My presentation is all about specialised bioreactors - design and their functions,advantages and dis-advantages: Air-lift Bio reactor,Tower Bio reactor, Membrane Bio reactor.

1. SPECIALIZED BIOREACTOR -
DESIGN & THEIR FUNCTION
-AIR LIFT BIOREACTOR
-TOWER BIOREACTOR
-MEMBRANE BIOREACTOR
ANITHA.Y
14KUST4002

2. AIR-LIFT BIO-REACTOR
•Has promising role than stirred tank bioreactor –
aerobic digestion.
• It is a typical “motionless” bioreactor where
internal circulation & mixing – bubbling air.
• Employs pressurized air/force to circulate the
nutrient medium & cells.
• Used to culture cells - sensitive to shear.
•They usually employ gas-liquid or gas-slurry
contact process.
•Technically & Economically feasible – production
of beer, citric acid, vinegar, biomass of yeast ,
bacteria & fungi

3. DESIGN OF AIR-LIFT BIOREACTOR
•AL Bio-Reactor Consists of a liquid pool divided into
2 distinct zones
• Entire bioreactor is divided into 2 halves by a draft
tube : -inner (gassed)region - riser
-outer(ungassed)region-downcomer
• RISER- has a gas injection- air moves forward
• DOWNCOMER- has a degassed media & cells
• Mean density gradient b/w riser & down comer
•Difference of density- continuous circulation
• Oscillators(spargers)with nozzle - produce gas
• Headspace or vent – release of
gas,foam,flocculation
Draft
tube

4. CHARACTERISTICS OF ALR
 Liquid mixing
 Mass transfer
 Rate of gas transfer
 Energy dissipation
USES OF ALR
1. Mammalian cell culture
2. Waste water treatment
3. Biological processes involving
biocatalysts as solids
4. To produce bio-pharma proteins from
fragile cells

5. TYPES OF AIR-LIFT

6. MODIFICATIONS OF ALR

7. ADVANTAGES
 Homogenous mixing & distribution of gas.
 Simple design, with no moving parts or agitator
 Less maintenance, less risk of defects
 Easier Sterilization (no agitator/shaft)
 Low energy requirement ,low shear force
DIS-ADVANTAGES
 Greater pressure & air throughout
 Too much of Foaming
 No bubble breaker

8. TOWER BIO-REACTOR
Mainly it’s of the height: diameter 10:1
ratio (over all) but tubular section is 6:1.
Elongated, non-mechanically stirred
fermentor, uni-directinal flow of gases.
Production of yeast, beer, citric acid, &
tetracyclin.
Flow of substrate & air is concurrent-from
bottom to top
They are of 3 types :
Bubble column tower fermentor
Vertical tower beer fermentor
Multistage tower fermentor

9. DESIGN OF TOWER REACTOR
The tower consists of four to eight
compartments separated by sieve
plates.
High amount of air is passed from
bottom
Baffles at the base – uniform mixing of
liquid
Heating & cooling jackets
Settling zone- microbes
Outlet for retrieving products
Flow controller- products are lite

10. ADVANTAGES
 shorter fermentation time.
 no yeast lag phase
 very consistent product
 fewer beer losses due to reduced yeast growth
 less scope for different products
 less scope to respond to seasonal and short term variations in demand
 must use a highly-flocculent pure yeast culture
 difficult to maintain microbiological purity
 different flavour profile from batch process(BRAND)
 risk of yeast culture changing overtime is greater
 has to operate seven days a week
DIS ADVANTAGES

11. MEMBRANE BIO-REACTOR
Alternative to activated sluge process
It is the combination of membrane
technology(Microfilteration&ultrafilteration) in
suspended bioreactor
Used now in municipal & waste water treatment
Size of the plant-48,000 ltrs/day
Membrane size- 0.003-0.01
It is of 2 types :
External- Mixed liqour filtered under pressure in
a specific membrane module
Internal –Filtered in aerated basin by suction to
remove effluents
Screening
Clarification
Disinfection OR
Desalination

12. DESIGN OF MBR
 It largely relates to:
 the configuration of the membrane(Geometry
& direction of water flow)
(flat sheet,hollow fibre, multi-channel/tube)
 the membrane separation process,
and(placement of membrane module)
(External-side stream & internal-submerged)
 the biotreatment process(biochemistry of
pollutant)
(oxygen oxyanions
carbon co2
ammonia nitrates
phosphate in-org phosphate
 Ancillary equipement (screening, membrane
controll)

13. CHARACTERISTICS OF MBR
 Membrane pore size
 surface charge
 hydrophillicity
 surface roughness
 Sludge biomass conc
 particle size.structure
 colloidal conc
 solluble microbial product
 Operation biology (HRT,SRT,TEMPERATURE)
condition memebrane (TRANSMEMBRANE
PRESSURE,TOCIXITY,AERATION)

14. ADVANTAGES
 No settlement problems
 No further polishing required for disinfection/clarification
 No equalisation of hydraulic and organic loadings required
DISADVANTAGES
 Membrane surface fouling
 Membrane channel clogging
 Process complexity
 High capital cost
 High running costs

15. REFERENCES
 SLIDE SHARE
 YOU TUBE
 https://www.researchgate.net
 Diederik Rousseau & Tineke Hooijmans, Membrane bioreactors (MBRs) for
wastewater treatment-PPT
 onlinelibrary.wiley.com
 pharmacologyonline.silae.it/files/newsletter
Thank you one & all !!