Influence of Flow Regime on the Concentration of Cyanide Producing Anaerobic Process Inhibition

1999 ◽  
Vol 40 (8) ◽  
pp. 177-185 ◽  
Author(s):  
Olga Rojas Ch. ◽  
Didier Alazard ◽  
Leonardo Aponte R. ◽  
Luis F. Hidrobo
Keyword(s):  
Potassium Cyanide ◽  
Anaerobic Sludge ◽  
Batch Reactors ◽  
Bacterial Populations ◽  
Methanogenic Activity ◽  
Synthetic Substrate ◽  
Entire Experiment ◽  
Specific Methanogenic Activity ◽  
Exposure Stage ◽  
Anaerobic Sludge Blanket

A study was conducted to analyze the effects of cyanide on methanogenic bacterial populations in both continuous and batch reactors. The appropriate toxicity assays were divided into two parts, i.e. 1) batch assays, and 2) continuous flow assays, using a 6.5-litre up-stream anaerobic sludge blanket reactor (UASB). A synthetic substrate was used as feed for both assays using 99% sucrose as a carbon source, and potassium cyanide (KCN) as a free cyanide source. In the first part, the treatments with the lowest and highest percentages of Specific Methanogenic Activity (SMA %) were 3 and 10 mg CN−/l. A 0.96 mg/l concentration of cyanide caused methanogenic activity inhibition by 50% during the exposure stage. During the recovery stage, Methanogenic Activity of treatments had a considerable increase compared to the results from direct cyanide exposure, except for treatments of 7 and 10 mg CN−/l. The concentration of cyanide that inhibits Specific Methanogenic Activity by 50% was 6.1 mg CN−/l during this stage. In the second part, the reactor was continuously fed with a synthetic substrate (COD≈ 1500 mg/l). After the anaerobic sludge became acclimated, cyanide concentrations from 0.5 and 130 mg CN−/l were progressively added. The hydraulic retention time remained constant at 12 hours throughout the entire experiment. Results indicated that while partial inhibition occurred for concentrations of 3, 20 and 100 mg CN−/l, severe inhibition occurred for 130 mg CN−/l.

Acid Endurance and Sorption of Zn2+ of Anaerobic Granular Sludge Acclimated by Flue Gas Pretreatment Wastewater

2013 ◽  
Vol 634-638 ◽  
pp. 182-186
Author(s):  
Juan Wang ◽  
Qin Zhong
Keyword(s):  
Flue Gas ◽  
Ph Value ◽  
Granular Sludge ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Anaerobic Granular Sludge ◽  
Methanogenic Activity ◽  
Activity Inhibition ◽  
Anaerobic Sludge Blanket

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.

The impact of metal transport processes on bioavailability of free and complex metal ions in methanogenic granular sludge

2012 ◽  
Vol 65 (10) ◽  
pp. 1875-1881 ◽  
Author(s):  
Jan Bartacek ◽  
Fernando G. Fermoso ◽  
Frank Vergeldt ◽  
Edo Gerkema ◽  
Josef Maca ◽  
...  
Keyword(s):  
Granular Sludge ◽  
Major Effect ◽  
Transport Processes ◽  
Metal Species ◽  
Anaerobic Sludge ◽  
Entire Volume ◽  
Methanogenic Activity ◽  
Magnetic Resonance Imaging Mri ◽  
Anaerobic Sludge Blanket ◽  
The Impact

Bioavailability of metals in anaerobic granular sludge has been extensively studied, because it can have a major effect on metal limitation and metal toxicity to microorganisms present in the sludge. Bioavailability of metals can be manipulated by bonding to complexing molecules such as ethylenediaminetetraacetate (EDTA) or diethylenetriaminepentaacetate (DTPA). It has been shown that although the stimulating effect of the complexed metal species (e.g. [CoEDTA]2−) is very fast, it is not sustainable when applied to metal-limited continuously operated reactors. The present paper describes transport phenomena taking place inside single methanogenic granules when the granules are exposed to various metal species. This was done using magnetic resonance imaging (MRI). The MRI results were subsequently related to technological observations such as changes in methanogenic activity upon cobalt injection into cobalt-limited up-flow anaerobic sludge blanket (UASB) reactors. It was shown that transport of complexed metal species is fast (minutes to tens of minutes) and complexed metal can therefore quickly reach the entire volume of the granule. Free metal species tend to interact with the granular matrix resulting in slower transport (tens of minutes to hours) but higher final metal concentrations.

DEGRADATION OF STARCH PARTICULATES IN A HYBRID REACTOR

1994 ◽  
Vol 30 (4) ◽  
pp. 97-104 ◽  
Author(s):  
Herbert H. P. Fang ◽  
Tin-Sang Kwong
Keyword(s):  
Loading Rate ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Hybrid Reactor ◽  
Anaerobic Sludge ◽  
Methanogenic Activity ◽  
Loading Rates ◽  
Granular Biomass ◽  
Abundant Supply ◽  
Anaerobic Sludge Blanket

The study was conducted over 265 days to study the feasibility of removing starch particulates from wastewater using an 8.5 L reactor which was a hybrid between the upflow anaerobic sludge blanket (UASB) and the anaerobic filter reactors. At pH 7.2-7.5 and 37°C, the reactor was effective for the removal of chemical oxygen demand (COD) from wastewater containing starch particulates equivalent to 5000 mglL of COD with 12 hours of retention time, corresponding to a loading rate of 10 g-COD/L.d. Despite their insoluble nature, the starch particulates did not cause noticeable adverse effeels on the granulation of biomass, probably due to its easy-to-biodegrade nature and the cautious startup strategy. About 5.8% of COD in wastewater remained in the effluent, 82.5% was converted to methane, and the remaining 11.7% was converted to granular biomass with an average sludge yield of 0.09 g-VSS/g-COD. The granules exhibited a layered microstructure. The methanogenic activity of the granular biomass was 0.86 g-methane-COD/g-VSS.d in the reactor, which was considerably lower than the 1.96 g-methane-COD/ g-VSS.d measured in serum vials with an abundant supply of substrate, suggesting that further increase of loading rates was possible for the hybrid reactor.

