Sewage treatment by anaerobic biological process associated with dissolved air flotation

2001 ◽  
Vol 43 (8) ◽  
pp. 91-98 ◽  
Author(s):  
M. A. P. Reali ◽  
J. R. Campos ◽  
R. G. Penetra
Keyword(s):  
Scale Up ◽  
Sewage Treatment ◽  
Pilot Scale ◽  
Cationic Polymer ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Mean Velocity ◽  
Dissolved Air Flotation ◽  
Flotation Process ◽  
Anaerobic Sludge Blanket

This paper presents the results of a study performed with a lab-scale batch DAF unit fed with previously coagulated (with FeCl3 or cationic polymer) effluent from a pilot scale up-flow anaerobic sludge blanket (UASB) reactor treating domestic sewage. The adequate coagulation/flocculation conditions – chemical dosage, time (Tf) and mean velocity gradient (Gf) in the flocculation step – and air requirements for flotation process were investigated. Best results were achieved for 65 mg.l−1 of FeCl3 at Tf around 15 min and Gf of 80 s−1. In the assays where only polymer was applied, 7 mg.l−1 of cationic polymer dosage gave optimum removals with Tf around 15 min and Gf of 30 s−1. Air requirements ranged from 9.5 to 19.0 g of air.m−1 wastewater. Best TSS (95% and residual of 2 mg.l−1), COD (85% and residual of 20 mg.l−1) and total phosphate (95% and residual of 0.6 mg.l−1) removals were obtained when applying FeCl3, although the use of cationic polymer also produced good level of TSS (74% and residual of14 mg.l−1) and COD (75% and residual of 45 mg.l−1) removals. For the UASB-DAF (batch) system and FeCl3, global efficiencies would be 97.2% for COD, 97.9% for phosphate and 98.9% for TSS.

Evaluation of sludge properties in a pilot-scale UASB reactor for sewage treatment in a temperate region

2011 ◽  
Vol 64 (10) ◽  
pp. 1959-1966 ◽  
Author(s):  
K. Syutsubo ◽  
W. Yoochatchaval ◽  
I. Tsushima ◽  
N. Araki ◽  
K. Kubota ◽  
...  
Keyword(s):  
Suspended Solids ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Methanogenic Activity ◽  
Working Volume ◽  
Anaerobic Sludge Blanket

In this study, continuous operation of a pilot-scale upflow anaerobic sludge blanket (UASB) reactor for sewage treatment was conducted for 630 days to investigate the physical and microbial characteristics of the retained sludge. The UASB reactor with a working volume of 20.2 m3 was operated at ambient temperature (16–29 °C) and seeded with digested sludge. After 180 days of operation, when the sewage temperature had dropped to 20 °C or lower, the removal efficiency of both total suspended solids (TSS) and total biochemical oxygen demand (BOD) deteriorated due to washout of retained sludge. At low temperature, the cellulose concentration of the UASB sludge increased owing to the rate limitation of the hydrolytic reaction of suspended solids in the sewage. However, after an improvement in sludge retention (settleability and concentration) in the UASB reactor, the process performance stabilized and gave sufficient results (68% of TSS removal, 75% of total BOD removal) at an hydraulic retention time (HRT) of 9.7 h. The methanogenic activity of the retained sludge significantly increased after day 246 due to the accumulation of Methanosaeta and Methanobacterium following the improvement in sludge retention in the UASB reactor. Acid-forming bacteria from phylum Bacteroidetes were detected at high frequency; thus, these bacteria may have an important role in suspended solids degradation.

