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SEPTIC INSTALLER TEST FOR
WASHINGTON STATE (WOSSA)
PRACTICE EXAM 300 QUESTIONS
AND ALL COMPLETE SOLUTIONS.
"Distribution Technology - CORRECT ANSWER=> any arrangement of equipment and/or material that
distributes sewage within and on-site sewage system."
"Drainfield - CORRECT ANSWER=> subsurface soil absorption system, and soil dispersal component"
"Drainrock - CORRECT ANSWER=> cleaned washed gravel or crushed rock ranging in size from 3/4" to
2.5", and containing no more than two percent by weight passing a US No.8 sieve and no more than one percent by weight passing through a US No. 200 Sieve."
"Effluent - CORRECT ANSWER=> liquid waste discharged to a septic tank or other on-site sewage
system"
"Expanding Clay - CORRECT ANSWER=> means a clay soil with the mineralogy of clay particles. Clay
particles expand when absorbing water"
"expansion - CORRECT ANSWER=> a change in residence, facility or site that results in the quantity of
sewage to exceed the original design"
"Extremely gravely - CORRECT ANSWER=> soils with 60% or more, but not less than 90% rock
fragments by volume."
"Failure - CORRECT ANSWER=> a condition of an on-site sewage component that threatens the public
health by inadequately treating the sewage, or creating a potential direct or indirect contact between sewage and the public."
"Fecal coliform bacteria - CORRECT ANSWER=> bacteria found in the intestinal tracts of warm-blooded
animals that are cultured in standard tests. Generally expressed as colonies per 100 ml."
"Gravely - CORRECT ANSWER=> Soils with 15% or more, but less than 35% rock fragments by volume."
"Gray Water - CORRECT ANSWER=> Sewage from bathtubs, showers, bathroom sinks, kitchen sinks,
washing machines, and dishwashers."
"Ground water - CORRECT ANSWER=> Subsurface water in the zone of saturated soils, seasonally,
permanently, or as the result of the tides."
"Holding tank sewage system - CORRECT ANSWER=> an on-site sewage system that a holding tank with
no discharge outlet"
"hydraulic loading rate - CORRECT ANSWER=> the amount of effluent applied to a given treatment
step, expressed as gallons per square foot per day, (gal./sq.ft./day)"
"industrial waste - CORRECT ANSWER=> Waste from production of consumer goods, mining,
agriculture and petroleum extraction and refining"
"Infiltrative surface - CORRECT ANSWER=> Surface within a treatment component or soil dispersal
component to which effluent is applied and through which effluent moves into original, undisturbed soil or other porous treatment media."
"Installer - CORRECT ANSWER=> a person approved by the local health office to install on-site sewage
systems or components"
"Local Health Officer - CORRECT ANSWER=> The provincial or municipal health officer."
"Maintenance - CORRECT ANSWER=> The actions necessary to keep the on-site sewage system
components functioning as designed"
"Massive structure - CORRECT ANSWER=> the condition of a soil layer in which the layer appears as a
coherent of solid mass not separated into peds of any kind"
"Moderated structure - CORRECT ANSWER=> Well- formed distinct peds evident in undisturbed soil.
When disturbed, soil material parts into mixture of whole peds, broken peds, and material that is not in peds."
"Monitoring - CORRECT ANSWER=> Periodic or continuous surveillance of on-site sewage system,
which is performed by observations and measurements, to determine if the system is functioning as intended and if system is in need of maintenance."
"On-site sewage system (OSS) - CORRECT ANSWER=> An integrated system of components , located on
or nearby the property it serves. that conveys, stores, treats, and/or provides subsurface soil treatment and dispersal of sewage. It consists of a collection system, a treatment component or treatment sequence, and a soil dispersal component."
"Reserve area - CORRECT ANSWER=> an area of land approved for the installation of a conforming
system that is protected and maintained for replacement of the OSS upon its failure"
"Residential Sewage - CORRECT ANSWER=> sewage having the constituency and strength of typical
wastewater from a domestic home"
"Restrictive Layer - CORRECT ANSWER=> A compact, dense layer in a soil that impedes the movement
of water and the growth of roots."
