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Automated Odor Control Chemical Dosing Systems 1152 West 2400 South Suite C Salt Lake City, Utah 84119

Automated Odor Control Chemical Dosing Systems 1152 West 2400 South Suite C Salt Lake City, Utah 84119. OVERVIEW What Causes Odor and Corrosion in Wastewater Systems? What are the Consequences of Not Treating Hydrogen Sulfide? How and Why Do You Treat or Prevent Odors?

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Automated Odor Control Chemical Dosing Systems 1152 West 2400 South Suite C Salt Lake City, Utah 84119

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  1. Automated Odor Control Chemical Dosing Systems 1152 West 2400 South Suite C Salt Lake City, Utah 84119

  2. OVERVIEW • What Causes Odor and Corrosion in Wastewater Systems? • What are the Consequences of Not Treating Hydrogen Sulfide? • How and Why Do You Treat or Prevent Odors? • What Makes AWS’ System Better? • Actual Results in Clarksville, TN.

  3. What Causes Odor and Corrosion in Wastewater Systems? • Primary cause of odors in wastewater is hydrogen sulfide (H2S). • H2S tends to form in wastewater anywhere sewage is allowed to go without oxygen for a significant amount of time. • The usual suspects are long force mains from pumping stations. • When sewage is discharged at the terminus of the force main the turbulence allows liquid sulfide to become airborne.

  4. Pumping Station Air relief valve Discharge Manhole Chemical Dosing System Force Main Wet Well with Sewage Pump Diagrammatic View of a Pumping Station and Force Main Diagram not to scale

  5. What are the Consequences of Not Treating Hydrogen Sulfide • Worker Health and Safety • Odor • Corrosion and Destruction of Infrastructure

  6. Worker Health and Safety H2S Toxicity Spectrum ppm 0.1 Odor Threshold 0.2 3.0 “Rotten Egg” Odor Alarm Offensive Odor 5.0 10 OSHA/ACGIH TWA Exposure limit Headaches/Nausea Throat and Eye Irritation Threshold of Serious Injury 50 100 Loss of Sense of Smell Conjunctivitis/Respiratory Tract Irritation/Olfactory Paralysis 300 Imminent Life Threat 500 Strong Nervous System Stimulation Apnea 1000 Immediate Collapse With Respiratory Paralysis Death!!! Death!!! 2000

  7. Rotten Eggs – H2S Odor • Properties • Most noticeable of all odors • Colorless toxic gas • Moderately soluble in water • pH, temperature, and turbulence driven

  8. Diagram of Typical Cross Section of Force Main with no Odor Control Treatment. This could cause the following odors in local neighborhoods. • Garlicky • Skunk • Decayed cabbage • Fishy • Rancid

  9. Corrosion and Destruction of Infrastructure Hydrogen Sulfide Corrosion Damage of Common Wastewater Infrastructures: Left Photo of Wet Well, Right Photo of Manhole

  10. 10 9 8 7 6 5 4 3 2 1 0 1 1.5 2 3 4 5 6 7 8 H2S Vs the Life Expectancy of Reinforced Concrete Pipes < 5 Years 5-10 Years Dissolved Sulfide (mg/L) 10-25 Years 25-50 Years > 50 Years Pipe Diameter (Feet)

  11. Diagram of Typical Cross Section of Force Main with no Odor Control Treatment. • As shown on the Graph, depending on the amount of Hydrogen Sulfide in your system, within 5 years can cause as much as $1 million in damage to infrastructure.

  12. An Ounce of Prevention is Worth a Pound of Cure Cost of AWS System over 5 year period Installation and Service Charge $2500.00 Monthly Service Fee $400.00 X 60 months = $24,000.00 Total $26,500.00 Estimated Cost of Infrastructure Damage $500k-$1 Mil

  13. How and Why Do You Treat or Prevent Odors? How: • Most cost effective method is usually chemical treatment at the wet well. • Most common chemical used is calcium nitrate (Bioxide). • Other effective chemicals are sodium nitrate, iron salts, hydrogen peroxide. • Conventional method is to drip chemical into wet well at a constant rate.

  14. How and Why Do You Treat or Prevent Odors? Why: • Citizen Complaints • Law suits • Consent order • Worker safety • Sewer line and component failures • Premature failure of system appurtances

  15. How and Why Do You Treat or Prevent Odors? How: • Most cost effective method is usually chemical treatment at the wet well. • Most common chemical used is calcium nitrate (Bioxide). • Other effective chemicals are sodium nitrate, iron salts, hydrogen peroxide. • Conventional method is to drip chemical into wet well at a constant rate.

  16. What makes the AWS system better? • Utilizing proprietary software and a patent pending process, our system monitors the rate of change of the wet well level to apply a chemical dose rate to meet the system demand rather than a constant dose. • The AWS system saves significant amounts of chemicals and therefore saves the customer significant amounts of money. • The AWS system prevents harmful slug dosing of the wet well during low flow periods. This makes alternative chemicals to nitrate much more feasible to the customer.

  17. Typical Odor Control Chemical Feed System

  18. AWS Dosing System

  19. Comparison

  20. Actual Results in Clarksville, TN • The AWS system is currently installed in Clarksville, TN at the Sugar Tree pumping station and has lowered their chemical consumption by greater than 50 percent. The savings at this site equate to around $11,000 per year. • Initial testing at additional sites in Clarksville are also showing 50 percent or greater reductions in chemical usage.

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