Modeling simultaneous removal of primary substrates and chlorinated phenols in upflow anaerobic sludge blanket reactors

2001 ◽  
Vol 28 (6) ◽  
pp. 910-921 ◽  
Author(s):  
K J Kennedy ◽  
Z Ning ◽  
L Fernandes
Keyword(s):  
Dynamic Model ◽  
Model Development ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Chlorinated Phenols ◽  
Degradation Rates ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors

A dynamic model describing the simultaneous degradation of easily degradable substrates (sucrose and acetic acid (HAc)) and 2,4-dichlorophenol (2,4-DCP) in upflow anaerobic sludge blanket (UASB) reactors was developed. The two critical factors considered in the model development were sorption and substrate interaction during degradation. Data obtained from experiments on the multiple substrate degradation in continuous UASB reactors were used to validate and verify the dynamic model. The model predicts the system responses for 2,4-DCP, 4-monochlorophenol (4-MCP), HAc, propionic acid (HPr), and chemical oxygen demand (COD) concentration in the effluent. The modeling results indicated that the degradation rates for 2,4-DCP and for cosubstrates, HAc and HPr, changed inversely as a function of the specific organic loading rate for UASB reactors.Key words: dynamic, modeling, UASB, 2,4-dichlorophenol, sorption, degradation, co-metablism.

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.

Toxicity and treatability of leachate: application of UASB reactor for leachate treatment from Okhla landfill, New Delhi

2012 ◽  
Vol 65 (10) ◽  
pp. 1887-1894 ◽  
Author(s):  
V. Singh ◽  
A. K. Mittal
Keyword(s):  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
New Delhi ◽  
Leachate Treatment ◽  
Feed Composition ◽  
Laboratory Scale Reactor ◽  
Anaerobic Sludge Blanket

This study reports applicability of upflow anaerobic sludge blanket (UASB) process to treat the leachate from a municipal landfill located in Delhi. A laboratory scale reactor was operated at an organic loading rate of 3.00 kg chemical oxygen demand (COD)/m3 d corresponding to a hydraulic retention time (HRT) of 12 h for over 8 months. The effect of toxicity of leachate, and feed composition on the treatability of leachate was evaluated. Average COD of the leachate, during the study period varied between 8,880 and 66,420 mg/l. Toxicity of the leachate used during a period of 8 months varied from LC50 1.22 to 12.35 for 96 h. The removal efficiency of soluble COD ranged between 91 and 67% for fresh leachate and decreased drastically from 90 to 35% for old leachate having high toxicity. The efficiency varied from 81 to 65%. The reactor performed more efficiently for the treatment of fresh leachate (less toxic, LC50 11.64, 12.35, and 12.15 for 96 h) as compared with old leachate (more toxic, LC50 1.22 for 96 h). Toxicity of the leachate affected its treatment potential by the UASB.

Mathematical modeling of upflow anaerobic sludge blanket (UASB) reactor treating domestic wastewater

2013 ◽  
Vol 67 (1) ◽  
pp. 24-32 ◽  
Author(s):  
Tarek Elmitwalli
Keyword(s):  
Chemical Oxygen Demand ◽  
Dynamic Model ◽  
Empirical Model ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Model Based ◽  
Anaerobic Sludge Blanket

Although the upflow anaerobic sludge blanket (UASB) reactor has been widely applied for domestic wastewater treatment in many developing countries, there is no sufficient mathematical model for proper design and operation of the reactor. An empirical model based on non-linear regression was developed to represent the physical and chemical removal of suspended solids (SS) in the reactor. Moreover, a simplified dynamic model based on ADM1 and the empirical model for SS removal was developed for anaerobic digestion of the entrapped SS and dissolved matter in the wastewater. The empirical model showed that effluent suspended chemical oxygen demand (CODss) concentration is directly proportional to the influent CODss concentration and inversely proportional to both the hydraulic retention time (HRT) of the reactor and wastewater temperature. For obtaining sufficient CODss removal, the HRT of the UASB reactor must be higher than 4 h, and higher HRT than 12 h slightly improved CODss removal. The dynamic model results showed that the required time for filling the reactor with sludge mainly depends on influent total chemical oxygen demand (CODt) concentration and HRT. The influent CODt concentration, HRT and temperature play a crucial role on the performance of the reactor. The results indicated that shorter HRT is needed for optimization of CODt removal, as compared with optimization of CODt conversion to methane. Based on the model results, the design HRT of the UASB reactor should be selected based on the optimization of wastewater conversion and minimization of biodegradable SS accumulation in the sludge bed, not only based on COD removal, to guarantee a stable reactor performance.

