N.J. Admin. Code § 7:9A-10.2

Current through Register Vol. 56, No. 21, November 4, 2024

Section 7:9A-10.2 - Disposal field sizing requirements

(a) The minimum required disposal field size or the maximum allowable hydraulic loading rate shall be determined, using sizing criteria as prescribed below, based upon the volume of sanitary sewage, determined as prescribed in 7:9A-7.4, and the results of permeability tests or percolation tests performed as prescribed in N.J.A.C. 7:9A-6.

1. The disposal field sizing criteria to be used shall be determined based upon the type of disposal field, disposal field installation and the method of effluent distribution used, as follows:

TABLE 10.2(a) APPLICABLE DISPOSAL FIELD SIZING CRITERIA
Typeof	Typeof	Methodof	Applicable
DisposalField	Disposal	Distribution	Sizing
Installation	Field	Criteria
Conventional	Trench	Gravity	N.J.A.C.
7:9A-10.2(b)
Pressure	N.J.A.C.
7:9A-10.2(b)
Bed	Gravity	N.J.A.C.
7:9A-10.2(c)
Pressure	N.J.A.C.
7:9A-10.2(c)
Soil Replacement,	Trench	Gravity	N.J.A.C.
7:9A-10.2(c)
Bottom-lined	Pressure	N.J.A.C.
7:9A-10.2(d)
Bed	Gravity	N.J.A.C.
7:9A-10.2(c)
Pressure	N.J.A.C.
7:9A-10.2(d)
Soil Replacement,	Trench	Gravity	N.J.A.C.
7:9A-10.2(b)
Fill-enclosed	Pressure	N.J.A.C.
7:9A-10.2(b)
Bed	Gravity	N.J.A.C.
7:9A-10.2(c)
Pressure	N.J.A.C.
7:9A-10.2(d)
Mound, Mounded Soil	Trench	Gravity	N.J.A.C.
7:9A-10.2(b)
Replacement	Pressure	N.J.A.C.
7:9A-10.2(b)
Bed	Gravity	N.J.A.C.
7:9A-10.2(c)
Pressure	N.J.A.C.
7:9A-10.2(d)

2. Systems that incorporate an advanced wastewater pretreatment device may, at the administrative authority's discretion, alternatively use Table 10.2(d) below for Table 10.2(b) below and Table 10.2(e) below for (d) below or Table 10.2(c) below, as applicable, for the criteria used to calculate the size of a disposal field.

(b) All disposal fields using trenches, except for bottom-lined soil replacement installations, shall meet the following size requirements:

1. The minimum required length of trenches per gallon of daily sewage volume, L/Q, shall be determined from Table 10.2(b) below, based upon the trench width selected and the results of permeability tests or percolation tests, performed as prescribed in N.J.A.C. 7:9A-6.

2. The minimum required length of trenches, L, shall then be determined by multiplying the value of L/Q obtained from the table by the daily volume of sewage, Q, determined as prescribed in 7:9A-7.4.

(c) All disposal beds using gravity flow or gravity dosing, all conventionally installed disposal beds using pressure dosing and all bottom-lined soil replacement trench installations using gravity flow or gravity dosing shall meet the following size requirements.

1. The minimum required bottom area of disposal field per gallon of daily sewage volume, A/Q, shall be determined from Table 10.2(c) below, based upon the results of permeability tests or percolation tests performed as prescribed in N.J.A.C. 7:9A-6.

2. The minimum required bottom area shall then be determined by multiplying the value of A/Q obtained from the table by the daily volume of sewage, Q, in gallons, determined as prescribed in 7:9A-7.4.

(d) All disposal beds using pressure dosing except for conventional installations and all bottom-lined soil replacement trench installations using pressure dosing shall have a minimum size of 1.33 square feet of bottom area per gallon of daily sewage volume.

