1. Article Report
S. R. H. Abadi, M. R. Sebzari, M. Hemati, F. Rekabdar, T. Mohammadi
Group 4 | 5ChEC
February 1, 2014
Casillan|Feleo|Liggayu|Manabat|Taruc|Trumata

2. Background of the Study

3. Oily Wastewater
• main pollutants emitted into water by industry
and domestic sewage
• major pollution problem due to its distinctive
characteristics

4. Why membrane separation?
Membrane separation have
1. high oil removal efficiency
2. low energy cost
3. compact design

5. What type of membrane to use?
Ceramic membrane

6. Why ceramic membrane?
Advantages
o it has the ability to accomplish the
current regulatory treatment objectives
with no chemical pretreatment
o higher fluxes
o resistance to mechanical, thermal, and
chemical stress allows better recovery
of membrane performance

7. What type of ceramic membrane?
Alpha-Al2O3
o chemically very inert
o usable in pH range of 1 to 14
o no limitations in temperature and pH when
using standard membrane cleaners
o produces lower refluxes as compared with
zirconia and ZrO2 based on past studies

8. TMP
TOC
Removal
Permeate
Flux
OBJECTIVE
Operating
Parameters
CFV
Fouling
Resistance
Temp

9. Materials

10. Ceramic Membrane
• Tubular ceramic membrane
• Pore size of 0.2 micron
• With a stainless steel housing

12. Process Feed
• Outlet of the API unit of Tehran refinery was
used as a feed
• The feed was taken daily and used
immediately
• Original temperature = 25-30oC
• Characterization was required to ensure
existence of oil emulsion
• Drop size was below 20 microns, which
indicated emulsified oil in water mixture

13. Pilot System
• Has three loops in the system (main,
backwashing, and chemical washing loop)
• Main Loop – cross flow MF processing as it
started from TK-101
• The P-101 pumps the feed from TK-101 to the
bottom of the membrane module and was fed
to the membrane channels
• Cross flow configuration

14. Pilot System
• Carried out in a total recycle mode of
filtration, where retentate and permeate were
continuously recirculated into the feed tank by
using V-03 and V-01
• Feed concentration remained virtually
constant
• Backwashing Loop – contained a backwashing
tank (TK-02)

15. Pilot System
• Hot distilled water was used as a backflash
from TK-102 using P-102
• V-104 was opened to send hot water into the
membrane from the permeate side
• Chemical cleaning was used if recovery of
permeate flux is necessary
• To start cleaning, TK-103 was filled with
chemical agents and pumped towards the
membrane using P-101.

16. Pilot System
• There was a heater and coil of cooling water
to control temperature
• Two analog flow meters in the way of feed and
permeate streams
• Tank Volume = 90 L
• TMP = 0.75-1.75 bar
• CFV = 0.75-2.25 m/s
• Temperature = 35-40oC

17. Method

20. Placement of
membrane in
module
Stablization of
membrane
•
Experimental
Procedure
Rinsing of the system
measurement of
pure water flux
Introduction of oil
emulsion in tank
Measurement of
permeation
• Pre-heated to a desired temp
• Adjustment of operating
pressure & CFV
• Using a flow meter

21. Experimental
Procedure
• Difference between the steady-state pure water
fluxes was taken as a measure of the membrane
fouling tendency
• Each run consisted of:
 forward filtration time: 280 s
 backwashing filtration time: 15 s
 rest time: 5 s

22. Membrane Cleaning
The membrane was cleaned and regenerated
between subsequent runs as follows, after every 90
min. operation:
 Rinse with clean and hot water
 Clean with an alkaline cleaner
Cleaning procedure:
 first 10 min. with a closed permeate outlet
 20 min. with an opened permeate outlet
 temperature: 75 – 80 degC

23. Membrane Cleaning: Backwashing
• Membrane is hydraulically backwashed with hot water
( high pressure with a max. value of 2 bars for 15 s)
• reversed-flow: to flush the membrane pores from the
permeate side; releasing of retained materials in pores

24. Membrane Cleaning:
Chemical cleaning
• used when flux was decreased to 40 – 50% of its original
value
• chemical solutions were prepared in chemical tank
• added chemicals depend on the material to be flushed out:
 to remove organic scales: NaOH solution @ 70 – 80 °C
 to remove inorganic scales: Citric acid solution @ 70 – 80 °C

25. Wastewater Analysis
• TOC estimation using TOC
Analyzer
(Model DC-190)
• Oil and grease content values were
estimated using the FTIR
spectrometer set to scan 2930 /cm
 TOG/TPH Analyzer Infracal
(USA) Wilks Enterprise

26. Wastewater Analysis
• TSS values were analyzed by the
procedure outlined in the standard
methods (ASTM 2540D) using
Whatman 2.5 cm GF/C-Class
Microfiber
• water sample was filtered through a
pre-weighed filter.
•The residue retained on the filter was
dried in an oven
at 103–105 °C until the weight of the
filter became constant.