Degradation of chlorinated aromatic compounds in UASB reactors

1995 ◽  
Vol 31 (1) ◽  
pp. 249-259 ◽  
Author(s):  
Nina Christiansen ◽  
Hanne V. Hendriksen ◽  
Kimmo T. Järvinen ◽  
Birgitte K. Ahring
Keyword(s):  
Metabolic Pathways ◽  
Granular Sludge ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Ring Cleavage ◽  
Anaerobic Sludge ◽  
Chlorinated Phenols ◽  
Desulfomonile Tiedjei ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors

Data on anaerobic degradation of chloroaromatic compounds in Upflow Anaerobic Sludge Blanket Reactors (UASB-reactor) are presented and compared. Special attention is given to the metabolic pathways for degradation of chlorinated phenols by granular sludge. Results indicate that PCP can be degraded in UASB-reactors via stepwise dechlorination to phenol. Phenol will subsequently be converted to benzoate before ring cleavage. Dechlorination proceeds via different pathways dependent upon the inocula used. Results are further presented on the design of special metabolic pathways in granules which do not possess this activity using the dechlorinating organism, Desulfomonile tiedjei. Additionally, it is shown that it is possible to immobilize Dechlorosporium hafniense, a newly isolated dechlorinating anaerobe, into granular sludge, thereby introducing an ability not previously present in the granules.

scholarly journals Black water treatment by an upflow anaerobic sludge blanket (UASB) reactor: a pilot study

2019 ◽  
Vol 80 (8) ◽  
pp. 1505-1511 ◽  
Author(s):  
Nathalie Dyane Miranda Slompo ◽  
Larissa Quartaroli ◽  
Grietje Zeeman ◽  
Gustavo Henrique Ribeiro da Silva ◽  
Luiz Antonio Daniel
Keyword(s):  
Removal Efficiency ◽  
Phase 1 ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Phase 3 ◽  
Black Water ◽  
Anaerobic Sludge Blanket

Abstract Decentralized sanitary wastewater treatment has become a viable and sustainable alternative, especially for developing countries and small communities. Besides, effluents may present variations in chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total nitrogen values. This study describes the feasibility of using a pilot upflow anaerobic sludge blanket (UASB) reactor to treat wastewater with different organic loads (COD), using black water (BW) and sanitary wastewater, in addition to its potential for preserving nutrients for later recovery and/or reuse. The UASB reactor was operated continuously for 95 weeks, with a hydraulic retention time of 3 days. In Phase 1, the reactor treated simulated BW and achieved 77% CODtotal removal. In Phase 2, treating only sanitary wastewater, the CODtotal removal efficiency was 60%. Phase 3 treated simulated BW again, and CODtotal removal efficiency was somewhat higher than in Phase 1, reaching 81%. In Phase 3, the removal of pathogens was also evaluated: the efficiency was 1.96 log for Escherichia coli and 2.13 log for total coliforms. The UASB reactor was able to withstand large variations in the organic loading rate (0.09–1.49 kg COD m−3 d−1), in continuous operation mode, maintaining a stable organic matter removal.

