Discovery and design of toilet malodor counteractants for managing offending smells and increasing consumer acceptance (Firmenich, Switzerland)

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Discovery and design of toilet malodor counteractants for managing offending smells and increasing consumer acceptance (Firmenich, Switzerland)

Dear all,

Please find below some information about an interesting research project on odour and "malodor counteractants" funded by the Bill & Melinda Gates Foundation. The information was compiled via publicly available sources (unlike for the other grant introductions where the information was provided directly by the grantees specifically for the forum). I'll check if Firmenich wants to clarify or edit some of the information that I have compiled here.

Title of grant: Discovery and design of toilet malodor counteractants for managing offending smells and increasing consumer acceptance of reinvented toilets

Name of lead organization: Firmenich

Primary contact at lead organization: Maria Ines Velazco (second contact: Charles Chappuis)

Grantee location: Meyrin, Switzerland

Developing country where the research is being tested: India, Kenya, South Africa

Start and end date: November 2013 - December 2016

Grant type: Other

Grant size in USD: $6,344,590 as per BMGF grant database here

The red arrows indicate where odour is produced in the sanitation system

Short description of the project:

Malodor can deter people to use pit latrines. There are different approaches to odor control, such as biological filters and highly adsorbents filters (activated carbon or biochar). Another method is to capture the odor using chemical misting. Odor molecules can be destructed, transformed or masked. Firmenich creates fragrances and delivery technologies and conducts research on perfume creation in order to develop an odor control method for latrine malodor.

Volatiles in the latrine's sludge were analysed and a sensory survey was conducted in India, Kenya, South Africa and Switzerland in order to identify the pleasantness of different odors. Research showed that butyric acid, p-cresol, indole and dimethyl trisulfide are strong contributors to the human fecal odor. Identification of these chemical compounds is important for synthetic reconstitution of pit latrine malodor which in turn is essential for perfume creation.

Important conclusions from Firmenich's work to date, as presented at FSM3 Conference in Hanoi in January 2015 (see full presentation here: www.susana.org/_resources/documents/defa...25-22-1427453363.pdf ):
  1. The fecal reconstitution (4 molecules) produced similar results as the latrine reconstitution (same 4 molecules + 4 others found in latrines sludge) in every country.
  2. A reconstitution with butyric acid, p-cresol, indole and dimethyl trisulfide can evoke an olfactory experience similar to the one during the use of latrines in three different continents.
  3. This confirms and consolidates previous studies on fecal odors that butyric acid, p-cresol, indole and dimethyl trisulfide are strong contributors to the human fecal odor.
  4. Stable synthetic reconstitution of pit-latrine malodor is essential for perfume creation, the development of odor control method and for a better understanding of the perception of the latrine malodor.
Goal / objective:

The purpose of this project is to bring performing and affordable malodor counteracting solutions to the beneficiaries of the Foundation’s WSH initiatives by making the use of affected toilets a more desirable experience.


Research or implementation partners:

From the below mentioned paper:
We would like to express our appreciation to the following people:
  • Dr. Myles F. Elledge, Senior Director of RTIInternational (USA), for helping us organize the survey in Ahmadabad; Ritu A. Sinha, Head-Strategic Alliances, RTI India;
  • the team from SEWA (Self Employed Women Association) in Ahmadabad for organizing the odor sampling;
  • in Durban, South Africa, Prof. Chris Buckley of the University of KwaZulu Environmental Natal for coordinating the odor sampling, along with Dr. Lungi Zuma from e Thekwini Municipality.
Links, further readings – results to date:

For more information see SuSanA library entry: www.susana.org/en/resources/library/details/2225

Paper from May 2015 an "Quantitative Headspace Analysis of Selected Odorants from Latrines
in Africa and India"
by Charles Jean-François Chappuis, Yvan Niclass, Christine Vuilleumier, and Christian Starkenmann*
Corporate R&D Division, Firmenich SA, P.O. Box 239, CH-1211 Geneva 8, Switzerland

See:
www.susana.org/_resources/documents/defa...25-22-1434095390.pdf
or:
pubs.acs.org/doi/abs/10.1021/acs.est.5b00692

ABSTRACT:

This analytical investigation focuses on the quantification of odorant
molecules in the headspace of latrines. Hydrogen sulfide and methyl mercaptan were
derivatized under a more stable N-ethyl maleimide conjugate. Since the amount of odorant
molecules is very low in the gas phase, we developed a method that had two steps of
concentration. The first step consisted of the accumulation of volatiles in buffered water by
bubbling 350 L of air in a bottle. The second step consisted of loading the water on a 1 g
solid-phase extraction cartridge, shipping it to our laboratories, and desorbing with Et2O,
which achieved a total concentration factor of 3.5 × 106. The acidification of the water
phase gave us access to the acids, and an additional bottle containing an acidic ionexchange
resin gave us access to trimethyl amine. The limits of quantification in the gas
phase were 8.7 × 10−4 μg/L air for hydrogen sulfide, 1 × 10−4 μg/L air for methyl
mercaptan, 1 × 10−3 μg/L air for butyric acid, 1 × 10−4 μg/L air for p-cresol, 1 × 10−5 μg/
L air for indole, and 1 × 10−5 μg/L air for skatole. The system was calibrated by using
olfactometers, which can deliver a precisely known quantity of volatiles into the air. We were able to quantify all compounds near their odor detection thresholds (ODTs). All ODTs were measured in our laboratory with the same olfactometry method. This allowed accurate and comparable ODT values for malodorant compounds from toilets.


Current state of affairs: Odor issues in fecal sludge management have to be further discussed as well as the contribution of malodor as a barrier to toilet/latrine adoption. Further information about the current state of affairs of the project is currently not available

Biggest successes so far: Not available

Main challenges / frustration: Not available

Regards,
Elisabeth


P.S. If you wonder about the difference about odor and malodor, this Wikipedia page might help:
en.wikipedia.org/wiki/Odor

It says:

The terms fragrance and aroma are used primarily by the food and cosmetic industry to describe a pleasant odor, and are sometimes used to refer to perfumes. In contrast, malodor, stench, reek, and stink are used specifically to describe unpleasant odor.

I think for us in the sanitation industry, when we hear "odor" we automatically think of something that smells bad, don't we?

By the way, I would love for people to improve this Wikipedia page because it does not mention odor from fecal matter or any other sanitation issues yet... A lost opportunity for awareness raising, isn't it?

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This email address is being protected from spambots. You need JavaScript enabled to view it. Twitter: @EvMuench
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  • F H Mughal
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Re: Bill Gates: A Perfume that Smells Like Poop?

Bill Gates: A Perfume that Smells Like Poop?

Bill Gates’s blog ( www.gatesnotes.com/Development/Smells-of-Success ) makes an interesting reading, though the point projected, may be debatable.

Bill Gates says: Millions of new toilets are being built around the world to help end open defecation, including in India where a massive new toilet construction program is currently underway. This is great news. Unfortunately, many of these new toilets, especially the pit latrines, don’t get used because they smell bad and people continue to relieve themselves in the open where the air is fresher. This is a worrying trend that threatens to undermine the progress that’s been achieved in global sanitation.

Bill Gates wants the smell of feces to be masked. He says: Our noses have 350 olfactory receptors, each one awakening us to new sensations from the smell of a rose to stinky feet. Just a handful of them allow us to smell repulsive odors. Firmenich researchers used this knowledge to develop fragrances that block certain receptors in our noses, making us unable to register certain malodors.

The approach is similar to noise-canceling headphones which many people use to block out jet engine noise on flights. Electronics in the headsets create a sound wave that is 180 degrees out of phase with the ambient noise that needs to be blocked. This wave cancels unpleasant sounds and allows you to enjoy peace and quiet. Likewise, the ingredients in the fragrances developed by Firmenich inhibit the activation of the olfactory receptors sensitive to malodors. By blocking the receptors, our brains do not perceive the bad smells.


Assuming that the technology is perfected, the point is who will spray the fragrance spray or powder – - - no one, as the persons mandated in poor developing countries will simply sell the stuff in the market and earn extra bucks – free of cost.

The question now is whether this technology is good enough to make a difference in communities with poor sanitation. That’s why Firmenich is launching pilot projects in communities across India and Africa to understand whether the fragrances will make toilets and pit latrines more inviting for users. They also need to determine if it’s better to distribute the fragrance as a spray, a powder, or something else. The ultimate goal is to make the product affordable and easy-to-use.