27. Wastewater Analysis
• Calculation of TSS
TSS (mg/L)=([A−B]*1000)/C
Where
A = End weight of the filter
B = Initial weight of the filter
C = Volume of water filtered

28. Wastewater Analysis
• Turbidity values were
estimated using a Turbidimeter
(Model 2100A HACH)
• Droplet size distribution of the
emulsified oil in water
was estimated using Laser Light
Scattering (LLS) Method using LLS
instrument
(SEMATech laboratory — SEM-633)

29. Important parameters in MF
• Permeate flux
• TOC removal efficiency
• Fouling resistance

30. Permeate Flux
Each membrane has a special
unique resistance which depends on its pore size and other properties.
This resistance known as Rm, can be calculated using the initial flux of
deionized water (Jwi) according to the following equation:

31. Permeate Flux
The resistance observed after feed filtration can be calculated using
flux of deionized water after fouling and washing with water (Jww).
This resistance is known as Rf and is the hydraulic resistance of the
surface adsorption and pore plugging and is calculated using the
following equation:

32. Oil Removal Efficiency
The oil removal efficiency can be evaluated according to the value
of TOC removal efficiency (RTOC), which is defined as:
Where TOCfeed is TOC concentration in the feed and TOCpermeat is
TOC concentration in the permeate (mg/L).

33. Results & Discussion

34. Effect of TMP

35. Effect of TMP
• Higher TMP results in droplets to pass rapidly through the
membrane pores, so more oil droplets accumulate on the
membrane surface and consequently in the membrane pores,
leading to membrane fouling

36. Effect of TMP

37. Effect of TMP
•For TMP above 1.25 bar, oil and grease droplets can pass through
the membrane pores and so TOC removal efficiency decreases;
TMP above 1.25 bar is not appropriate for a high effluent quality
• increasing TMP increases Rf severely (more tendency to cake/gel
on membrane surface resulting in Rf growth)

38. Effect of CFV

39. Effect of CFV
• Increasing CFV promotes turbulence and mass transfer
coefficient.
• increasing CFV up to 2.25 m/s increases permeate
flux and simultaneously decreases fouling resistance
• At higher CFV, high shear rate and turbulence sweep the
deposited particles away from the membrane surface; therefore,
the fouling layer on the membrane surface is made thinner and
more natural organic matter can pass through the membrane

40. Effect of CFV

41. Effect of temperature

42. Effect of temperature

43. Effect of temperature
• has double effects on permeation flux:
• increase in temp lowers viscosity, increase in permeate flux
• increase in temp increases osmotic pressure, decrease in
permeate flux
• increasing temp. decreases fouling resistance (higher oil solubility)
• however, at higher temp, oil and grease could easily permeate,
giving a lower TOC removal efficiency

44. Effect of temperature
• running the system at a higher temperature increases its operational
costs. Based on the results, a temperature of 32.5 °C can be
recommended to achieve high permeation flux at low operational
costs.

45. Effect of backwashing

46. Effect of backwashing
• It is possible to recover 95% of the original flux by
backwashing; continues backwashing removes oil
and particulates that block membrane pores
• However, as the operation goes on, more severe
fouling is observed since oil and particulates that
pass through the ceramic membrane are
adsorbed and accumulate within the porous
ceramic membrane

47. Effect of backwashing
• For a very long operation, it is not effective
for flux restoration; a flux decline of up to
40% of original flux was observed.
• Chemical cleaning should be used to
regenerate the ceramic membrane.

48. MF versus biological treatment method

49. Conclusion

50. Conclusion
MF process was more preferred and can
replace the conventional biological method
for the treatment of API effluent of Tehran
Refinery.
The results showed that the optimum
parameters for the said treatment are:
– TMP: 1.25 bar
– CFV: 2.25 m/s
– Temperature: 32.5 o C.

51. Conclusion
Analysis of the MF process shows decline of oil
and grease content of 85%, TSS of 100% and
98.6% of Turbidity.
To remove reversible fouling, Backwashing
process was applied. Periodic Backwashing
prevents the flux to decline and the results show
that it can possibly recover 95% of the original
flux.
However, when the permeate flux was reduced to
40 to 50% of its original value, a chemical
cleansing is required for a long term operation.

52. THE END
Thank you for listening!