Odor Updates

For all questions or concerns regarding odors please contact us at jcarson@hvssd.org

Our top priority is addressing and alleviating the odor issues. We have created this section of the website to keep you updated on developments and our ongoing efforts. We are committed to identifying and implementing the most effective short- and long-term solutions for the Heber Valley.




HVSSD has been working with the Wasatch County Health Department, WCHD, and the Utah Division of Health and Human Services Environmental Epidemiology Program, DHHS, to conduct odor monitoring for Hydrogen Sulfide gas, H2S, at our facility as well as locations in the surrounding community. DHHS had to rent the specilaized instruments, which was a lengthy process and upon arrival found they were not calibrated for our site's elevation.  Recalibration of the instruments was estimated to take approximately two months.  DHHS therefore decided to postpone odor monitoring within the community until next spring since strong odors typically don't occur in the late summer/fall.  Next spring DHHS expects to deploy three instruments-one at our facility and two within the community.

In the meantime, DHHS has purchased their own H2S instrument and plans to deploy it at HVSSD's facility this June and monitor odors for about three months.

DHHS would like to provide an update to the public and have tentatively scheduled a public meeting for June 20th at HVSSD's administrative building.  DHHS will lead the meeting and answer any questions or concerns from the community.  The notice of the meeting will be posted on our website once it has been confirmed.

In the past our facility has typically produced odors for several days in the spring when the treatment lagoons are in the "turnover" phase.  We beleive that with the warmer weather we are currently in that phase but odors have not been as intense as years past.  We have recently installed chemical injection systems that add hydrogen peroxide solution and calcium nitrate solution into the lagoons.  HVSSD hired a consultant to perform a study of our treatment lagoons and these systems were recommended as a result of that study.  We are pleased with these systems so far and a hopeful that these measures will mitigate odors from spring "turnover"  


March 2024

HVSSD sent out a press release on March 7, 2023 to address the health and safety concerns.  HVSSD is committed to the health and safety of our community as we provide essential water treatment services to the Heber Valley.  We have appreciated the input from neighbors of our wastewater treatment plant reporting odor concerns.  Since these concerns began last year, investigation of reports and mitigation of any odors coming from the treatment plant has been our top priority.  In collaboration with our partners at Midway Sanitation District (MSD) we have taken several steps to investigate these concerns.  Please check out the full document at the bottom of this section that addresses the steps we have taken to help resolve this issue.

If you would like to express your concern please go to the forms and reports section of the website to find a link to report concerns you may have.


We want the residents in the area of the HVSSD plant to be aware that we have been doing some work today that may create an odor for a few hours.  We have installed a new mixer motor in the mechanical plant.  This new equipment will be an improvement over the old equipment, but with the increased mixing today they have generated some odors.  It is not significant, but want you to know that we are aware of the odor and it should be short term today.  Also, the local dairy farmer is hauling manure off of Michie Lane today.  


On the 29th we received several complaints from residends in the Michie Lane area of a very strong and unpleasant odor coming from the area.  Our staff found no odors coming from the plant area.  On the morning of the 30th the went out to the Michie Lane area and found a field that had a very strong odor.  The previous evening they had applied manure on the field.  We feel that this was what the residents had smelled.  Again, there have been no odors from the plant.  We have diligently, as the staff of HVSSD, monitored the plant area and want to be on top of any odor issues that may occur.  


At the HVSSD board meeting on October 12, 2023, Heber City Mayor Heidi Franco stated that they are still waiting for the Odalog equipment.  There are supply chain issues but have been told that delivery is eminent.  They did look into possible borrowing one from another entity.  They have begun the manhole inspections.  They have been using the monitors that they currently have and have found the levels to be low.  When they do get the Odalog it will monitor 24 hours.

Clair Provost, from Midway Sanitation reported that they have the same issue with their order for an Odalog.  They have placed eight solid manhole covers along Michie Lane and the surrounding area.  He asked that the public report if they find an area around a manhole cover that has an odor issue to let the know at MSD.  A member of that neighborhood reported at this meeting that they put a solid cover on her manhole, and it did make a difference. 

Mala Hettiarachchi, from ERG, an independent company, reported their findings from their evaluation of the current conditions of Cell 1, with respect to odor and to prepare a contingency plant during pond turnovers.  She stated that there is a good amount of oxygen and nitrates, which are a byproduct of aerobic action.  She stated that they are a little anerobic, but she sees good results.  They do not expect any sulfide odors for the fall turnover.  They will have a system in place in case they do see any odors.  They have calculated the dosing of hydrogen peroxide that will kill the H2s.  They will inject it into Cell 1 and Cell 1 A. 

The board addressed the timeline for repair of the aerators.  Mala stated that the water has its own movement during turning so they expect a good mixing of chemicals even with the aerators that are not working.  This treatment will be effective even without all the aerators.

