The effect of extreme temperatures (70–80°C) on the effluent quality and sludge characteristics of UASB reactors

1997 ◽  
Vol 36 (6-7) ◽  
pp. 325-332 ◽  
Author(s):  
Raghida Lepistö ◽  
Jukka Rintala

The study focused on the effluent quality and sludge characteristics during the start-up and operation of extreme thermophilic (70 to 80°C) upflow anaerobic sludge bed (UASB) reactors, inoculated with mesophilic and thermophilic granular sludge and fed with acetate, volatile fatty acids (VFA), and thermomechanical pulping (TMP) whitewater. Low effluent quality and long start-up periods were observed during the start-up of the 70 to 76°C, VFA-fed UASB reactors inoculated with mesophilic granulae, while better effluent quality and considerably shorter start-up periods were observed when thermophilic (55/70°C) inocula were used. With VFA feed, a significant amount of acetate was removed at 70°C and even at 80°C, while propionate removal was negligible. With TMP whitewater feed, low VFA effluent concentration was obtained at 70°C. The volatile solids (VS) and the VS/total solids (TS) content of the sludge decreased significantly during the first 2–3 months of operation when mesophilic inocula were used. The initial specific methanogenic activity (ISMA) of the extreme thermophilic sludge decreased with increasing temperature and was slightly higher on glucose than on acetate. At 70 to 80°C, various rod-like bacteria were dispersed through the granulae in either individual or in low density micro colonies surrounded with a varying degree of precipitates.

1991 ◽  
Vol 24 (1) ◽  
pp. 69-74 ◽  
Author(s):  
J. Rintala

Anaerobic mesophilic treatment of synthetic (a mixture of acetate and methanol) and thermomechanical pulping (TMP) wastewater was studied in laboratory-scale upflow anaerobic sludge blanket (UASB) reactors and filters with emphasis on the process start-up. The reactors were inoculated with nongranular sludge. The start-up of mesophilic and thermophilic processes inoculated with mesophilic granular sludge was investigated in UASB reactors fed with diluted vinasse. The start-up proceeded faster in the filters than in the UASB reactors with TMP and synthetic wastewater. Loading rates of over 15 kgCODm−3d−1 with 50-60 % COD removal efficiencies were achieved in 10 days in the mesophilic and in 50 days in the thermophilic UASB reactor treating vinasse. The results show that high-rate anaerobic treatment can be applied to different types of industrial wastewaters under varying conditions.


2002 ◽  
Vol 45 (10) ◽  
pp. 145-150 ◽  
Author(s):  
P.L. Paulo ◽  
B. Jiang ◽  
K. Roest ◽  
J.B. van Lier ◽  
G. Lettinga

Experiments were performed to study the change in sludge characteristics and sludge granulation during the start-up of a thermophilic methanol-fed upflow anaerobic sludge bed (UASB) reactor. The laboratory scale reactor, was inoculated with thermophilic granular sludge and operated at 55°C over 130 days at organic loading rates (OLR) varying from 2.7 to 47 gCOD.L−1.d−1. Physical characterisation was performed for both the seed and the cultivated sludge. Results demonstrated that a good quality, well settleable granular sludge was cultivated and retained in the reactor, allowing an OLR of 47 gCOD.L−1.d−1 with 93% of methanol removal, where 79% was converted into methane. Using a community analysis of the cultivated consortia, high numbers of rod-shaped hydrogenotrophic methanogens were enumerated. Biomass washout coincided with a high specific gas load, but was not detrimental to the system in the conditions tested.


1999 ◽  
Vol 40 (8) ◽  
pp. 91-97 ◽  
Author(s):  
D. Jeison ◽  
R. Chamy

In the present study an upflow anaerobic sludge blanket (UASB) reactor and an expanded granular sludge bed (EGSB) reactor were operated with different substrates under the same conditions. Ethanol, diluted beer (as a brewery effluent model) and wastewater from a coffee industry were tested. Ethanol was fed at two different concentrations: 0.5 and 10 gCOD/l. Beer was diluted to a concentration of 3gCOD/l and coffee wastewater had a concentration of approximately 7 gCOD/l. During the operation, samples of sludge were taken from both reactors to measure TSS, VSS, size distribution and methanogenic activity. Batch assays were performed in a third reactor using ethanol at two different superficial velocities to measure substrate uptake. The overall COD removal for ethanol at 500 gCOD/l in EGSB and UASB reactors was similar (around 80% for a sludge loading rate of 0.8 gCOD/day/gVSS). Granular sludge experienced an important development in its characteristics during the operation with ethanol. Superficial velocity showed a positive effect on COD removal for ethanol below 5m/h. There were no big differences in the removal rates during the operation with coffee wastewater. Probably in this effluent the process is limited by the reaction kinetics instead of by the mass transfer, due to the complex nature of the waste. With diluted beer, EGSB reactor showed a better performance than the UASB.


