Ronald E. Graeber Program Manager Ground Water Discharges Section Division of Water Resources
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Transcript of Ronald E. Graeber Program Manager Ground Water Discharges Section Division of Water Resources
Spray Irrigation of Treated WastewaterSpray Irrigation of Treated Wastewater
A Sensible Approach to Wastewater A Sensible Approach to Wastewater ManagementManagement
Promoting Beneficial Reuse of Reclaimed Promoting Beneficial Reuse of Reclaimed WaterWater
Ronald E. GraeberRonald E. GraeberProgram ManagerProgram ManagerGround Water Discharges SectionGround Water Discharges SectionDivision of Water ResourcesDivision of Water Resources
(302) 739-9948(302) [email protected]@state.de.us
What is Spray Irrigation???What is Spray Irrigation???• Reuse and Recycling of Treated WastewaterReuse and Recycling of Treated Wastewater
• Controlled application of treated wastewater Controlled application of treated wastewater (Reclaimed Water) onto vegetated land (Reclaimed Water) onto vegetated land surfacesurface
• Application rate based on crop nutrient needsApplication rate based on crop nutrient needs
• Nutrients in reclaimed water used to grow Nutrients in reclaimed water used to grow cropscrops
• Level of wastewater treatment based on reuse Level of wastewater treatment based on reuse type:type:– Restricted Public Access SitesRestricted Public Access Sites– Limited Public Access SitesLimited Public Access Sites– Unlimited Public Access sitesUnlimited Public Access sites
Typical Waste Water CharacteristicsTypical Waste Water Characteristics
ParameterParameterPrior to Prior to
TreatmentTreatment
Treated WW/ Treated WW/ Prior to Spray Prior to Spray
IrrigationIrrigation
3 feet 3 feet Below the Below the
Soil SurfaceSoil SurfaceNitrogenNitrogen 5050 mg/Lmg/L 2525 mg/Lmg/L <5<5 mg/Lmg/L
PhosphorusPhosphorus 1212 mg/Lmg/L 88 mg/Lmg/L 00 mg/Lmg/L
Fecal Fecal ColiformsColiforms
>1,000,0>1,000,00000 col/100mLcol/100mL 10 - 200 *10 - 200 *
col/col/100mL100mL 00 col/100mLcol/100mL
BODBOD 250250 mg/Lmg/L 10 - 50 *10 - 50 * mg/Lmg/L 00 mg/Lmg/L
TSS TSS 220220 mg/Lmg/L 10 - 50*10 - 50* mg/Lmg/L 00 mg/Lmg/L
ChloridesChlorides 3030 mg/Lmg/L 3030 mg/Lmg/L 3030 mg/Lmg/L
* The lower concentrations must be met if the public may come into contact The lower concentrations must be met if the public may come into contact with the reclaimed water, such as in Golf Course Irrigationwith the reclaimed water, such as in Golf Course Irrigation
Benefits of using reclaimed water Benefits of using reclaimed water include:include:
• Aquifer rechargeAquifer recharge
• Reduces current demand on aquiferReduces current demand on aquifer
• Keeps water in watershedKeeps water in watershed
• Maintains Open SpaceMaintains Open Space
• Preserves agricultural landsPreserves agricultural lands
• Reduces agricultural operating costsReduces agricultural operating costs
• Reduces import of nutrients to WatershedReduces import of nutrients to Watershed
• Alternative to Surface Water DischargeAlternative to Surface Water Discharge
• Helps protect surface water qualityHelps protect surface water quality
Types of Beneficial ReuseTypes of Beneficial Reuse
• Agricultural ApplicationsAgricultural Applications– Dedicated Ag SitesDedicated Ag Sites– Voluntary Ag sitesVoluntary Ag sites
• Irrigation of Wooded TracksIrrigation of Wooded Tracks
• Irrigation of Residential LawnsIrrigation of Residential Lawns
• Irrigation of Open SpacesIrrigation of Open Spaces
• Golf Course IrrigationGolf Course Irrigation
Agricultural applicationsAgricultural applications
• Irrigate fieldsIrrigate fields• Supply supplemental nutrientsSupply supplemental nutrients• Promotes fertigationPromotes fertigation• Nutrient content of reclaimed water is Nutrient content of reclaimed water is