"Rock fragments - CORRECT ANSWER=> Rock or mineral fragments having a diameter of 2 millimeters
or more; for example, pebbles, cobbles, stones, and boulders."
"Seepage pits - CORRECT ANSWER=> an excavation more than 3' deep where the sidewalls of the
excavation are designed to dispose septic tank effluent, also called "dry wells""
"Septage - CORRECT ANSWER=> the mixture of solid wastes, scum, sludge, and liquids pumped from
within septic tanks, pump chambers, holding tanks, and OSS components"
"Sewage - CORRECT ANSWER=> any urine, feces, and the water carrying human wastes, including
kitchen, bath, and laundry wastes from residences, buildings, industrial establishments or other places."
"Sewage quality - CORRECT ANSWER=> contents in sewage that include: CBOD5, TSS, and O&G, PH,
temperature and dissolved oxygen,"
"Sewage Tank - CORRECT ANSWER=> a prefabricated or cast- in- place septic tank/dosing chamber,
holding tank, grease interceptor, recirculating filter tank or any other tanks as they relate to on-site sewage systems including tanks for use with proprietary pruducts"
"Soil dispersal component - CORRECT ANSWER=> a technology that releases effluent from a treatment
component into the soil dispersal , final treatment and recycling"
"Soil log - CORRECT ANSWER=> a detailed description of soil characteristics providing information on
the soils capacity to act as an acceptable treatment and dispersal medium for sewage"
"Soil scientist - CORRECT ANSWER=> a persons certified by the American Society of Agronomy as a
Certified Soil Scientist"
"Soil type - CORRECT ANSWER=> one of seven numerical classifications of fine earth particles and rock
fragments as described in WAC 246-272A-0220 (2)(e)"
"Strong structure - CORRECT ANSWER=> peds are distinct in undisturbed soil. They separate cleanly
when soil is disturbed, and the soil material separates mainly into peds when removed,"
"Subdivsion - CORRECT ANSWER=> a division of land of creation of parcels, described under RCW
58.17, including both long and short subdivisions, planned unit developments, including mobile home parks"
"Subsurface drip system - CORRECT ANSWER=> an effluent pressurized wastewater distribution system
that can deliver small, precise doses of effluent to soil surrounding the drip distribution pipping."
"Subsurface soil absorption system (SASS) - CORRECT ANSWER=> a soil dispersion component of
trenches of beds containing either a distribution pipe within a layer of drainrock covered with a geotextile, or a approved graveless distribution technology, designed and installed in original, undisturbed soil, with either gravity or pressure distribution of the treated effluent"
"Subsurface Water - CORRECT ANSWER=> any body of water flowing of contained in natural or
artificial unlined depressions for a significant periods of the year."
"Times dossing - CORRECT ANSWER=> delivery of discrete volumes of sewage at prescribed time
intervals."
"Treatment component - CORRECT ANSWER=> a technology that treats sewage in preparation for
further treatment and/or disposal into a soil enviornment"
"Treatment Level (1-6) - CORRECT ANSWER=> A,B,C,D,E, & N Used to match site conditions of vertical
separation and soil type with treatment components"
"Trench - CORRECT ANSWER=> a soil dispersal component consisting of an excavation with a width of
three feet or less"
"Unit volume of sewage - CORRECT ANSWER=> (A) Flow from a single family residence
(B) Flow from a mobile home site in a mobile home park (C) Four hundred and fifty gallons of sewage per day where the proposed development is not a single family residence or mobile home park"
"Very gravely - CORRECT ANSWER=> soil containing 35% or more , but less that 60% rock fragments by
volume"
"Water Table - CORRECT ANSWER=> the upper surface of the groundwater , weather permanent or
seasonal"
"Well (In terms of OSS) - CORRECT ANSWER=> (A) a temporary observation or monitoring well used to
