Experience with UASB reactor start-up under different operating conditions

1996 ◽  
Vol 34 (5-6) ◽  
pp. 421-428 ◽  
Author(s):  
M. M. Ghangrekar ◽  
S. R. Asolekar ◽  
K. R. Ranganathan ◽  
S. G. Joshi
Keyword(s):  
Steady State ◽  
Operating Conditions ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Operating Parameters ◽  
Reactor Performance ◽  
Loading Rates ◽  
Start Up ◽  
Sludge Production

Four laboratory upflow anaerobic sludge blanket (UASB) reactors were operated at different operating parameters viz., hydraulic retention time (HRT), upflow velocity, organic concentration, and Ca2+ concentration in the wastewater. These operating parameters gave different values of organic loading rates (OLRs) and sludge loading rates (SLRs). The reactor performance during start-up was evaluated at different values of the above listed parameters. Also, the effects of these parameters on the granule characteristics were investigated. It was observed that COD removal efficiency at steady state was profoundly influenced by SLR. The reactor started with SLR of 0.6 kgCOD/ kg VSS.d could result in about 50% COD removal at steady state. The reactor performance could not improve even after three months of operation. Up to 0.3 kgCOD/ kgVSS.d the reactor performance was good with more than 90% COD removal at steady state. The OLD and SLR also determine time required for the reactor to achieve steady state. Different operating conditions also have the bearing on the strength of the granules cultivated. The methanogenic activity measured on acetate for each reactor was observed between 0.259 and 0.909 kg CH4 COD/ kgVSS.d. The sludge production in all the reactors was between 0.087 and 0.13 kgVSS/ kgCODin. The mathematical model was developed in order to predict sludge production.

Start-Up Strategy to Achieve Excellent Efficiency of Degradation Acetate,Ethanol and Propionate in UASB

2011 ◽  
Vol 71-78 ◽  
pp. 2103-2106
Author(s):  
Ming Yue Zheng ◽  
Ming Xia Zheng ◽  
Kai Jun Wang ◽  
Hai Yan
Keyword(s):  
Loading Rate ◽  
Anaerobic Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Organic Loading ◽  
Metabolic Intermediate ◽  
Loading Rates ◽  
Start Up ◽  
Anaerobic Sludge Blanket

The performance of upflow anaerobic sludge blanket (UASB) fed with three metabolic intermediate (acetate, ethanol, and propionate) respectively was studied. The degradation of metabolic intermediate were investigated to discuss the reason for propionate inhibition problem in anaerobic treatment. The hydraulic retention time (HRT) in the reactors started with 8.0h.The yield rate of biogas were 237ml/gCOD, 242ml/gCOD, 218ml/gCOD for acetate, ethanol and propionate, respectively when finishing start-up under OLR of 5.0 kgCOD/(m3·d) (HRT=9.6h).The HRT remained constant 9.6h,and the substrate concentration was gradually increased from 1,000 to 16,000mg/L as COD,and the organic loading rates(OLR) was from 3.0 to 40.0 kgCOD/(m3·d).The maximum propionate concentration was 41.6 gHPr-COD/L at the organic loading rate of 43.9 kgCOD/(m3·d) (HRT, 9.6h) as well as acetate and ethanol.

Removal of COD from Piggery Wastewater Using a Lab-Scale UASB Reactor

2012 ◽  
Vol 534 ◽  
pp. 221-224
Author(s):  
Fei Yan ◽  
Jin Long Zuo ◽  
Tian Lei Qiu ◽  
Xu Ming Wang
Keyword(s):  
Granular Sludge ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Synthetic Wastewater ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Volume Loading ◽  
Piggery Wastewater ◽  
Start Up ◽  
Anaerobic Sludge Blanket

It took 55 days to start up a lab-scale upflow anaerobic sludge blanket (UASB) reactor at ambient temperature 27-28 oC by using the synthetic wastewater, and piggery wastewater was used as the influent after the reactor start-up. From day 120 onwards, COD removal efficiency maintained in the range of 85% to 95% with 6.79-9.66 kg COD/ (m3•d) of volume loading, and the effluent COD concentration ranged between 400 mg/L and 600 mg/L. Granular sludge formation was observed in the reactor after 40-day operation, and the sludge diameter reached 2-4 mm in the 120 day-old reactor. The pH changes in the influent had little influence on COD removal from piggery wastewater using the UASB reactor.