knownknown• Nutrient application based on crop needsNutrient application based on crop needs• Conventional irrigation equipment used, Conventional irrigation equipment used,
such as:such as:•Center pivotsCenter pivots•Traveling gunsTraveling guns•Solid set sprinklersSolid set sprinklers
Agricultural Benefits to Using Reclaimed Agricultural Benefits to Using Reclaimed WaterWater
• Provides supplemental nutrientsProvides supplemental nutrients• Provides water at pressure suitable for Provides water at pressure suitable for
irrigationirrigation– Reduces electrical and equipment costsReduces electrical and equipment costs– Reduces demand on ground water supplyReduces demand on ground water supply
• Available even during drought restrictionsAvailable even during drought restrictions• Improves crop yieldsImproves crop yields• Allows for accurate nutrient loading rates, Allows for accurate nutrient loading rates,
at all stages of crop growth (FERTIGATION)at all stages of crop growth (FERTIGATION)
Types of Agricultural Reuse SitesTypes of Agricultural Reuse Sites
• Dedicated Agricultural Reuse SitesDedicated Agricultural Reuse Sites– Purchased by WWTF, or long-term contractPurchased by WWTF, or long-term contract– Maximize hydraulic loading ratesMaximize hydraulic loading rates– Year-round applicationYear-round application– Grass and hay, or grain cropsGrass and hay, or grain crops– Monitoring wells requiredMonitoring wells required– Buffers to property lines, surface watersBuffers to property lines, surface waters– Public access restrictedPublic access restricted– Ag. field is permittedAg. field is permitted– Secondary treatment requiredSecondary treatment required– ~125 to 150 acres of irrigatable land ~125 to 150 acres of irrigatable land
needed per MGDneeded per MGD
Types of Agricultural Reuse Sites Types of Agricultural Reuse Sites (continued)(continued)
• VoluntaryVoluntary Agricultural Reuse SitesAgricultural Reuse Sites– All activities controlled by farm managerAll activities controlled by farm manager– Hydraulic loading rates based on crop needsHydraulic loading rates based on crop needs– Most crops can be grownMost crops can be grown– Only prohibition is on crops that will be Only prohibition is on crops that will be
consumed rawconsumed raw– Tertiary treatment is required (Unlimited Tertiary treatment is required (Unlimited
Public Access Criteria)Public Access Criteria)– Minimal buffersMinimal buffers– No public access restrictionsNo public access restrictions– May use lands under Ag PreservationMay use lands under Ag Preservation
Agricultural Land PreservationAgricultural Land Preservation
• 2005 MOU between DNREC and DDA 2005 MOU between DNREC and DDA encourages Spray Irrigation on Ag encourages Spray Irrigation on Ag Preservation Lands:Preservation Lands:– For production of conventional cash cropsFor production of conventional cash crops– Requires treatment to Unlimited Access levelsRequires treatment to Unlimited Access levels
• Irrigation Preservation Task ForceIrrigation Preservation Task Force– House Concurrent Resolution No. 67 (July 2008)House Concurrent Resolution No. 67 (July 2008)– Preservation of Agricultural landsPreservation of Agricultural lands– Preserve ground water resourcesPreserve ground water resources– Maintain/improve farming economyMaintain/improve farming economy– Promote utilization of reclaimed water on farmPromote utilization of reclaimed water on farm– Report to General Assembly by January 15, Report to General Assembly by January 15,
20092009
Beneficial Reuse in DelawareBeneficial Reuse in Delaware
• Started in the 1970’sStarted in the 1970’s• Currently, 24 permitted spray irrigation facilitiesCurrently, 24 permitted spray irrigation facilities
– Sussex County operates 3 Regional Spray Irrigation Sussex County operates 3 Regional Spray Irrigation Facilities in Inland Bays BasinFacilities in Inland Bays Basin