Startup of thermophilic (55°C) UASB reactors using different mesophilic seed sludges

1996 ◽  
Vol 34 (5-6) ◽  
pp. 445-452 ◽  
Author(s):  
Herbert H. P. Fang ◽  
Ivan W. C. Lau
Keyword(s):  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Methanogenic Activity ◽  
The Third ◽  
Uasb Granules ◽  
Thermophilic Condition ◽  
Anaerobic Sludge Blanket ◽  
The Impact ◽  
Uasb Reactors

Performances during startup of three 2.8-litre UASB (upflow anaerobic sludge blanket) reactors operated under thermophilic condition were investigated. All reactors were seeded with mesophilic sludges: one with flocculent digester sludge (Reactor-F), another with UASB granules (Reactor-G), and the third with disintegrated granules (Reactor-D). The reactors were operated in parallel at 55°C and 24 hours of retention time, using sucrose and milk as substrate at COD (chemical oxygen demand) loadings up to 10 g-COD/l·day. Immediately after temperature was step-increased from 37°C to 55°C, all reactors encountered sludge washout and deterioration of COD removal efficiency; however, the impact of temperature increase was more severe on Reactor-F. Sludge granulation took place in all reactors; first granules became noticeable after 45 days in Reactor-D, and after 90 days in Reactor-F. Reactor-G and Reactor-D were capable of removing 95% of soluble COD after 75 days, while Reactor-F after 110 days. Throughout this study, there was little difference in performance between Reactors G and D. The thermophilic granule were estimated to have a yield of 0.099 g-VSS/g-COD, and a methanogenic activity of 0.71-1.55 g-methane-COD/g-VSS·day, comparable to that of mesophilic granules.

Toxicity of Sodium and Potassium Ions on Performance of UASB System

2014 ◽  
Vol 953-954 ◽  
pp. 1105-1108 ◽  
Author(s):  
Seni Karnchanawong ◽  
Kraiwet Kabtum
Keyword(s):  
Biogas Production ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Synthetic Wastewater ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Working Volume ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors ◽  
Sodium And Potassium

The objective of this study was to investigate the toxicity of Na+and K+ions on performance of upflow anaerobic sludge blanket (UASB) system. Three laboratory-scale UASB reactors, 15.8 - l working volume, were employed with 1 reactor operated as control. They were loaded at organic loading rate (OLR) of 5 kg COD/(m3-d), treating synthetic wastewater with COD concentration ~ 5000 mg/l. Na+and K+ions were added in the range of 1010 - 7180 and 41 - 7320 mg/l, respectively. No toxicity was observed at influent Na+and K+concentrations up to 3340 and 2750 mg/l, respectively. Slight inhibitions on COD removal were founded at Na+and K+concentrations of 4610 and 3920 mg/l, respectively, but moderate effect on biogas production had occurred. When Na+and K+concentrations were increased to 7180 and 7320 mg/l, respectively, strong inhibitions were observed with COD removal dropped to 45.5 and 48.8 %, respectively. Ratios of biogas productions, as compared to the control reactor, were dropped to 0.31 and 0.32, respectively. Increasing cation concentrations had more detrimental effect on biogas production than COD removal.

The closure of water circuits by internal thermophilic (55 and 70°C) anaerobic treatment in the thermomechanical pulping process

1997 ◽  
Vol 35 (2-3) ◽  
pp. 49-56 ◽  
Author(s):  
Sigrun J. Jahren ◽  
Jukka A. Rintala
Keyword(s):  
Lignin Content ◽  
Water System ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Thermomechanical Pulp ◽  
Thermomechanical Pulping ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors

The suitability of an internal thermophilic anaerobic treatment system for closing the water circuits in thermomechanical pulp (TMP) production was studied. The dissolution of wood organics in the water circuit was simulated by hot disintegration of TMP pulp, while the water system closure was simulated by repeated hot disintegration of TMP pulp with recirculated water. The upflow anaerobic sludge blanket (UASB) reactors were started at 55 and 70°C with mesophilic inoculum, and stable performances were established within 60 days at both temperatures. Closing the water circuits without internal treatment rapidly resulted in increased chemical oxygen demand (COD) in the recirculated water. In the closed, internally treated water circuits, the UASB reactors removed all the COD and ultraviolet absorbance at 280 nm (UV280; estimation for lignin content) dissolved in the recirculated water during the hot disintegration of the TMP pulp (carbohydrates were not dissolved). The results of this study suggest that thermophilic anaerobic treatment could be feasible at least as a part of an internal purification system to close the water circuit in the TMP process.