determine the depth to a water table for locating an OSS (B) used to monitor the affects of an OSS (C) an interceptor or curtain drain constructed to lower the water table"
"Building foundation/in-ground swimming pool Set backs: - CORRECT ANSWER=> ~ 10' from edge of
drain field and reserve drain field ~ 5' from sewage tank, and distribution box ~ 2' from building sewer and non-perforated distribution line"
"Property or easement line Set backs: - CORRECT ANSWER=> ~ 5' from edge of drain field and reserve
drain field ~ 5' from sewage tank, and distribution box ~ N/A from building sewer and non-perforated distribution line"
"Interceptor/curtain drains/foundation drains/drainage ditches (Down-gradient) Set backs: - CORRECT
ANSWER=> ~ 30' from edge of drain field and reserve drain field
~ 5' from sewage tank, and distribution box ~ N/A from building sewer and non-perforated distribution line"
"Interceptor/curtain drains/foundation drains/drainage ditches (Up-gradient) Set backs: - CORRECT
ANSWER=> ~ 10' from edge of drain field and reserve drain field
~ N/A from sewage tank, and distribution box ~ N/A from building sewer and non-perforated distribution line"
"Other site features that may allow effluent to surface (Down-gradient) Set backs: - CORRECT
ANSWER=> ~ 30' from edge of drain field and reserve drain field
~ 5' from sewage tank, and distribution box ~ N/A from building sewer and non-perforated distribution line"
"Other site features that may allow effluent to surface (Up-gradient) Set backs: - CORRECT ANSWER=>
~ 10' from edge of drain field and reserve drain field ~ N/A from sewage tank, and distribution box ~ N/A from building sewer and non-perforated distribution line" "Down-gradient cuts or banks with less than 5 ft. of original undisturbed soil above a restrictive layer due
to a structural or textural change Set backs: - CORRECT ANSWER=> ~ 25' from edge of drain field and
reserve drain field ~ N/A from sewage tank, and distribution box ~ N/A from building sewer and non-perforated distribution line" "Down-gradient cuts or banks with at least 5 ft. of original undisturbed soil above a restrictive layer due
to a structural or textural change Set backs: - CORRECT ANSWER=> ~ 50' from edge of drain field and
reserve drain field ~ N/A from sewage tank, and distribution box ~ N/A from building sewer and non-perforated distribution line"
"Other adjacent soil dispersal components/subsurface storm water infiltration systems Set backs: -
CORRECT ANSWER=> ~ 10' from edge of drain field and reserve drain field
~ N/A from sewage tank, and distribution box ~ N/A from building sewer and non-perforated distribution line"
"Soil Type Descriptions: Soil Type: 1 - CORRECT ANSWER=> Soil Textural Classifications:
Gravelly and very gravelly coarse sands, all extremely gravelly soils excluding soil types 5 and 6, all soil types with greater than or equal to 90% rock fragments."
"Soil Type Descriptions: Soil Type: 2 - CORRECT ANSWER=> Soil Textural Classifications:
Coarse sands."
"Soil Type Descriptions: Soil Type: 3 - CORRECT ANSWER=> Soil Textural Classifications:
Medium sands, loamy coarse sands, loamy medium sands."
"Soil Type Descriptions: Soil Type: 4 - CORRECT ANSWER=> Soil Textural Classifications:
Fine sands, loamy fine sands, sandy loams, loams."
"Soil Type Descriptions: Soil Type: 5 - CORRECT ANSWER=> Soil Textural Classifications:
Very fine sands, loamy very fine sands; or silt loams, sandy clay loams, clay loams and silty clay loams with a moderate or strong structure (excluding platy structure)."
"Soil Type Descriptions: Soil Type: 6 - CORRECT ANSWER=> Soil Textural Classifications:
Other silt loams, sandy clay loams, clay loams, silty clay loams." "Soil Type Descriptions: Soil Type: 7
(Unsuitable for treatment or dispersal) - CORRECT ANSWER=> Soil Textural Classifications:
Sandy clay, clay, silty clay, strongly cemented or firm soils soil with a moderate or strong platy structure any soil with a massive structure any soil with appreciable amounts of expanding clays."