• 3100 acres of land currently permitted3100 acres of land currently permitted• Over 200 individual, and community drip Over 200 individual, and community drip
irrigation systems currently in useirrigation systems currently in use• Applied to agricultural sites, golf courses, Applied to agricultural sites, golf courses,
wooded tracks, open spaces and residential wooded tracks, open spaces and residential lawnslawns
• 650,000 pounds of Nitrogen and 210,000 650,000 pounds of Nitrogen and 210,000 pounds of Phosphorus reclaimed through reuse pounds of Phosphorus reclaimed through reuse in 2007 in 2007
How Land Treatment Systems Reduce How Land Treatment Systems Reduce Nutrient Loads and Help Meet TMDL GoalsNutrient Loads and Help Meet TMDL Goals
•Agricultural SettingAgricultural Setting–Nutrients supplied by treated wastewaterNutrients supplied by treated wastewater
•Nutrient loading rates are limited, matched Nutrient loading rates are limited, matched to crop uptake needsto crop uptake needs
•Nutrients are applied in small quantities, Nutrients are applied in small quantities, over timeover time
–Maximizes nutrient uptake, reduces loss to Maximizes nutrient uptake, reduces loss to water tablewater table
•Vegetated buffers reduce erosion and Vegetated buffers reduce erosion and runoffrunoff
–Phosphorus controlPhosphorus control
•Eliminates Surface Water DischargesEliminates Surface Water Discharges
•Wastewater runoff is prohibitedWastewater runoff is prohibited
Ground Water ConsiderationsGround Water Considerations
• Impact to Ground WaterImpact to Ground Water– Improve ground water quality under siteImprove ground water quality under site– Promotes local recharge of aquiferPromotes local recharge of aquifer– No mounding of water tableNo mounding of water table– Verified through on site ground water Verified through on site ground water
monitoringmonitoring
• Comparison with Disposal OptionsComparison with Disposal Options– Hydraulic Loading RatesHydraulic Loading Rates
Comparison of Hydraulic Loading Rates for Various Wastewater Disposal Options
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Ground Water ConsiderationsGround Water Considerations
• Impact to Ground WaterImpact to Ground Water– Improve ground water quality under siteImprove ground water quality under site– Promotes local recharge of aquiferPromotes local recharge of aquifer– No mounding of water tableNo mounding of water table– Verified through on site ground water Verified through on site ground water
monitoringmonitoring
• Comparison with Disposal OptionsComparison with Disposal Options– Hydraulic Loading RatesHydraulic Loading Rates– Nitrogen Loading RatesNitrogen Loading Rates
Comparison of Nitrogen Discharge Rates for Various Wastewater Disposal Options
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Is Spray Irrigation Suitable for Is Spray Irrigation Suitable for Rehoboth Beach?Rehoboth Beach?
• Seasonal FlowsSeasonal Flows
• Level of Wastewater TreatmentLevel of Wastewater Treatment
• Storage RequirementsStorage Requirements
• Availability of Agricultural LandsAvailability of Agricultural Lands
• Alternative Reuse OptionsAlternative Reuse Options– Horticultural UsesHorticultural Uses– Irrigation of Recreational AreasIrrigation of Recreational Areas– Golf Course IrrigationGolf Course Irrigation
Future uses of reclaimed water in Future uses of reclaimed water in DelawareDelaware
• Eliminate current surface water dischargesEliminate current surface water discharges
• Wetland restoration / Wetland creationWetland restoration / Wetland creation
• Greenhouse production of ornamental Greenhouse production of ornamental floraflora
• Residential and commercial lawn wateringResidential and commercial lawn watering
• Grey water reuseGrey water reuse
• Only limited by our imaginationOnly limited by our imagination
QUESTIONS?
COMMENTS
Thank-you