Feasibility of Anaerobic Pre-Treatment for the Effluents from Hardboard and Laminated Board Industry

1994 ◽  
Vol 29 (5-6) ◽  
pp. 391-397 ◽  
Author(s):  
V. Eroglu ◽  
I. Oztürk ◽  
G. Ubay ◽  
I. Demir ◽  
E. N. Korkurt
Keyword(s):  
High Energy ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Biological Sludge ◽  
Study Results ◽  
Wide Range ◽  
Pre Treatment ◽  
Board Industry ◽  
Sludge Production

This paper presents results of a comparative evaluation of the feasibility of anaerobic pre-treatment for the effluents from a hardboard and laminated board industry. The problems associated with the treatment of hardboard mill wastewaters using activated sludge process have been observed as relatively low COD removal, high energy cost and high amounts of excess biological sludge production. The purpose of the study is to evaluate the effectiveness and feasibility of the anaerobic pre-treatment to reduce the excess biological sludge production and energy consumption in the aerobic stage. Anaerobic treatability studies were carried out by a lab-scale upflow anaerobic sludge blanket reactor (UASBR) with an effective volume of 10 litres. The UASBR was operated for a wide range of organic and hydraulic loadings during the experimental studies of more than 4 months. Anaerobic treatability studies have shown that a COD removal of 60% is possible at organic loading rates of 5-11 kg COD/m3.d. Anaerobic treatability study results have shown that 70 percent reduction both in the excess sludge production and in energy for aeration are possible by applying anaerobic pre-treatment. Considering these findings, it was demonstrated that anaerobic pre-treatment is a feasible option for waste management of the hardboard mill effluents.

Anaerobic treatment of olive mill effluents

1997 ◽  
Vol 36 (2-3) ◽  
pp. 287-294 ◽  
Author(s):  
G. Ubay ◽  
I. Öztürk
Keyword(s):  
Retention Time ◽  
Anaerobic Treatment ◽  
Operating Conditions ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Volume Index ◽  
Anaerobic Sludge ◽  
Substrate Removal ◽  
Anaerobic Sludge Blanket ◽  
Olive Mill

The anaerobic treatability of olive mill effluent was investigated using a laboratory scale upflow anaerobic sludge blanket reactor (UASBR) operated for about six months. The effects of various operating conditions including pH, feed strength and hydraulic retention time on the performance of the anaerobic treatment process were determined. In the first part of this study, the reactor was operated with feed COD concentrations from 5000 to 19,000 mg/l and a retention time of 1 day, giving organic loading rates from 5 to 18 kg COD/m3d. Soluble COD removal was around 75% under these conditions. In the second part of the study, feed CODs were varied from 15,000 to 22,600 mg/l while retention times ranged from 0.83 to 2 days; soluble COD removal was around 70%. A methane conversion rate of 0.35 m3 per kg COD removed was achieved during the study. The average volatile solids (VS) concentration in the reactor had increased from 12.75 g l−1 to 60 g l−1 by the end of the study. Sludge volume index (SVI) determinations performed to evaluate the settling characteristics of the anaerobic sludge in the reactor indicated excellent settleability with SVI values of generally less than 20 ml g−1. Sludge granules ranging from 3 to 8 mm in diameter were produced in the reactor. The second order substrate removal kinetics was applied by assuming that hydraulic conditions in the UASBR are approximately completely mixed and the model fitted well to the steady state operating results.

Hybrid Upflow Anaerobic Sludge Blanket Reactor (HUASBR) Treatment of Dairy Effluents

1993 ◽  
Vol 28 (2) ◽  
pp. 77-85 ◽  
Author(s):  
I. Öztürk ◽  
V. Eroglu ◽  
G. Ubay ◽  
I. Demir
Keyword(s):  
Dairy Industry ◽  
Operating Conditions ◽  
Cod Removal ◽  
Laboratory Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Anaerobic Reactor ◽  
Anaerobic Sludge Blanket ◽  
Dairy Effluents

This paper covers the treatability results of a laboratory-scale hybrid upflow anaerobic sludge blanket reactor (HUASBR) treating dairy effluents from a large integrated industry with a maximum production capacity of 500 tons of milk per day. The study began wilb the determination of effluent characteristics and pollution profile for the investigated dairy industry. As a result of observations, by-product recovery and waste reduction alternatives were investigated by in-plant control measures. Anaerobic treatability studies were conducted by a laboratory-scale hybrid upflow anaerobic reactor with an effective volume of 81. The reactor was operated more that 270 days under mesophilic conditions and it was fed wilb the combined effluents from the investigated dairy industry. The hydraulic retention times ranged from 0.21 to 0.96 days under normal operating conditions after the start up. COD removal efficiencies of more than 87% were achieved at an organic loading rate (OLR) of 8.5 kg COD/m3·d OLR was gradually increased from 2.54 to 7.1 kg COD/m3·d within 15 days but the anaerobic reactor performances did not change significantly. The reactor was operated under varying feed characteristics to test the response of the system to high strength acid whey. The system can tolerate OLRs as high as 17 kg COD/m3·d with an average COD removal efficiency of 75% for two weeks. Although the reactor was fed by diluted effluent with an average COD of 1070 mg/l at very high hydraulic loadings (HRT=5 hours), 75% removals of COD were achieved under these conditions.