"How many Soil Type Descriptions are there? - CORRECT ANSWER=> 7 (Soil Type Descriptions)
"Treatment Component Performance Levels and Method of Distribution (Vertical Separation in inches) :
12" < 18" - CORRECT ANSWER=> (Soil Type: 1, 2 ,3) - (Treatment Levels A, B, C, E)
1.) A - pressure with timed dosing 2.) B - pressure with timed dosing 3-6.) B - pressure with timed dosing" "Treatment Component Performance Levels and Method of Distribution (Vertical Separation in inches) :
≥ 18 < 24 - CORRECT ANSWER=> (Soil Type: 1, 2 ,3) - (Treatment Levels A, B, C, E)
1.) B - pressure with timed dosing 2.) B - pressure with timed dosing
"Non-residential volume of sewage tank: - CORRECT ANSWER=> For OSS treating sewage from a
nonresidential source, three times the design flow"
"Maximum Hydraulic Loading Rate Calculation - CORRECT ANSWER=> -Soil Type
-Soil Textural Classification Description -Loading Rate for Residential Effluent Using Gravity or Pressure Distribution (gal./sq. ft./day)"
"WAC 246-272A-0250 Installation (Only installers may construct OSS, Installers Must:) - CORRECT
ANSWER=> (a) Follow the approved design;"
"WAC 246-272A-0250 Installation (Only installers may construct OSS, Installers Must:) - CORRECT
ANSWER=> (b) Have the approved design in possession during installation;"
"WAC 246-272A-0250 Installation (Only installers may construct OSS, Installers Must:) - CORRECT
ANSWER=> (c) Make no changes to the approved design without the prior authorization of the designer
and the local health officer;"
"WAC 246-272A-0250 Installation (Only installers may construct OSS, Installers Must:) - CORRECT
ANSWER=> (d) Only install septic tanks, pump chambers, and holding tanks approved by the
department;"
"WAC 246-272A-0250 Installation (Only installers may construct OSS, Installers Must:) - CORRECT
ANSWER=> (e) Be on the site at all times during the excavation and construction of the OSS;"
"WAC 246-272A-0250 Installation (Only installers may construct OSS, Installers Must:) - CORRECT
ANSWER=> (f) Install the OSS to be watertight, except for the soil dispersal component;"
"WAC 246-272A-0250 Installation (Only installers may construct OSS, Installers Must:) - CORRECT
ANSWER=> (g) Cover the installation only after the local health officer has given approval to cover; and"
"WAC 246-272A-0250 Installation (Only installers may construct OSS, Installers Must:) - CORRECT
ANSWER=> (h) Back fill with six to twenty-four inches of cover material and grade the site to prevent
surface water from accumulating over any component of the OSS."
"Holding Tank Sewage System (HTSS): a - CORRECT ANSWER=> Is an alternative to a conventional on-
site sewage system with very special and limited applications. Simply, the HTSS provides a means to collect and temporarily store sewage from a facility or dwelling, for subsequent removal and transport to an approved treatment and disposal site."
"Holding Tank Sewage System (HTSS): b - CORRECT ANSWER=> A HTSS is an on-site sewage system that
incorporates a holding tank, the services of a sewage pumper/hauler, and the off-site treatment and disposal of the sewage generated at the site served by the HTSS."
"Holding Tank Sewage System (HTSS): Pemiting - CORRECT ANSWER=> The permit should include
specific information and requirements for pumping service frequency and approved disposal of holding tank contents."
"Holding Tank Sewage System (HTSS): Overflow Provisions - CORRECT ANSWER=> The holding tank
system must be designed and installed such that no overflow is allowed, other than within the structure at the elevation of the lowest fixture served."
"Holding Tank Sewage System (HTSS): Surface Water - CORRECT ANSWER=> Landscaping adjacent to
the holding tank system should direct surface water flow away from the tank and access points."
"Holding Tank Sewage System (HTSS): Materials - CORRECT ANSWER=> Construction materials used
throughout the holding tank system must be able to function as designed while exposed to sewage, sewage gases, and physical forces caused by repeated tank filling and pumping which is inherent to system operation."
"Holding Tank Sewage System (HTSS): Disposal of Contents - CORRECT ANSWER=> A wastewater
treatment facility approved by the Department of Ecology; or, Other treatment and disposal sites approved by the local health officer."
