 ◽  
Author(s):  
J. Oh ◽  
S. M. Yoon ◽  
J. M. Park
Keyword(s):  
Critical Point ◽  
Loading Rate ◽  
Biomass Concentration ◽  
Reactor Performance ◽  
Loading Rates ◽  
Space Saving ◽  
High Nitrate Concentration ◽  
Small Change ◽  
Biofilm Process ◽  
Volumetric Loading

To understand the possibilities and limitations of the treatment of concentrated nitrate in wastewater, a space-saving biofilm process was introduced to investigate how efficiently concentrated nitrate was utilized in a biofilm process. Lab-scale submerged biofilters stuffed with plastic pall-ring media were developed for the treatment of wastewater containing high nitrate concentration. Two identical biofilters were operated at 2 and 4 hr media HRT in parallel and the concentration of nitrate in the influent was increased stepwise from 50 to 3000 mg-N/L. The concentration of NOx in the effluent was measured at various volumetric loading rates that were proportional to influent nitrate concentrations. There was a critical point for volumetric loading rate (9 kg NO3–N/m3/day) distinguishing the biofilter performances. At the volumetric loading rate below this critical point, the effluent NOx concentration was maintained steadily in spite of the drastic change in the loading rates. However, the effluent NOx concentration severely fluctuated for the small change when the loading rate was higher than the critical point. It was found that the reactor performance was closely related with the biomass concentration (g-dw/ring) in the biofilters.

Coarse filters for pond effluent polishing: comparison of loading rates and grain sizes

2007 ◽  
Vol 55 (11) ◽  
pp. 121-126 ◽  
Author(s):  
M. von Sperling ◽  
J.G.B. de Andrada ◽  
W.R. de Melo Júnior
Keyword(s):  
Loading Rate ◽  
Uasb Reactor ◽  
E Coli ◽  
Effluent Quality ◽  
Loading Rates ◽  
Hydraulic Loading ◽  
Grain Sizes ◽  
Belo Horizonte ◽  
The City ◽  
Rock Size

A system comprising a UASB reactor, shallow polishing ponds and shallow coarse filters, treating actual wastewater from the city of Belo Horizonte, Brazil, has been evaluated. The main focus of the research was to compare grain sizes and hydraulic loading rates in the coarse filters. Two filters operating in parallel were investigated, with the following grain sizes: Filter 1: 3 to 10 cm; Filter 2: 8 to 20 cm. Two hydraulic loading rates were tested: 0.5 and 1.0 m3/m3.d. The filter with the lower rock size had a better performance than the filter with the larger rock size in the removal of SS and, as a consequence, BOD and COD. A better performance was obtained with the hydraulic loading rate of 0.5 m3/m3.d, as compared to the rate of 1.0 m3/m3.d. The effluent quality during the period with the lower loading rate was very good for discharge into water bodies or for agricultural reuse (median effluent concentrations from Filter 1: BOD: 20 mg/L; COD: 106 mg/L; SS: 28 mg/L; E. coli: 528 MPN/100 mL).

Application of the UASB-Reactor for Anaerobic Treatment of Paper and Board Mill Effluent

1985 ◽  
Vol 17 (1) ◽  
pp. 61-75 ◽  
Author(s):  
L H A Habets ◽  
J H Knelissen
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Energy Savings ◽  
Hydraulic Retention Time ◽  
Waste Water Treatment ◽  
Anaerobic Treatment ◽  
Raw Material ◽  
Uasb Reactor ◽  
Seed Sludge ◽  
Uasb Reactors

Within the holding of Bührmann-Tetterode NV, 7 Dutch paper and board mills are operating, all of them using mainly waste paper as raw material. While three of them completely closed their watercircuits, two other mills put into practice biological waste water treatment namely anaerobic and anaerobic/aerobic. Number 6 is realising an anaerobic plant this year and for number 7 research is still being carried out, dealing with several unfavourable aspects. In September 1981 research for anaerobic treatment (UASB reactors) was started. After good results had been achieved on laboratory scale (301), further investigations were started on semitechnical scale (50 m3). In both cases the anaerobic seed sludge granulated after a while and loadings up to 20 kg COD/m3.d could be handled. COD-removal was 70 per cent, even when the hydraulic retention time was only 2.5 hours. In April 1983 a 70 m3 practical scale UASB reactor was started up at the solid board mill of Ceres. In October 1983 a full scale plant was started up at Papierfabriek Roermond. This plant consists of a 1,000 m3 UASB reactor and a 70 m3 gasholder. It has been designed and constructed by Paques BV and is used for pretreatment of effluent, in order to reduce the loading of the activated sludge plant. Besides energy savings on the oxygen input, about 1 million m3/year of biogas is being generated and is used for steamproduction. Both plants are working satisfactorily. Investment costs appeared to be relatively low. At Ceres, pay-out time is 1.5 year, while at Papierfabriek Roermond waste water treatment is cheaper than before, although capacity is doubled.

