11

CTC 450 ReviewCTC 450 Review

Advanced WW TreatmentAdvanced WW Treatment Removal of NitrogenRemoval of Nitrogen Removal of phosphorusRemoval of phosphorus Complete removal of pathogensComplete removal of pathogens Removal of other toxicsRemoval of other toxics

22

ObjectivesObjectives

Understand the basics with respect Understand the basics with respect to reusing wastewaterto reusing wastewater

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Water ReuseWater Reuse

Reuse is defined as direct application Reuse is defined as direct application of treated WW for agricultural and of treated WW for agricultural and urban irrigation, industrial reuse, urban irrigation, industrial reuse, groundwater recharge, and othersgroundwater recharge, and others

Discharging WW to a receiving water Discharging WW to a receiving water that is ultimately used downstream for that is ultimately used downstream for a water source is not considered reuse a water source is not considered reuse (dilution/separation in time and space)(dilution/separation in time and space)

44

Water Reuse - FunctionsWater Reuse - Functions

Treated effluent is used as a water Treated effluent is used as a water resource for beneficial purposesresource for beneficial purposes

Effluent is kept out of streams, lakes Effluent is kept out of streams, lakes and beaches and beaches

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Water Reuse – Main Water Reuse – Main ConcernsConcerns

Reliable treatment of WWReliable treatment of WW Protection of public healthProtection of public health Gaining public acceptanceGaining public acceptance

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Matter of EconomicsMatter of Economics

Water reuse may be less costlyWater reuse may be less costly Use N/P for irrigation instead of Use N/P for irrigation instead of

providing tertiary processes to prevent providing tertiary processes to prevent eutrophicationeutrophication

Water shortages – a future possibility Water shortages – a future possibility (CA/AZ/FL)(CA/AZ/FL)

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Potential DrawbacksPotential Drawbacks

Pathogens via physical contact or Pathogens via physical contact or aerosolsaerosols

Public perceptionPublic perception

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Water StatisticsWater Statistics

Recycled WW Recycled WW 983 MGD (1995)983 MGD (1995) 2% of total wastewater release (41,000 2% of total wastewater release (41,000

mgd)mgd) CA/AZ/FL account for majorityCA/AZ/FL account for majority

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Water Quality Effluent StdsWater Quality Effluent Stds

Dependent upon reuse applicationDependent upon reuse application Agricultural irrigation (restrictedAgricultural irrigation (restricted-with respect to human -with respect to human

activityactivity)) fodder,fiber,seed cropsfodder,fiber,seed crops

Agricultural irrigation (unrestricted)Agricultural irrigation (unrestricted) processed food, food eaten rawprocessed food, food eaten raw

Urban irrigation (restricted)Urban irrigation (restricted) Golf courses, cemeteries, highway mediansGolf courses, cemeteries, highway medians

Urban irrigation (unrestricted)Urban irrigation (unrestricted) Parks, playgrounds, residences, comml landscapingParks, playgrounds, residences, comml landscaping

1010

Advantages/Disadvantages of Advantages/Disadvantages of Agricultural IrrigationAgricultural Irrigation

Already contains Already contains nutrients and soil nutrients and soil amendmentsamendments

Agricultural areas Agricultural areas may be nearbymay be nearby

Money for cash Money for cash cropscrops

In arid regions, ww In arid regions, ww may be the only may be the only source of watersource of water

Nitrate - Nitrate - groundwatergroundwater

Heavy metals - Heavy metals - soilssoils

Pathogens - farm Pathogens - farm workersworkers

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Agricultural Irrigation Agricultural Irrigation

Storage required to balance Storage required to balance supply/demandsupply/demand

1212

Design of Irrigation SystemsDesign of Irrigation Systems

Balance water to determine storage Balance water to determine storage requirementsrequirements

Balance nitrogen to prevent Balance nitrogen to prevent migrationmigration

1313

Urban Irrigation Urban Irrigation

Piping systems color-codedPiping systems color-coded Cross-connections prohibitedCross-connections prohibited Warning signsWarning signs Reuse water pipes placed 3’ below Reuse water pipes placed 3’ below

potable water pipespotable water pipes

1414

Groundwater RechargeGroundwater Recharge

Surface infiltration (surface spreading)Surface infiltration (surface spreading) Direct injectionDirect injection