TABLE 10.2(b) MINIMUM REQUIRED DISPOSAL TRENCH LENGTH PER GALLON OF
DAILY SANITARY SEWAGE VOLUME, L/Q (ft/gal per day)
Permeability	Percolation	Trench	L/Q <1>
(ft/gal per day)
(in/hr)	Rate	Width	1.5	2.0	2.5	3.0
(min/in)	(ft):
>6-20	<3-15	0.65	0.54	0.46	0.40
>2-6	<15-30	0.83	0.69	0.59	0.52
>0.6-2	<30-45	1.03	0.85	0.73	0.64
>0.2-0.6	<45-60	1.18	0.98	0.84	0.74

TABLE 10.2(c) MINIMUM REQUIRED DISPOSAL FIELD BOTTOM AREA OF ZONE OF
TREATMENT PER GALLON OF DAILY SANITARY SEWAGE VOLUME A/Q<1> (ft<2>/gal per day)
Permeability	PercolationRate	A/<Q(1)>
(in/hr)	(min/in)	(ft<2>/gal
perday)
>6-20	<3-15	1.61
>2-6	<15-30	2.08
>0.6-2	<30-45	2.56
>0.2-0.6	<45-60	2.94

TABLE 10.2(d) MINIMUM REQUIRED DISPOSAL TRENCH LENGTH PER GALLON OF
DAILY SANITARY SEWAGE VOLUME, L/Q < 1 > (ft/gal per day) WITH AN ADVANCED
WASTEWATER PRETREATMENT DEVICE
Permeability	Percolation	AdjustedL/Q < 1 <
Rate	(ft/galperday)
Trench	1.5	2.0	2.5	3.0
Width (ft)
> 6-20	< 3-15	0.50	0.42	0.36	0.31
> 2-6	< 15-30	0.68	0.57	0.49	0.43
> 0.6-2	< 30-45	0.89	0.73	0.63	0.55
> 0.2-0.6	< 45-60	1.04	0.86	0.74	0.65

TABLE 10.2(d) MINIMUM REQUIRED DISPOSAL TRENCH LENGTH PER GALLON OF
DAILY SANITARY SEWAGE VOLUME, L/Q<1> (ft/gal per day) WITH AN ADVANCED
WASTEWATER PRETREATMENT DEVICE
Permeability	Percolation	AdjustedL/Q<1>
Rate	(ft/galperday)
Trench	1.5	2.0	2.5	3.0
Width (ft)
>6-20	<3-15	0.50	0.42	0.36	0.31
>2-6	<15-30	0.68	0.57	0.49	0.43
>0.6-2	<30-45	0.89	0.73	0.63	0.55
>0.2-0.6	<45-60	1.04	0.86	0.74	0.65

[LESS THAN]1[GREATER THAN] Additional Requirements:

a. Where garbage disposal units or grinder/ejector pumps are installed or proposed, the value obtained from this table shall be increased by a factor of 50 percent for use in disposal field sizing.

(e) Any system designed in accordance with Table 10.2(d) or (e) above shall not be sized less than 400 square feet of total bottom area and shall also include at least one of the following restrictions, at the administrative authority's discretion, in the application for the proposed design:

1. An area reserved for sanitary sewage disposal, including all necessary separation distance requirements, equal to the total area required if advanced wastewater pretreatment was not included in the design. This area reserved for sanitary sewage disposal may include the area where the proposed disposal area is located; and/or

2. A deed restriction placed on the property prior to the issuance of any certificate of compliance for the system, a copy of which must be maintained in the administrative authority's records that identifies the need for the advanced wastewater pretreatment system and accompanying requirements to maintain that system in perpetuity, as required by 7:9A-12.3, including any repairs or alterations to the system as long as the structure served exists on the property.

N.J. Admin. Code § 7:9A-10.2

Amended by R.1993 d.294, effective 6/21/1993.
See: 24 N.J.R. 1987(a), 25 N.J.R. 2704(b).
Amended by R.2012 d.066, effective 4/2/2012.
See: 43 N.J.R. 478(a), 44 N.J.R. 1047(a).
Added (a)2; in Table 10.2(b), inserted "SANITARY" in the heading, and substituted "<15-30" for "<16-30", "<30-45" for "<31-45" and "<45-60" for "<46-60" in the second column; in Table 10.2(c), inserted "OF ZONE OF TREATMENT" and "SANITARY" in the heading, and substituted "<15-30" for "<16-30", "<30-45" for "<31-45", and "<45-60" for "<46-60" in the second column; added Tables 10.2(d) and 10.2(e); in footnote 1a, inserted "or grinder/ejector pumps", and substituted "50" for "25"; and added (e).