1. Stone media TF design Example 1
Calculate the BOD loading, hydraulic loading, BOD removal efficiency, and effluent BOD concentration of a single-stage trickling filter based on the following data:
Design assumptions:
Influent flow =1530 m3/d
Recirculation ratio = 0.5
Primary effluent BOD = 130 mg/L
Diameter of filter = 18 m
Depth of media = 2.1 m
Water temperature =18oC

2. Stone media TF design Solution) (1) BOD loading rate (kg/m3/d)
BOD load = BOD Conc. x Influent flow
= 130 mg/L x m3/d =198.9 kg/d
Volume of filter = surface area of filter x depth
= π (18 m x 18m)/4 X 2.1 m = 533 m3
BOD loading rate = BOD load / volume of filter
=0.37 kg/m3/d

3. Stone media TF design Solution) (2) Hydraulic loading rate (m3/m2/d)
Total flow to the media = influent + recirculation flow
= 1530 m3/d + (1530 m3/d x 0.5)
Surface area of filter = π (18 m x 18m)/4 = 254 m3
Hydraulic loading rate = Total flow to the media / area of filter = 9.04 m3/m2/d

4. Stone media TF design Solution) (3) Effluent BOD (mg/L)
BOD removal efficiency for first-stage filter at 20oC, %

5. Stone media TF design Example 2
A municipal wastewater having a BOD of 200 mg/L is to be treated by a two-stage trickling filter. The desired effluent quality is 25 mg/L of BOD. If both of the filter depths are to be 1.83 m and the recirculation ratio is 2:1, find the required filter diameters. Assume the following design assumptions apply.
Design assumptions:
Influent flow =7570 m3/d
Recirculation ratio = 2
Depth of media = 1.83 m
Water temperature =20oC
BOD removal in primary sedimentation = 35%
E1=E2 =0.65

6. Stone media TF design Example 2 BOD=200mg/L BOD=25mg/L
Primary Clarifier
Secondary Clarifier
TF1
TF2

7. Stone media TF design Solution) (1) Compute the recirculation factor
= (1+2)/ (1+0.2)2 = 2.08

8. Stone media TF design Solution)
(2) Compute the BOD load for the first filter
BOD load = BOD Conc. x Influent flow
= 200mg/L*(1-0.35) x m3/d =1234kg/d
(3) Compute the volume for the first stage
V= 388 m3

9. Stone media TF design Solution)
(4) Compute the diameter of the first filter
A= V/depth = 388 m3/1.83m = 212 m2
Diameter = 16.4 m
(5) Compute the BOD load for the second filter
BOD load to the second filter
= (1-E1) x BOD load to the first filter
= ( ) x 1234 kg BOD/d
= 437 kg BOD/d

10. Stone media TF design Solution)
(6) Compute the volume for the first stage
V= 1096 m3
(7) Compute the diameter of the first filter
A= V/depth = 1096 m3/1.83m 599 m2
Diameter = 27.6 m

11. Stone media TF design Solution)
(8) Compute the BOD loading to each filter
(9) Compute the hydraulic loading to each filter

12. Plastic media

13. Plastic media Schulze formula
The liquid contact time (t) of applied wastewater
Where:
t = liquid contact time, min
D= depth of media (m)
q = hydraulic loading, (m3/m2/h)
C, n = constants related to specific surface & configuration of media

14. Plastic media hydraulic loading (q) Where: Q= influent flow rate L/min
A=filter cross section area m2

15. Plastic media TF design
Schulze formula
Where:
Se= BOD concentration of settled filter effluent, mg/L
So= influent BOD concentration to the filter, mg/L
k=wastewater treatability and packing coefficient, (L/s)0.5/m2
D=packing depth, m
q= hydraulic application rate of primary effluent, excluding recirculation, L/m2*s
n=constant characteristic of packing used (assumed to be 0.5).

16. Plastic media TF design
Example 3
Given the following design flow rates and primary effluent wastewater characteristics, determine the following design parameters for a trickling filter design assuming 2 reactors at 6.1 m depth, cross-flow plastic packing with a specific surface area of 90 m2/m3, a packing coefficient n value of 0.5, & a 2-arm distributor system. The required minimum wetting rate=0.5L/m2*s. Assume a secondary clarifier depth of 4.2m and k value of 0.23.
Design conditions
Item
unit
Primary effluent
Target effluent
Flow
m3/d
15,140
BOD
mg/L
125 20
TSS 65
Temp oC 14

17. Plastic media TF design
Example 3
Calculate the followings
Diameter of TF, m
Volume of packing require, m3

18. Plastic media TF design
Solution
(1) Diameter of tower trickling filter, m
Correct k for temperature effect

19. Plastic media TF design
Solution
(1) Diameter of tower trickling filter, m
Determine the hydraulic loading rate
Determine the tower area
Determine the tower diameter