Long-term performance of a UASB reactor treating acid mine drainage: effects of sulfate loading rate, hydraulic retention time, and COD/SO42− ratio

2018 ◽  
Vol 30 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Mirabelle Perossi Cunha ◽  
Rafael Marçal Ferraz ◽  
Giselle Patrícia Sancinetti ◽  
Renata Piacentini Rodriguez
Keyword(s):  
Acid Mine Drainage ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Mine Drainage ◽  
Uasb Reactor ◽  
Acid Mine ◽  
Long Term Performance ◽  
Term Performance

scholarly journals Simple estimation of granule size distribution and sludge bed porosity in a UASB reactor

2013 ◽  
Vol 10 (1) ◽  
pp. 73-79
Keyword(s):  
Size Distribution ◽  
Granular Sludge ◽  
Granule Size ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
Efficient Operation ◽  
Mathematical Algorithm ◽  
Bed Porosity

Granular sludge is the key factor for an efficient operation of an upflow anaerobic sludge blanket (UASB) reactor. In order to monitor the granularity of anaerobic sludge, the determination of the granule size distribution is of vital importance. Another critical parameter for the UASB reactor performance is the sludge bed porosity. For this reason, several techniques have been proposed, however they are either tedious, imprecise or expensive and hardly applicable in full scale treatment plants. There was then the need for a simple and low cost technique. This technique involves the determination of the settling velocities of a sludge sample and of extrapolating the corresponding diameters using a mathematical algorithm. In the proposed algorithm, the granules density was calculated, the flow regime was examined and finally the granule size distribution was obtained. Some very important correlations were suggested by the experimental results. The granule density and diameter as well as the sludge bed porosity were strongly correlated with the VSS/TSS ratio.

scholarly journals The Concept of Wastes to Energy Using Sugary Wastes

2012 ◽  
Vol 9 ◽  
pp. 57-62
Author(s):  
Fiza Sarwar ◽  
Wajeeha Malik ◽  
Muhammad Salman Ahmed ◽  
Harja Shahid
Keyword(s):  
Volatile Fatty Acids ◽  
Loading Rate ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Loading Rates ◽  
Sugar Mills ◽  
Anaerobic Sludge Blanket

Abstract: This study was designed using actual effluent from the sugary mills in an Up-flow Anaerobic Sludge Blanket (UASB) Reactor to evaluate treatability performance. The reactor was started-up in step-wise loading rates beginning from 0.05kg carbon oxygen demand (COD)/m3-day to 3.50kg-COD/m3-day. The hydraulic retention time (HRT) was slowly decreased from 96 hrs to eight hrs. It was observed that the removal efficiency of COD of more than 73% can be easily achieved at an HRT of more than 16 hours corresponding to an average organic loading rate (OLR) of 3.0kg-COD/m3-day, at neutral pH and constant temperature of 29°C. The average VFAs (volatile fatty acids) and biogas production was observed as 560mg/L and 1.6L/g-CODrem-d, respectively. The average methane composition was estimated as 62%. The results of this study suggest that the treatment of sugar mills effluent with the anaerobic technology seems to be more reliable, effective and economical.DOI: http://dx.doi.org/10.3126/hn.v9i0.7075 Hydro Nepal Vol.9 July 2011 57-62

Simultaneous toxicity and nutrient removals in simulated DEPHANOX (anaerobic/anoxic/oxic sequentials) process treating dinitrotoluene and trichlorotoluene

2004 ◽  
Vol 49 (5-6) ◽  
pp. 237-244
Author(s):  
D.T. Sponza ◽  
H. Atalay
Keyword(s):  
Phosphorus Uptake ◽  
Uasb Reactor ◽  
Toxicity Tests ◽  
Methanogenic Activity ◽  
Anoxic Conditions ◽  
Toxic Organics ◽  
Sequential Treatments ◽  
Volumetric Loading ◽  
Completely Stirred Tank Reactor ◽  
Cstr System

A modified DEPHANOX process including two upflow sludge blanket reactors (USB) (anaerobic-upflow sludge blanket -UASB and anoxic-upflow anoxic sludge blanket -UANSB) and one completely stirred tank reactor (CSTR system was simulated in order to detect the simultaneous removal of dinitrotoulene (DNT), trichlorotoluene (TCT), and nutrients. The phosphorus uptake and nitrification was excessively determined in aerobic CSTR reactor. Influent DNT was transformed to toluene, NH4-N and total aromatic amines (TAA) while TCT was transformed to toluene and dichlorotoluene (DCT) under anaerobic and anoxic conditions. Increasing the volumetric loading rate of DNT and TCT from 18 mg/L.day and 0.35 g/L.day to 60 mg/l.day and 1.2 g/L.day, respectively, resulted in higher COD conversion (70-80%) rates and methane productions (250-300 ml/day) in anaerobic reactor. 90% NO3-N and 87% PO4-P were achieved in anoxic and aerobic reactors at DNT and TCT loading rates as high as 40-60 mg/L.day and 0.8-1.2 g/L.day, respectively. The TAA produced under anaerobic and anoxic conditions were ultimately removed under the aerobic stage. The UASB and anoxic UASB reactor effluents were less toxic relative to the influent when analyzed by anaerobic toxicity tests and specific methanogenic activity tests, indicating that such anaerobic/anoxic aerobic sequential treatments could be able to reduce toxic organics together with nutrient removal.

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