IssuesIssues Fate of particulatesFate of particulates Fate of bacteria/virusesFate of bacteria/viruses Fate of dissolved organic/inorganic Fate of dissolved organic/inorganic

constituents (particularly toxics)constituents (particularly toxics)

1515

Groundwater RechargeGroundwater Recharge

US federal requirements/standards US federal requirements/standards have not been establishedhave not been established

Currently regulated by state Currently regulated by state agenciesagencies

1616

Storage IssuesStorage Issues

Need for storageNeed for storage Type (open or closed)Type (open or closed) Discharge requirements Discharge requirements Problems:Problems:

Odors, loss of chlorine residual, low DOOdors, loss of chlorine residual, low DO Temperature stratification, bird/rodentsTemperature stratification, bird/rodents Algal blooms, regrowth of Algal blooms, regrowth of

microorganismamicroorganisma

1717

Agricultural Irrigation-ExampleAgricultural Irrigation-ExampleTallahassee, FLTallahassee, FL

2000 acres; 2000 acres; 16 pivot irrigators16 pivot irrigators

irrigators controlled by computerirrigators controlled by computer low-drift nozzleslow-drift nozzles

Vegetation-canola, corn, sorghum, grassVegetation-canola, corn, sorghum, grass Monitoring wells Monitoring wells Capacity-23 mgdCapacity-23 mgd Four parallel treatment plants (fig 14-4) Four parallel treatment plants (fig 14-4)

1818

Residential Lawn WateringResidential Lawn WateringEl Dorado Hills, CAEl Dorado Hills, CA

Dual plumbed distribution systemDual plumbed distribution system 66 mg reservoir66 mg reservoir Drip irrigators-no restriction timesDrip irrigators-no restriction times Spray irrigators-restricted to 9pm-6amSpray irrigators-restricted to 9pm-6am Back-up: potable lake waterBack-up: potable lake water

Plant doesn’t meet required water qualityPlant doesn’t meet required water quality System can’t meet peak irrigation System can’t meet peak irrigation

demandsdemands

1919

Urban ReuseUrban ReuseSt. Petersburg, FLSt. Petersburg, FL

Irrigation of parks, school, golf Irrigation of parks, school, golf courses, comm’l and residential courses, comm’l and residential irrigationirrigation

Some water injected into deep-well Some water injected into deep-well systemsystem

Effluent requirements:Effluent requirements: SS-5 mg/l (in practice 1-3 mgl/l)SS-5 mg/l (in practice 1-3 mgl/l) Chlorine residual-1 mg/l after 15 min Chlorine residual-1 mg/l after 15 min

(in practice 4 mg/l)(in practice 4 mg/l)

2020

Industrial ReuseIndustrial ReuseLos Medanos Energy Center, Los Medanos Energy Center,

CACA WW treatment plant provided recycled WW treatment plant provided recycled

water to the energy centerwater to the energy center Water is used for the heat recovery steam Water is used for the heat recovery steam

generator make-up and water for the generator make-up and water for the evaporative cooling systemevaporative cooling system

Treatment processes:Treatment processes: Dual-media, ultra- and activated carbon Dual-media, ultra- and activated carbon

filtration for TOC removalfiltration for TOC removal Antiscalant chemical added for evaporative Antiscalant chemical added for evaporative

systemsystem Reverse osmosis for evaporative coolingReverse osmosis for evaporative cooling

Final Exam ReviewFinal Exam Review

Water Processing-Clarifier following Water Processing-Clarifier following Coagulation (25 pts)Coagulation (25 pts)

Wastewater Processing-Trickling Filter Wastewater Processing-Trickling Filter (25 pts)(25 pts)

Wastewater Processing-Clarifier (25 Wastewater Processing-Clarifier (25 pts)pts)

25 pts – will cover material presented 25 pts – will cover material presented after the midterm after the midterm

2121

Final Exam ReviewFinal Exam Review

Open book/open notes/Open book/open notes/ Can use computer Can use computer (but monitored)(but monitored)

No cell phones; no old testsNo cell phones; no old tests Show all work Show all work Know the standardsKnow the standards Don’t forget unitsDon’t forget units Conversions-concentration to massConversions-concentration to mass

2222