How does ACWWA minimize odors at the wastewater treatment plant?

ACWWA currently operates the Lone Tree Creek Water Reuse Facility (LTCWRF) using best management practices that ensure the facility processes are operating in an effective manner.  If the processes are operating correctly, then odors are kept to a minimum.  The best management practices followed by ACWWA are listed below:

  • On/Off Aeration – The On/Off Aeration process is used to help stabilize the waste storage tanks. Following an on/off schedule, staff is able to introduce denitrification (removal of nitrogen) in a process which would not typically be supported. On/Off Aeration not only aids in the ability to settle and dewatering separation, but it also creates an electrical cost savings because the blowers are shut-off for a period of the day. Slight odors can be emitted when we reactivate the aeration system after it has been off. Experience has shown that a 4-6 hour off period is the limit where the least amount of odors is emitted when the blowers are turned back on.  Temperature can affect the time-off duration.

  • Physical Barriers – All high odor areas are either covered or remain behind closed doors. The beginning of the treatment process is the most odorous. The doors to the Headworks, which is the first step in the treatment process, remain closed at all times.  The Parshall Flume, which is an influent measuring structure, and the Junction Structure 2, which allows staff the ability to dump into our emergency pond, or go to Headworks, all have covers that remain in place.

  • Process Monitoring – LTCWRF’s processes are carefully monitored twenty-four hours a day, seven days a week, for health and effectiveness.  The monitoring allows staff to proactively change processes prior to any upsets occurring, which potentially can cause unusual odors.

  • Aerobic Digestion – Aerobic Digestion is the process of stabilizing sludge (the residual, semi-solid material that is produced as a by-product during sewage treatment) and can operate in one of two ways. Aerobic Digestion, which uses air to mix and sustain the biology or Anaerobic Digestion, where the digester is operating in a covered tank, which prevents air from entering the tank). Anaerobic Digestion is more prone to upsets and resulting odors.

  • Primary Clarification – LTCWRF does not have a primary clarifier. Primary clarification is used to settle out and remove grit, solids and grease from the influent prior to Headworks. Primary clarification is the highest cause of odors in facilities that utilize them.


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1. Are baby/adult wipes flushable?
2. Is reclaimed water safe?
3. Is there lead in my drinking water, and if so what can I do about it?
4. Should I put my used cooking grease down the drain?
5. What is reclaimed water?
6. Why do we use reclaimed water and what are the benefits of reuse?
7. Why do we sometimes smell odors near the wastewater treatment plant?
8. What causes these odors?
9. How does ACWWA minimize odors at the wastewater treatment plant?
10. What can I do if I smell an odor I think is coming from the plant?
11. What happens when the LTCWRF receives an odor complaint?