This document discusses integrated fixed-film activated sludge (IFAS) systems for biological wastewater treatment. IFAS systems combine suspended and attached growth in aeration tanks by adding media. Three studies showed IFAS improved nutrient removal at full-scale plants. A lab study found IFAS effective for industrial wastewater. An IFAS-MBR system had better removal and less fouling than MBR alone. Pilot and full-scale IFAS successfully achieved nitritation-anammox for nitrogen removal. Overall, IFAS is cost-effective for retrofitting plants to increase capacity or improve effluent quality.

2. CIVI 6621 – Engineering aspects of
Biological treatment of water and air
Ibrahim Jammal - ID# 27683642
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3. *
• Introduction
• Uses and Applications
• Types of Media
• Recent Studies and Developments
• Conclusion

5. *
• Industry practice for upgrading WWTP usually
focuses on increasing the bioreactor volume by
building new reactors to meet the system needs.
What’s Integrated Fixed-Film Activated sludge (IFAS)?
• IFAS is a modification of the conventional activated sludge
process.
• It is achieved by adding media to the aeration tanks of the
Activated sludge process.
• Creates a hybrid suspended- attached-growth system.

6. *IFAS using polypropylene
textile media.

7. Why IFAS?
•IFAS systems allow for the additional bacterial
population to exist on a fixed surface, therefore no
need to increase the suspended growth population.
•Increased nutrient removal and better effluent quality.
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8. •The fixed biomass increases the Sludge Retention
Time (SRT), promoting better nitrification.
•Recent research indicates that autotrophic bacteria
tend to grow more on fixed-film surfaces than in a
suspended growth environment.
•Resistant to Organic and Hydraulic Shock Loads.
Applications:
1. Increase plant capacity while providing same
treatment level.
2. Improve existing treatment performance in existing
process at same plant capacity.

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• This study was conducted in the USA.
• Study conducted on three full-scale plants :
1. A trickling filter/solids contact process,
2. A conventional plug flow activated sludge process,
3. An extended aeration process.
The three plants were facing challenges before the IFAS
upgrade. They were not able to meet the new ammonia limits
due to either cold weather conditions or shock loadings.

11. • They either lacked the land needed for constructing new
tanks, or it was not cost-effective to construct new tanks.
• So PVC structured sheet media (SSM) was used as an IFAS.

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• SSM IFAS systems are a viable solution for retrofitting
under-designed AS systems to increase ammonia
removal (even under cold weather conditions)
• potential to nitrify consistently with a high ammonia
loading rate.
• The IFAS system can significantly improve sludge
settleability and reduce sludge production. It also
improves BOD and TSS removal.
• Operation and maintenance of a SSM IFAS system is very
similar to that of an AS process and Attention to the
media is minimal.
This study just confirmed the efficiency of the IFAS, since
IFAS was applied in full scales since 1980’s in Germany.

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• A similar problem was faced in China, they had AS WWTPs built
before the development of industries in some areas.
• A lab-scale IFAS system was employed to investigate the
performance of pollutants removal in industrial effluent.
Schematic of
IFAS and the
bio-carriers
(polyurethane
Plastic)

14. Results:
• COD, NH4
+-N and TN removal efficiency of 74, 93 and 76%,
respectively.
• More nitrifying bacteria in the suspended-growth than in
the attached-growth biomass.
• Denitrifying bacteria were found enriched in the biofilms.
• Aerobic denitrification was achieved in IFAS due to the
accumulation of denitrifying bacteria in the bio-carriers.
Better Processes could be used

15. *
• The main aim of this study is to compare between IFAS-MBR and
MBR systems.
• Two lab-scale reactors were operated in parallel to treat
synthetic municipal wastewater with continuous operation.
• Polyethylene plastic bio-carriers were used in the Aerobic tank.
Drawing
showing the
IFAS-MBR &
MBR

16. Results:
• This process result in a very compact process.
• The carriers introduced to support the biomass duplicates
the capacity of a conventional plant.
• The IFAS–MBR showed a lower membrane fouling
tendency during the whole operation.
• IFAS–MBR showed a higher ability to remove COD.
• Both systems had the same high removal efficiency of
ammonium.

17. *
• Nitrogen removal integrated with anaerobic ammonium
oxidizing (anammox) process has been considered as a
promising alternative to the conventional nitrogen removal
processes (nitrification and denitrification).
• It can be achieved under the conditions of low organic
carbon sources and low aeration, reducing the operational
cost and sludge production.

18. • Pilot and full-scale (IFAS)
reactors were used.
• Full Scale Reactor treating
sludge dewatering liquors
(V = 500 m³).
• The pilot-scale was tested
in treating high ammonium
wastewater.
• The biofilm carriers used in
this study were cubic
sponge polyesters.
The Fig. shows (A) Scheme of
pilot-scale IFAS reactor used in
the experiment. (B) Scheme of
full-scale IFAS reactor.

19. Results:
• Nitritation–anammox process was successfully achieved in
the IFAS system.
• An average nitrogen removal efficiency of 85%.
• Molecular analysis showed that ammonium oxidizing bacteria
(AOB) were more abundant in in flocculent activated sludge
while anammox bacteria were mostly located in the biofilm.
• It was noted that high influent suspended solids would
seriously affect the performance of the IFAS system.
Therefore, a pre-treatment was proposed to reduce
suspended solid.

20. *
• Overall, IFAS proved to be a cost-effective method to
retrofit existing AS plants, to either receive bigger flow,
or improve the effluent quality.
• Also it can be employed with other processes as the MBR
or with Anamox to improve their performance.
• In my opinion IFAS best application is treating municipal
wastewater. Iince It didn’t show the ability to deliver
high quality effluent in treating industrial wastewater.
• At the end, I think all wastewater treatment methods
are effective, But what makes the difference, is knowing
when to apply these methods.

21. Thank You!