Sludge deterioration in a full scale UASB reactor after a pH drop working under low loading conditions

2008 ◽  
Vol 57 (5) ◽  
pp. 797-802 ◽  
Author(s):  
L. Borzacconi ◽  
I. López ◽  
M. Passeggi ◽  
C. Etchebehere ◽  
R. Barcia
Keyword(s):  
Removal Efficiency ◽  
Biogas Production ◽  
Industrial Process ◽  
Full Scale ◽  
Cod Removal ◽  
Normal Operation ◽  
Uasb Reactor ◽  
Organic Load ◽  
Reactor Performance ◽  
Cod Removal Efficiency

A full scale UASB reactor treating the effluent of a malting plant was operated during nearly two years. During 37 weeks of operation the reactor worked with a COD removal efficiency of 80% and a biogas production of nearly 300 m3/d with a methane content of 77%. After the start up and during these months of operation the volumetric organic load was 4 kgCOD/m3.d and the specific organic load was between 0.2–0.4 kgCOD/kgVSS.d. The sludge SMA in this period was around 0.25 kgCOD/kg VSS.d. On week 37 as a result of a problem at the industrial process the pH in the reactor dropped to a value of 4.8. After pH recovering, the reactor worked with fluctuating COD values in the exit and showed a downward trend in the COD removal efficiency. On week 81 the presence of filaments in the granules was detected. High proportion of Chloroflexi filaments were detected by FISH in the sludge. Changes in the microbial population caused by the low pH probably destabilize the reactor performance. The presence of filamentous granules in the sludge and its further growing could be encouraged by the pH drop and the low specific organic load applied to the reactor. The low specific organic load was a consequence of the high VSS content in the UASB reactor, due to the lack of purges. The length of the filaments attached to the granules grew throughout time. In order to eliminate the sludge with poor settlement properties a recycle was applied to the reactor. As a consequence, low amount of granular sludge stayed in the reactor. At the end, COD concentration in the influent reached higher values than in normal operation; at the same time a complete sludge wash out occurred. On the other hand, using the same sludge (after the recycle implementation) in a bench scale reactor the good properties of the sludge were completely recovered.

Effect of trace metals on the anaerobic degradation of volatile fatty acids in molasses stillage

1995 ◽  
Vol 32 (12) ◽  
pp. 121-129 ◽  
Author(s):  
A. Espinosa ◽  
L. Rosas ◽  
K. Ilangovan ◽  
A. Noyola
Keyword(s):  
Trace Metals ◽  
Propionic Acid ◽  
Removal Efficiency ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Cod Removal ◽  
Uasb Reactor ◽  
Organic Load ◽  
Methanogenic Activity ◽  
Cod Removal Efficiency

A laboratory UASB reactor was fed with cane molasses stillage at organic loadings from 5 to 21.5 kg COD/m3 d. With an organic load of 17.4 kg COD/m3 d, an accumulation of VFA, principally propionic acid, was observed due to little bioavailability or lack of trace metals (Fe, Ni, Co and Mo). Associated to this, the performance of the UASB reactor was low (44% COD removal efficiency), with an alkalinity ratio above 0.4. The addition of Fe (100 mg/l), Ni (15 mg/l), Co (10 mg/l) and Mo (0.2 mg/l) to the influent reduced significantly the level of propionic acid (5291mg/l to 251 mg/l) and acetic acid (1100 mg/l to 158 mg/l). The COD removal efficiency increased from 44% to 58%, the biogas production from 10.7 to 14.8 l/d (NTP) and 0.085 to 0.32 g CH4-COD/g SSV d for specific sludge methanogenic activity with propionic acid as substrate. These improved results were obtained with high COD (68.9 g/l) and organic load (21.5 kg COD/m3 d).

UASB-reactor in the fruit juice industry

1997 ◽  
Vol 36 (6-7) ◽  
pp. 407-414 ◽  
Author(s):  
Ute Austermann-Haun ◽  
Carl Franz Seyfried ◽  
Karl-Heinz Rosenwinkel
Keyword(s):  
Removal Efficiency ◽  
Industrial Wastewater ◽  
Fruit Juice ◽  
Loading Rate ◽  
Full Scale ◽  
Cod Removal ◽  
Uasb Reactor ◽  
Cod Removal Efficiency ◽  
Pre Treatment ◽  
Volumetric Loading

