Haluk Bafrali Anue Water Technologies November 19, 2015

Transcription

1 Collection System Odor Control Haluk Bafrali Anue Water Technologies November 19, 2015

2 Outline Collection Systems Hydrogen Sulfide Formation Various Types of Solutions Oxygen and Ozone Odor Control Case Studies

3 Collection System to the WWTP Underground Pipeline (Sanitary Sewers) Sometimes they are combination sewers that include storm water also

4 Along the way other components Force Mains Manholes Gravity Interceptors Wet Wells Dry Wells

5 Hydrogen Sulfide Other Names: Hydrogen Sulphide, Hydrosulfuric Acid Chemical Formula: H 2 S Color: Colorless Physical Form : Gas Odor Characterization: Rotten Egg Odor In solution: Weak acid Relative Gas Density: 1.19 HYDROGEN SULFIDE

6 Hydrogen Sulfide Health Effects Revised IDLH = 100 ppmv HYDROGEN SULFIDE

7 Hydrogen Sulfide is a. Nuisance Odor Odor Control Health Hazard Odor Control The above items take into consideration the Infrastructure aspect. However, there is another aspect to consider: HYDROGEN SULFIDE??????????

8 When all the puzzle pieces combine WATER SULFUR OXIDIZING BACTERIA OXYGEN HYDROGEN SULFIDE

9 the combination forms Sulfuric Acid SULFURIC ACID

10 Sulfuric Acid deteriorates Concrete PVC liner peeling off the concrete surface below the manhole frame. SULFURIC ACID Exposed aggregate beside a mortar covered surface.

11 Sulfuric Acid corrodes Metallic Surfaces Metallic sanitary sewer pipe crossing a storm sewer. SULFURIC ACID Gate Valve with corroded surfaces.

12 Hydrogen Sulfide Generation H 2 S may be generated from the biological reduction of sulfate (SO 4-2 ) under anaerobic conditions by Sulfur Reducing Bacteria leading to Septic conditions. Septic conditions are present once the dissolved oxygen (O 2 ) and nitrate (NO 3- ) oxygen are depleted. SO C + 2H 2 O Bacteria 2HCO H 2 S HYDROGEN SULFIDE

13 Oxygen Uptake Declension O 2 NO 3 - SO 4-2 O= R-C-R' Oxygen Type Dissolved Nitrate Sulfate Organic Relative Uptake Time Minutes Hours Hours Days Days Weeks Weeks Months Industry Jargon Aerobic Anaerobic Anoxic Septic Anoxic Fermentation

14 Oxygen Uptake Declension O 2 NO 3 - SO 4-2 O= R-C-R' Oxygen Type Dissolved Nitrate Sulfate Organic Relative Uptake Time Minutes Hours Hours Days Days Weeks Weeks Months Industry Jargon Aerobic Anaerobic Anoxic Septic Anoxic Fermentation

15 Oxygen Uptake Declension O 2 NO 3 - SO 4-2 O= R-C-R' Oxygen Type Dissolved Nitrate Sulfate Organic Relative Uptake Time Minutes Hours Hours Days Days Weeks Weeks Months Industry Jargon Aerobic Anaerobic Anoxic Septic Anoxic Fermentation Evolution of H 2 S - Odor Control

16 Oxygen Uptake Declension O 2 NO 3 - SO 4-2 O= R-C-R' Oxygen Type Dissolved Nitrate Sulfate Organic Relative Uptake Time Minutes Hours Hours Days Days Weeks Weeks Months Industry Jargon Aerobic Anaerobic Anoxic Septic Anoxic Fermentation

17 Biological Sulfide Production In Sewers

18 Biological Sulfur Transformation Summary Sulfate Is Reduced to Sulfide in the Slime Layer Sulfide Is Produced (Along With Alkalinity) and Is Released As H2S Gas by Turbulence H2S Gas Is Oxidized to Sulfuric Acid by Thiobacillus Bacteria Living on Sewer Walls Above the Sewage Sulfuric Acid Runs Back Down Into the Wastewater to Destroy the Alkalinity Produced Earlier and Become Sulfate Process Starts All Over Again With Sulfate Reduction

