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shallow bed
Bed installed in an excavation less than 18 inches deep such that the entire infiltrative surface is below the original ground elevation.
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shallow narrow trench
Final treatment and dispersal component in which highly-treated effluent is distributed into trenches installed in the upper portion (8 to 12 inches) of the soil profile and dosed via low-pressure distribution laterals.
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shallow trench
Trench installed in an excavation typically greater than 6 but less than 18 inches deep such that most of the entire infiltrative surface is below the original ground elevation; the orifices in the distribution piping are at or below original ground elevation.
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sheeting
Members of a shoring system that retain the earth in position and in turn are supported by other members of the shoring system.
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shield
Structure that is able to withstand the forces imposed on it by a cave-in and thereby protect employees within the structure; can be permanent structures or can be designed to be portable and moved along as work progresses; additionally, shields can be either pre-manufactured or job-built in accordance with OSHA 1926.652(c)(3) or (c)(4). Shields used in trenches are usually referred to as "trench boxes" or "trench shields."
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shoring
Structure such as a metal hydraulic, mechanical or timber shoring system that supports the sides of an excavation and which is designed to prevent cave-ins.
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shoulder
The hillslope-profile position that forms the convex, erosional uppermost inclined surface near the top of a slope. If present, it comprises the transition zone from summit to backslope. Compare summit, crest, backslope, footslope, and toeslope (Schoeneberger and Wysocki, personal communication, 2013; Hawley and Parsons, 1980).
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shrink/swell clay
See expansive clay mineralogy.
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shut off valve
Valve that prevents flow from entering a component.
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side feed
A geomorphic component of hills consisting of a laterally planar area of a hillside, resulting in predominantly parallel overland water flow (e.g., sheet wash); contour lines generally form straight lines. Side slopes are dominated by colluvium and slope wash sediments. Compare base slope, head slope, nose slope.
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side feed manifold
Configuration in which a long manifold is installed perpendicular to one set of distribution laterals that extend in one direction along the contour; the supply line may connect to the manifold in the center or at one end; used on level or nearly-level sites.
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side slope
A geomorphic component of hills consisting of a laterally planar area of a hillside, resulting in predominantly parallel overland water flow (e.g., sheet wash); contour lines generally form straight lines. Side slopes are dominated by colluvium and slope wash sediments. Slope complexity (downslope shape) can range from simple to complex (Schoeneberger and Wysocki, personal communication, 2013). Compare base slope, head slope, nose slope.
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sides
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sieve analysis
Use of specific size sieves to determine the gradation (the distribution of aggregate particles, by size, within a given sample) in order to determine compliance with design, production control requirements, and verification specifications.
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silt
Mineral particles that range in diameter from 0.02-0.002 mm in the International System or 0.05-0.002 mm in the USDA-NRCS system; see also soil separate, soil textural class and soil texture.
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simplex system
Control that operates a single device (e.g., a simplex pump system).
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single beam laser level
Laser level projecting a string line that can be seen on a target regardless of lighting conditions.
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single compartment
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single differential float
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single grain
Soil structure descriptor for soil consisting of non-coherent individual particles (e.g., loose sand).
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single pass coir filter
Flow configuration wherein effluent moves through a coir media filter only once.
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single pass media filter
Flow configuration wherein effluent moves through a media filter only once.
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single pass peat filter
Flow configuration wherein effluent moves through a peat media filter only once.
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single pass sand filter
Flow configuration wherein effluent moves through a sand media filter only once.
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siphon
Device used for demand dosing effluent from a tank at a given elevation to a component at a lower elevation, accomplished by means of suction created by the weight of the liquid in the conveying pipe.
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siphon tank
Dosing tank or compartment which provides storage of effluent and contains a siphon to convey effluent from the tank to another pretreatment process or to a final treatment and dispersal component.
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site drainage
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site evaluation
Description and evaluation of soil characteristics (morphology, including structure, texture, and mineralogy; depth to limiting condition such as seasonal wetness; unsuitable soil structure or rock); site characteristics (including topography and landscape position) and site features requiring setback distances (wells, water lines, structures, property lines, surface water, drainage and easements) and who performs any other activities necessary to determine site suitability for effective treatment and dispersal of effluent.
