Stone%20media%20TF%20design

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

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Stone media TF design

• Solution)
• (1) BOD loading rate (kg/m3/d)
• BOD load BOD Conc. x Influent flow
• 130 mg/L x 1530
  m3/d 198.9 kg/d
• Volume of filter surface area of filter x
  depth
• p (18 m x 18m)/4 X
  2.1 m 533 m3
• BOD loading rate BOD load / volume of filter
• 0.37 kg/m3/d

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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 p (18 m x 18m)/4
  254 m3
• Hydraulic loading rate Total flow to the
  media / area of filter
  9.04 m3/m2/d

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Stone media TF design

• Solution)
• (3) Effluent BOD (mg/L)
• BOD removal efficiency for first-stage filter at
  20oC,

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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 21, 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
• E1E2 0.65

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Stone media TF design

• Example 2

BOD200mg/L
BOD25mg/L
Primary Clarifier
Secondary Clarifier
TF2
TF1
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Stone media TF design

• Solution)
• (1) Compute the recirculation factor

(12)/ (10.2)2 2.08
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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 7570 m3/d
  1234kg/d
• (3) Compute the volume for the first stage

• V 388 m3

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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
• (1-0.646) x 1234 kg BOD/d
• 437 kg BOD/d

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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

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Stone media TF design

• Solution)
• (8) Compute the BOD loading to each filter
• (9) Compute the hydraulic loading to each filter

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Plastic media
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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

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Plastic media

• hydraulic loading (q)
• Where
• Q influent flow rate L/min
• Afilter cross section area m2

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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
• kwastewater treatability and packing
  coefficient, (L/s)0.5/m2
• Dpacking depth, m
• q hydraulic application rate of primary
  effluent, excluding recirculation, L/m2s
• nconstant characteristic of packing used
  (assumed to be 0.5).

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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 rate0.5L/m2s. 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 mg/L 65 20
Temp oC 14
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Plastic media TF design

• Example 3
• Calculate the followings
• Diameter of TF, m
• Volume of packing require, m3

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Plastic media TF design

• Solution
• (1) Diameter of tower trickling filter, m
• Correct k for temperature effect

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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

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