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P
Perched Ground Water - Occurring when water, infiltrating the soil from above,
reaches an underlying layer of impervious or relatively impervious soil that
restricts its downward movement. Perched water can result from heavy rainfall
and then disappear in a matter of hours, or the water may remain for months.
Percolation Rate - The rate in which water is absorbed in a percolation hole,
expressed in inches per minute.
Percolation Test - A field test for determining the suitability of soil for the
subsurface disposal of sewage as described in 310 CMR 15.106.
Permeability - The relative ease (or lack thereof) with which water moves
downward through soil. Permeability is measured in inches per hour. The
permeability of soil is a critical factor in the suitability/sizing of a leachfield for a
particular site.
Piloting Approval - Initial step in MassDEP's 3-tier approval process for I/A
technologies, requiring field testing and technical evaluation to demonstrate that
the technology is likely to provide environmental protection equivalent to a
conventional septic system.
Pollutant - A contaminant that adversely alters the physical, chemical, or
biological properties of the environment.
Pressure Distribution System - A type of SAS that uses a pump to pump effluent
out to the drainfield to a manifold where effluent is then distributed over the
entire area of the drainfield through a series of perforated PVC pipe.
Primary Treatment - In on-site systems, the initial treatment (separation of solids
from liquids and limited biodegradation of contaminants) that occurs in the
septic tank.
Provisional Use Approval - Stage in MassDEP's three-tier approval process for
I/A technologies, typically occurring after successful piloting in Massachusetts or
satisfactory past performance for two years of general use in one or more other
states. Provisional use evaluates the technology's performance under actual
field conditions in Massachusetts.
reaches an underlying layer of impervious or relatively impervious soil that
restricts its downward movement. Perched water can result from heavy rainfall
and then disappear in a matter of hours, or the water may remain for months.
Percolation Rate - The rate in which water is absorbed in a percolation hole,
expressed in inches per minute.
Percolation Test - A field test for determining the suitability of soil for the
subsurface disposal of sewage as described in 310 CMR 15.106.
Permeability - The relative ease (or lack thereof) with which water moves
downward through soil. Permeability is measured in inches per hour. The
permeability of soil is a critical factor in the suitability/sizing of a leachfield for a
particular site.
Piloting Approval - Initial step in MassDEP's 3-tier approval process for I/A
technologies, requiring field testing and technical evaluation to demonstrate that
the technology is likely to provide environmental protection equivalent to a
conventional septic system.
Pollutant - A contaminant that adversely alters the physical, chemical, or
biological properties of the environment.
Pressure Distribution System - A type of SAS that uses a pump to pump effluent
out to the drainfield to a manifold where effluent is then distributed over the
entire area of the drainfield through a series of perforated PVC pipe.
Primary Treatment - In on-site systems, the initial treatment (separation of solids
from liquids and limited biodegradation of contaminants) that occurs in the
septic tank.
Provisional Use Approval - Stage in MassDEP's three-tier approval process for
I/A technologies, typically occurring after successful piloting in Massachusetts or
satisfactory past performance for two years of general use in one or more other
states. Provisional use evaluates the technology's performance under actual
field conditions in Massachusetts.
