scholarly journals Biological treatment of whey in an UASFF bioreactor followed a three-stage RBC

2010 ◽  
Vol 16 (2) ◽  
pp. 175-182 ◽  
Author(s):  
Atiye Ebrahimi ◽  
Ghasem Najafpour ◽  
Maedeh Mohammadi ◽  
Babak Hashemiyeh
Keyword(s):  
Biological Treatment ◽  
High Strength ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
Anaerobic Sludge ◽  
Aerobic Treatment ◽  
Rotating Biological Contactor ◽  
Anaerobic Process ◽  
Fixed Film ◽  
Removal Efficiencies

Biological treatment of a high strength chesses whey wastewater was investigated in a series of aerobic-anaerobic experiments. Aerobic treatment of the wastewater was conducted in a three-stage rotating biological contactor (NRBC), while the anaerobic process was performed in an up-flow anaerobic sludge fixed film (UASFF) bioreactor. Various concentrations of wastewater with influent COD of 40,000 to 70,000 mg/L were introduced in to NRBC system. Treatability of the samples at various HRTs of 8, 12 and 16 h was evaluated in the NRBC reactor. The effluent streams of the NRBC system were introduced into UASFF bioreactor. Anaerobic treatment of the pretreated samples was investigated in an UASFF with the same HRTs of 8, 12 and 16 h. The obtained results revealed that more than 53, 69 and 78% of the influent COD (50,000 mg/L) were removed in NRBC reactor at HRTs of 8, 12 and 16 h, respectively. Maximum COD removal efficiencies of 96, 96.8, 97.4 and 96.4% were achieved in the combined systems at total HRT of 32 h for influent COD of 40,000, 50,000, 60,000 and 70,000 mg/L, respectively.

Low temperature treatment of domestic sewage in upflow anaerobic sludge blanket and anaerobic hybrid reactors

1999 ◽  
Vol 39 (5) ◽  
pp. 177-185 ◽  
Author(s):  
Tarek A. Elmitwalli ◽  
Marcel H. Zandvoort ◽  
Grietje Zeeman ◽  
Harry Bruning ◽  
Gatze Lettinga
Keyword(s):  
Low Temperature ◽  
Sewage Treatment ◽  
Average Diameter ◽  
Anaerobic Treatment ◽  
Domestic Sewage ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Removal Efficiencies

The treatment of sewage at a temperature of 13°C was investigated in three reactors (each 3.84 litre) a UASB and two anaerobic hybrid (AH) reactors with small sludge granules with an average diameter of 0.73 mm. The media used in the AH reactors were vertical polyurethane foam sheets. The reactors were operated at a HRT of 8 h. The use of small sludge granules and operating the reactors at low upflow velocity (1.8 m/d) improved suspended COD removal efficiencies for the UASB reactor. Moreover, the use of sheets in the AH reactors significantly increased suspended COD removal efficiencies as compared to the UASB and reached to 87% for pre-settled sewage treatment. The treatment of pre-settled sewage instead of raw sewage in AH reactors significantly increased colloidal and dissolved COD removal efficiencies with 13% and 12% respectively and colloidal COD removal efficiency for the UASB reactor with 13%. At ‘steady state’ for pre-settled sewage treatment, the AH reactors removed 64% of the total COD which is significantly higher by 4% than the UASB reactor. Therefore, the anaerobic treatment of domestic sewage at low temperature can be improved by treating pre-settled sewage in shallow AH reactors containing small sludge granules.

Anaerobic filter and DSFF reactors in anaerobic treatment of tuna processing wastewater

1994 ◽  
Vol 30 (12) ◽  
pp. 425-432 ◽  
Author(s):  
M. C. Veiga ◽  
R. Méndez ◽  
J. M. Lema
Keyword(s):  
Anaerobic Treatment ◽  
Cod Removal ◽  
Organic Loading ◽  
Processing Industry ◽  
Loading Rates ◽  
Anaerobic Filter ◽  
Anaerobic Reactors ◽  
Start Up ◽  
Fixed Film ◽  
Removal Efficiencies

An anaerobic filter (AF) and a downflow stationary fixed film (DSFF) reactor were used for the treatment of a tuna processing wastewater. Start-up of the anaerobic reactors was improved using lactose as co-substrate. The AF removed up to 75% of the influent COD concentrations at organic loading rates (OLR) of 11-13 kg COD m−3 d−1, whereas the DSFF reactor removed 70% at 3 kg COD m−3 d−1. Based on these results it appears that anaerobic treatment systems are applicable to tuna processing industry wastewaters and that the AF shows a much better performance, allowing higher organic loadings and COD removal efficiencies than the DSFF reactor.

