Frequently Asked Questions

ACWWA has not detected lead in the treated water leaving our plant or in the source water. However, lead can come from the customers plumbing.

According to the EPA, two types of homes may be at risk for lead contamination:

1. Homes that are very old (pre-WWII) with lead services or pipe lines

2. Homes that were built between 1983 and 1987, which used copper pipe with lead based solder. Lead based solder was banned from use on domestic drinking water plumbing in 1987.

Here are some ways to reduce your exposure to lead:

1. When water has been standing in your pipes, run the cold water tap until the water gets noticeably colder. The lower temperature indicates you have cleared the water that has been standing in the pipes.

2. Use only water from the cold water tap for drinking, cooking, and for making baby formula. Hot tap water dissolves lead faster and is likely to contain higher levels of lead if present.

3. When repairing or replacing plumbing, insist on lead-free solder and lead-free fixtures.

Odors are a natural part of the substances handled and treated at any wastewater treatment plant. Odors are typically contained to the wastewater treatment plant site; but occasionally odors drift from the plant site depending on weather conditions and wind direction.

Routine treatment operations are designed to reduce the amount of odors present; however, certain weather conditions and equipment maintenance may lessen the effectiveness of these routine odor control operations.

Most of the odors detected in and around wastewater treatment plants are signals that nature’s treatment process is working; organic matter is decomposing and pollutants are being removed from the wastewater.

As the table Odorous Compounds In Wastewater shows, three major odorous compounds naturally occurring in the treatment process, hydrogen sulfide, amines and mercaptans, are detectable by the human nose at extremely low concentrations.

Odorous Compounds In Wastewater

Were it not for odor control measures, all wastewater treatment processes are capable of emitting odors.

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.

First of all, it is important to understand that odors are generated from every phase of wastewater management, including collection, treatment, and disposal, and that odors are impossible to prevent.  Please wait at least one hour before you consider calling our office.  Most odors, if detected, are temporary and will dissipate as quickly as they occur.  If the odor persists for over an hour and occurs in the same location you originally noticed it, you may call ACWWA, 303-790-4830, to inform the staff you detect an odor. Staff will ask you for the following information:

- Your name, address, and phone number;

- Information about the odor; such as, what time you noticed it, is it still noticeable, a description of the odor (refer to the Odorous Compounds In Wastewater table) and how strong is the odor.

Staff will record all of the complainant’s information described above; as well as, temperature, humidity, weather conditions, wind velocity, and wind direction.

All of the information combined helps staff determine if the odor is being emitted from the LTCWRF or from elsewhere, and most importantly if there is anything beyond best management practices that can be done to correct the issue.