Need to Know:



Designer - Need to KnowA designer will locate and design the onsite wastewater treatment system using good design judgment, and relies on appropriate design methods and calculations, and ensures that the design is constructible.Demonstrate Knowledge of Wastewater Characteristics Needed to Design Onsite Wastewater Treatment SystemsWastewater sourcesDomesticNon-DomesticCommercialDefinitionGeneral solutionsNon-sewage wastesDefinitionsolutionsHydraulicsDetermine flows from residential dwelling Determine the number of bedroomsDetermine the number of fixturesDetermine flows from non-residential dwellingUse applicable Arizona Administrative Code provisionsMeasuredPeak daily flow for tank sizingPeak 7 day for drainfield sizingBiomat developmentPart-time and vacation useWaste strengthDemonstrate knowledge of definition, impacts upon the onsite wastewater treatment system, and typical amounts of wastewater characteristicsBiochemical oxygen demand (BOD)Understand measurement and typical valuesCalculate BOD loadingUnderstand how it impacts systemsTotal suspended solids (TSS)Understand measurement and typical valuesUnderstand how it impacts systemsFats, oils, and grease (FOG)Understand measurement and typical valuesUnderstand how can impact systemsOther pollutants of source waterBacteria and virusesDefinitionFecal ColiformImpacts on onsite wastewater treatment systemsNitrogen DefinitionCycle throughout systemImpacts on onsite wastewater systemsTreatmentPhosphorus DefinitionImpacts on onsite wastewater systemsTreatmentDissolved oxygen (DO)DefinitionImpacts on onsite wastewater systemsTreatmentTemperatureDefinitionImpacts on onsite wastewater systemsTreatmentChemicalsTypesPharmaceuticalsHousehold chemicalsDetergentsFabric softenersDisinfectantsHazardous wasteDefinitionsImpacts on onsite wastewater treatment systemsTreatmentWater treatment devicesWater softenersReverse osmosis unitsCommercial ice makersImpacts on onsite wastewater treatment systemsMiscellaneousSanitary wipesGray waterImpacts on onsite wastewater treatment systemsInterpret Site Characteristics and Constructability IssuesA designer needs to be able to interpret site characteristics and identify all constructability ographySlopes, elevations, and benchmarksUpslope conditionsAvoiding surface water run-onDiversionsDownslopes and surfacingOnsite wastewater treatment system orientation to slopeSoilsCoarse sand treatment concernsHeavy clay acceptance and smearing concernsPlastic limit Above ground system requiredPercent rockProperty boundaries, improvement, obstructions, easements, and setbacksVertical separationLimiting conditionsSpecial equipment neededAccessibility for installation and maintenanceEquipment limitationsTraffic patterns to minimize compactionMaximum lift of typical pump trucksWinter operation and protection from freezingImpact to siteFloodplainConsequences of locating in floodplainDesigning systems in floodplainDemonstrate Design of Collection and Building SewersBuilding sewersAcceptable pipe materialsSlopeDiameterMin and max depthsFreezingCleanoutsAccessibilityDiameterSpacingBasement grinder and injector pump consideration Consequences for septic tankDemonstrate Sizing and Installation of Septic TanksTreatment achieved with domestic sewageBODTSSFOGTank sizing for residential dwellingsWith no garbage disposal or pump in basementSizing with garbage disposalsSizing with pump in basementSizing with both garbage disposals and pump in basementTank sizing for non-residential dwellingsCompartmentalizationDouble chambersSingle chambers in sequenceBury depthTankRisersInspection pipesBuoyancy calculationsSetbacks, easementsEffluent screensTypesApplicationsDemonstrate Knowledge of Applications and Design of Trench and Bed Soil Treatment SystemsDetermine loading ratesTrenchesDetermine size (loading rates given soil textures, structures, and percolation rates)Determine geometry (width, height, depth)Number of trenchesLocationTopographySetbacks, easements Unknown buried items (fuel oil tanks, old drainfields)Inspection pipesUsesSize and locationsSecuringDistribution media Rock, pipe, and geotextileChambersGravelless pipeOther mediaDistribution methodsParallelSerialDropboxesDistribution boxes (D-boxes)Distribution valvesGravityPressureSurface water diversion and erosion controlBedsDetermine size (loading rates given soil textures, structures, and percolation rates)Determine geometry (width, height, depth)LocationTopographySetbacksInspection pipesUsesSize and locationsSecuringSurface water