How Much is E “ “N N” ”OUGH? OUGH? How Much is E Optimizing Nitrification and Denitrification Denitrification Optimizing Nitrification and at the Water Reclamation Plants at the Water Reclamation Plants Joe Chang, Water Reclamation Plants
LA County Sanitation Districts: LA County Sanitation Districts: LA County Sanitation Districts: Background Information Background Information Background Information • Established in 1923 Established in 1923 • • Provide Wastewater and Solid Waste Provide Wastewater and Solid Waste • Management for ~ 5.7 million people Management for ~ 5.7 million people • 1400 miles of main trunk sewers 1400 miles of main trunk sewers • • 11 wastewater treatment plants 11 wastewater treatment plants • • 3 active landfills 3 active landfills •
Presentation Outline Presentation Outline Presentation Outline • Regulatory Requirements Regulatory Requirements • • Nitrification/ Nitrification/Denitrification Denitrification Basics Basics • • Case Studies: Case Studies: • • Valencia WRP Valencia WRP •
New Nitrogen Discharge Limits New Nitrogen Discharge Limits New Nitrogen Discharge Limits • In 1994, Los Angeles RWCQB set new In 1994, Los Angeles RWCQB set new • nitrogen discharge limits effective in 2003: nitrogen discharge limits effective in 2003: • Ammonia: Nominally 2 mg/L Ammonia: Nominally 2 mg/L • • Nitrate + Nitrite: 10 mg/L (in some cases Nitrate + Nitrite: 10 mg/L (in some cases • lower) lower)
Biological Removal of Nitrogen Biological Removal of Nitrogen Biological Removal of Nitrogen Nitrification/Denitrification Denitrification (NDN) Process (NDN) Process Nitrification/ Nitrification/Denitrification (NDN) Process Denitrifying Denitrifying Nitrifying Denitrifying Nitrifying Nitrifying Nitrifying Bacteria & & Bacteria Bacteria Bacteria & Bacteria Bacteria Bacteria Carbon Source Carbon Source (Nitrobactor) - - - Carbon Source (Nitrosomonas) (Nitrobactor) - - N (Nitrosomonas) - - + - - + - - N N 2 + - N N NO 3 - N N N 2 NO NH 4 - N N NO 3 NH NH 4 NO 2 - N N NO NO 2 2 3 4 2 Anoxic Aerobic Anoxic Aerobic Aerobic Anoxic Aerobic Aerobic Aerobic Nitrogen Nitrogen Nitrogen Nitrate Nitrite Nitrate Ammonia Ammonia Nitrite Nitrate Nitrite Ammonia Gas Gas Gas Reduction Reduction Oxidation Reaction Oxidation Reaction Reaction Reaction Nitrification Denitrification Nitrification Denitrification (Aerobic) (Anoxic) (Aerobic) (Anoxic)
• Modified • Modified Ludzack Ettinger Ludzack Ettinger (MLE) NDN Process (MLE) NDN Process • Modified Ludzack Ettinger (MLE) NDN Process Primary Primary Final Final Final Tertiary Tertiary Anoxic Zone Aerobic Zone Anoxic Zone Aerobic Zone Effluent Effluent Anoxic Zone Aerobic Zone Clarifier Clarifier Clarifier Treatment Treatment Internal Recycle Internal Recycle Internal Recycle Waste Activated Waste Activated Sludge (WAS) Sludge (WAS) Return Activated Sludge Return Activated Sludge • Step Feed NDN Process • Step Feed NDN Process Step Feed NDN Process • Tertiary Tertiary Tertiary Primary Primary Primary Final Final Final Treatment Treatment Treatment Anoxic Aerobic Anoxic Aerobic Anoxic Aerobic Anoxic Aerobic Effluent Effluent Effluent Anoxic Aerobic Anoxic Aerobic Clarifier Clarifier Clarifier Waste Activated Waste Activated Waste Activated Sludge (WAS) Sludge (WAS) Sludge (WAS) RAS RAS RAS
Valencia Water Reclamation Plant Valencia Water Reclamation Plant Valencia Water Reclamation Plant Valencia Valencia J A O J A O
Valencia WRP Valencia WRP Valencia WRP Aerial Photo Aerial Photo Aerial Photo Six Flags Magic Six Flags Magic Mountain Mountain Santa Clara River Santa Clara River Golden State Freeway Golden State Freeway North North
Valencia Water Reclamation Plant: Valencia Water Reclamation Plant: Valencia Water Reclamation Plant: Background Information Background Information Background Information • Built in 1967 Built in 1967 • • Serves ~ 170,000 residents in Santa Serves ~ 170,000 residents in Santa • Clarita Valley Clarita Valley • Rated for 21.6 MGD Rated for 21.6 MGD • • Current influent flow ~16 MGD Current influent flow ~16 MGD • • Discharges to Santa Clara River Discharges to Santa Clara River • • Handles all solids from Valencia and Handles all solids from Valencia and • Saugus WRPs Saugus WRPs
Nitrogen Discharge Limits at Nitrogen Discharge Limits at Nitrogen Discharge Limits at Valencia WRP Valencia WRP Valencia WRP • In 1994: In 1994: • RWQCB set new nitrogen limits effective in RWQCB set new nitrogen limits effective in June 2003: June 2003: Ammonia: 2.0 mg/L Ammonia: 2.0 mg/L Nitrate + Nitrite: 10 mg/L Nitrate + Nitrite: 10 mg/L