The bad odor of feces is beneficial, as it will keep a person away from it. I tend to support the views of Curtis, et al. (2011):

We have seen that disgust, hygiene behaviour and culture form an interlinked adaptive system, which has long served to reduce the dangers of disease. We have argued that disgust in the brain and the disease avoidance behaviour that it motivates is universal in humans (and in other animals) and is a product of the selection pressure of pathogens in the environment. However, disgust is also plastic, being able to retune according to signals from within the body and from the social and biological environment. Heightened disgust sensitivity leads to heightened disease avoidance behaviour (hygiene). However, as a social species, group hygiene behaviour is not just an aggregate of individual behaviour but the consequence of individuals using each other as models to be imitated, and as resources for cooperation in healthy behaviours. Changes in group hygiene behaviour, including cooperative public health activities, can reduce pathogen prevalence. The tendency to defect on responsibilities to the group can be countered by norms imposed by culture. The content of culture is itself biased by learning mechanisms based in the disgust system in individual brains.

Disgust as an adaptive system for disease avoidance behaviour, Valerie Curtis*, Mı´chea´l de Barra and Robert Aunger, Phil. Trans. R. Soc. B (2011) 366, 389401 doi:10.1098/rstb.2010.0117

F H Mughal

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  • bsoutherland
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Re: Bill Gates: A Perfume that Smells Like Poop?

Hopefully this comment is not too far afield. I have found the use of crop-waste derived charcoal to be completely effective in controlling odors in a UDDT. The charcoal/urine is used as fertilizer and the feces/charcoal is turned into cooking briquettes. Feces/charcoal is rendered pathogen free by the excess heat generated by pyrolysis of crop waste.
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  • muench
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Re: Bill Gates: A Perfume that Smells Like Poop?

Yesterday I saw a tweet of Bill Gates that got me back to this topic. He wrote on Twitter:

Bill Gates
‏@BillGates
I had a first in 2016…I sniffed poop perfume. Trust me, there’s a good story behind it: b-gat.es/2jde9YK


Here's the video that he linked to in his blog post:



Mughal had also mentioned Bill's blog post from November in his post on 1 January (see above in this thread).

I think it's awesome that Bill Gates uses his position - of someone that people listen to - to stress time and time again the need to improve sanitation worldwide. It is one giant awareness raising campaign for which we should be tremendously grateful.

Regarding this particular research on odour: Again I think it is really great that he's thinking out of the box. Most of us here on the forum are probably focusing on coming up with toilets that don't smell or smell less (see forum post above this one). But he's saying "what can we do to reduce the smell in existing toilets, instead of chaning the toilet?". Also, I think the smell issue is someone that we can ALL relate to - whether you live in a wealthy or in a poor country, because even flush toilets can be very smelly, e.g. in the context of public toilets. Babies' soiled nappies are smelly, dog poo is smelly, especially when we step into it - we all know the smell of feces and urine!

However, I have a couple of concerns:
  1. Where is the evidence that poor peopole would be willing or able to pay for such a new "toilet smell masking perfume" if it existed - given that they cannot even afford (or are not willing to spend their scarce income on) soap, for example? Or toilet paper or menstrual pads? (Mughal made a similar point above in his post)
  2. When a toilet is "filthy" then usually odour is only part of the problem. The other problem is often visual aspects: feces visible on the side of the drop hole or in the toilet bowl, flies flying in and out of the hole if it is a very wet pit latrine, perhaps maggots, perhaps feces visible from the previous user, perhaps urine on the ground etc. This visual impression will not be masked by a perfume, and is equally off-putting.
Looking forward to learning more about the progress with this research and how it gets implemented in practice!

Regards,
Elisabeth

Community manager and chief moderator of this forum
(Funded via GIZ short term consultancy contract)

Dr. Elisabeth von Muench
Independent consultant located in Brisbane, Australia
This email address is being protected from spambots. You need JavaScript enabled to view it. Twitter: @EvMuench
Sanitation Wikipedia project leader: en.wikipedia.org/wiki/Wikipedia:WikiProject_Sanitation
My Wikipedia user profile: en.wikipedia.org/wiki/User:EMsmile
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