Sequential anaerobic/aerobic biotreatment of bark leachate

2003 ◽  
Vol 48 (6) ◽  
pp. 203-209 ◽  
Author(s):  
J.C. Frigon ◽  
R. Cimpoia ◽  
S.R. Guiot
Keyword(s):  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Phenol Removal ◽  
Aerobic Treatment ◽  
Hydraulic Residence Time ◽  
Operational Conditions ◽  
Fixed Film ◽  
Air Diffusion

Bark leachate is generated from sawmill operations such as log storage sites and contains polymeric tannins, carbohydrates, organic acids, phenolic and resin compounds. The present study was aimed at assessing the performance of a sequential anaerobic and aerobic treatment, for both chemical oxygen demand (COD) and phenol removal, under various combinations of operational conditions, in the continuous mode. After anaerobic treatment in a five litres upflow anaerobic sludge bed (UASB) reactor, the leachate was directed into two parallel aerobic reactors, either an activated sludge unit or a fixed film submerged filter (packed with polyethylene Flexirings), both of a volume of one litre and oxygenated by air diffusion. For a leachate of 22 gCOD/l, an overall COD removal of 96Ð98% was achieved at an hydraulic residence time (HRT) of 4 days for the anaerobic reactor and one day for either aerobic systems. The phenol concentration generally increased after anaerobic treatment but was below the detection limit (50 ppb) after aerobic polishing. Radiorespirometric microcosms with 14C-labelled phenol confirmed that phenol was mineralized in the aerobic reactors. The performances of both aerobic systems were similar for COD and phenol removal. Thus, a sequential anaerobic/aerobic treatment was able to effectively address the contamination of a bark leachate discharge, including phenols.

Anaerobic treatment of natural tannin extracts in UASB reactors

2003 ◽  
Vol 48 (6) ◽  
pp. 157-163 ◽  
Author(s):  
J. López-Fiuza ◽  
F. Omil ◽  
R. Méndez
Keyword(s):  
Volatile Fatty Acids ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Tannin Extract ◽  
Aqueous Environments ◽  
Removal Efficiencies ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors

Tannin extracts are substances commonly used in leather production processes. Since most of the steps of tannery manufacturing processes are carried out in aqueous environments, the presence of these compounds in the wastewaters is important. The aim of this work is to study the feasibility of the anaerobic degradation of three natural tannin extracts in three Upflow Anaerobic Sludge Blanket (UASB) reactors, which were fed with increasing concentrations of two condensed (quebracho and wattle) and one hydrolysable tannin extract (chestnut). Concentrations of applied extracts were 100, 200, 400, 800 and 1,000 mg/l, and 5 g/l of glucose was used as cosubstrate. Reactors were operated during 210 days and their performance was evaluated from the values of total and soluble COD, total and intermediate alkalinity, volatile fatty acids, pH and UV absorption at 280 nm. COD removal efficiencies higher than 85% were achieved in all cases. However, tannin extract removal efficiencies (based on UV-280 nm absorption measurements) were significantly lower, around 20% for condensed extracts and 60% for the hydrolysable one, when the reactors operated with the highest tannin extract concentration. The operation of the reactors was stable, commonly with alkalinity ratios below 0.30. Mass balances carried out indicate that most of the COD removal efficiencies are due to the removal of the readily biodegradable organic matter (glucose), whereas the tannin extracts are hardly anaerobically biodegradable, especially condensed extracts (wattle and quebracho).

Dairy Waste Treatment with Anaerobic Stationary Fixed Film Reactors

1983 ◽  
Vol 15 (8-9) ◽  
pp. 359-368 ◽  
Author(s):  
L van den Berg ◽  
K J Kennedy
Keyword(s):  
Cheese Whey ◽  
Loading Rate ◽  
Cod Removal ◽  
High Loading ◽  
Loading Rates ◽  
Dairy Wastes ◽  
Plant Waste ◽  
Fixed Film ◽  
Dairy Plant ◽  
Removal Efficiencies

Cheese whey and a dilute waste from a cheese factory with a Chemical Oxygen Demand of 66,000 and 4,000 mg (COD)/L respectively, were treated at high loading rates in 0.7 to 1.2 L downflow anaerobic stationary fixed film reactors and an upflow sludge bed reactor. In downflow stationary fixed film reactors treating cheese whey, COD removal efficiencies of 97% were achieved at a loading rate of 5 kg COD/m3/day and 92% at a maximum loading rate of 22 kg COD/m3/day. With dairy plant waste, loading rates of up to 15 kg COD/m3/day were possible with COD removal efficiencies averaging 75%, decreasing slightly with increasing loading rates. In an upflow sludge bed reactor the COD removal efficiency of dairy plant waste, decreased from 87% at 5 kg COD/m3/day to 73% at 15 kg COD/m3/day. A stationary fixed film reactor treating a skim milk powder waste (4,000 ppm) could only be operated at up to 10 kg COD/m3/day with a treatment efficiency of 72%. Methane was produced from all wastes at rates corresponding to 0.32 m3 CH4 (0°C, 1 atm) per kg COD removed. Results show that stationary fixed film reactors are capable of treating dairy wastes at high loading rates and high COD removal efficiencies.

