1. (a) Trickling filters treating domestic wastes shall be sized according to Table 714-1 below, subject to the notes in (b) below:

   Table 714-1: Trickling Filter Design Criteria

   Design Parameter

   Roughing

   Carbon Oxidizing (cBOD₅ removal)

   cBOD₅ and Nitrification

   Nitrification

   Media typically used

   Vertical Flow

   Rock, cross-flow or vertical flow

   Rock, cross-flow or vertical flow

   Cross-flow

   Media-specific surface area, sf/cf

   31 to 40

   14 to 68

   14 to 68

   30 to 68

   Wastewater Source

   Primary effluent

   Primary effluent

   Primary effluent

   Secondary effluent

   Hydraulic loading, gpm/sf

   0.9 to 2.9

   0.25 to 1.5

   0.25 to 1.5

   0.6 to 1.5

   Lb BOD₅/d-1000 cf

   100 to 220

   20 to 60

   5 to 15

   not applicable

   Lb NH₃ -N/d-1000 cf

   not applicable

   not applicable

   0.04 to 0.2

   0.1 to 1.5

   Effluent quality, mg/L unless noted

   50 to 75% filtered cBOD₅ conversion

   15 to 30 cBOD₅ and TSS

   <10 cBOD₅

   <3 NH₃ –N ^A

   0.5 to 3 NH₃ –N

   Predation

   No appreciable growth

   Beneficial

   Detrimental (nitrifying biofilm)

   Detrimental

   Filter flies

   No appreciable growth

   No appreciable growth

   No appreciable growth

   No appreciable growth

   Depth

   3 to 20

   5 to 40

   5 to 40

   5 to 40

2. (b) In Table 714-1, the letter “A” means the concentration remaining in the clarifier effluent stream.

Source. (See Revision Note at chapter heading for Env-Wq 700) #8590, eff 3-25-06; ss by #10693, eff 10-15-14; ss by #14258, eff 7-1-25, EXPIRES: 7-1-35