[Code of Federal Regulations]

[Title 40, Volume 29]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 40CFR503.21]



[Page 836-837]

 

                   TITLE 40--PROTECTION OF ENVIRONMENT

 

         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

 

PART 503_STANDARDS FOR THE USE OR DISPOSAL OF SEWAGE SLUDGE--Table of 

Contents

 

                       Subpart C_Surface Disposal

 

Sec.  503.21  Special definitions.



    (a) Active sewage sludge unit is a sewage sludge unit that has not 

closed.

    (b) Aquifer is a geologic formation, group of geologic formations, 

or a portion of a geologic formation capable of yielding ground water to 

wells or springs.

    (c) Contaminate an aquifer means to introduce a substance that 

causes the maximum contaminant level for nitrate in 40 CFR 141.62(b) to 

be exceeded in the ground water or that causes the existing 

concentration of nitrate in ground water to increase when the existing 

concentration of nitrate in the ground water exceeds the maximum 

contaminant level for nitrate in 40 CFR 141.62(b).

    (d) Cover is soil or other material used to cover sewage sludge 

placed on an active sewage sludge unit.

    (e) Displacement is the relative movement of any two sides of a 

fault measured in any direction.

    (f) Fault is a fracture or zone of fractures in any materials along 

which strata on one side are displaced with respect to strata on the 

other side.

    (g) Final cover is the last layer of soil or other material placed 

on a sewage sludge unit at closure.

    (h) Holocene time is the most recent epoch of the Quaternary period, 

extending from the end of the Pleistocene epoch to the present.

    (i) Leachate collection system is a system or device installed 

immediately above a liner that is designed, constructed, maintained, and 

operated to collect and remove leachate from a sewage sludge unit.

    (j) Liner is soil or synthetic material that has a hydraulic 

conductivity of 1x10-7 centimeters per second or less.

    (k) Lower explosive limit for methane gas is the lowest percentage 

of methane gas in air, by volume, that propagates a flame at 25 degrees 

Celsius and atmospheric pressure.

    (l) Qualified ground-water scientist is an individual with a 

baccalaureate or post-graduate degree in the natural sciences or 

engineering who has sufficient training and experience in ground-water 

hydrology and related fields, as may be demonstrated by State 

registration, professional certification, or completion of accredited



[[Page 837]]



university programs, to make sound professional judgments regarding 

ground-water monitoring, pollutant fate and transport, and corrective 

action.

    (m) Seismic impact zone is an area that has a 10 percent or greater 

probability that the horizontal ground level acceleration of the rock in 

the area exceeds 0.10 gravity once in 250 years.

    (n) Sewage sludge unit is land on which only sewage sludge is placed 

for final disposal. This does not include land on which sewage sludge is 

either stored or treated. Land does not include waters of the United 

States, as defined in 40 CFR 122.2.

    (o) Sewage sludge unit boundary is the outermost perimeter of an 

active sewage sludge unit.

    (p) Surface disposal site is an area of land that contains one or 

more active sewage sludge units.

    (q) Unstable area is land subject to natural or human-induced forces 

that may damage the structural components of an active sewage sludge 

unit. This includes, but is not limited to, land on which the soils are 

subject to mass movement.



[58 FR 9387, Feb. 19, 1993, as amended at 64 FR 42570, Aug. 4, 1999]