"Holding Tank Sewage System (HTSS): Inspection - CORRECT ANSWER=> The holding tank system
installation must be inspected by the local health officer before use."
"Holding Tank Sewage System (HTSS): Inspection - CORRECT ANSWER=> WAC 2.4.1. Water-tightness of
the tank, tested at site after installation, by filling with water;"
"Holding Tank Sewage System (HTSS): Inspection - CORRECT ANSWER=> WAC 2.4.2. Non-buoyancy in
high groundwater areas or conditions;"
"Holding Tank Sewage System (HTSS): Inspection - CORRECT ANSWER=> WAC 2.4.3. Leak-proof nature
of the service access(es), access ports, risers, lids, and covers;"
"Holding Tank Sewage System (HTSS): Inspection - CORRECT ANSWER=> WAC 2.4.4. Methods to secure
the lids and covers from inappropriate or unapproved access;"
"Holding Tank Sewage System (HTSS): Inspection - CORRECT ANSWER=> WAC 2.4.5. Methods of
venting provided by the design and the installation. Venting should exhaust above the roof line of the building;"
"Holding Tank Sewage System (HTSS): Inspection - CORRECT ANSWER=> WAC 2.4.6. Impervious
surfaces around the access ports, equipment and methods for cleaning sewage spills; and"
"Mound System: Permitting - CORRECT ANSWER=> WAC 2.1.2.1. recording the requirement for an on-
going service contract on the property deed"
"Mound System: Permitting - CORRECT ANSWER=> WAC 2.1.2.2. issuing an operating permit (in
addition to the initial installation permit), with the requirement for maintaining a service contract;"
"Mound System: Permitting - CORRECT ANSWER=> WAC 2.1.2.3. requiring a management entity to
provide O&M assurance. Examples of management entities include: cities & towns, public utility districts, water & sewer districts, special-use districts, and corporations with demonstrated capacity to assure long-term management."
"Mound System: Mound Location - CORRECT ANSWER=> Locate the mound in open areas for exposure
to sun and wind where evaporation and transpiration will be maximized."
"Mound System: Mound Location - CORRECT ANSWER=> WAC 2.2.1. Do not construct mound systems
in drainage ways, depressions, or areas subject to flooding."
"Mound System: Mound Location - CORRECT ANSWER=> WAC 2.2.2. Upslope runoff must be diverted
around the mound."
"Mound System: Mound Location - CORRECT ANSWER=> WAC 2.2.3. Good design practice must
consider drainage constraints for both upgradient and downgradient area drainage. The local health officer may require additional site evaluations and/or testing to analyze the site before siting the mound system."
"Mound System: Mound Location - CORRECT ANSWER=> A crested site is the most desirable because
the mound can be situated such that the effluent can move laterally down both slopes. The level site allows lateral flow in all directions, but may present problems as the groundwater mound that develops under the mound may rise to the ground surface beneath the mound in slowly permeable soils. The most common application is the sloping site where all the liquid moves in one direction away from the mound (Figure 3). However, proper design can overcome this limitation. The mound should be placed on the upper portions of the slope, not at the base of the slope. On a site with a complex slope (two directions), the mound should be located so that the treated wastewater is not concentrated in one area downslope."
"Mound System: Mound Location - CORRECT ANSWER=> Sites with large trees, numerous smaller
trees or large boulders are less desirable for installing a mound system because of difficulty in preparing the surface and because of the reduced infiltration area (exposed soil) available beneath the mound. Tree roots, stumps and boulders are like rock fragments, they occupy space, and thus reduce the amount of soil available for receiving and transmitting treated wastewater away from the mound area."
"Mound System: Mound Location - CORRECT ANSWER=> If no other site is available, leave the tree
stumps cut off at ground level rather than disturbing the native soil by removing them. A larger-than- normal mound area may be necessary if many, or large, stumps or boulders are involved, so sufficient soil is available to accept the effluent. The amount of increased basal area and/or mound size should be technically justified and sufficient to make up for the soil infiltration area lost to the tree trunks, stumps, and boulders."