This paper presents experiences with a full scale UASB-reactor in a fruit juice factory. The focus is on demonstrating that a UASB-reactor is as suitable for campaign industries running only 2 months a year with higher concentrated wastewater as well as for the time outside the campaign when the wastewater concentrations are very low (average COD 1000 mg/l). A number of operating results and recommendations are given, resulting from the experiences in order to show solutions for handling these very different situations. Examples of recommendations are: discontinuous feeding 8 hours a day outside the campaign, removal of pellet sludge at the end of the campaign. These frame conditions provided a COD removal efficiency in the UASB-reactor consistently above 80% throughout the year. Furthermore, it is shown that the anaerobic pre-treatment of industrial wastewater is the cheapest way in regard to the running expenses. Another point of research was the co-fermentation of the kieselguhre-sludge-mixture. Although only 10% of the load was based on this substrate at a volumetric loading rate of 3 kg COD/(m3 · d), there was a quick drop in pH to a level of 3.5 and the pellet structure of the biomass got lost.

scholarly journals UASB Performance and Perspectives in Urban Wastewater Treatment at Sub-Mesophilic Operating Temperature

Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 115
Author(s):  
Daniele Cecconet ◽  
Arianna Callegari ◽  
Andrea G. Capodaglio
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Biogas Production ◽  
Operating Temperature ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
Uasb Reactor ◽  
Urban Wastewater ◽  
Cod Removal Efficiency

UASBs present several advantages compared to conventional wastewater treatment processes, including relatively low construction cost facilities, low excess sludge production, plain operation and maintenance, energy generation in the form of biogas, robustness in terms of COD removal efficiency, pH stability, and recovery time. Although anaerobic treatment is possible at every temperature, colder climates lead to lower process performance and biogas production. These factors can be critical in determining the applicability and sustainability of this technology for the treatment of urban wastewater at low operating temperature. The purpose of this study is the performance evaluation of a pilot-scale (2.75 m3) UASB reactor for treatment of urban wastewater at sub-mesophilic temperature (25 °C), below the optimal range for the process, as related to biogas production and organic matter removal. The results show that, despite lower methane production and COD removal efficiency compared to operation under ideal conditions, a UASB can still achieve satisfactory performance, and although not sufficient to grant effluent discharge requirements, it may be used as a pretreatment step for carbon removal with some degree of energy recovery. Options for UASB pretreatment applications in municipal WWTPs are discussed.

scholarly journals Investigation of Heavy Metal Effects on the Anaerobic Co-Digestion Process of Waste Activated Sludge and Septic Tank Sludge

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Quang-Minh Nguyen ◽  
Duy-Cam Bui ◽  
Thao Phuong ◽  
Van-Huong Doan ◽  
Thi-Nham Nguyen ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Biogas Production ◽  
Cod Removal ◽  
Septic Tank ◽  
Waste Activated Sludge ◽  
Digestion Process ◽  
Cod Removal Efficiency

The effect of copper, zinc, chromium, and lead on the anaerobic co-digestion of waste activated sludge and septic tank sludge in Hanoi was studied in the fermentation tests by investigating the substrate degradation, biogas production, and process stability at the mesophilic fermentation. The tested heavy metals were in a range of concentrations between 19 and 80 ppm. After the anaerobic tests, the TS, VS, and COD removal efficiency was 4.12%, 9.01%, and 23.78% for the Cu(II) added sample. Similarly, the efficiencies of the Zn(II) sample were 1.71%, 13.87%, and 16.1% and Cr(VI) efficiencies were 15.28%, 6.6%, and 18.65%, while the TS, VS, and COD removal efficiency of the Pb(II) added sample was recorded at 16.1%, 17.66%, and 16.03% at the concentration of 80 ppm, respectively. Therefore, the biogas yield also decreased by 36.33%, 31.64%, 31.64%, and 30.60% for Cu(II), Zn(II), Cr(VI), and Pb(II) at the concentration of 80 ppm, compared to the raw sample, respectively. These results indicated that Cu(II) had more inhibiting effect on the anaerobic digestion of the sludge mixture than Zn(II), Cr(VI), and Pb(II). The relative toxicity of these heavy metals to the co-digestion process was as follows: Cu (the most toxic) > Zn > Cr > Pb (the least toxic). The anaerobic co-digestion process was inhibited at high heavy metal concentration, which resulted in decreased removal of organic substances and produced biogas.

