N.J. Admin. Code § 7:14A-8.18 - Specific operating criteria and construction standards applicable to permit by rule authorizations for underground injection into seepage pits
(a) This section
sets forth the operating criteria and construction standards for underground
injection into seepage pits under a permit-by-rule pursuant to
7:14A-8.5(b)4 or
5.
(b) Design requirements are as
follows:
1. When required to protect against
accumulation of fine particles that would impair the proper functioning of the
seepage pit, a multiple compartment septic tank shall be designed and
constructed in accordance with
7:9A-8.2.
2. The percolating area shall be the total
outside surface area of the seepage pit lining below the inlet and exclusive of
any soil horizons with a percolation rate slower than 40 minutes per inch. The
bottom of the seepage pit shall not be counted as part of the percolating area.
The minimum percolating area shall be determined from the following table based
upon the maximum daily volume of discharge and a weighted average of the
percolation or permeability rates of all soil layers exposed in the sidewalls.
In no case, however, shall the percolating area be less than 110 square feet.
Minimum Area Required for Seepage Pits, Based on One | |
Gallon Liquid Per Day, and Based on the Percolation Rate of the Soil | |
Average Percolation Rate | Minimum Area Per Gallon Per Day |
(Min/inch) | (Square feet) |
10 or less | 0.48 |
11 to 20 | 0.72 |
21 to 30 | 0.96 |
31 to 40 | 1.20 |
over 40 | not acceptable |
(c) Construction requirements are as follows:
1. Seepage pits shall be constructed within
an excavation affording adequate working space and shall be constructed of
stone, brick, cinder, precast concrete or concrete block, or similar material
laid dry with open joints where permeable strata have been penetrated, except
that if the seepage pit is not of circular construction or if the surrounding
ground is subject to cave-in, all horizontal joints shall be mortared so as to
prevent structural failure. The following requirements shall be met:
i. All joints above the inlet, in all cases,
shall be made watertight;
ii.
Before placement of backfill, all sidewall areas shall be scarified;
and
iii. The bottom of the seepage
pit shall be filled with coarse gravel to a depth of one foot unless the bottom
is in a sand or gravel formation.
2. Seepage pits shall be backfilled according
to the following procedure:
i. The space
between the excavation and the seepage pit wall shall be backfilled with at
least three inches of coarse gravel or filter material meeting New Jersey
Department of Transportation's standards for coarse aggregate sizes 3, 4 and
24.
ii. Where cinder or concrete
blocks are laid with core openings exposed, the space between the excavation
and seepage pit wall shall be backfilled with at least six inches of two and
one-half inch crushed stone or gravel.
iii. Backfill above the inlet shall be of
earth similar to that found at the site which is free from large stones, tree
stumps, broken masonry or waste construction material, and shall be thoroughly
compacted by hand or mechanical tamping methods. The use of heavy machinery for
this purpose is prohibited.
3. Covers shall be constructed of reinforced
concrete, shall be a minimum of three inches in thickness, watertight, and
shall be designed and constructed so as not to be damaged by any load which is
likely to be placed upon them.
4.
At least one access opening with a removable, watertight cover and a minimum
dimension of 24 inches shall be provided. Access openings shall meet the
following requirements:
i. Access shall be
adequate to permit pumping out of the pit as well as inspection and maintenance
of the inlet;
ii. When the cover of
the seepage pit is deeper than 12 inches below finished grade, the access
opening shall be extended to within 12 inches of finished grade by means of a
concrete riser with cast-iron manhole cover;
iii. When the access opening is below
finished grade, a permanent marker at finished grade shall be provided to
indicate its location; and
iv. When
the access opening is at or above finished grade, the cover shall be bolted,
locked or otherwise secured to prevent access by children.
(d) Requirements for the
submission of certifications are as follows:
1. Any facility qualifying for this permit by
rule shall submit an as-built certification from a New Jersey licensed
professional engineer which certifies that the system was designed and
constructed in accordance with the requirements of this section. The
certification and a NJPDES-1 form shall be submitted within 30 days of the
completion of construction to:
NJDEP
Division of Water Quality
Bureau of Nonpoint Pollution Control
PO Box 029
Trenton, New Jersey 08625-0029
Notes
See: 35 N.J.R. 169(a), 35 N.J.R. 1331(a), 36 N.J.R. 813(a).
In (d), updated address.
Amended by R.2009 d.7, effective
See: 40 N.J.R. 1478(a), 41 N.J.R. 142(a).
In (a), updated the N.J.A.C. reference.
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