"Mound System: Mound Location - CORRECT ANSWER=> In addition to increasing the size of the
system extra care and consideration must be given to adequately prepare the soil infiltrative surface under less-than-ideal conditions. Such a site may very well necessitate meticulous hand spading of part or all of the area under the mound. Like the amount of additional area required to make up for the lost infiltration area, the method employed and care required to satisfactorily prepare the site is a designer's responsibility."
"Mound System: Minimum Original Soil Depth - CORRECT ANSWER=> WAC 2.3.1. Mound systems must
meet the minimum vertical separation requirements specified by WAC 246-272A-0230 and WAC 246- 272A-0280. See Table 5 for possible applications for mounds consistent with the vertical separation requirements in rule. A minimum of 12 inches of undisturbed, unsaturated, original soil as measured from the original ground surface is required for placement of a mound after all clearing, leveling and other site disturbance during lot development is complete."
"Mound System: Minimum Original Soil Depth - CORRECT ANSWER=> WAC 2.3.2. A minimum of 24
inches of undisturbed, unsaturated, original soil as measured from the original ground surface is required for mounds meeting the treatment component performance level effluent of Treatment Level C. (See 3.8.2)."
"Mound System: Minimum Original Soil Depth - CORRECT ANSWER=> WAC 2.3.3. A minimum of 12
inches of undisturbed, unsaturated, original soil as measured from the original ground surface is required when the mound is preceded by a treatment technology identified on the List of Registered On- site Treatment and Distribution Products as meeting Treatment Level A or B and (See 3.8.3):"
"Mound System: Minimum Original Soil Depth - CORRECT ANSWER=> WAC 2.3.3.1. the mound is used
for dispersal only, or"
"Mound System: Minimum Original Soil Depth - CORRECT ANSWER=> WAC 2.3.3.2. the mound has a
minimum of 24 inches of media depth and is being used on a site with conditions requiring Treatment Level A."
"Mound System: Minimum Original Soil Depth - CORRECT ANSWER=> WAC 2.3.4. Generally, when the
site evaluation indicates the depth of soil to a water table is less than 18 inches, there is a need to confirm that there are at least 12 inches during the wet season. Therefore when there is any doubt that there is sufficient unsaturated soil depth, the permit should be held for a wet season evaluation to identify accurately the location of high water tables. As potential vertical separation (or soil depth)
distribution system must be designed in accordance with the Recommended Standards and Guidance for Pressure Distribution or Recommended Standards and Guidance for Subsurface Drip Systems. Design, layout, and installation of the pump chamber-to-mound transmission line must consider, and satisfactorily address, the potential for channeling groundwater or surface water to either the mound or the pump chamber causing infiltration-related problems."
"Mound System: Monitoring Ports - CORRECT ANSWER=> Each mound should have a minimum of two
monitoring ports, one placed in the infiltration bed down to the gravel-sand interface (except where subsurface drip distribution system is used), and one downslope from the bed down to the sand-native soil interface. Another useful monitoring port would be installed through the sandnative soil interface into the native soil several inches. See Figure 9 for examples of monitoring ports and anchoring methods"
"Mound System: Construction Plan - CORRECT ANSWER=> WAC: 3.15.1. The routes for ingress and
egress for construction vehicles, assuring that adequate protection is afforded the mound, and surrounding areas, especially downslope areas. The mound system, including the area around the base and downslope, must be protected to prevent damage caused by vehicular, livestock, or excessive pedestrian traffic."
"Mound System: Construction Plan - CORRECT ANSWER=> A construction plan must be developed and
submitted as a part of the project design"
"Mound System: Construction Plan - CORRECT ANSWER=> WAC: 3.15.2. The means to assure that the
reserve area is not subject to damage or soil compaction from vehicular or other site development activity."
"Mound System: Construction Plan - CORRECT ANSWER=> WAC: 3.15.3. Instructions for erecting a
temporary construction fence or protective barrier around the proposed mound, designated reserve, and the adjacent area (particularly downslope from the primary and reserve mound sites) to assure that the area is not damaged by other construction activity before installation of the mound system. These areas must be unmistakably identified on the site so as to preclude potential site damage. Such fencing or identification is the responsibility of the sewage system designer."