1999 ◽  
Vol 40 (11-12) ◽  
pp. 67-75 ◽  
Author(s):  
Sigrun J. Jahren ◽  
Jukka A. Rintala ◽  
Hallvard Ødegaard

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.


2021 ◽  
Vol 11 (2) ◽  
pp. 510
Author(s):  
Elza R. Mikheeva ◽  
Inna V. Katraeva ◽  
Andrey A. Kovalev ◽  
Dmitriy A. Kovalev ◽  
Alla N. Nozhevnikova ◽  
...  

This article presents the results of the start-up of continuous production of biohydrogen from cheese whey (CW) in an anaerobic filter (AF) and anaerobic fluidized bed (AFB) with a polyurethane carrier. Heat and acid pretreatments were used for the inactivation of hydrogen-scavengers in the inoculum (mesophilic and thermophilic anaerobic sludge). Acid pretreatment was effective for thermophilic anaerobic sludge to suppress methanogenic activity, and heat treatment was effective for mesophilic anaerobic sludge. Maximum specific yields of hydrogen, namely 178 mL/g chemical oxygen demand (COD) and 149 mL/g COD for AFB and AF, respectively, were obtained at the hydraulic retention time (HRT) of 4.5 days and organic load rate (OLR) of 6.61 kg COD/(m3 day). At the same time, the maximum hydrogen production rates of 1.28 and 1.9 NL/(L day) for AF and AFB, respectively, were obtained at the HRT of 2.02 days and OLR of 14.88 kg COD/(m3 day). At the phylum level, the dominant taxa were Firmicutes (65% in AF and 60% in AFB), and at the genus level, Lactobacillus (40% in AF and 43% in AFB) and Bifidobacterium (24% in AF and 30% in AFB).


2000 ◽  
Vol 42 (10-11) ◽  
pp. 247-255 ◽  
Author(s):  
J. Paing ◽  
B. Picot ◽  
J. P. Sambuco ◽  
A. Rambaud

Sludge accumulation and the characteristics of anaerobic digestion in sludge had been investigated in a primary anaerobic lagoon. Methanogenic potential of sludge was evaluated by an anaerobic digestion test which measured the methane production rate. Sludge was sampled at several points in the lagoon to determine spatial variations and with a monthly frequency from the start-up of the lagoon to observe the development of anaerobic degradation. Maximum amounts of sludge accumulated near the inlet. The mean methane production of sludge was 2.9 ml gVS–1 d–1. Sludge near the outlet presented a greater methanogenic activity and a lesser concentration of volatile fatty acids than near the inlet. The different stages of anaerobic degradation were spatially separated, acidogenesis near the inlet and methanogenesis near the outlet. This staged distribution seemed to increase efficiency of anaerobic fermentation compared with septic tanks. Methane release at the surface of the lagoon was estimated to be very heterogeneous with a mean of 25 l m–2 d–1. The development of performance and sludge characteristics showed the rapid beginning of methanogenesis, three months after the start-up of the anaerobic lagoon. Considering the volume of accumulated sludge, it could however be expected that methanogenic activity would further increase.


2004 ◽  
Vol 49 (11-12) ◽  
pp. 69-76 ◽  
Author(s):  
J.E. Schmidt ◽  
D.J. Batstone ◽  
I. Angelidaki

