“SOURCE”, Summer 2014

Wastewater Treatment Plant

article-fr-(press)Urbanization and Wastewater Treatment Plant are Seldom Compatible


Article from the Magazine Source, Summer 2014 – Vol. 01, n1


In North America, the number of lawsuits and class action lawsuits related to odor nuisances increases threefold every two years. The time has definitely arrived for urban planning departments to take olfactory criteria into consideration in their zoning plans.


Whether they are for municipal or industrial use, whether they are used to manage tens of thousands of flushes generated by citizens or the liquid residue from food-processing plants, wastewater treatment plants have have been significantly affected by urbanization in recent decades. The decrease in distances separating the plants and residents combined with the increase in the amount of water to be treated are the two main factors associated with the rise in odor nuisance complaints, which is becoming a sometimes irresolvable challenge for wastewater treatment plant managers.

Fewer Buffer Zones

Pour certaines station de traitement, l'adaptation est nécessaire pour permettre l'évaluation adaptée des conditions de rejets

As the occupation of the municipal territory increases, zoning changes are frequently made in some buffer zones initially assigned


close to wastewater treatment plants. When demographic pressure is very strong, occupation of these areas can reach the fences.

Unfortunately, these strips of land are rarely used for cemeteries; more often than not, they are used for condominiums, even luxurious ones, hospitals, schools and other sports facilities: places frequented by the public on a daily basis. This new proximity nearly always leads to a proliferation of odor complaints and a certain amount of discouragement among wastewater managers.

Factors of Social Tension

In many cases, social tension can greatly escalate for several reasons: first of all, the categorical refusal from the new residents who want to take full advantage of their new neighbourhood. Also, it must be said, the increasing sensitivity of a society that no longer tolerates any olfactory deviation, either in odor concentration or quality (do you know many people who do not use deodorant?).

But these families are also intolerant be they have no emotional, historical or economic connection to the plants: nobody works there and nobody knows the how important the plant’s activities are for the environment, whether it is processing municipal wastewater or sewage from dairy or fruit juice production.

Increased Processing Loads and Accountability

Although much of the responsibility in such cases rests on the urbanization departments, they are not legally accountable for these zoning issues. Nor are they the only ones to be blamed: many plants were sized between 1960 and 1990 and in many cases the estimated population increase only covered an additional 50%. Therefore, when a wastewater treatment plant that has been in operation for 20 years is suddenly surrounded by apartment buildings and the load it must process increases by 250%, odor complaints are not really surprising. It seems unfair to blame the plant managers!

Olfactory First Aid

In some cases, odor nuisance can be reduced temporarily with odor neutralizing chemicals, however, it is important not to confuse these products with masking products which can increase odors and make the situation worse very quickly. Olfactometry experts can help wastewater managers in several ways: by objectively certifying and optimizing the effectiveness of using various neutralizers; by carrying out diagnostics on various odor sources to prioritize treatments; and through odor impact studies to scope out solutions perfectly adapted to odors before they are dispersed into the environment.

Political Factors and Legal Consequences of the Wait-and-See Policy

If the amount of lawsuits surrounding odors continues to increase, it is most certainly linked to the failure to integrate the olfactory parameter into the territory’s management plan. Yet, this “Odor” parameter can be factored in just as easily as the noise parameter before any changes are made to municipal zoning. Taxes and services associated with new residential projects can quickly be wiped out by class action suits which generally start after five to ten years of continuous complaints and a the authorities’ wait-and-see policy.

As for election promises vowing to end olfactory episodes, one must be very conscious of the enticement of “zero odor” objectives (to learn more, watch the Dansmonsoussol video clip on You Tube). Just like water purification plants, many environmental activities cannot reduce the impacts below a certain frequency and certain acceptable severity rates. Don’t miss the next article in which these characteristics will be clearly established.

To understand clearly the differences between odour neutralisation and odour masking, consult the link below :

To learn more about the possibilities of olfactometry and learn how to prepare a legal case, click on the link below :

Consult the original version online.

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