"Mound System: Construction Plan - CORRECT ANSWER=> WAC: 3.15.4. Instructions, layout and
specifications for proper grading, diking, ditching and subsurface drainage to prevent the intrusion of off- site surface and subsurface waters into the mound area,"
"Mound System: Construction Plan - CORRECT ANSWER=> WAC: 3.15.5. Requirements for proper
installation equipment and construction procedures. (See Appendix G. Site Preparation and Construction.)"
"Mound System: Construction Plan - CORRECT ANSWER=> The procedures used in the construction of
a mound system are just as critical as the design of the system. Good design with poor construction will result in system failure. It should be emphasized that the soil must only be worked when the moisture
content is low to avoid compaction and puddling. Consequently, installations must be made only when the soil is as dry as required. The approved construction plan must be followed."
"Intermittent Sand Filter Systems: Introduction: 1 - CORRECT ANSWER=> Intermittent sand filters
provide biodegradation and decomposition of wastewater constituents by bringing the wastewater into close contact with a well-developed aerobic biological community attached to the surfaces of the filter media."
"Intermittent Sand Filter Systems: Introduction: 2 - CORRECT ANSWER=> This process requires
unsaturated downward flow of the effluent through the filter media. The filter media may be mineral sand or equivalently sized crushed glass meeting one of the media."
"Intermittent Sand Filter Systems: Introduction: 3 - CORRECT ANSWER=> The media is either contained
in a watertight vessel below the surface of the ground, or wholly or partially elevated in a containment vessel. Proper function requires that influent to the filter be distributed over the media in controlled, uniform doses."
"Intermittent Sand Filter Systems: Introduction: 4 - CORRECT ANSWER=> In order to achieve accurate
dosing, these systems require timed dosing with associated pump chambers, electrical components, and distribution network, with a minimum of 4 to 18 doses per day (depending on the sand media) spread evenly over a 24-hour period. Filtrate (treated effluent) is collected and discharged from the bottom of the sand filter by either a gravity discharge underdrain or a pump discharge underdrain."
"Intermittent Sand Filter Systems: Introduction: 5 - CORRECT ANSWER=> This technology is used on
sites with shallow soil conditions where treatment must be accomplished before the effluent is discharged into the soil. Intermittent sand filter effluent may be dispersed to a soil profile containing as little as 12 inches of vertical separation in soil types 2 through 6. Intermittent sand filters are also used as part of a mitigation strategy when horizontal separations are reduced."
"Intermittent Sand Filter Systems: 1. Performance Standards: - CORRECT ANSWER=> When properly
sited, designed, installed, operated, and maintained, an intermittent sand filter system consistent with these recommended standards and guidance is expected to achieve treatment performance equal to Treatment Level B." "Intermittent Sand Filter Systems: 2. Application Standards,
2.5. Location Requirements: - CORRECT ANSWER=> WAC: 2.5.1. The minimum setback requirements
for intermittent sand filters are the same as required for sewage tanks (WAC 262-272A-0210)." "Intermittent Sand Filter Systems: 2. Application Standards,
2.1. Listing: - CORRECT ANSWER=> WAC: 2.1.1. Intermittent sand filters are a public domain treatment
technology and are included in the Department of Health's List of Registered On-site Treatment and Distribution Products (Registered List) as a Category 1 treatment technology" "Intermittent Sand Filter Systems: 2. Application Standards,
levels become increasingly critical to the on-site sewage system design, function, and the protection of public health." "Intermittent Sand Filter Systems: 3. Design Standards
3.4. Minimum Dosing Frequency: - CORRECT ANSWER=> WAC: 3.4.1. A timed dosing system is
required. The dosing frequency or dose volume is dependent on the media specification used with the sand filter. To assure that appropriate dose volumes are delivered to the sand filter, the timer must be set to dose the filter at the following minimum dosing frequency:" "Intermittent Sand Filter Systems: 3. Design Standards
3.4. Minimum Dosing Frequency: - CORRECT ANSWER=> WAC: 3.4.1 Media Specification Minimum
Number of Doses/Day :
- Coarse Sand Media: 18 times per day
- ASTM C-33: 4 times per day" "Intermittent Sand Filter Systems: 3. Design Standards
3.4. Minimum Dosing Frequency: - CORRECT ANSWER=> With frequent dosing (i.e., greater than 12
