Water and Wastewater Treatment Processes Crystal Penton, E.I. Will Larsen, E.I.

Water and Wastewater Water and Wastewater Treatment ProcessesTreatment Processes

Crystal Penton, E.I.Crystal Penton, E.I.

Will Larsen, E.I. Will Larsen, E.I.

Key ConceptsKey Concepts

• Water CycleWater Cycle

• Neuse River BasinNeuse River Basin

• Water Treatment ProcessWater Treatment Process

• Wastewater Treatment ProcessWastewater Treatment Process

Key TermsKey Terms

• CoagulationCoagulation

• FlocculationFlocculation

• SedimentationSedimentation

• FiltrationFiltration

• DisinfectionDisinfection

• Activated SludgeActivated Sludge

• Activated Sludge Activated Sludge ProcessProcess

• DigestionDigestion

The Water CycleThe Water Cycle

NC Watershed BasinsNC Watershed Basins

The Neuse River BasinThe Neuse River Basin• 33rdrd largest river basin in North Carolina largest river basin in North Carolina

• Roughly 1/6 of North Carolina’s Roughly 1/6 of North Carolina’s population lives within the Neuse River population lives within the Neuse River BasinBasin– Approximately 1,596,364 PeopleApproximately 1,596,364 People

• Covers 18 Counties and 77 towns & Covers 18 Counties and 77 towns & citiescities

• One of only 4 river basin that is One of only 4 river basin that is completely contained within North completely contained within North CarolinaCarolina

The Neuse River BasinThe Neuse River Basin

• Neuse River – 248 Neuse River – 248 miles long from the miles long from the Falls Lake Reservoir Falls Lake Reservoir Dam to the Pamlico Dam to the Pamlico SoundSound

• At its mouth it’s the At its mouth it’s the widest river in America widest river in America – 6 miles across– 6 miles across

• Home to several rare or Home to several rare or endangered speciesendangered species

• Water quality is Water quality is effected by sediment, effected by sediment, nutrients, toxins, and nutrients, toxins, and coliform bacteriacoliform bacteria

Dwarf WedgemusselAlasmidonta heterodon

Neuse River WaterdogNecturus lewisi

Carolina MadtomNoturus furiosus

Roanoke BassAmbloplites cavifrons

The Neuse River BasinThe Neuse River Basin

Water Treatment ProcessWater Treatment Process

Raw Water Intake and Raw Water Intake and ScreensScreens

• Intake structure - delivers water to Intake structure - delivers water to the water treatment plantthe water treatment plant– Lake or ReservoirLake or Reservoir– Stream or RiverStream or River– GroundwaterGroundwater

• Screens – prevent trash, logs, or fish Screens – prevent trash, logs, or fish from entering the treatment plantfrom entering the treatment plant

Coagulation and Coagulation and FlocculationFlocculation• Coagulation – clumping together of fine Coagulation – clumping together of fine

particles into larger particles (flocs) particles into larger particles (flocs) caused by the use of chemicals caused by the use of chemicals (coagulant)(coagulant)

• Flocculation – the gathering together of Flocculation – the gathering together of fine particles after coagulation to form fine particles after coagulation to form larger particles by a process of gentle larger particles by a process of gentle mixingmixing

Coagulation and Coagulation and FlocculationFlocculation

SedimentationSedimentation• Removes suspended solids that are denser than Removes suspended solids that are denser than

waterwater• Factors that effect sedimentation:Factors that effect sedimentation:

– Particle sizeParticle size– Particle shapeParticle shape– Density of particlesDensity of particles– Temperature of the waterTemperature of the water

Sedimentation BasinSedimentation Basin

FiltrationFiltration• Filters out the remaining suspended Filters out the remaining suspended

solids solids

Sand FilterSand Filter

Sand FilterSand Filter

DisinfectionDisinfection• Disinfection – process designed to kill or Disinfection – process designed to kill or

deactivate most microorganisms in water, deactivate most microorganisms in water, including disease causing bacteriaincluding disease causing bacteria

• Types of disinfection:Types of disinfection:– PhysicalPhysical

• Ultraviolet (UV) raysUltraviolet (UV) rays

• HeatHeat

– ChemicalChemical• ChlorineChlorine

• OzoneOzone

Giardia lamblia

Fecal Coliforms

Storage and DistributionStorage and Distribution• Storage – keeping Storage – keeping

water for later usewater for later use– Elevated tanksElevated tanks– Ground storage Ground storage

tankstanks

• Distribution system Distribution system – network of pipes – network of pipes and pump stations and pump stations that transports that transports finished water from finished water from the treatment plant the treatment plant to the userto the user

Smithfield Water Treatment Smithfield Water Treatment FacilityFacility

Wastewater Treatment Wastewater Treatment ProcessProcess

Screens and Grit RemovalScreens and Grit Removal

• Screens - used to remove large Screens - used to remove large suspended or floating object in the suspended or floating object in the wastewaterwastewater

• Grit Chamber – chamber where the Grit Chamber – chamber where the wastewater’s velocity is reduced to wastewater’s velocity is reduced to allow heavier grit to settle out and be allow heavier grit to settle out and be removedremoved

Screens and Grit RemovalScreens and Grit Removal

Screens and Grit RemovalScreens and Grit Removal

Primary ClarifierPrimary Clarifier• Primary Clarifier – causes the velocity of Primary Clarifier – causes the velocity of

the wastewater to slow, allowing denser the wastewater to slow, allowing denser sludge to settle to the bottomsludge to settle to the bottom

Oxidation Ditches & Activated Oxidation Ditches & Activated SludgeSludge• Activated SludgeActivated Sludge

– Produced in wastewater by the growth of Produced in wastewater by the growth of organismsorganisms

– Contains many living organisms that feed on Contains many living organisms that feed on the wastewaterthe wastewater

– Organisms grow in the presence of dissolved Organisms grow in the presence of dissolved oxygenoxygen

Free Swimming Ciliate

Stalked Ciliate

Nematode

Rotifer

Oxidation Ditches & Activated Oxidation Ditches & Activated SludgeSludge

• Activated Sludge Activated Sludge Process – uses the Process – uses the microorganisms in the microorganisms in the activated sludge to activated sludge to speed up the speed up the decomposition of decomposition of wastes. As the wastes. As the organisms grow more organisms grow more waste is removed waste is removed leaving the water leaving the water partially cleaned.partially cleaned.

Oxidation Ditches & Activated Oxidation Ditches & Activated SludgeSludge

Secondary ClarifierSecondary Clarifier• Secondary Clarifier - causes the velocity of Secondary Clarifier - causes the velocity of

the wastewater to slow, allowing sludge to the wastewater to slow, allowing sludge to settle to the bottomsettle to the bottom

DisinfectionDisinfection• Disinfection – Disinfection –

process designed process designed to kill or deactivate to kill or deactivate most most microorganisms in microorganisms in wastewater, wastewater, including disease including disease causing bacteriacausing bacteria

Chlorine Contact Chamber

Ultraviolet Disinfection

DigesterDigester

• Digestion – sludge is aerated for an Digestion – sludge is aerated for an extended period of time. As the extended period of time. As the supply of food is depleted the supply of food is depleted the microorganisms begin to consume microorganisms begin to consume one another. The result is inert one another. The result is inert components and organic compounds components and organic compounds that are not biodegradable.that are not biodegradable.

DigesterDigester

OutfallOutfall• Outfall – wastewater effluent is discharged Outfall – wastewater effluent is discharged

into the receiving waterinto the receiving water

Benson Wastewater Treatment Benson Wastewater Treatment PlantPlant