Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time

2013 ◽  
Vol 67 (6) ◽  
pp. 1353-1361 ◽  
Author(s):  
M. Esparza-Soto ◽  
O. Arzate-Archundia ◽  
C. Solís-Morelos ◽  
C. Fall

The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 ± 0.6 °C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m3/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 ± 0.3 h). The CODsol removal efficiency was low (59–78%). The measured biogas production increased from 240 ± 54 to 431 ± 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m3 of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700–4,800 mg/L) and high effluent VSS (177–313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater.

2011 ◽  
Vol 64 (8) ◽  
pp. 1629-1635 ◽  
Author(s):  
M. Esparza Soto ◽  
C. Solís Morelos ◽  
J. J. Hernández Torres

The aim of this work was to evaluate the performance of a pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of cereal-processing industry wastewater under low-temperature conditions (17 °C) for more than 300 days. The applied organic loading rate (OLRappl) was gradually increased from 4 to 6 and 8 kg CODsol/m3d by increasing the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (5.2 h). The removal efficiency was high (82 to 92%) and slightly decreased after increasing the influent CODsol and the OLRappl. The highest removed organic loading rate (OLRrem) was reached when the UASB reactor was operated at 8 kg CODsol/m3d and it was two times higher than that obtained for an OLRappl of 4 kg CODsol/m3d. Some disturbances were observed during the experimentation. The formation of biogas pockets in the sludge bed significantly complicated the biogas production quantification, but did not affect the reactor performance. The volatile fatty acids in the effluent were low, but increased as the OLRappl increased, which caused an increment of the effluent CODsol. Anaerobic treatment at low temperature was a good option for the biological pre-treatment of cereal processing industry wastewater.


2012 ◽  
Vol 9 ◽  
pp. 57-62
Author(s):  
Fiza Sarwar ◽  
Wajeeha Malik ◽  
Muhammad Salman Ahmed ◽  
Harja Shahid

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


2019 ◽  
Vol 79 (12) ◽  
pp. 2251-2259 ◽  
Author(s):  
M. Esparza-Soto ◽  
A. Jacobo-López ◽  
M. Lucero-Chávez ◽  
C. Fall

Abstract The objective of the present study was to determine the optimum operating temperature of laboratory-scale upflow anaerobic sludge blanket (UASB) reactors during the treatment of a chocolate-processing industry wastewater at medium applied organic loading rates (OLRappl). Four UASB reactors were operated at different temperature (15, 20, 25 and 30 °C) and three OLRappl (2, 4 and 6 kg soluble chemical oxygen demand (CODs)/(m3 d)). The flowrate and the hydraulic retention time were constant (11.5 L/d and 6 h, respectively). The monitored parameters were pH, temperature, CODs, and total and volatile suspended solids. The CODs removal efficiency (RE) and biogas production rate (BPR) were calculated. The 15 °C UASB reactor had the lowest RE (39 to 78%) due to the low operating temperature. Regardless of the OLRappl, the RE of the 20, 25 and 30 °C reactors was high and similar to each other (between 88 and 94%). The BPR of the four UASB reactors had the same behaviour as the RE (BPR of 15 °C: 0.3 to 0.5 Lbiogas/(Lreactor d) (Lb/(Lr d)) and BPR of 20, 25 and 30 °C: 0.5 to 1.9 Lb/(Lr d)).


2002 ◽  
Vol 45 (10) ◽  
pp. 243-248 ◽  
Author(s):  
L. Seghezzo ◽  
R.G. Guerra ◽  
S.M. González ◽  
A.P. Trupiano ◽  
M.E. Figueroa ◽  
...  

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.


2009 ◽  
Vol 59 (11) ◽  
pp. 2265-2272 ◽  
Author(s):  
S. Satyanarayan ◽  
A. Karambe ◽  
A. P. Vanerkar

Herbal pharmaceutical industry has grown tremendously in the last few decades. As such, literature on the treatment of this wastewater is scarce. Water pollution control problems in the developing countries need to be solved through application of cost effective aerobic/anaerobic biological systems. One such system—the upflow anaerobic sludge blanket (UASB) process which is known to be cost effective and where by-product recovery was also feasible was applied for treatment of a high strength wastewater for a period of six months in a pilot scale upflow anaerobic sludge blanket (UASB) reactor with a capacity of 27.44 m3. Studies were carried out at various organic loading rates varying between 6.26 and 10.33 kg COD/m3/day and hydraulic retention time (HRT) fluctuating between 33 and 43 hours. This resulted in chemical oxygen demand (COD), biochemical oxygen demand (BOD) and suspended solids (SS) removal in the range of 86.2%–91.6%, 90.0%–95.2% and 62.6%–68.0% respectively. The biogas production varied between 0.32–0.47 m3/kg COD added. Sludge from different heights of UASB reactor was collected and subjected to scanning electron microscopy (SEM). The results indicated good granulation with efficient UASB reactor performance.