Performance and Modeling of a Pilot-Scale Up-Flow Anaerobic Sludge Blanket (UASB) Treating Pharmaceutical Wastewater Containing Berberine

2012 ◽  
Vol 518-523 ◽  
pp. 2625-2630 ◽  
Author(s):  
Ya Dong Guo ◽  
Cui Ting Fu ◽  
Guo Rong Liu ◽  
Chun Shuang Liu
Keyword(s):  
Scale Up ◽  
Back Propagation ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Pilot Scale ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Pharmaceutical Wastewater ◽  
Average Percentage ◽  
Anaerobic Sludge Blanket

A pilot-scale test was conducted with an up-flow anaerobic sludge blanket (UASB) treating pharmaceutical wastewater containing berberine. The aim of this study was to investigate the performance of UASB in the condition of a high chemical oxygen demand (COD) loading rate from 4.64 to 8.68 kg/m3d and a wide berberine concentration from 254 to 536 mg/L, in order to provide a reference for treating the similar pharmaceutical wastewater containing berberine. The results demonstrated that the UASB average percentage reduction in COD and berberine 68.14% and 57.39%, respectively. Granular sludge was formed during this process. In addition, a model, built on the back propagation neural network (BPNN) theory and linear regression techniques was developed for the simulation of the UASB system performance in the biodegradation of pharmaceutical wastewater containing berberine. The average errors of COD and berberine were -0.55% and 0.24%, respectively. The results indicated that this model built on the BPNN theory was well-fitted to the detected data, and was able to simulate and predict the removal of COD and berberine by UASB reactor.

Impact of microaeration bioreactor on dissolved sulfide and methane removal from real UASB effluent for sewage treatment

2020 ◽  
Vol 81 (9) ◽  
pp. 1951-1960 ◽  
Author(s):  
C. S. Cabral ◽  
A. L. Sanson ◽  
R. J. C. F. Afonso ◽  
C. A. L. Chernicharo ◽  
J. C. Araújo
Keyword(s):  
Sewage Treatment ◽  
Oxygen Demand ◽  
Post Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Sulfide Removal ◽  
Dissolved Sulfide ◽  
Removal Efficiencies ◽  
Anaerobic Sludge Blanket

Abstract Two bioreactors were investigated as an alternative for the post-treatment of effluent from an upflow anaerobic sludge blanket (UASB) reactor treating domestic sewage, aiming at dissolved sulfide and methane removal. The bioreactors (R-control and R-air) were operated at different hydraulic retention times (HRT; 6 and 3 h) with or without aeration. Large sulfide and methane removal efficiencies were achieved by the microaerated reactor at HRT of 6 h. At this HRT, sulfide removal efficiencies were equal to 61% and 79%, and methane removal efficiencies were 31% and 55% for R-control and R-air, respectively. At an HRT of 3 h, sulfide removal efficiencies were 22% (R-control) and 33% (R-air) and methane removal did not occur. The complete oxidation of sulfide, with sulfate formation, prevailed in both phases and bioreactors. However, elemental sulfur formation was more predominant at an HRT of 6 h than at an HRT of 3 h. Taken together, the results show that post-treatment improved the anaerobic effluent quality in terms of chemical oxygen demand and solids removal. However, ammoniacal nitrogen was not removed due to either the low concentration of air provided or the absence of microorganisms involved in the nitrogen cycle.

Post-Treatment of Effluents from Anaerobic Reactor Treating Domestic Sewage by Dissolved-Air Flotation

1999 ◽  
Vol 40 (8) ◽  
pp. 137-143 ◽  
Author(s):  
R. G. Penetra ◽  
M. A. P. Reali ◽  
E. Foresti ◽  
J. R. Campos
Keyword(s):  
Scale Up ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Domestic Sewage ◽  
Uasb Reactor ◽  
Dissolved Air Flotation ◽  
Operational Conditions ◽  
Apparent Color ◽  
Air Flotation ◽  
Dissolved Air

This paper presents the results of a study performed with a lab-scale dissolved-air flotation (LSDAF) unit fed with previously coagulated effluent from a pilot scale up-flow anerobic sludge blanket (UASB) reactor treating domestic sewage. Physical operational conditions for coagulation (rapid mix) and flocculation/flotation were maintained constant. Chemical (FeCl3) dosages ranged from 30 to 110 mg.l−1. The effect of pH was also verified in the range of 5.1 to 7.6 for each dosage. Best results were achieved for 65 mg.l−1 of FeCl3 and pH values between 5.3 and 6.1. For these conditions, the removal efficiencies obtained in the LSDAF unit were: between 87% and 91% for chemical oxygen demand (COD), between 95% and 96% for total phosphate (TP), 94% for total suspended solids (TSS), between 96% and 97% for turbidity (TU), between 90% and 93% for apparent color (AC) and more than 96% for sulfide (S). For the UASB-DAF system, global efficiencies would be around 98% for COD, 98% for TP, 98.4% for TSS, 99.3% for TU and 98% for AC. The stripped gases treatment is desirable.