diversion and erosion controlDesign a gravity distribution system for trenches and bedsPipe diameter and specificationsPerforation diameter and spacingElevationsDemonstrate Knowledge of Applications and Design of Seepage Pit Soil Treatment SystemsDetermine loading rates Determine size (loading rates given soil textures, structures, and percolation rates)Recognize location limitations based on Arizona soils mapsDemonstrate Knowledge of Applications and Sizing of a Pump TankDetermine capacityDetermine proper dosing frequency and amountDoseFriction lossDrain backBuoyancy calculationsWiringWiring diagramsControl panelsMaintenance access locationProtection from freezingDrain backBackflow preventer removalTelemetryDistinguish When to Use Different Types of PumpsSumpEjectorGrinderTurbineCentrifugalMulti-stage?Demonstrate Ability to Size Pumps Based on the ApplicationCalculating total dynamic headCalculating gallons per minuteSiphonsUneven pressure distribution Demonstrate Knowledge of Applications and Design of Pressure Distribution SystemsIdentify when requiredDesign hydraulic componentsAcceptable pipe diameter and specificationsLateral spacing, perforation diameter, and perforation spacingDesign for pipes at different elevationsGoal is even distributionDemonstrate Knowledge of Applications and Design of At-grade SystemsIdentify types of at-grade systemsDetermine size and linear loading rate (loading rates given soil textures, structures, and percolation rates)Determine geometry (width, height, depth)LocationTopographySetbacksUnknown buried items (fuel oil tanks, old drainfields)Distribution media Rock, pipe, and geotextileChambersGravelless pipeOther mediaDistribution methodsParallelSerialDropboxesDistribution boxes (d-boxes)Distribution valvesGravityPressureEvenUnevenInspection pipesUsesSize and locationsSecuringMore than one at-grade unit in designSurface water diversion and erosion controlDemonstrate Knowledge of Applications and Design of Mound SystemsDetermine sizing and linear loading rate (loading rates given soil textures, structures, and percolation rates)Determine geometry (width, height, depth)Rock bedAbsorption widthLocationTopographySetbacksUnknown buried items (fuel oil tanks, old drainfields)Inspection pipesUsesSize and locationsSecuringPressure distribution system Uneven pressure distributionMultiple mounds in designSurface water diversion and erosion controlDemonstrate general knowledge about system operation, performance and applications drip distribution.DefinitionTreatment processApplicationsPerformanceDemonstrate Knowledge of Applications and Design of Greywater SystemsIdentify types of greywater systems availableCompare benefits and drawbacks of available greywater systemsCode requirements for a greywater systemCode requirements for designing an onsite wastewater treatment system with a greywater systemLocationTopographySetbacks, easementsRecognize that there is NO size reduction for soil treatment areaDetermine loading rates Determine size (loading rates given soil textures, structures, and percolation rates)Determine geometry (width, height and depth) Rock bedabsorption widthCalculating wastewater flowUnderstand the design of collector systemsDetermining sizing and linear loading rate (loading rates give4nsoil textures, structures and percolation rates) and geometry (width, height and depth) Rock bedabsorption widthLocationTopography, blend mound into landscapesetbacks, easementsinspection pipesUnknown buried items (fuel oil tanks, old drainfields)Calculating wastewater flow. Demonstrate Knowledge of Applications and Design of AlternativeNon-treatment SystemsHolding Tanks (Sewage Vaults)UseCapacityAccessAlarm Emergency overflowMaintenance contractFloodp plainlainLocation – flood fringeNo inspection pipesPump shut off and backflow preventionIf tank is covered with water sewage generation must stopMound designRock bed elevation Inspection pipesHolding tank sizingMaintenance after a floodPit Toilet (Earth pit Privies), fixed or transportable chemical toilets, incinerator toilet or privy, or pail- or can-type privy; APP 1.08 general permit)Code requirements for these systemsAPP: In Arizona currently: IF allowed by a county health or environmental departmentOther applicable codeDesign reference = Bulletin 23 foot separation requirement or over a vaultSetbacksMust have 25 ft3 of capacityVentingMaintenance Demonstrate knowledge of types of systems and regulatory requirements with Other systemsRegulatory requirements3 feet of soil treatmentMedium