Dennis Gunn stated that they have not had issues with fall turnover in the past and since ERG has stated that there are no sulfides in the water it is physically impossible to smell sulphur in the water.  He stated with approval from the board they will go ahead with the treatment as a proactive measure.   The board made a motion to go ahead with the mitigation of the hydrogen peroxide treatment by ET Technology.  The treatment will be measured before and after the process and they will have it ready for next year also.


Thursday September 14, 2023

Midway and Heber both gave updates at the September board meeting.  Heidi Franco reported that they have been assessing and have found that the readings in the manholes have been lower than they expecteed.  Heber City has ordered 2 odaloggers.  They are waiting for them to be delivered and hope to have them within the next week.  They are designed specifically for the wastewater industry and they help with locating and monitoring the source of possible Hydrogen Sulfide gas emissions.

Clair Provost, from Midway Sanitation District, stated that they have hired a company to come and clean the sewer lines in the areas of concern.  They have performed readings in the complaint area and all readings have been at normal limits.  They are working on putting solid manhole covers in the area of complaints.  They did this in an area about 3 years ago and have had no issues since.  They are also purchasing a continuous monitor that reads in 15 minute intervals for seven days.

Tuesday August 15, 2023
Heber City: In HVSSD’s August 10th Board meeting, Heber City Mayor Heidi Franco reported that Heber is considering a probiotic treatment of wastewater in its collection system to minimize odor from the water as it comes into the plant. This organic treatment can help prevent formation of H2S in the system and has been used with some success by other cities. It can be implemented relatively quickly without disrupting other necessary chemical processes at the treatment plant. Heber City Manager, Matt Brower will continue evaluating possible use and report back.

Midway Sanitation District: MSD vice chair Clair Provost reported MSD is moving forward with manhole and line testing for H2S, carbon dioxide, and oxygen levels. Manhole testing will be done at the 6-foot, 3-foot and surface levels of the manholes in areas of reported odor. Test results are expected in the next week and can be evaluated for manhole-specific trends and potential cleaning and treatment needs.

Thursday August 17, 2023
Update from MSD
Midway Sanitation District (MSD) sewer collection system has recently undergone testing of approximately 160 manholes to measure the presence of Hydrogen Sulfide (H2S) gases in the vicinity of the HVSSD plant. MSD hired a third party, independent contractor to conduct the testing. All tests resulted in very low H2S levels and well below OSHA safety standards of 20 ppm. MSD is planning to purchase an H2S testing device and will continue to monitor levels of H2S in our system. Additionally, MSD has pushed up our annual cleaning schedule to include the Michie Lane portion of our system in order to help with any additional odors. Periodic line flushings will also be completed on an as-needed basis.

Thursday August 3, 2023
On July 21, HVSSD began an emergency engagement with Environmental Resources Group (ERG) to assess the odor complaints, investigate causes, and propose both short- and long-term solutions to reduce odors.

The HVSSD Board held a special meeting on July 31, 2023 and moved to support the Wasatch County Health Department request to the Utah Department of Health and Human Services to conduct an environmental epidemiological study at the treatment plant.

Heber City officials met with Manager Dennis Gunn and odor mitigation experts to outline a plan for odor mitigation of the Heber sewer lines that feed into HVSSD.

Midway Service District (MSD) has hired a third party to test for odors at approximately 140 manholes in areas of potential concern in their collection system. The tests will help identify priority areas for collection system cleaning and maintenance.

Wednesday, July 19, 2023

The following is a list of items we are and have been working on since the July 13, 2023 board meeting:

• Created this “Odor Updates” section of the website to provide regular updates on odor mitigation efforts
• Working to set up social media and email channels for updates on odor mitigation efforts
• Manager Dennis Gunn and Board Member Clair Provost inspected manholes to assess potential odors in the collection lines
• Midway Sanitation District has agreed to hire an independent inspection company to conduct a more thorough inspection of all manholes on Michie Lane
• Coordination with Wasatch County Health Department to request analysis of any health risks posed by the facility and to coordinate evaluation by the Utah Department of Health and Human Services
• Request to the Wasatch County Health Department to hold a public meeting regarding odor issues. The health department has asked to coordinate with others more expert in this area before a public meeting
• Working with Midway and Heber City to look for and diagnose any odors coming from the sewage collection systems that feed into the treatment facility.
• Planning a board meeting this week to discuss and potentially approve an emergency engagement with Environmental Resources Group, an outside engineering firm out of Wixom, MI which has special expertise in sewer treatment facility odor mitigation to assess the odor complaints, investigate causes, and propose both short- and long-term solutions to reduce odors.
• Engaged Brad Rasmussen of Aqua Engineering, a water engineer with over 30 years of experience engineering sewage treatment facilities, to provide cost estimates for potential changes and upgrades to the treatment facility.
• Preparing recommendations for a Citizen Advisory Committee to provide support and feedback for our odor response efforts.
• Ongoing spot monitoring and response to community concerns.


To learn more, please check out the Resources page on this website.

Relevant Documents