Biological wastewater treatment for removal of polymeric resins in UASB reactor: influence of oxygen

2008 ◽  
Vol 57 (7) ◽  
pp. 1047-1052 ◽  
Author(s):  
U. Durán ◽  
O. Monroy ◽  
J. Gómez ◽  
F. Ramírez
Keyword(s):  
Acrylic Acid ◽  
Vinyl Acetate ◽  
Removal Efficiency ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Uasb Reactor ◽  
Cod Removal Efficiency ◽  
Consumption Rates ◽  
Polymeric Resins

The biological elimination of polymeric resins compounds (PRC) such as acrylic acid and their esters, vinyl acetate and styrene under methanogenic and oxygen-limited methanogenesis conditions was evaluated. Two UASB reactors (A and B) were used and the removal of the organic matter was studied in four stages. Reactor A was used as methanogenic control during the study. Initially both reactors were operated under methanogenic conditions. From the second stage reactor B was fed with 0.6 and 1 mg/L·d of oxygen (O2). Reactor A had diminution in chemical oxygen demand (COD) removal efficiency from 75±4% to 37±5%, by the increase of PRC loading rate from 750 to 1125 mg COD/L·d. In this reactor there was no styrene elimination. In reactor B the COD removal efficiency was between 73±5% and 80±2%, even with the addition of O2 and increase of the PRC loading rate, owing to oxygen being used in the partial oxidation of these compounds. In this reactor the yields were modified from 0.56 to 0.40 for CH4 and from 0.31 to 0.60 for CO2. The O2 in low concentrations increased 40.7% the consumption rates of acrylic acid, methyl acrylate and vinyl acetate, allowing styrene consumption with a rate of 0.103 g/L·d. Batch cultures demonstrated that under methanogenic and oxygen-limited methanogenesis conditions, the glucose was not used as an electron acceptor in the elimination of PRC.

Effective Anaerobic Bio-Treatment of Fresh Leachate From Municipal Solid Waste Incineration Plant by Full-Scale Internal Circulation Reactor

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Tao Wang ◽  
Zhenxing Huang ◽  
Hongyan Ren ◽  
Hengfeng Miao ◽  
Minxing Zhao ◽  
...  
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Removal Efficiency ◽  
Full Scale ◽  
Cod Removal ◽  
Anaerobic Sludge ◽  
Internal Circulation ◽  
Biogas Yield ◽  
Cod Removal Efficiency ◽  
Effluent Recirculation

This study aimed to investigate the effectiveness of the full-scale internal circulation (IC) reactor in biodegrading of municipal solid waste (MSW) fresh leachate under mesophilic conditions, where the anaerobic process stability, biogas yield, and sludge granulation were intensively investigated. The effects of operational parameters on the influent organic loading rate (OLR), chemical oxygen demand (COD) removal efficiency, alkalinity (ALK), pH, volatile fatty acids (VFAs) accumulation, and effluent recirculation were also studied. The results showed that the reactor operated stably and effectively. The COD removal efficiency and biogas yield could be maintained at (92.8 ± 2.0)% and (0.47 ± 0.05) m3/kg CODremoval, respectively, with the influent OLR (24.5 ± 0.9) kg COD/(m3 d) and hydraulic retention time (HRT) 2.7d during the stable operation phase. Meanwhile, this study demonstrated that 1.5–3.0 m/h would be the optimal Vup for the reactor, corresponding to the effluent recirculation of 32.5–78.0 m3/h. Moreover, it was found that the content of extracellular polymeric substances (EPS) in the anaerobic sludge increased from 50.3 to 140.7 mg/g volatile suspended solids (VSS), and the sludge had good granular performance during the reactor operation.

Phenolic refinery wastewater biodegradation by an expanded granular sludge bed reactor

2005 ◽  
Vol 52 (1-2) ◽  
pp. 391-396 ◽  
Author(s):  
F.J. Almendariz ◽  
M. Meraz ◽  
A.D. Olmos ◽  
O. Monroy
Keyword(s):  
Toxic Effect ◽  
Removal Efficiency ◽  
Methane Production ◽  
Granular Sludge ◽  
Cod Removal ◽  
Organic Load ◽  
Refinery Wastewater ◽  
Mineral Supplements ◽  
Cod Removal Efficiency

Refinery spent caustics (SC) were diluted with sour waters (SW) in a ratio 1:7, neutralized with CO2 (SC/SWCO2) and 83% of H2S was striped during this procedure, remaining an aromatic portion that contained 2123, 2730 and 1379 mg L−1 of phenol, p-cresol and o-cresol, respectively. The mixture was treated anaerobically in an EGSB reactor fed with 1.5 gCOD L−1 d−1, without mineral supplements causing loss of COD removal efficiency that dropped to 23%, methane production ceased and no phenol or cresols were biodegraded. The EGSB experiments were resumed by feeding the reactor with nutrients and phenol at 1.0 gCOD L−1 d−1. The mixture SC/SWCO2 added to the phenol load, was step increased from 0.10 to 0.87 gCOD L−1 d−1 maximum. When total organic load was increased to 1.6, COD removal efficiency was 90% and at the highest load attained, 1.87, efficiency dropped to 23% attributed to the toxic effect produced by cresols.