Removal efficiency and methanogenic activity profiles in a pilot-scale UASB reactor treating settled sewage at moderate temperatures

2002 ◽  
Vol 45 (10) ◽  
pp. 243-248 ◽  
Author(s):  
L. Seghezzo ◽  
R.G. Guerra ◽  
S.M. González ◽  
A.P. Trupiano ◽  
M.E. Figueroa ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Retention Time ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Pilot Scale ◽  
Cod Removal ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Methanogenic Activity

The performance of a sewage treatment system consisting of a settler followed by an Upflow Anaerobic Sludge Bed (UASB) reactor is described. Mean ambient and sewage temperature were 16.5 and 21.6°C, respectively. Total Chemical Oxygen Demand (CODt) concentration averaged 224.2 and 152.6 mg/L, for raw and settled sewage, respectively. The effluent concentration was 68.5 mgCODt/L. Total and suspended COD removal efficiencies of approximately 70 and 80%, respectively, have been observed in the system at a mean Hydraulic Retention Time (HRT) of 2 + 5 h. Maximum COD removal efficiency was achieved in the UASB reactor when upflow velocity (Vup) was 0.43 m/h (HRT = 6 h). Mean Specific Methanogenic Activity (SMA) and Volatile Suspended Solids (VSS) concentration in the granular sludge bed were 0.11 gCOD-CH4/gVSS.d and 30.0 gVSS/Lsludge, respectively. SMA was inversely related to VSS concentration, and both parameters varied along the sludge bed height. The Solids Retention Time (SRT) in the reactor was 450 days. Sludge characteristics have not been affected by changes of up to one month in Vup in the range 0.28–0.85 m/h (HRT 3–9 h). This system or two UASB reactors in series could be an alternative for sewage treatment under moderate temperature conditions.

Combination of up-flow anaerobic sludge blanket reactor and a novel cascade sponge reactor for sewage treatment

2011 ◽  
Vol 63 (6) ◽  
pp. 1255-1264 ◽  
Author(s):  
K. Patel ◽  
A. K. Mungray
Keyword(s):  
Fecal Coliform ◽  
Sewage Treatment ◽  
Total Coliform ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Combined Process ◽  
Effluent Quality ◽  
Anaerobic Sludge Blanket ◽  
The Cost

Performance of the combined process of up-flow anaerobic sludge blanket (UASB) reactor and cascade sponge reactor (CSR) for sewage treatment was studied. UASB-CSR system was operated at HRTs of 24 h, 16 h, and 8 h at an average wastewater temperature of 29°C. It comprises of the most efficient combined process not only for CODT (98.9%), BODT (98.5%), TSS (99.3%), total nitrogen (89.1%), total phosphorus (99.0%), total coliform (99.9%) and fecal coliform (99.9%) removal but also for reducing excess sludge production. Fecal coliform counts were found 23 MPN/100 ml only in final effluents. The effluent quality of the system sufficiently meets the discharged standards which regulate wastewater discharge into drains. The parameters of CSR are closely related to those of the potable water after certain advanced treatment which can be reused in many ways. Moreover, it does not require any external aeration and thus the cost associated with energy and devices required for aeration are cut to zero.