doses/day) very little effluent is applied to the filter at any one dose resulting in unsaturated film-like flow. If the dose volume exceeds the water holding capacity of the filter media, the applied liquid fills the pore spaces allowing the wastewater to pass through the filter untreated. However, if the dose volume does not exceed the water holding capacity of the media, the applied wastewater will flow around the sand grains in a thin film maximizing oxygen diffusion, and maximizing contact between the organics in the effluent and the microbial growth on the media. The filter media meeting the Coarse Sand Media specification has a lower water holding capacity than the sand meeting the ASTM C-33 specification. Thus, a smaller dose volume or higher dosing frequency is required to promote the unsaturated film-like flow. Because of the larger unit wetted surface area of ASTM C-33 sand, a larger volume of wastewater may be applied at one time without exceeding its water holding capacity. The large surface allows unsaturated flow conditions to occur at a higher dose volume or lower dosing frequency"
"Intermittent Sand Filter Systems: Filter Media Specifications - CORRECT ANSWER=> Media may be
either mineral sand or equivalently sized crushed glass."
"Intermittent Sand Filter Systems: Containment Vessel Standards - CORRECT ANSWER=> Synthetic
Membrane Lined Pit"
"Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) - CORRECT
ANSWER=> 1. Patches, repairs, and seams of membrane liners must have the same physical properties
as the parent membrane material" "Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) 2. Site
considerations and preparation: - CORRECT ANSWER=> a. The supporting surface slopes and
foundation to accept the liner must be stable and structurally sound including appropriate compaction. Make sure the potential for sink hole development and differential settlement is avoided;"
"Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) 2. Site
considerations and preparation: - CORRECT ANSWER=> b. Soil stabilizers such as cementations or
chemical binding agents must not adversely affect the membrane because they are potentially abrasive agents."
"Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) - CORRECT
ANSWER=> 3. To avoid deterioration of the membrane liner caused by exposure to weather or sunlight,
the liner must be protected by being fully buried. In cases where portions of the liner may be subjected to direct exposure to the weather, the exposed portions of the liner must be covered. A construction option to accomplish this is to install a finish rim over the exposed liner portions."
"Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) - CORRECT
ANSWER=> 4. Non-reinforced liners have high elongation and can conform to irregular surfaces and
follow settlements within limits. Unreasonable strain reduces thickness and may reduce life expectancy by lessening the chemical resistance of the thinner (stretched) material. Membrane liners must be installed to minimize strain (or elongation to the fabric) anywhere in the flexible membrane liner system;" "Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) 5.
Construction and installation: a. The bottom of the pit must be covered with? - CORRECT ANSWER=>
(1) Sand to "bed" liner, at a minimum depth of 3 inches to protect liner from punctures," "Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) 5.
Construction and installation: a. The bottom of the pit must be covered with? - CORRECT ANSWER=>
(2) A non-woven, needle-punched synthetic geotextile fabric with a thickness strong enough to protect the liner." "Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) 5.
Construction and installation: a. The bottom of the pit must be covered with? - CORRECT ANSWER=>
(3) Grade the bottom to provide a sloping liner surface, from the outside edge of the filter toward the point of underdrain collection. Slopes must be equal to 8 inches fall overall or 1 inch of fall per 1 foot of run, whichever is the greater." "Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) 5.
Construction and installation: - CORRECT ANSWER=> b. The sides of the pit must be smooth and free
of possible puncture points from foreign objects." "Intermittent Sand Filter Systems: Containment Vessel Standards (B. Installation Standards) 5.
Construction and installation: c. Climatic conditions: - CORRECT ANSWER=> (1) Temperature. The
desirable temperature range for membrane installation is 42° F to 78° F. Lower or higher temperatures may have an adverse effect on transportation, storage, field handling and placement, seaming and backfilling and attaching boots and patches may be difficult. Installing liners outside the desirable temperature range should be avoided at all times"