Valencia WRP Valencia WRP Valencia WRP Stage Five Expansion and NDN Facilities Stage Five Expansion and NDN Facilities Stage Five Expansion and NDN Facilities GO BEARS GO BEARS
Valencia WRP Valencia WRP Valencia WRP Aeration Modifications Aeration Modifications Aeration Modifications RAS/Filtrate Treatment Tanks RAS/Filtrate Treatment Tanks RAS/Filtrate Treatment Tanks Unit 1 Unit 1 Unit 2 Unit 2 Unit 3 Unit 3 Unit 4 Unit 4 Unit 5 Unit 5
Valencia WRP Valencia WRP Valencia WRP Filtrate Filtrate Filtrate Raw and Waste Raw and Waste Activated Activated Solids dewatering Solids dewatering Sludge Sludge filter press filter press (Valencia & (Valencia & Saugus WRPs) Saugus WRPs) Anaerobic Anaerobic digesters digesters
Valencia WRP Valencia WRP Valencia WRP Filtrate Filtrate Filtrate Raw and Waste Raw and Waste Activated Activated Biosolids Biosolids Sludge Sludge for land for land (Valencia & (Valencia & application application Saugus WRPs) Saugus WRPs) Anaerobic Solids dewatering Anaerobic Solids dewatering digesters filter press digesters filter press R A S/Filtrate R A S/Filtrate Filtrate (1.5 MG/wk Filtrate (1.5 MG/wk treatment tanks treatment tanks ammonia conc. ~900 mg/l) ammonia conc. ~900 mg/l)
Valencia WRP Valencia WRP Valencia WRP Filtrate Filtrate Filtrate Raw and Waste Raw and Waste Activated Activated Biosolids Biosolids Sludge Sludge for land for land (Valencia & (Valencia & application application Saugus WRPs) Saugus WRPs) Anaerobic Solids dewatering Anaerobic Solids dewatering digesters filter press digesters filter press R A S/Filtrate R A S/Filtrate treatment tanks treatment tanks Filtrate (1.5 MG/wk Filtrate (1.5 MG/wk Aeration Aeration ammonia conc. ~900 mg/l) ammonia conc. ~900 mg/l) Units Units
Valencia WRP Valencia WRP Valencia WRP Ammonia Load Ammonia Load Ammonia Load 38.6 38.6 38.6 40 40 From Filtrate From Filtrate 13.0 13.0 30 30 26.1 26.1 25.5 25.5 25.6 24.8 24.8 24.1 24.1 24.1 24.1 23.7 23.7 Ammonia Ammonia 22.6 22.6 Conc. Conc. 20 20 25.6 (mg/L) (mg/L) 10 10 0 0 VAL SJC-E SJC-E SJC-W SJC-W L C L C L B L B POM POM W N W N SAUG SAUG Water Reclamation Plants Water Reclamation Plants Water Reclamation Plants Water Reclamation Plants Water Reclamation Plants Water Reclamation Plants
Valencia WRP NDN Start- -Up Up Valencia WRP NDN Start Valencia WRP NDN Start-Up • Modified Modified Ludzack Ettinger Ludzack Ettinger (MLE) Mode (MLE) Mode • • Modified Ludzack Ettinger (MLE) Mode • Start Start- -Up began in May, 2003 Up began in May, 2003 • • Start-Up began in May, 2003 Pri. Effluent . Effluent Pri Pri. Effluent Anoxic Zone Anoxic Zone Aerobic Zone Aerobic Zone RAS/Filtrate RAS/Filtrate RAS/Filtrate 150%Q 150%Q 150%Q I R I R Aerobic Zone Aerobic Zone * * * To Final Clarifiers To Final Clarifiers * Effluent * Sample Goal Sample Goal Effluent + - + Ammonia (NH 4 -N) N) < 1 mg/L < 2 mg/L Ammonia (NH < 1 mg/L < 2 mg/L 4 - - - 14 mg/L Nitrate (NO 3 Nitrate (NO -N) N) 14 mg/L < 10 mg/L < 10 mg/L 3
Valencia WRP High Nitrate: Valencia WRP High Nitrate: Valencia WRP High Nitrate: Rising Sludge Rising Sludge Rising Sludge Rising Sludge due Rising Sludge due Rising Sludge due Normal situation in Normal situation in Normal situation in to high nitrate to high nitrate to high nitrate the final clarifier the final clarifier the final clarifier Mixed Liquor Mixed Liquor Mixed Liquor sample sample sample N 2 - - N - D N NO 3 - N N D N NO D N 2 3 Nitrogen Nitrogen Anoxic Anoxic Anoxic Nitrate Nitrate Gas Gas Solids settle to the Solids settle to the bottom of the tank bottom of the tank
Valencia WRP Start- -Up Problems: Short Up Problems: Short Valencia WRP Start Valencia WRP Start-Up Problems: Short Circuiting Circuiting Circuiting Primary Primary Primary Effluent Effluent Effluent Anoxic Zone Aerobic Zone Anoxic Zone Aerobic Zone Anoxic Zone Aerobic Zone RAS/Filtrate RAS/Filtrate RAS/Filtrate I R I R I R Aerobic Zone Aerobic Zone Aerobic Zone To Final Clarifiers To Final Clarifiers To Final Clarifiers • Internal Recycle Pump Discharge piping: 30” diameter
Short Circuiting Solution Short Circuiting Solution Short Circuiting Solution • Eliminate Internal Recycle flow Short Circuiting • Eliminate Internal Recycle flow Short Circuiting • When IR rate at 250%Q: Effluent Nitrate: ~10 mg/L When IR rate at 250%Q: Effluent Nitrate: ~10 mg/L •
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