Advanced Monitoring of an Anaerobic Pilot Plant Treating High Strength Wastewaters

1999 ◽  
Vol 40 (8) ◽  
pp. 237-244 ◽  
Author(s):  
A. Puñal ◽  
A. Lorenzo ◽  
E. Roca ◽  
C. Hernández ◽  
J. M. Lema
Keyword(s):  
Pilot Plant ◽  
Gas Flow ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
High Strength ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Anaerobic Sludge Blanket

The operation of an industrial pilot scale treating wastewater from a fibreboard-processing factory was monitored by an advanced system. The plant, an anaerobic hybrid UASB-UAF bioreactor (Upflow Anaerobic Sludge Blanket-Upflow Anaerobic Filter), was equipped with the following measurement devices: biogas flow-meter, feed and recycling flow-meters, thermometer Pt-100, biogas analyser (CH4 and CO), Hydrogen analyser and pH-meter. Other parameters such as alkalinity, Chemical Oxygen Demand (COD) and Volatile Fatty Acids (VFA) were determined off-line. All the on-line sensor measurements were monitored, through a PLC (Programmable Logic Controller), which indicated about the plant failures, including the measuring devices (giving messages or alarms to the operator) and provided the set points for the PLC. The pilot plant was started-up at an initial Organic Loading Rate (OLR) of 2 kg COD/m3.d (Hydraulic Retention Time (HRT) 5 days and 10 kg COD/m3), this value increasing up to 10 kg COD/m3.d by decreasing HRT to 1 day. The behaviour of the bioreactor during start-up and steady state operation was studied. After that, an experiment was performed to analyse the response of the bioreactor to an organic overload. From the results, different variables were evaluated as useful control parameters. Monitoring of CO concentration did not permit the prediction of destabilisation of the bioreactor. However, H2 concentration is quite a sensitive variable, which must be analysed together with other parameters such as methane composition or gas flow-rate. Besides, alkalinity is easy to measure and provides immediate information about the state of the plant, as was shown through the off-line measurements.

Performance of plastic- and sponge-based trickling filters treating effluents from an UASB reactor

2013 ◽  
Vol 67 (5) ◽  
pp. 1034-1042 ◽  
Author(s):  
P. G. S. Almeida ◽  
A. K. Marcus ◽  
B. E. Rittmann ◽  
C. A. L. Chernicharo
Keyword(s):  
Organic Matter ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Total N ◽  
Trickling Filters ◽  
N Removal ◽  
Anaerobic Sludge Blanket

The paper compares the performance of two trickling filters (TFs) filled with plastic- or sponge-based packing media treating the effluent from an upflow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated with an organic loading rate (OLR) of 1.2 kgCOD m−3 d−1, and the OLR applied to the TFs was 0.30–0.65 kgCOD m−3 d−1 (COD: chemical oxygen demand). The sponge-based packing medium (Rotosponge) gave substantially better performance for ammonia, total-N, and organic matter removal. The superior TF-Rotosponge performance for NH4+-N removal (80–95%) can be attributed to its longer biomass and hydraulic retention times (SRT and HRT), as well as enhancements in oxygen mass transfer by dispersion and advection inside the sponges. Nitrogen removals were significant (15 mgN L−1) in TF-Rotosponge when the OLRs were close to 0.75 kgCOD m−3 d−1, due to denitrification that was related to solids hydrolysis in the sponge interstices. For biochemical oxygen demand removal, higher HRT and SRT were especially important because the UASB removed most of the readily biodegradable organic matter. The new configuration of the sponge-based packing medium called Rotosponge can enhance the feasibility of scaling-up the UASB/TF treatment, including when retrofitting is necessary.

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