19 Solutions to H 2 S Production Chemical addition: Iron salts Nitrate solutions Peroxide addition Ventilation Difficult to get entire pipeline

20 Chemical Addition

21 Vapor Phase Treatment Chemical Wet Scrubbers

22 Vapor Phase Treatment Activated Carbon Systems

23 Vapor Phase Treatment Biotrickling Filter

24 New Solution Oxygen and ozone addition Keep pipeline aerobic Stops the formation of H 2 S Stops odors and corrosion

25 Ozone Oxidation Chemistry of Hydrogen Sulfide The oxidation of dissolved H 2 S in the presence of O 3 is a thermodynamically favorable reaction with a theoretical ratio of 4:1. S O 3 SO O 2 SO O 3 SO O 2 S O 3 SO O 2 Step 1 Step 2 Overall The reaction rate with O 3 is ph dependent as H 2 S is a diprotic acid. H 2 S HS - + H + HS - S 2- + H + pka = 7.0 pka = 19.0 In normal ph ranges though, hydrogen sulfide exits only in the form of H 2 S and HS - in water.

26 Ozone Oxidation Chemistry of Hydrogen Sulfide Ozone Oxidation Chemistry of Hydrogen Sulfide Example of Calculating the Amount of Ozone to Oxidize H 2 S in a Process Stream O 3 Oxidation of H 2 S in a Well Water Sample Matrix [H 2 S] O 3 Demand (mg/l) Molar Ratio : : :1 The actual molar oxidation ratio of O 3 to S 2- is less than the theoretical 4:1. This is due to possible side reactions with hydroxyl radicals and some contribution from the high concentration of dissolved oxygen.

27 Fast Action Infusion Untreated force main wastewater Treatment after two minutes Treatment <5 minutes

28 Limited Access Infuser System FORSe 5 O 2 / O 3 Generator Control Single Tap Infuser Grinder pump in lift station Venturi with infuser Treated wastewater infused through 2 tap O 2 / O 3 Lift Station Venturi Infuser Treated Flow Return Untreated Flow to Infuser Grinder Pump

29 System Packaging- High Flow Four cell ozone generator High output oxygen system Systems up to 1400 grams/hr ozone & 600 liters/minute oxygen Flows of up to 20 MGD

30 SYSTEM COMPONENTS Compressor

31 SYSTEM COMPONENTS AirSep Unit with Oxygen Receiver

32 SYSTEM COMPONENTS FloSpec Cabinet with HMI Display

33 SYSTEM COMPONENTS Force Main Tap

34 FORSe 5 System (O3 + O2) Treat odor and corrosion in force main, lift stations, or combination of the two Attack H2S at it source Break sulfide production cycle Sustainable technology FORSe 2 System (O2 Only) FORSe 5/FORSe 2 System

35 CASE STUDIES Equipment used Locations Monitoring of sites for H 2 S and DO

36 Test Equipment Application Capacity: Ozone: 300 grams/hour Oxygen: 75 liters/ minute Components: Oxygen generator Ozone Generator Control with Cellular MODEM Transformer

37 CASE STUDY Lift Station Treatment: Lebanon, TN

38 Sulfides vs DO at Force Main Outfall

39 CASE STUDY Lift Station Treatment: Lavergne, TN

40 Average of Daily Readings at Lift Station 60.0 Start Treatment H2S ppm- Vapor- OdaLog System Turned ON System settings: 120 gph O 3 20 lpm O H2S ppm- Vapor- OdaLog 20.0 System Shut OFF End Treatment Apr 7-Apr 8-Apr 9-Apr 10-Apr 11-Apr 12-Apr 13-Apr 14-Apr 15-Apr 16-Apr 17-Apr 18-Apr WednesdayThursday Friday Saturday Sunday Monday TuesdayWednesdayThursday Friday Saturday Sunday Monday

41 Thank You - Questions