When Nitrification Fails: Fixing Ammonia Breakthrough in Activated Sludge
The Wastewater Enthusiast
4,091 views
Ammonia breakthrough is one of the most stressful problems a wastewater operator can face, and it almost always points to nitrification failure in your activated sludge process. In this video, I walk through why nitrification fails in wastewater treatment plants, how to diagnose it quickly, and the practical steps to recover before you hit a permit violation.
We’ll cover the most common causes of nitrification failure: low dissolved oxygen, insufficient alkalinity, cold temperatures, toxic shock, washed-out solids retention time (SRT), and pH crashes. You’ll learn how to read your data, identify which lever to pull first, and stabilize your nitrifiers before ammonia keeps climbing.
Whether you’re a wastewater operator, plant manager, engineer, or student studying activated sludge and biological nutrient removal (BNR), this video gives you a practical troubleshooting framework you can apply on your next shift.
Topics covered:
What ammonia breakthrough actually means
Why nitrifiers are so sensitive
Diagnosing nitrification failure step by step
Fixing alkalinity, DO, SRT, and temperature issues
Preventing future breakthrough events
Welcome to The Wastewater Enthusiast! I’m Shawn Powell, a California Grade V Wastewater Treatment Plant Operator and Chief Plant Operator. This channel is dedicated to helping operators understand treatment processes, prepare for certification exams, and improve real-world plant performance.
Who this is for:
Wastewater treatment plant operators, Grade 2/3/4 operators studying for certification exams, environmental engineers, plant superintendents, and anyone working in activated sludge, BNR, or municipal wastewater.
Drop your nitrification questions in the comments — happy to dig into specific scenarios.
Chapters:
00:00 - 02:04 Ammonia Breakthrough in My MBR System
02:04 - 05:47 How I Fixed the Ammonia Breakthrough
05:47 - 08:02 Getting Nitrification Back on Track
08:02 - 11:15 What is Ammonia Breakthrough in Wastewater Treatment?
11:15 - 12:51 What is Nitrification in Wastewater Treatment?
12:51 - 18:25 pH and Alkalinity in Nitrification
18:25 - 26:29 Dissolved Oxygen Requirements for Nitrification
26:29 - 30:06 Hydraulic Retention Time and Nitrification
30:06 - 31:52 MCRT/SRT and Nitrification
31:52 - 35:02 Temperature and Nitrification Inhibitors
35:02 - 36:04 Nitrification Troubleshooting Key Takeaways
Links:
Infiltration and Inflow: Infiltration & Inflow (I/I) in Wastewater ...
pH vs Alkalinity: pH vs Alkalinity in Wastewater & Drinking ...
Nitrification and Denitrification in Wastewater: Wastewater Nitrification & Denitrification...
Detention Time Math Problem: Wastewater Math Basics: Detention Time
Operator Mindset Aeration Oxygen Saturation (the video I referenced): Wintertime Aeration rates, Adjusting the a...
#WastewaterTreatment #Nitrification #ActivatedSludge #AmmoniaBreakthrough #WastewaterOperator #BNR
11 Comments
It’s interesting to compare a standard system to ours. Because we burn our sludge in a fluidized bed reactor (the only one in Oceania), our HRAS system effectively just "skims the cream." We maintain a very short sludge age of 10–16 hours to ensure we retain maximum energy content in the sludge. This helps us optimize the incineration process and significantly reduce our diesel consumption. We also keep our DO setpoint between 1.0 and 1.5 mg/L.
Our incoming effluent is generally alkaline (basic?) so we tend to inject more H2SO4 to bring the pH down to 7.3 . In the MBBR pH will rise to around 7.9, probably due to the aeration which drives out the dissolved carbon dioxide. If we need to raise the pH, we add Sodium Hydroxide instead.
In the lab, my alkalinity analysis will give me a result in the 140mg/l to 200mg/l range. During heavy load downturns when I get elevated shedding of the biofilm, the alkalinity goes even higher (maybe they are unconsumed?) which also corresponds to the MBBR higher pH that can run in the region of about 8.3
In fact the influent is of such "clean" quality that we are frequently in a nutrient deficient state and have to dose ammonium hydroxide and Phosphoric acid in order to create an environment where AOBs/NOBs and PAOs can still exist in small populations.
When Nitrification Fails: Fixing Ammonia Breakthrough in Activated Sludge
The Wastewater Enthusiast
4,091 views
Ammonia breakthrough is one of the most stressful problems a wastewater operator can face, and it almost always points to nitrification failure in your activated sludge process. In this video, I walk through why nitrification fails in wastewater treatment plants, how to diagnose it quickly, and the practical steps to recover before you hit a permit violation.
We’ll cover the most common causes of nitrification failure: low dissolved oxygen, insufficient alkalinity, cold temperatures, toxic shock, washed-out solids retention time (SRT), and pH crashes. You’ll learn how to read your data, identify which lever to pull first, and stabilize your nitrifiers before ammonia keeps climbing.
Whether you’re a wastewater operator, plant manager, engineer, or student studying activated sludge and biological nutrient removal (BNR), this video gives you a practical troubleshooting framework you can apply on your next shift.
Topics covered:
What ammonia breakthrough actually means
Why nitrifiers are so sensitive
Diagnosing nitrification failure step by step
Fixing alkalinity, DO, SRT, and temperature issues
Preventing future breakthrough events
Welcome to The Wastewater Enthusiast! I’m Shawn Powell, a California Grade V Wastewater Treatment Plant Operator and Chief Plant Operator. This channel is dedicated to helping operators understand treatment processes, prepare for certification exams, and improve real-world plant performance.
Who this is for:
Wastewater treatment plant operators, Grade 2/3/4 operators studying for certification exams, environmental engineers, plant superintendents, and anyone working in activated sludge, BNR, or municipal wastewater.
Drop your nitrification questions in the comments — happy to dig into specific scenarios.
Chapters:
00:00 - 02:04 Ammonia Breakthrough in My MBR System
02:04 - 05:47 How I Fixed the Ammonia Breakthrough
05:47 - 08:02 Getting Nitrification Back on Track
08:02 - 11:15 What is Ammonia Breakthrough in Wastewater Treatment?
11:15 - 12:51 What is Nitrification in Wastewater Treatment?
12:51 - 18:25 pH and Alkalinity in Nitrification
18:25 - 26:29 Dissolved Oxygen Requirements for Nitrification
26:29 - 30:06 Hydraulic Retention Time and Nitrification
30:06 - 31:52 MCRT/SRT and Nitrification
31:52 - 35:02 Temperature and Nitrification Inhibitors
35:02 - 36:04 Nitrification Troubleshooting Key Takeaways
Links:
Infiltration and Inflow: Infiltration & Inflow (I/I) in Wastewater ...
pH vs Alkalinity: pH vs Alkalinity in Wastewater & Drinking ...
Nitrification and Denitrification in Wastewater: Wastewater Nitrification & Denitrification...
Detention Time Math Problem: Wastewater Math Basics: Detention Time
Operator Mindset Aeration Oxygen Saturation (the video I referenced): Wintertime Aeration rates, Adjusting the a...
#WastewaterTreatment #Nitrification #ActivatedSludge #AmmoniaBreakthrough #WastewaterOperator #BNR
Since this is such a technical video I want to pin a comment adding a bit of context: the numbers and ranges I used come from industry-standard references and state design criteria, combined with my own operating experience. Values can vary slightly between references and states, so if your study materials for a specific state exam show a different number, go with that source. What we see on exams and what we see in reality can be different. Curious what ranges you’re seeing in your plant! Questions or comments below!