Evaluation of a hybrid upflow anaerobic sludge-filter bed reactor: effect of the proportion of packing medium on performance

2010 ◽  
Vol 61 (6) ◽  
pp. 1441-1450 ◽  
Author(s):  
Rajinikanth Rajagopal ◽  
Indu Mehrotra ◽  
Pradeep Kumar ◽  
Michel Torrijos
Keyword(s):  
Cod Removal ◽  
Anaerobic Sludge ◽  
Average Value ◽  
Working Volume ◽  
Removal Efficiencies ◽  
Filter Bed

The aim of this study was to determine the effects of the volume occupied by the filter bed zone on the behavior of an anaerobic hybrid UASFB reactor. This configuration contains a sludge bed in the lower part of the reactor and a filter bed in the upper part. Three such reactors, each with a working volume of 9.8-L, were studied; these differed in proportion of packing medium occupying 50, 35 and 20% of the working volume of the reactors, respectively. All the reactors were fed with wine distillery vinasse and were operated for a period of 232 days at 33 ± 1°C with increasing OLRs. No significant differences were observed between the reactors for the range of OLRs studied. Indeed, relatively high OLRs could be reached for all the three reactors with an average OLR of about 18 g COD/L d towards the end of the experiment, while maintaining a constant HRT of 26 h. CODt and CODs removal efficiencies were always more than 80 and 86%, respectively, even for the highest OLR. High quantities of VS were accumulated in the reactors with an average value of 438 ± 17 g per reactor. Most of the biomass was in the sludge bed zone suggesting that this part was playing a major role in COD removal. The internal packing medium on the top of the reactor had a key role in retaining the small flocculated particles inside the reactor, while minimizing the escape of solids in the effluent. This study suggests that low packing volume ratios can be used in the design of UASFB reactors, which allows a reduction in the costs of packing medium required as the supports are expensive.

Anaerobic and Aerobic Treatment for AOX Removal

1994 ◽  
Vol 29 (5-6) ◽  
pp. 149-162 ◽  
Author(s):  
John F. Ferguson
Keyword(s):  
Biological Treatment ◽  
Anaerobic Treatment ◽  
Reductive Dehalogenation ◽  
Aerobic Treatment ◽  
Abiotic Degradation ◽  
In Series ◽  
Kraft Mill ◽  
Significant Chemical ◽  
Aox Removal ◽  
Aerobic And Anaerobic

A two-year study has focused on AOX removal from bleaching wastewaters in anaerobic and aerobic biological treatment, using bench scale bioreactors operated in parallel and in series. Significantly higher removals have been found in anaerobic than in aerobic treatment. Earlier work with dilute kraft bleaching wastes has been extended in additional laboratory tests and at a nearby kraft mill. 50-75% fractions of bleaching wastes were treated. Toxicity in the anaerobic process was encountered at 85% bleach waste fractions. Total AOX removal experienced in aerobic treatment is 30-35%, in anaerobic treatment 40-45%, and in an anaerobic/aerobic sequence 50-55%. Percentage removals were not sensitive to the fraction of bleaching wastewater. Several process modifications were attempted to try to obtain higher removals with only marginal success. Studies at a kraft mill confirmed the AOX removals that had been found in lab studies. AOX removal occurs by several mechanisms. There is a very significant chemical or abiotic degradation that occurs after neutralization, perhaps enhanced by reductants or other inorganic salts. Biological processes are much more significant in anaerobic than in aerobic treatment. Anaerobic reductive dehalogenation affects specific chlorinated compounds and catalyzed AOX degradation is facilitated by reduced coenzymes that are produced by bacteria. Removal by sorption or insolubilization is relatively minor in aerobic and anaerobic processes.