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site evaluator
Service provider who conducts preconstruction site visits to describe and evaluate soil characteristics (morphology, including structure, texture, and mineralogy; depth to limiting condition such as seasonal wetness; unsuitable soil structure or rock); site characteristics (including topography and landscape position) and site features requiring setback distances (wells, water lines, structures, property lines, surface water, drainage and easements) and who performs any other activities necessary to determine site suitability for effective treatment and dispersal of effluent.
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site plan
Plan-view drawing that provides a graphical representation of existing and proposed natural and manmade physical features on a site.
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site restoration
Reconstitution of the surface of a site to approach as nearly as possible the original grade and vegetative cover.
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siting
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slag
Bottom ash (a by-product of coal-fired power plants), the coarse fraction of which may be used as distribution media.
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sleeve
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slickensides
Stress surfaces in soil that are polished and striated and are produced by one mass sliding past another.
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slope
1. Ratio of the rise divided by the run between two points, typically described as a percentage (rise/run multiplied by 100). 2. Landscape form or feature; see also slope, concave; slope, convex; and slope, linear.
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slope break
Configuration for piping installed on steep slopes to slow the flow coming from the structure to the first tank; typically includes the installation of cleanouts to prevent obstruction.
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slope shape
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slope stake
In earthwork, a stake marking the line where a cut or fill meets the original grade.
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sloping (sloping system)
Method of protecting personnel by excavating in a manner to form sides that are inclined away from the excavation to prevent cave-ins; the angle of incline required to prevent a cave-in varies with the soil type, environmental conditions of exposure, and application of surcharge loads.
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sloping site
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sloughing
Shedding material (typically biofilm) from the surface of media.
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sludge
Accumulated solids and associated entrained water within a pretreatment component, generated during the biological, physical, or chemical treatment; coagulation; or clarification of wastewater.
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sludge pipe
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sludge recycling
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sludge return
Process that sends the material (sludge) settled in a clarifier back to a septic or processing tank for further treatment or to maintain adequate microbial populations for treatment.
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sludge return pump
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soft malfunction
Component malfunction that does not disrupt overall system performance and can typically be corrected via maintenance or operational activities.
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soil
1. Unconsolidated mineral and/or organic material on the immediate surface of the earth that serves as a medium for the growth of plants; 2. Unconsolidated mineral or organic matter on the surface of the earth that has been subjected to and shows effects of pedogenic and environmental factors of climate (including water and temperature effects), and macro- and microorganisms, conditioned by relief, acting on parent material over a period.
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soil absorption field
See soil treatment area (STA).
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soil consistence
Attribute of soil expressed in degree of cohesion and adhesion, or in resistance to deformation or rupture; consistence includes: the resistance of soil material to rupture, resistance to penetration, the plasticity, toughness, or stickiness of puddled soil material, and the manner in which the soil material behaves when subjected to compression; general classifications of soil consistence include loose, friable, very friable, firm, very firm, and extremely firm.
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soil horizon
Layer of soil or soil material approximately parallel to the land surface and differing from adjacent related layers in physical, chemical, and biological properties or characteristics such as color, structure, texture, consistence, kinds and number of organisms present, degree of acidity or alkalinity, etc.
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soil morphology
1. Physical constitution of a soil profile as exhibited by the kinds, thickness, and arrangement of the horizons in the profile; and by the texture, structure, consistence, and porosity of each horizon; 2. Visible characteristics of the soil or any of its parts.
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soil mottles
Subordinate color in a soil horizon of a differing Munsell Color System notation; see also redoximorphic feature.
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soil porosity
Volume percentage of the total bulk not occupied by solid particles.
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soil profile
Vertical section of the soil through all its horizons and extending into the parent material.
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soil separate
Mineral particle that is sand-, silt-, or clay-sized.
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soil smearing
Degradation of the infiltrative surface through the sealing of soil pores.
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soil structure
Combination or arrangement of primary soil particles into secondary units or peds; secondary units are characterized on the basis of shape, size class, and grade (degree of distinctness); see also structureless.
