Salamonie Reservoir: Wastewater Treatment

1. Salamonie Reservoir: Wastewater Treatment Presentation by Chelsea Smith March 11, 2014

2. My Background • Southern Wells (K-12) • Graduated in 2010 • Ball State University (2010-2014) • BS in Environmental Management • Minor in Criminal Justice • Minor in Music Theory

3. 2013 Summer Internship • Salamonie Reservoir and Lake (DNR) • Duties included: • Assisting the Wastewater Treatment Operator • Sampling drinking water • Serving as a boat ramp attendant • Lawn mowing and weed whacking • Other

4. Wastewater Treatment Plant • Operations proceed 24/7 • 6 Stations • Influent enters the plant (aka raw sewage) • Main treatment (aka mixed liquor) • Effluent exits the plant (aka final clear water) • Lab tests occur at least once each week

7. 1. Headworks/ Screen Unit • Raw flows in • Headworks: primary removal of large items before the water can be treated • Screen unit removes debris and trash • Leaves, toys, rocks, towels, … • Grit channel removes sand and smaller particles • Purpose: To remove contaminants which improves later water treatment, making it more effective

9. 2. Grease Separator • Removes grease and oils from raw influent • Purpose: To make water treatment more effective • Grease may cause clogs • It is difficult for microbes to digest grease = slow process

11. www.americanbiofuelscorp.com

12. 3. Chemical Feed Pump • Treats water based of flow • Ferric chloride (FeCl3) • Highly corrosive • Low pH = Acidic • Reddish-brown liquid (stains easily) • Purpose: To remove sewage particles out of suspension in the water by coagulation • Suspended particles attach to ferric salts and clump • Clumps become bigger and heavier; settle to bottom

15. 4. Clarifier (Main Treatment) • Wastewater enters AerationTank • Small air bubbles break up solids and mix water • Microbes need oxygen to digest organic matter (sewage) • Water moves from aeration tank to Clarifier • Solids settle to the bottom of the Clarifier • Sludge at bottom pumped to Sludge Holding Tank • Clear water spills over Clarifier rings • Purpose: To separate solids from clear water AND to digest organic compounds via microbial processes

20. 5. UV Disinfection • Clear water flows from clarifier into the UV basin • Must move slowly = more retention time • UV lights used instead of chlorine • Cl harmful to aquatic life • UV bulbs and basin must be kept clean • Purpose: To kill any residual microorganisms and microbial pathogens (especially E. coli)

23. 6. Final Aeration Basin • Clear water moves through a flow meter and into the final basin • Water cascades down many steps • Discharged into the stream which flows into the lake • Purpose: To improve oxygen content in the water, thus provided aquatic organisms with needed oxygen

27. Wastewater Weekly Tests • pH • Dissolved Oxygen (DO) • Carbonaceous Biological Oxygen Demand (BOD) • Total Suspended Solids (TSS) • Percent Settleable Solids in 30 minutes • Ammonia • Total Phosphorus • E. coli

28. pH • pH probe inserted into 100 mL sample • Stir rod helps give an accurate sample throughout • Measures: amount of hydrogen ions in solution • Importance: Aquatic organisms need pH 6-9 to survive • Solution: Control amount of ferric acid added preparatorychemistry.com

30. Dissolved Oxygen (DO) • DO probe inserted into 100 mL sample • Sensors must be fully submerged • Measures: amount of oxygen molecules in water • Importance: Aquatic organisms need DO levels above 5.0 mg/L to survive easily • Solution: Increase aeration rate or allow sewage to have more retention time in aeration tanks

32. Biological Oxygen Demand (BOD) • 9 different bottles prepared and incubated for 5 days • DO measured before and after incubation • Measures: amount of oxygen needed for microbes to decompose the organic (carbonaceous) matter available in water • Relates to DO levels (inverse reactions) • Importance: Too much BOD can deplete DO levels • Solution: Increase aeration rate and allow microbes to digest more organic matter

36. Total Suspended Solids (TSS) • Filter water sample through glass fiber filter and dry • Weigh filters before and after sample is added • Measures: amount of suspended solids in water • Importance: Lower amount of suspended solids = lower turbidity of final clear water • Solution: Increase retention time in aeration tank and increase amount of ferric acid added

41. Settleable Solids in 30 minutes • Let a 1000 mL mixed liquor sample settle solids for 30 minutes • Level of solids at the bottom = % solids in water • Measures: amount of larger solids in water that will settle to the bottom • Importance: Microbes in the aeration tank need 15-25% solids for efficient and effective treatment • Solution: Alter amount of solids (organic matter) in the aeration tank

43. Ammonia • Add water sample to prepared vials • Use spectrophotometer to read ammonia levels after reaction completed • Measures: amount of ammonia (NH3) molecules in the water • Importance: Too much nitrogen in water can cause algae growth, which will deplete DO • Solution: Increase aeration rates and retention time of mixed liquor in aeration basin www.uh.edu

46. Total Phosphorus • Add water sample to prepared vials • Use spectrophotometer to read phosphorus levels after reaction completed • Measures: amount of phosphorus molecules in water • Importance: High amounts can cause depletion of dissolved oxygen and lead to algae growth • Solution: Increase addition of ferric acid to remove phosphorus by coagulation www.advancedaquarist.com

48. Spectrophotometer www.keison.co.uk

49. Escherichia coli • Sample is poured into a tray with many wells • After 24 hour incubation, number of luminescent wells correlates to amount of E. coli • Measures: number of colony forming units (CFU) that are present in a 100 mL water sample • Importance: E. coli is a disease-causing human pathogen • Solution: Increase retention time in the UV basin and clean UV bulbs

50. wikieducator.org www.etsnclab.com