Pretreatment and biotreatment of saline industrial wastewaters

2006 ◽  
Vol 53 (3) ◽  
pp. 17-25 ◽  
Author(s):  
B.J.W. Tuin ◽  
R. Geerts ◽  
J.B. Westerink ◽  
C.G. van Ginkel
Keyword(s):  
Biological Treatment ◽  
Chloride Concentration ◽  
High Strength ◽  
Aerobic Biodegradation ◽  
Aerobic Treatment ◽  
Chloride Level ◽  
Akzo Nobel ◽  
Adaptation Time ◽  
Saline Waters ◽  
Anaerobic Pretreatment

Wastewater from an Akzo Nobel production site contains more than 50 g/l total dissolved salts, mainly chlorides and sulphates, and is currently being treated after 10–20× dilution. Biological treatment of undiluted or less diluted wastewater is very desirable for environmental and economic reasons. Possibilities were investigated in laboratory scale reactors to treat this highly saline and high strength wastewater aerobically, either after long adaptation or after removing part of the salts by a pretreatment. Adaptation and selection from mixed activated sludge populations took approximately 40 days to finally achieve a COD removal in aerobic treatment of 55–65% at two times dilution (11–16 g/l chloride and 5–7 g/l sulphate). Undiluted wastewater was not treatable. A higher removal percentage (>80%) was possible at the original high salt concentration only when the sludge load was limited to approximately 0.4–0.5 kg COD/kg sludge/day. A longer adaptation time was required. Nanofiltration (NF) and crystallization could be used as a pretreatment to remove and recover up to 80% of the sulphate in the form of crystallized Glauber salt. Recovery strongly depended on the sulphate and chloride concentration in the NF concentrate and on crystallization temperature. The salt (sulphate) reduction through the NF improved the removal efficiency of a consecutive biotreatment only at a relatively low chloride level, demonstrating that the combination of nanofiltration-crystallization-aerobic biodegradation is less feasible for very saline wastewaters. Anaerobic pretreatment of saline waters turned out to be rather sensitive to high salinities. Only wastewater diluted to 10 g/l chloride could be treated well: sulphate concentration decreased by 80% and COD by 40%. Removal efficiencies of the combined anaerobic-aerobic treatment were approximately 80–85%, proving that this was a feasible route for 2–3× diluted wastewater. The study has shown that several alternatives are available for treatment of the very saline wastewaters at a much lower degree of dilution than currently practiced.

Anaerobic treatment of landfill leachate by sulfate reduction

2000 ◽  
Vol 41 (3) ◽  
pp. 239-246 ◽  
Author(s):  
J.G. Henry ◽  
D. Prasad
Keyword(s):  
Landfill Leachate ◽  
High Surface ◽  
High Strength ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
Sulphate Reduction ◽  
High Rate ◽  
Organic Loading Rate ◽  
Filter Performance ◽  
Low Strength

The present study was conducted to investigate the effectiveness of the sulphate-reduction pathway in the anaerobic treatment of landfill leachate. The effects of several COD/SO4 ratios (keeping COD constant) and loadings on anaerobic filter performance were studied and compared with the results from anaerobic filters which followed the methanogenic pathway. Results indicated that the treatability of leachate by sulphate reducing bacteria (SRB) was dependent upon the leachate strength. With high strength leachate (COD=15000 mg/L) from the Keele Valley Landfill, it was found that at lower COD/SO4 ratios (≤1.6) toxic conditions developed in the system that were more inhibitory to the SRB than to the methane producing bacteria (MPB). As the COD/SO4 ratio increased, methanogenesis predominated. No predominance of SRB occurred at any COD/SO4 ratio with high strength leachate. The highest COD removal achieved was about 70% of which 20% was accomplished by the SRB at a COD/SO4 ratio of 1.6 and an organic loading rate (OLR) of 4 kg COD/m3.d. With low strength leachate (COD=1500-3300 mg/L) from the Brock West Landfill, and a COD/SO4 ratio <1, SRB became predominant. In these anaerobic filters in which SRB were predominant, the SRB reduced the COD as well as the MPB could. Sulphide inhibition did not take place at any loading in units treating low strength leachate. Consequently, both SRB and MPB should function at COD/SO4 ratios between 1 and 3. About 60% COD removal was achieved at a loading of 2.8 kg COD/m3.d and a COD/SO4 ratio of 1.0. However at a loading of 6 kg COD/m3.d only 27% COD removal was achieved, all of it through the sulphate-reduction pathway. These OLR values are comparable to those applied in systems where methanogenesis was dominant. It was also observed that once the methanogens were established in the units, it was not possible to displace them completely. However, where methanogenesis had not been previously established, it was found that sulphate-reduction could be the sole pathway for COD removal. From this study, it can be concluded that there is no advantage to the sulphate-reduction pathway in the anaerobic treatment of landfill leachate. The other options for increasing the loadings, i.e. the use of high surface/volume filter media (to achieve higher biomass concentrations) or high rate systems are likely to be more successful.

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