Association of a UASB reactor and a submerged aerated biofilter for domestic sewage treatment

1998 ◽  
Vol 38 (8-9) ◽  
pp. 189-195 ◽  
Author(s):  
Ricardo Franci Gonçalves ◽  
Vera Lúcia de Araújo ◽  
Carlos Augusto L. Chernicharo
Keyword(s):  
Granular Media ◽  
Sewage Treatment ◽  
Experimental Period ◽  
Domestic Sewage ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Hydraulic Load ◽  
Reactor Operating ◽  
Anaerobic Sludge Blanket

This paper presents exploratory results on the association of an Upflow Anaerobic Sludge Blanket - UASB reactor (46 L) and a submerged aerated biofilter – BF (6.3 L) for domestic sewage treatment. The experimental period extended for 322 days, during which the hydraulic and organic loads were gradually increased in both reactors. Having the UASB as a reference, the following hydraulic loads were tested: 0.4 m3/m2.h (θ = 16 h); 0.6m3/m2.h (θ = 10h); 0.8 m3/m2.h (θ = 8 h); 1.0 m3/m2.h (θ = 6 h) and 1.45 m3/m2.h (θ = 4h). During the experiments carried out with the UASB reactor operating at a hydraulic detention time of 6 hours, related to a θ < 11′ in the granular media of the BF, the mean removal efficiency in terms of SS, BOD5 and COD, in both reactors, were respectively 94%, 96% and 91%. The final effluent, related to the BF effluent, presented the following mean characteristics: SS = 10 mg/L, BOD5 = 9 mg/L and COD = 38 mg/L. The results obtained in the last phase of the experiments, when the hydraulic load in the UASB reactor reached 1.45 m3/m2.h (θ = 4h), were similar to those obtained in the previous phase. These results demonstrate that submerged aerated biofilters can be considered a viable alternative for the post-treatment of effluents from UASB reactors treating domestic sewage. These reactors are capable of being operated with very short hydraulic detention times.

Performance review of large scale up-flow anaerobic sludge blanket sewage treatment plants

2011 ◽  
Vol 63 (1) ◽  
pp. 100-107 ◽  
Author(s):  
B. Heffernan ◽  
J. B. van Lier ◽  
J. van der Lubbe
Keyword(s):  
Large Scale ◽  
Recent Literature ◽  
Scale Up ◽  
Sewage Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Sewage Treatment Plants ◽  
Lower Performance ◽  
Short Period ◽  
Anaerobic Sludge Blanket

This article evaluates the performance of 10 large scale upflow anaerobic sludge blanket (UASB) sewage treatment plants (STP) located in semi-tropical areas, 7 plants were located in Brazil, 2 in India and 1 in the Middle East. In addition to the UASB, essential functional units of the STP which potentially impact on the UASB are also evaluated. Most grit removal systems were performing adequately, however in one plant very little grit was being removed. This could have serious implications for the performance of the plant as in a relatively short period of time the reactors could become full of grit. The performance results obtained in this study (COD, BOD and TSS removal efficiencies) are compared to the results of recent literature publications and also to the results of some early pilot and full scale studies. The results found here are broadly similar to those result reported in the recent literature but show a lower performance in comparison with the early pilot scale plants. Factors such as improper design, poor operating procedures, insufficient maintenance and the presence of high sulphate concentrations have been identified as the main reasons for the lower performance.

Treatment of Sweet Potato Starch Wastewater with UASB

2013 ◽  
Vol 699 ◽  
pp. 234-237
Author(s):  
Hong Fen Wang
Keyword(s):  
Sweet Potato ◽  
Potato Starch ◽  
Granular Sludge ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Starch Wastewater ◽  
Sweet Potato Starch ◽  
Anaerobic Sludge Blanket

A pilot-scale upflow anaerobic sludge blanket (UASB) reactor was used to study the sweet potato starch wastewater treatment performance and its influencing factors. Under normal temperature conditions, the operating parameters of sweet potato starch wastewater from UASB treatment was optimized, and the better conditions from different influent CODcr concentrations was obtained. The impacts from trace elements MgCl2, FeCl2, CoCl2, NiCl2 on physiological and biochemical characteristics of anaerobic granular sludge was developed.

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