sand or finerLoad at a rate of no greater than 1.2 gpd/ft2Flow measurement, monitoring and mitigation planTypes of systemsMounds built on unnatural soil or with less the 12” of unsaturated soilPartially buried systemsTile drainageSoil treatment system downsized but not loaded at greater than 1.2 gpd/ft2Sand or peat filters with soil treatment systems totaling 3 feet of soil treatmentDemonstrate knowledge of types of systems and regulatory requirements with Performance systemsRegulatory requirementsFlow measurement, monitoring and mitigation planOperating PermitMust have “some separation”25’ horizontally from the system fecal coliform = 0If lot adjoins a lake the total phosphorus must be <1 mg/l 50 feet from the systemTypes of systemsSoil treatment system downsized loaded greater than 1.2 gpd/ft2Non-soil based pretreatment units followed by less then 3’ of separationATUGravel filtersTextile filtersConstructed wetlandsDemonstrate general knowledge about system operation, performance and applications drip distribution.DefinitionTreatment processApplicationsPerformanceDemonstrate Knowledge of Applications and Design of general knowledge about system operation, performance and applications of pretreatmentAlternative Systemstechnologies.System TypesAerobic treatment unitsIdentify typesSand filtersPeat filtersTextile filtersConstructed wetlandsEngineering padsAerobic treatment unitsPressure distributionAt-gradeIdentify types of at-grade systemsDetermine size and linear loading rate (loading rates given soil textures, structures, and percolation rates)Determine geometry (width, height, depth)LocationTopographySetbacksUnknown buried items (fuel oil tanks, old drainfields)Distribution media Rock, pipe, and geotextileChambersGravelless pipeOther mediaDistribution methodsParallelSerialDropboxesDistribution boxes (d-boxes)Distribution valvesGravityPressureEvenUnevenInspection pipesUsesSize and locationsSecuringMore than one at-grade unit in designSurface water diversion and erosion controlMoundsDrip distributionOtherDefinitionsTreatment processesApplicationsLocatingSetbacksTopography Surface water diversion and erosion controlDistribution methodsSingle passRecirculatingDetermine loading rates Determine size (loading rates given soil textures, structures, and percolation rates)Determine geometry (width, height, depth)PerformanceDemonstrate Knowledge of Applications and Design of Pressure Distribution SystemsIdentify when requiredDesign hydraulic componentsAcceptable pipe diameter and specificationsLateral spacing, perforation diameter, and perforation spacingDesign for pipes at different elevationsGoal is even distributionInspection pointsTypesSize and locations SecuringMedia FiltersDefinition and TypesSandPeatTextileGravelOtherRecirculatingTreatment processApplicationsPerformanceAccommodating site conditionsConstructed wetlandsDefinitionTreatment processApplicationsPerformanceDemonstrate general Knowledge of Design Solutions to Difficult LotsSmall lotsWater conservationSmall field with holding tankPretreatment to reduced sized drainfieldTime dosing from large pump tankLack of unsaturated soilPretreatment technologiesReduced linear loading rateRecycle systemKarst voidsHigh groundwaterPresence of bedrockCalicheGravelly texturedExcessively permeable soilsPretreatment unitsMound systemsLiner systemsApplicable treatment and dispersal systemsExcessively tight soilsApplicable treatment and dispersal systemsDamaged soilsExcavate outPretreatment Reduced linear loading rateApplicable treatment and dispersal systemsFloodplainsSteep slopesCut banksCuts created by constructionSetbacksEarth fissuresProximity to surface watersDemonstrate General Math SkillsThe Professional must be able to demonstrate competency with general math skills.Add, subtract, multiply, and divideSlopeUnit conversionMetric vs. EnglishBasic algebra/geometryGraphing (pump curves)Reading and communication skillsDemonstrate the Ability to Develop a Management Plan for the Entire Onsite Wastewater Treatment SystemThe professional must have the ability to develop a management plan for the entire onsite wastewater treatment system including all sub-municate plan to owner when availableInclude greywater system (if present)Topics Omitted for Advanced/Master DesignerCommercial establishment designflowwaste strengthpretreatmentseptic tank detentionaerobic tankssand filtersSoil treatment sizingCluster designAdvanced Treatment Unit and drip design ................
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