1996 ◽  
Vol 34 (5-6) ◽  
pp. 509-515 ◽  
Author(s):  
Huub J. Gijzen ◽  
Frank Kansiime

The start-up and performance of an Upflow Anaerobic Sludge Blanket (UASB) reactor and a Polyurethane Carrier Reactor (PCR) was investigated under similar operational conditions. The presence of polyurethane cubes as a carrier material in the PCR resulted in fast reactor start-up due to quick immobilization of methanogenic associations. Start-up of the UASB was slower compared to the PCR, which was mainly reflected in a lower biogas production and acetate degradation efficiency. However, when enough biomass had accumulated in the UASB reactor after 15 weeks of operation, the performance of the two reactors was almost the same in terms of biogas production and volatile fatty acids degradation. Efficient VFA degradation (about 90%) and biogas production (5.2 l/l.d) were achieved at an organic loading rate of 13.2 g/l.d) and HRT of 6 h. When hydraulic retention time was subsequently reduced from 6 to 2 h, the performance of the UASB reactor was better than that of the PCR. The inferior performance of the PCR may have been attributed to channelling of the influent in the reactor at high liquid flow rate.


2000 ◽  
Vol 42 (3-4) ◽  
pp. 43-50 ◽  
Author(s):  
Y.-H. Huang ◽  
G.-H. Huang ◽  
S. Chou ◽  
S.-S. Cheng

This study investigates the influence of organic shock loading on H2 production in an upflow anaerobic sludge bed (UASB) reactor. An esterification wastewater produced from a polyethylene terephthalate (PET) manufacturing plant was applied; the major organic pollutants are ethylene glycol and acetaldehyde. Experiments of two influent modes were performed here: a continuous-flow mode with a step input of shock loading and a batch mode with a pulse input of shock loading. Results of the continuous-flow experiments indicate that biogas production parameters such as H2 concentration and biogas production rate are more sensitive than water quality parameters such as pH, ORP, COD and TOC. In particular, H2, increasing by 140% within 1 hour, is a very important index upon the organic shock loading. It changes from 120 ppm to over 600 ppm as the organic loading rate increases from 4.4 to 13.2 kgCOD/m3·day through 4 hours of shock loading. Experiments of the batch shock loading with different pulse dosagesof ethylene glycol, acetaldehyde and the raw wastewater were also investigated. The amount of H2 production increased in proportion to an increase of organic load. Furthermore, the sequence of H2 production among the three types of shock loading is acetaldehyde> ethylene glycol> raw wastewater. To sum up, H2 shows a faster response rate than the other parameters. Therefore, H2 can be adopted as an important parameter for organic shock loading in UASB.


2013 ◽  
Vol 33 (2) ◽  
pp. 367-378 ◽  
Author(s):  
Estevão Urbinati ◽  
Rose M. Duda ◽  
Roberto A. de Oliveira

In this study it was evaluated the effects of hydraulic retention time (HRT) and Organic Loading Rate (OLR) on the performance of UASB (Upflow Anaerobic Sludge Blanket) reactors in two stages treating residual waters of swine farming. The system consisted of two UASB reactors in pilot scale, installed in series, with volumes of 908 and 188 L, for the first and second stages (R1 and R2), respectively. The HRT applied in the system of anaerobic treatment in two stages (R1 + R2) was of 19.3, 29.0 and 57.9 h. The OLR applied in the R1 ranged from 5.5 to 40.1 kg CODtotal (m³ d)-1. The average removal efficiencies of chemical oxygen demand (COD) and total suspended solids (TSS) ranged, respectively, from 66.3 to 88.2% and 62.5 to 89.3% in the R1, and from 85.5 to 95.5% and 76.4 to 96.1% in the system (R1 + R2). The volumetric production of methane in the system (R1 + R2) ranged from 0.295 to 0.721 m³CH4 (m³ reactor d)-1. It was found that the OLR applied were not limiting to obtain high efficiencies of CODtotal and TSS removal and methane production. The inclusion of the UASB reactor in the second stage contributed to increase the efficiencies of CODtotal and TSS removal, especially, when the treatment system was submitted to the lowest HRT and the highest OLR.


Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 372 ◽  
Author(s):  
Rajinikanth Rajagopal ◽  
Mahbuboor Choudhury ◽  
Nawrin Anwar ◽  
Bernard Goyette ◽  
Md. Rahaman

The up-flow anaerobic sludge blanket (UASB) process has emerged as a promising high-rate anaerobic digestion technology for the treatment of low- to high-strength soluble and complex wastewaters. Sewage, a complex wastewater, contains 30–70% particulate chemical oxygen demand (CODP). These particulate organics degrade at a slower rate than the soluble organics found in sewage. Accumulation of non-degraded suspended solids can lead to a reduction of active biomass in the reactor and hence a deterioration in its performance in terms of acid accumulation and poor biogas production. Hydrolysis of the CODP in sewage prior to UASB reactor will ensure an increased organic loading rate and better UASB performance. While single-stage UASB reactors have been studied extensively, the two-phase full-scale treatment approach (i.e., a hydrolysis unit followed by an UASB reactor) has still not yet been commercialized worldwide. The concept of treating sewage containing particulate organics via a two-phase approach involves first hydrolyzing and acidifying the volatile suspended solids without losing carbon (as methane) in the first reactor and then treating the soluble sewage in the UASB reactor. This work reviews the available literature to outline critical findings related to the treatment of sewage with and without hydrolysis before the UASB reactor.


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