Bulk Liquid
1.0
Case b
Attachment Surface
Case a
0.50
Sf / Ss
0.75
Case a: τ1 = 11 µm, Lf /τ1 = 9.1
Case b: τ1 = 450 µm, Lf /τ1 = 0.22
0.25
0
20
40
60
80
100
z, µm
Substrate concentration profiles for characteristic deep (case a) and nearly fully penetrated (case b) biofilms.
The ratio Lf /τ determines if the biofilm is deep. Many values of k1, Df , and Xf can give the same τ1 value,
and Rittman and McCarty (2001) illustrate how this affects J1.
Figure by MIT OCW.
Adapted from: Rittman, Bruce E., and Perry L. McCarty. Environmental Biotechnology: Principals and
Applications. New York, NY: McGraw-Hill, 2001.
z
Bulk Liquid
Diffusion
Layer
Biofilm
Fully penetrated
Attaching
Surface
Ss
al
Sh
Concentration
Sb
lo
w
Sw
De
ep
L
Lf
Distance normal to the surface of the biofilm
Characteristic Substrate Concentration Profiles within a Biofilm
Figure by MIT OCW.
Adapted from: Suidan, M. T., B. E. Rittman, and U. K. Traegner. "Criteria establishing biofilm-kinetic types." Water Research 21,
no. 4 (April 1987): 491-498.
Approaching 1/2 - order
0
1st Order
Sdeep
log10J
-1
-2
Deep
-3
-4
-5
Steady-state
solution
Smin = K
-6
-3
-2
-1
b'
Yq - b'
0
+1
log10S
Typical response of a steady-state biofilm to changes in S.
For this example, Smin = 0.0204 mg/cm3. S has units mg/cm3,
and J has units mg/cm2-d.
Figure by MIT OCW.
Adapted from: Rittman, B. E., and P. L. McCarty. Environmental Biotechnology: Principles and Applications.
Boston, MA: McGraw-Hill Higher Education, 2001.
Trickling
filter
Source: U.S. EPA, 2000. Wastewater Technology Fact Sheet: Trickling Filters. Report No. EPA 832-F-00-014. Office of Water, U.S.
Environmental Protection Agency, Washington, D.C. September 2000.
TRICKLING FILTER DETAILS
Effluent Channel
Floor slope
B
B
A
A
Underdrain
blocks
A
A UNDERDRAIN BLOCK
B
A FLOOR PLAN
Top of Bed
Top of Bed
Depth of Media or Packing
Depth of Media or Packing
Effluent Channel
Underdrain
block
Slab
C
A SECTION A-A
D
A SECTION B-B
Figure by MIT OCW.
Adapted from: Reynolds, T. D., and P. A. Richards. Unit Operations and Processes in Environmental
Engineering. 2nd ed. Boston, MA: PWS Publishing Company,1996, p. 543.
Primary settling
Secondary settling
Raw waste
water
Treated
wastewater
Sludge to treatment or disposal
Figure by MIT OCW.
Adapted from Gonzalez, J. F. Wastewater Treatment in the Fishing Industry.