MEMORANDUM 

TO: Brian D’Amico, USEPA/OW/OST/EAD 

FROM: Cortney Itle, ERG 

DATE: August 31, 2010 

SUBJECT: Summary of Anaerobic Fluidized Bed Applications 

Anaerobic Fluidized Beds (AFBs) are a type of reactor that can be used to complete multiphase 

chemical reactions. In these reactors, granular substrates are fluidized by the flow of liquids or 

gas through the system. Historically, AFBs have been used in the petroleum industry to process 

petroleum. However, AFBs are becoming more commonly used to biologically treat 

wastewaters. AFBs have advantages over other anaerobic treatment systems because they have 

larger surface areas for biological treatment. This allows AFBs to treat higher strength wastes 

and have shorter treatment times than other systems. In addition, AFBs are less likely to clog or 

retain sludge and they have smaller volume and area requirements compared to other systems. 

AFBs have been successful in treating many different types of wastewaters. The purpose of this 

memorandum is to provide a brief overview of examples of the applications of AFBs. A select 

number of journal articles were reviewed that discussed various uses of AFBs. An exhaustive 

literature review was not performed; this memorandum does not provide a complete list of all of 

the potential applications of AFBs and instead provides a brief overview of a few selected 

applications. 

The articles reviewed include: 

 Borja and Banks (1995).

 Garcia-Calderon, et al. (1998) 

 Haroun and Idris (2009) 

 Heijnen, et al. (1989) 

 Sowmeyan and Swaminathan (2008) 

 Toldra, et al. (1987) 

Full citations of the articles are provided in the reference list. Brief descriptions of the articles 

are included below. 

Borja and Banks (1995) 

The Borja and Banks study reviewed the effectiveness of AFB to treat ice cream wastewater, 

which is a complex mixture including milk proteins, carbohydrates, and lipids. Because of the 

high lipid content and chemical oxygen demand (COD), off site disposal of the wastewater has 

proven to be difficult and expensive. Previous studies have shown that other anaerobic treatment 

systems can be effective treatment methods for these wastewaters. The purpose of this study was 
Memorandum 

August 31, 2010 

Page 2 of 4 

to document the efficiency of AFB and to determine the effects of changing parameters (influent 

COD, temperature, etc) on the reactor effluent. The wastewater was treated in a bench scale 

reactor. The reactor was able to remove COD up to 94 percent with COD loading rates of 15.6 

grams per liter per day. 

Garcia-Calderon, et al. (1998)

Wastewater from a red wine distillery was treated in a downflow AFB in the Garcia-Calderon 

study. A bench scale AFB reactor which included perlite as the fluidized substrate was used in 

this study. The reactor achieved 85 percent removal of total organic carbon (TOC) removal, at 

an organic loading rate of 4.5 kg TOC per m3 per day. 

Haroun and Idris (2009) 

Textile wastewater has high COD, biochemical oxygen demand (BOD), and color. Haroun and 

Idris investigated the effects of varying hydraulic retention times (HRTs), organic loading rates 

(OLRs), and amounts of supplemented glucose (an external carbon source) on the removal of 

COD, BOD, and color from textile wastewater. The study determined that the most efficient 

system included the addition of 600 mg/l glucose. This system was able to achieve a 98 percent 

reduction in soluble COD on a loading rate of 4.4 kg COD per m3

 per day. 

Heijnen, et al. (1989) 

Heijnen et al. provided an overview of the application of AFBs in wastewater treatment by 

providing a historical summary of AFB development and research. The article states that the 

understanding of AFB treatment progressed in the 1980’s, and historic disadvantages of AFBs 

have been overcome. A summary table of research articles is provided that lists the type of 

waste treated and the characteristics of the systems and treatment achieved for each article. In 

addition, summaries of several full scale systems are provided that treat soft drink wastewater 

plant, a soy protein factory, and a yeast factory. 

Sowmeyan and Swaminathan (2008) 

Sowmeyan and Swaminathan researched the ability of a downflow AFB to treat distillery 

wastewater with varying HRTs and OLRs. A bench scale reactor was constructed and fed a 

synthetic wastewater that was given the characteristics of distillery waste. The AFB was found 

to be adaptable to different HRTs and OLRs and it maintained a removal of approximately 84 

percent of COD with OLRs of up to 35 kg COD per m3

 per day. 

Toldra, et al. (1987) 

Toldra et al. used 3 bench scale AFB reactors to treat wastewater from a hog slaughterhouse, a 

dairy processing plant, and a brewery. The different types of wastewater exhibited different 

treatment characteristics depending on temperature and OLR. For slaughterhouse waste, 75 

percent of soluble COD was removed with influent concentrations of 430-850 mg/L COD. 
Memorandum 

August 31, 2010 

Page 3 of 4 

Dairy waste with 200-500 mg/L COD was treated to 80 percent of soluble COD removal. 

Brewery waste achieved 50 percent removal of soluble COD with influents of 860-2500 mg/L 

COD. 

Table 1 presents a summary of the articles reviewed, including the type of waste, the scale of the 

system, the strength of the waste, and the removal of the system. 

Table 1. Summary of AFB Articles Reviewed 

Reference Type of Waste Scale of system Strength of waste Removal 

Borja and Banks 

1995 

Ice cream Bench scale 5.2 g/l 94% COD 

Garcia-Calderon et 

al. 1998 

Distillery Bench scale 5.5 to 6.5 kg/m TOC 

4.5 kg TOC/m3-day 

11.3 kg COD/m3/day 

85% TOC 

Haroun and Idris 

2009 

Textile Bench scale 2200 mg/L COD 

4.4 kg COD/m3/day 

98% soluble COD 

Heijnen et al.1989 Multiple Multiple Multiple Multiple 

Sowmeyan and 

Swaminathan 2008 

Distillery Bench scale 35 kg COD/m3-day 84% COD 

Toldra et al.1987 Slaughterhouse 

Dairy 

Brewery 

Bench scale 430-850 

200-500 

860-2500 

mg/L COD 

75% 

80% 

50% 

soluble COD 
Memorandum 

August 31, 2010 

Page 4 of 4 

References 

Borja, Rafael and Charles J. Banks. Response of an anaerobic fluidized bed reactor treating icecream wastewater to organic, hydraulic, temperature and pH shocks. Journal of Biotechnology, 

1995, Volume 39, Pages 251-259.

Garcia-Calderon, D. and P. Buffiere, R. Moletta, S. Elmaleh. Anaerobic digestion of wine 

distillery wastewater in down-flow fluidized bed. Water Research, Volume 32, Issue 12, 

December 1998, Pages 3593-3600.

Haroun, Mahdi and Azni Idris. Treatment of textile wastewater with an anaerobic fluidized bed 

reactor. Desalination, Volume 237, Issues 1-3, February 2009, Pages 357-366.

Heijnen, J.J. and A. Mulder, W. Enger, F. Hoeks. Review on the application of anaerobic 

fluidized bed reactors in waste-water treatment. The Chemical Engineering Journal, Volume 41, 

Issue 3, September 1989, Pages B37-B50. 

Sowmeyan, R. and G. Swaminathan. Evaluation of inverse anaerobic fluidized bed reactor for 

treating high strength organic wastewater. Bioresource Technology, Volume 99, Issue 9, June 

2008, Pages 3877-3880.

Toldra, F. and A. Flors, J. L. Lequerica, S. Valles. Fluidized bed anaerobic biodegradation of 

food industry wastewaters. Biological Wastes, Volume 21, Issue 1, 1987, Pages 55-61.