Anaerobic Thermophilic (55°C) Treatment of TMP Whitewater in Reactors Based on Biomass Attachment and Entrapment

1999 ◽  
Vol 40 (11-12) ◽  
pp. 67-75 ◽  
Author(s):  
Sigrun J. Jahren ◽  
Jukka A. Rintala ◽  
Hallvard Ødegaard
Keyword(s):  
Granular Sludge ◽  
Biofilm Reactor ◽  
Upflow Anaerobic Sludge Blanket ◽  
Hybrid Reactor ◽  
Anaerobic Sludge ◽  
Loading Rates ◽  
Anaerobic Reactors ◽  
Multi Stage ◽  
Degradation Rates ◽  
Thermomechanical Pulping

Thermomechanical pulping (TMP) whitewater was treated in thermophilic (55°C) anaerobic laboratory-scale reactors using three different reactor configurations. In all reactors up to 70% COD removals were achieved. The anaerobic hybrid reactor, composed of an upflow anaerobic sludge blanket (UASB) and a filter, gave degradation rates up to 10 kg COD/m3d at loading rates of 15 kg COD/m3d and hydraulic retention time (HRT) of 3.1 hours. The anaerobic multi-stage reactor, consisting of three compartments, each packed with granular sludge and carrier elements, gave degradation rates up to 9 kg COD/m3d at loading rates of 15-16 kg COD/m3d, and HRT down to 2.6 hours. Clogging and short circuiting eventually became a problem in the multi-stage reactor, probably caused by too high packing of the carriers. The anaerobic moving bed biofilm reactor performed similar to the other reactors at loading rates below 1.4 kg COD/m3d, which was the highest loading rate applied. The use of carriers in the anaerobic reactors allowed short HRT with good treatment efficiencies for TMP whitewater.

scholarly journals Bioenergy recovery from cattle wastewater in an UASB-AF hybrid reactor

2017 ◽  
Vol 76 (9) ◽  
pp. 2268-2279 ◽  
Author(s):  
Henrique Vieira de Mendonça ◽  
Jean Pierre Henry Balbaud Ometto ◽  
Marcelo Henrique Otenio ◽  
Alberto José Delgado dos Reis ◽  
Isabel Paula Ramos Marques
Keyword(s):  
Biogas Production ◽  
Upflow Anaerobic Sludge Blanket ◽  
Hybrid Reactor ◽  
Anaerobic Sludge ◽  
The Novel ◽  
Organic Loading ◽  
Loading Rates ◽  
Volatile Solids ◽  
Anaerobic Sludge Blanket

Abstract New data on biogas production and treatment of cattle wastewater were registered using an upflow anaerobic sludge blanket-anaerobic filter (UASB-AF) hybrid reactor under mesophilic temperature conditions (37 °C). The reactor was operated in semi-continuous mode with hydraulic retention times of 6, 5, 3 and 2 days and organic loading rates of 3.8, 4.6, 7.0 and 10.8 kg CODt m−3 d−1. Biogas volumes of 0.6–0.8 m3 m−3 d−1 (3.8–4.6 kg CODt m−3 d−1) and 1.2–1.4 m3 m−3 d−1 (7.0–10.8 kg CODt m−3 d−1), with methane concentrations between 69 and 75%, were attained. The removal of organic matter with values of 60–81% (CODt) and 51–75% (CODs) allowed methane yields of 0.155–0.183 m3 CH4 kg−1 CODt and 0.401–0.513 m3 CH4 kg−1 CODs to be obtained. Volatile solids were removed in 34 to 69%, with corresponding methane yields of 0.27 to 0.42 m3 CH4 kg−1 VSremoved. The good performance of the novel hybrid reactor was demonstrated by biogas outputs higher than reported previously in the literature, along with the quality of the gas obtained in the various experimental phases. The hybrid reactor investigated in this study presents comparative advantages, particularly in relation to conventional complete mixture units, considering economic factors such as energy consumption, reactor volume and installation area.