Upflow anaerobic sludge blanket reactors may offer a number of advantages over conventional mixed-tank, SBR, and biofilm reactors, including high space-loading, low footprint, and resistance to shocks and toxins. In this study, we assessed the use of upflow anaerobic sludge blanket (UASB) reactor technology as applied to anaerobic ammonia removal, or Anammox. Four 200 ml UASB reactors were inoculated with 50% (by volume) anaerobic granular sludge and 50% flocular sludge from different sources (all with the potential for containing Anammox organisms). Tools used to assess the reactors included basic analyses, fluorescent in-situ hybridisation, and mathematical modelling, with statistical non-linear parameter estimation. Two of the reactors showed statistically identical Anammox activity (i.e., identical kinetic parameters), with good ammonia and nitrite removal (0.14 kgNHx m-3 reactor day-1, with 99% ammonia removal). The third reactor also demonstrated significant Anammox activity, but with poor identifiability of parameters. The fourth reactor had no statistical Anammox activity. Modelling indicated that poor identifiability and performance in the third and fourth reactors were related to an excess of reduced carbon, probably originating in the inoculum. Accumulation of Anammox organisms was confirmed both by a volume loading much lower than the growth rate, and response to a probe specific for organisms previously reported to mediate Anammox processes. Overall, the UASB reactors were effective as Anammox systems, and identifiability of the systems was good, and repeatable (even compared to a previous study in a rotating biological contactor). This indicates that operation, design, and analysis of Anammox UASB reactors specifically, and Anammox systems in general, are reliable and portable, and that UASB systems are an appropriate technology for this process.


2016 ◽  
Vol 11 (1) ◽  
pp. 47-55
Author(s):  
Nadeem Khalil ◽  
Tarique Ahmad

Amongst the technologies available, the up flow anaerobic sludge blanket (UASB) process has been one of the most widely applied methods for municipal waste water treatment especially in countries of warm climatic conditions like India. However, past about one decade has witnessed rapid decline in the UASB popularity and its implementation. There has been criticism from various sections on the performance of UASB reactors for not complying with the prescribed discharge standards. It is a general hypothesis that the UASB reactors are not meant for diluted waste water like municipal sewage when typically the BOD is less than 150 mg/l, COD 250 mg/l and sulphates are more than 150mg/l. An attempt has been made through this study to investigate the reasons on the basis of quality assessment and field observations on UASB reactors and it’s post-treatment of a newly commissioned (start-up) municipal (sewage) wastewater treatment plant commonly called ‘STP’ having capacity of 14 million litres per day (MLD). Study was aimed to know the gaps during the commissioning stage which could be related to poor removal efficiencies. This paper briefly discusses some issues related to operation and maintenance of the UASB plants with purpose for improvements.


2013 ◽  
Vol 634-638 ◽  
pp. 182-186
Author(s):  
Juan Wang ◽  
Qin Zhong

With the aim to use anaerobic granular sludge, the methanogenic activity inhibition and recovery of anaerobic granular sludge from an industrial anaerobic reactor (s1) were investigated by measuring the methane volume at low pH. A lab-scale upflow anaerobic sludge blanket (UASB) reactor was inoculated with s1.s1 was used to remove Zn2+ in wastewater. The results show that activity of s1 is similar when the pH value is 6.5 to 7.0. The methane volume is obviously decreased when the pH value is 6.0. The activity is completely inhibited when the pH value is 4.5. The activity is fully recovered when the pH is above 6.5 and hardly recovers when the pH fell to 4.5. The main Zn2+ removal mechanism is chemical adsorption.


2001 ◽  
Vol 44 (8) ◽  
pp. 49-56 ◽  
Author(s):  
M.H.A. van Eekert ◽  
G. Schraa

Chlorinated ethenes and chlorinated aromatics are often found as pollutants in sediments, groundwater, and wastewater. These compounds were long considered to be recalcitrant under anaerobic conditions. In the past years however, dechlorination of these compounds has been found to occur under anaerobic conditions at contaminated sites and in wastewater treatment systems. This dechlorination is mainly attributed to halo-respiring bacteria, which are able to couple this dechlorination to energy conservation via electron transport coupled phosphorylation. The dechlorinating activities of the halo-respiring bacteria seem to be confined to the dechlorination of chloroethenes and chlorinated aromatic compounds. In addition, methanogenic and acetogenic bacteria are also able to reduce the chlorinated ethenes via a-specific cometabolic pathways. Although these latter reactions may not be important in the remediation of contaminated sites, they may be of substantial influence in the start-up of remediation processes and in the application of granular sludge from UASB reactors. Specific halo-respiring bacteria may be used to increase the dechlorination activities via bioaugmentation in the case that the appropriate microorganisms are not present at the contaminated site or in the sludge.


Sign in / Sign up

Export Citation Format

Share Document