Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0011 - Water Quality
Chapter 15 - USE OF SURFACE DISPOSAL OF BIOSOLIDS, APP. A-C
Part C - SURFACE DISPOSAL
Section 21 - Special definitions

(a) "Active biosolids unit" is a biosolids 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) "Biosolids unit" is land on which only biosolids are placed for final disposal. This does not include land on which biosolids are either stored or treated. Land does not include waters of the state, as defined in W.S. 35-11-103 ( c) (vi).

(d) "Biosolids unit boundary" is the outermost perimeter of an active biosolids unit.

(e) "Contaminate an aquifer" means to introduce a substance that causes the maximum contaminant level for nitrate in Chapter 8, Wyoming Water Quality Rules and Regulations to be exceeded in 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 Chapter 8, Wyoming Water Quality Rules and Regulations.

(f) "Cover" is soil or other material used to cover biosolids placed on an active biosolids unit.

(g) "Displacement" is the relative movement of any two sides of a fault measured in any direction.

(h) "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.

(i) "Final cover" is the last layer of soil or other material placed on a biosolids unit at closure.

(j) "Holocene time" is the most recent epoch of the Quaternary period, extending from the end of the Pleistocene epoch to the present.

(k) "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 biosolids unit.

(l) "Liner" is soil or synthetic material that has a hydraulic conductivity of 1 x 10-7 centimeters per second or less.

(m) "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.

(n) "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 university programs, to make sound professional judgments regarding ground water monitoring, pollutant fate and transport, and corrective action.

(o) "Seismic impact zone" is an area that has a ten percent (10%) or greater probability that the horizontal ground level acceleration of the rock in the area exceeds 0.10 gravity once in 250 years.

(p) "Surface disposal site" is an area of land that contains one or more active biosolids units.

(q) "Unstable area" is land subject to natural or human-induced forces that may damage the structural components of an active biosolids unit. This includes, but is not limited to, land on which the soils are subject to mass movement.