Anaerobic treatment of proteinaceous wastewater under mesophilic and thermophilic conditions

1999 ◽  
Vol 40 (1) ◽  
pp. 77-84 ◽  
Author(s):  
H. H. P. Fang ◽  
D. Wai-Chung Chung
Keyword(s):  
Bacterial Species ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Loading Rates ◽  
Batch Tests ◽  
Thermophilic Conditions ◽  
Anaerobic Sludge Blanket ◽  
Hydrolysis Of

Experiments were conducted in two 2.8 liter UASB (upflow anaerobic sludge blanket) reactors treating proteinaceous wastewaters at 37° and 55°C with 9 hours of hydraulic retention. Results showed that the mesophilic reactor consistently removed 83.5-85.1% of COD (chemical oxygen demand) at loading rates ranging 8-22 g COD l−1 d−1 (corresponding to 3000-8250 mg l−1 of proteinaceous COD in wastewater), whereas the thermophilic reactor removed only 68.5-82.7%. At 32 g COD l−1 d−1 (i.e. 12000 mg COD l−1), the removal efficiencies were lowered to 75.7% in the mesophilic reactor and 65.1% in the thermophilic reactor. At 42 g COD l−1 d−1, severe sludge washout occurred in the mesophilic reactor; at the same loading rate, the thermophilic reactor removed only 53.8% of COD even though sludge washout was under control. The degradation rate in the both reactors was limited by the initial hydrolysis of proteins. However, batch tests showed that thermophilic sludge had slightly higher methanogenic activities than mesophilic sludge in treating proteins and intermediate acids, except propionate. The sludge yields in mesophilic and thermophilic reactors were 0.066 and 0.099 g VSS g COD−1, respectively. Observations by scanning electron microscopy indicated that both types of sludge granules were of irregular shape. There was little noticeable difference between the two granules; both had neither a layered microstructure nor a predominant bacterial species.

Effect of micro-nutrients in anaerobic degradation of sulfate laden organics

2004 ◽  
Vol 31 (3) ◽  
pp. 420-431 ◽  
Author(s):  
S K Patidar ◽  
Vinod Tare
Keyword(s):  
Anaerobic Degradation ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Sulfide Concentration ◽  
Anaerobic Baffled Reactor ◽  
Sulfide Toxicity ◽  
Anaerobic Sludge Blanket

The effect of micro-nutrients, such as Fe, Ni, Zn, Co, and Mo, on anaerobic degradation of sulfate laden organics was investigated using bench-scale models of upflow anaerobic sludge blanket (UASB) reactor, anaerobic baffled reactor (ABR), and hybrid anaerobic baffled reactor (HABR), operating in varying conditions in ten phases (organic loading of 1.9–5.75 kg COD/(m3·d), sulfate loading of 0.54–1.88 kg SO42–/(m3·d), chemical oxygen demand (COD):SO42–ratio of 2.0–8.6). In the initial phase, no nutrient limitation was observed with COD removal of more than 94% in all three systems. Subsequently, increase in sulfate loading resulted in Ni and Co limitation and their supplementation restored COD removal in UASB system. However, baffled systems did not recover because of severe inhibition by sulfide. Results indicate that precipitation of nutrients could seriously deteriorate process performance, leading to failure even before sulfide concentration attains toxic level. The limitation of Fe coupled with high sulfate loading (1.88 kg SO42–/(m3·d)) resulted in growth of low-density, fragile, hollow, and granular biomass in UASB that washed out and caused process instability. Supplementation of Fe with other nutrients stabilized UASB process and also improved COD removal.Key words: anaerobic degradation, nutrients, UASB, ABR, HABR, sulfide toxicity, sulfate laden organics.

The periodic anaerobic baffled reactor

1998 ◽  
Vol 38 (8-9) ◽  
pp. 401-408 ◽  
Author(s):  
I. V. Skiadas ◽  
G. Lyberatos
Keyword(s):  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Switching Frequency ◽  
Reactor Performance ◽  
Active Biomass ◽  
Anaerobic Baffled Reactor ◽  
Stable Periodic ◽  
Reactor Type ◽  
Continuously Stirred Tank Reactor ◽  
Anaerobic Sludge Blanket

The most common bioreactor type used for anaerobic digestion is the Continuously Stirred Tank Reactor (CSTR). The main problem of this reactor type, i.e. the fact that the active biomass is continuously removed from the system leading to long retention times, has been overcome in a number of systems based on immobilization of the active biomass. Two represenstative types are the Upflow Anaerobic Sludge Blanket Reactor (UASBR) and the Anaerobic Baffled Reactor (ABR). The success of these reactor systems rests on the highly flocculated, well settling, compact methanogenic sludge granules which develop in these reactors. A novel reactor type named Periodic Anaerobic Baffled Reactor (PABR) has been designed, offering the following major advantage: it may be operated as an ABR, a UASBR or at an intermediate mode. The PABR hydraulic behavior has been characterized using residence time distribution experiments at different retention times. Simulating the PABR behavior, the dependence of the reactor performance on the switching frequency is determined as a function of the retention time. In particular, it is found that for high retention times the ABR mode is superior, whereas for low retention times, the UASBR mode should be preferred. In order to establish the accuracy of the predictions of the simulation study, the PABR behavior was experimentally verified using three different stable periodic states.

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