Tech Environmental e-Newsletter
July 2005

summertime: vacation season or odor season?

This weekend starts the unofficial summer vacation season; unfortunately for some, it also signals the peak odor season. Hazy and hot conditions outside increase odor potential from all sources. Increased odor potential coupled with open windows and outdoor activities can lead to odor nuisance conditions. Tech Environmental is often busy during the warmer months helping facilities limit their potential for odor nuisance conditions.

Is a single odor event a nuisance?

Not necessarily. Odor is everywhere, and every process (or homeowner for that matter) emits at least a very mild odor. We often refer to these seasonal odors fondly as the smells of summer: fragrant flowers, fresh cut grass, a neighbor's barbeque, a swimming pool, or suntan lotion. We can be exposed to these pleasant smells at high and low concentrations, for seconds or minutes, once or multiple times without any adverse reactions. In these cases a single odor event or even multiple odor events are generally not nuisances.

Is a single malodorous event a nuisance?

Again, not necessarily. For a "bad" odor to be considered a nuisance it must alter one's daily activities. Simply smelling an odor is not a nuisance; therefore, in most cases single, mild, short-lived odor events are not considered nuisances. However, if the same event is not short-lived, even a mild odor could be considered a nuisance.

How can I minimize my potential for odor nuisance?

There are three primary factors: odor strength, event frequency, and duration of event. If any of these factors are excessive, a nuisance condition is possible.

A combination of education, source assessment, odor control, and public involvement are key to minimizing nuisances. Educating staff on different odor characteristics and possible sources can help with response time, and therefore minimize duration.

Capturing, treating, or dispersing odors may be necessary steps to improve off-site conditions: however, simple process modifications, with odor in mind, can be all that is necessary to reduce odor strength.  Collecting source samples and modeling potential impacts into the surrounding neighborhood via dispersion modeling can help establish a baseline condition. In many cases dispersion improvements can reduce the frequency of odor events.

Is there a defined threshold for odor nuisance?

Odor is subjective, and therefore the actual odor nuisance threshold is subjective. If you involve the public in any odor response process, you can objectively define the nuisance threshold together, add science to track the potential condition, train those involved to respond to potential exceedances, and gain neighborhood trust. Too often a string of odor events can ruin any previous trust, and a detailed program is necessary to assess the situation and establish or regain that trust.

How can Tech Environmental help?

Tech Environmental has the experience and strategies to help our clients reach out to concerned parties in order to find the common ground necessary to achieve trust and assurance that odor impacts will be limited. While we will never promise to eliminate odor, we do promise to find the common ground necessary for public and private acceptance for all. Please give us a call if you have any odor concerns or questions about odor this summer, and most of all, enjoy the summer!

Michael T. Lannan, PE
Vice President
Extension 115

concord wastewater treatment plant odor control improvements 

As part of a new upgrade to the Concord wastewater treatment facility, Tech Environmental (TE) is in the process of assessing the odor situation, and recommending the proper level of odor control necessary, to alleviate potential nuisance conditions. TE has collected both total odor samples and odorant specific samples to assess the current baseline and future upgraded conditions. Sources are being bundled by location, character and potential variability to select the optimal odor control package. The final odor recommendations will be incorporated into the plant upgrade design.

As part of the program, TE has developed a neighborhood odor survey and has completed a historical odor complaint analysis. This information helps determine the proper level of control necessary to minimize nuisance impacts. TE will present this complaint and survey information, coupled with the odor dispersion modeling results and the odor control recommendations, at public works meetings or at the annual Town Meeting.  This will demonstrate that the optimal level of control is sufficient and that additional control is not warranted. 



Mr. Michael T. Lannan is a chemical engineer who has provided odor solutions for facilities all over the United States and the world. He has piloted new odor control technologies, updated United States odor sampling standards, improved vendors' "standard" products, provided odor nuisance litigation support, and executed over one hundred odor control studies, designs, permit acquisitions, installations, start-ups, and system optimization studies.

As a chemical engineer, Mr. Lannan has an excellent understanding of the specific individual compounds in an odorous mixture and how each reacts, can be removed, and can have an odor impact on neighbors. Mr. Lannan has examined, designed, or replaced every commonly accepted odor control technology on the market today. He is a registered professional engineer in Massachusetts, New Hampshire, Maine, Vermont, and New York.

We are conveniently located on Trapelo Road at Reservoir Place on Route 128 at Exit 28 in Waltham, Massachusetts


1601 Trapelo Road

Waltham, Massachusetts 02451

ph. 781-890-2220

fax 781-890-9451

If you have been forwarded this email and wish to receive it regularly then click
here to subscribe.

TECH ENVIRONMENTAL is an environmental consulting firm specializing in air quality, odor control, noise abatement, and environmental due diligence.  General services include facility siting, licensing, permitting, compliance auditing, monitoring, and environmental impact studies.  Tech Environmental has worked for industrial, manufacturing and commercial clients in the private sector as well as municipalities and other public agencies.

For more Information visit us at

To no longer receive this newsletter from us click here, or reply with the word "REMOVE" in your message.