N.H. Code Admin. R. Env-Wq 714.02

Current through Register No. 25, June 20, 2024

Section Env-Wq 714.02 - Trickling Filters: Size Requirements

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

(b) In table 714-1, the letter "A" means the concentration remaining in the clarifier effluent stream.

N.H. Code Admin. R. Env-Wq 714.02

(See Revision Note at chapter heading for Env-Wq 700) #8590, eff 3-25-06

Amended byVolume XXXIV Number 46, Filed November 13, 2014, Proposed by #10693, Effective 10/15/2014, Expires10/15/2024.