The effect of operational conditions on the sludge specific methanogenic activity and sludge biodegradability

2009 ◽  
Vol 59 (9) ◽  
pp. 1847-1853 ◽  
Author(s):  
R. C. Leitão ◽  
S. T. Santaellla ◽  
A. C. van Haandel ◽  
G. Zeeman ◽  
G. Lettinga
Keyword(s):  
Municipal Wastewater ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Treatment Unit ◽  
Methanogenic Activity ◽  
Operational Conditions ◽  
Anaerobic Reactors ◽  
Specific Methanogenic Activity

The effects of hydraulic retention time (HRT) and influent COD concentration (CODInf) on Specific Methanogenic Activity (SMA) and the biodegradability of an anaerobic sludge need to be elucidated because of the discordant results available in literature. This information is important for the operation of anaerobic reactors and design of the sludge post-treatment unit. For this study, sludge samples obtained from eight pilot-scale Upflow Anaerobic Sludge Blanket (UASB) reactors were tested. The reactors were fed with municipal wastewater and operated with different sets of HRT and influent concentrations until the steady state was established. The results show that at a lower HRT, sludge with relatively higher SMA develops. A slight trend of declining SMA at increasing CODInf was found for reactors operated at longer HRTs; however, further experiments are necessary for more definitive conclusions. The sludge from reactors operated at longer HRTs and with lower CODInf resulted in lower biodegradability. Results also showed that it is ineffective to design a UASB reactor with a longer HRT to cope with organic shock loads.

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.

scholarly journals Design optimization of a simple, single family, anaerobic sewage treatment system

2017 ◽  
Vol 12 (1) ◽  
pp. 55-71
Author(s):  
Silvânia Lucas dos Santos ◽  
João Paulo de Oliveira Simões ◽  
Francisco Vieira Paiva ◽  
Adrianus van Haandel
Keyword(s):  
Large Scale ◽  
Sewage Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Septic Tank ◽  
Anaerobic Sludge ◽  
Single Family ◽  
Reactor Performance ◽  
Methanogenic Activity ◽  
Anaerobic Sludge Blanket ◽  
High Degree

Anaerobic sewage treatment systems, notably the upflow anaerobic sludge blanket reactor, have been applied successfully in Brazil in dozens of large scale units. In this paper a small reactor is proposed for use in single family houses, without a connection to a sewerage network. The proposed reactor is much smaller than the traditional septic tank and yet the treatment efficiency is much higher. It comprises a lower cylindrical digestion zone and an upper settling zone, connected by a transition zone. Several configurations with different digestion and settling zone diameters were tested to establish their influence on reactor performance. A high degree of organic matter removal was obtained with 250 L reactors with retention times of 6 to 12 hours. A large sludge mass was retained in the digestion zone and high treatment capacity was maintained throughout the study. Tests showed that sludge settled better in the reactor than it did after discharge with the effluent. In contrast the, methanogenic activity of the sludge in the reactor was the same as that of the sludge expelled.

Use of external carbon sources derived from biowaste for short-cut nutrient removal from anaerobic effluents

2014 ◽  
Vol 69 (9) ◽  
pp. 1853-1858 ◽  
Author(s):  
Evina Katsou ◽  
Nicola Frison ◽  
Simos Malamis ◽  
Francesco Fatone
Keyword(s):  
Acetic Acid ◽  
Nutrient Removal ◽  
Carbon Sources ◽  
Phosphorus Uptake ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Fermentation Liquid ◽  
Anaerobic Sludge Blanket

This work evaluated the use of different external carbon sources to promote the via-nitrite nutrient removal from anaerobic effluents. The carbon sources consisted of fermentation liquid produced from the organic fraction of municipal solid waste (OFMSW FL), drainage liquid produced from OFMSW, fermentation liquid produced from vegetable and fruit waste (VFW FL) and acetic acid. Denitritation and phosphorus uptake via nitrite were evaluated in two sequencing batch reactors, one treating the anaerobic supernatant produced from the co-digestion of OFMSW and activated sludge (highly nitrogenous anaerobic effluent – HNAE), and the other one treating the weakly nitrogenous anaerobic effluent (WNAE) from an upflow anaerobic sludge blanket reactor. The use of OFMSW FL to treat HNAE resulted in high nitrite (27 mgN/(gVSS·h) (VSS – volatile suspended solids) and phosphate uptake (15 mgP/gVSS·h). In the WNAE, nutrient kinetics were much slower. The use of acetic acid and VFW FL performed poorly, while the use of OFMSW FL, which was rich in butyric acid and propionic acid, resulted in significant nutrient removal (7 mgN/gVSS·h and 6 mgP/gVSS·h). The economic evaluation showed that the use of OFMSW FL is a less expensive option than the acetic acid use.

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.

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