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soil substitution
Trench or bed installed after native soil is excavated and replaced with approved soil material; configurations and terminology vary among jurisdictions; may be referred to locally as sand-lined trenches, liner systems, etc.
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soil substitution bed
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soil substitution trench
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soil textural class
Percentage by weight of sand, silt, and clay such that each class possesses unique physical characteristics and management relative to the other textural classes; textural class names are modified by the addition of suitable adjectives when rock fragments are present in substantial amounts (for example, ‘stony silt loam’); see also soil classification system, OSHA.
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soil texture
Relative proportions by weight of the various inorganic primary particles in a soil as described by the classes of soil texture.
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soil treatment area
Physical location and associated structures (trenches, beds, fields, as appropriate) and distribution piping where final treatment and dispersal of effluent occurs.
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solenoid
Electro-magnetically operated mechanical device (electric coil); see also valve, solenoid.
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solenoid valve
Valve that uses an electro-magnetically operated mechanical device (electric coil) to turn on, shut off, or regulate the flow of effluent.
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solids
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solids handling
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solids storage
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solids transport
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sorption
Removal of an ion or molecule from solution by adsorption and/or absorption; term often used when the exact nature of the mechanism of removal is not known.
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source
Residence, business, institution or other facility where wastewater is generated.
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spalling
Condition in which the surface of a concrete component is physically degraded (flaking), exposing aggregate and/or structural reinforcement materials.
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spillway
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spin filter
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spirit level
Device for determining true horizontal or vertical directions by the centering of a bubble in a slightly curved glass tube or tubes filled with alcohol or ether.
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splash plate
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splash pool
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split base
Method of dividing effluent flowing through a recirculating media filter using a physical barrier in the bottom of the filter resulting in multiple discharge locations.
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splitter ball valve
See recirculating splitter valve (RSV).
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spodic horizon
Diagnostic subsurface horizon characterized by the illuvial accumulation of amorphous materials composed of aluminum and organic carbon with or without iron.
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spoil
Soil removed from its original location, typically stacked in a pile and may be reused.
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spray
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spray dispersal
Application of effluent over a soil treatment area via sprinkler heads and associated devices and parts (including pump, filters, controls, and piping).
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spray distribution
Pressurized distribution system that delivers treated effluent over an infiltrative surface through a network of piping, pressurized nozzles and associated devices.
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spray field
Above-grade soil treatment area where final treatment and dispersal occurs via application of effluent to the infiltrative surface via pressurized distribution heads utilizing nozzles.
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spray heads
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spray pattern
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spring
Groundwater seeping out of the earth where the water table intersects the ground surface.
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spring check valve
Non-return valve in which a spring causes a disc to seat against an opening within a cylindrical fluid line and stops flow.
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spring line
Horizontal axis defined by the greatest width dimension of piping, conduit, tank, or other structure; see diagram at bedding.
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sprinkler heads
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squirt height
Height achieved by the liquid in a pressurized lateral when an orifice is positioned such that the discharge is vertical into the atmosphere, typically expressed in feet of height.
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stabilize
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stable rock
Natural solid mineral material that can be excavated with vertical sides and will remain intact while exposed; unstable rock is considered to be stable when the rock material on the side or sides of the excavation is secured against caving-in or movement by rock bolts or by another protective system that has been designed by a registered professional engineer.
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stake
1. Stout stick or post sharpened at one end and driven into the earth as a support or boundary marker. 2. Action of placing stakes on the perimeter of a property or a portion thereof to establish visible boundaries.
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standard dimensional ratio (SDR)
Piping specification based upon the ratio of pipe diameter to wall thickness
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standard methods
Shortened title for the Standard Methods for the Examination of Water and Wastewater, a joint publication of the American Public Health Association, American Water Works Association, and Water Pollution Control Federation; widely-used manual that outlines the procedures used to analyze water and wastewater impurities and characteristics.
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standpipe
This document was developed by NOWRA with funding from the U.S. Environmental Protection Agency Treatment Works Program 25-28 administered by the Rural Community Assistance Partnership Incorporated (RCAP).