Two examples of anaerobic pre-treatment of wastewater in the beverage industry

1997 ◽  
Vol 36 (2-3) ◽  
pp. 311-319 ◽  
Author(s):  
Ute Austermann-Haun ◽  
Karl-Heinz Rosenwinkel
Keyword(s):  
Removal Efficiency ◽  
Fruit Juice ◽  
Anaerobic Treatment ◽  
Full Scale ◽  
Cod Removal ◽  
Load Variations ◽  
Cod Removal Efficiency ◽  
Beverage Industry ◽  
Pre Treatment ◽  
Uasb Reactors

Two examples of full scale UASB-reactors in a fruit juice factory and a brewery are given. In both cases, the design was based on semi-technical tests. Although the wastewater concentrations are rather similar and move within a low range, the parts of the anaerobic treatment plants and their design are different. In both cases, the COD removal efficiency in the UASB-reactors is consistently above 80%. It becomes apparent that UASB-reactors are very suitable for industries with seasonal load variations. The co-fermentation of a kieselguhre-sludge-mixture was tested in lab-scale experiments. It became obvious that the pellet structure of the biomass gets lost. Furthermore, it is shown that the running expenses of anaerobic pre-treatment are very low, even when combined with an aerobic stage.

Study on Granulation of Anaerobic Sludge in UASB Reactor Adding Cationic Polymer Treating Low Strength Wastewater at Room Temperature

2011 ◽  
Vol 71-78 ◽  
pp. 2974-2977 ◽  
Author(s):  
Zong Lian She ◽  
Jian Wu ◽  
Xiao Hui Fu ◽  
En Shi ◽  
Bao Shi Li ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Room Temperature ◽  
Control Experiment ◽  
Cationic Polymer ◽  
Cod Removal ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Cod Removal Efficiency ◽  
Low Strength ◽  
To Receive

Effect of cationic polymer on granulation and COD removal efficiency in lab scale UASB reactors was examined, treating low-strength wastewater (COD 300-500mg l-1) at room temperature. It was shown that cationic polymer was more effective for enhancing sludge granulation and COD removal efficiency as compared to the control experiment (without additives). After day 166 of operation, the amount of granules size above 0.5mm accounted for 32.1% of total sludge, higher than that of control experiment (19.3%). At 1.03 kg COD m-3 d-1 of OLR and 9.8 h of HRT, the effluent VFA had a maximum value of 168mg l-1 and 240mg l-1 in Reactor A and B respectively. The polymer-amended reactor took 36days to receive 1.44 kg COD m-3 d-1 of OLR at the 7.8 h of HRT, shorter than the control reactor (54days). The two reactors obtained above 80% in COD removal efficiency. It is shown that UASB reactor can also achieve higher COD removal treating low strength wastewater at room temperature.

Quali-quantitative characterization and wastewater treatment of a winery located in the mid-west of Santa Catarina state, South of Brazil

2009 ◽  
Vol 60 (4) ◽  
pp. 1025-1031 ◽  
Author(s):  
A. R. C. Ortigara ◽  
P. H. Sezerino ◽  
A. P. Bento ◽  
D. Scaratti
Keyword(s):  
Removal Efficiency ◽  
Cod Removal ◽  
Organic Load ◽  
Water Usage ◽  
Quantitative Characterization ◽  
Cod Removal Efficiency ◽  
Production Values ◽  
Production Area ◽  
South Of Brazil

This paper analyses variations in the quali-quantitative characterization of winery wastewater, and the behavior of the treatment of these effluents. The wastewater produced is sent to two disposition systems: Point A receives the wastewater from the production area whereas Point B receives the wastewater from the area where the washing of bottles takes place. Two Aerated Submerged Biofilter (ASB) reactors (with oyster shells as support material) were built at lab scale to promote the treatment of the winery effluent. Water usage and effluent production values of the 2008 harvest season indicate that grape processing accounted for 30% of the total water usage. The median value found for the effluent at Point A was 8,260 mg COD L−1 and at Point B 358 mg COD L−1. The average C/N/P ratio found at Point A was 100/0.29/0.28 during the harvest and 100/0.27/0.25 during the non harvest. For ASB 1 the COD removal efficiency ranged from 56% to 90%, with the removed organic load ranging from 1.5 kg COD m−3 d−1 to 2.7 kg COD m−3 d−1, respectively. For ASB 2 the COD removal efficiency ranged from 63% to 82%, with the removed organic load ranging from 1.8 kg COD m−3 d−1 to 1.7 kg COD m−3 d−1, respectively.

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