There are long-standing problems with odour management from rubbish chutes to bin centres and rubbish collection trucks, all the way to Incinerators (WtE).
Objectives
To test and measure the differences with and without MMD treatment and the lasting effects of the MMD treatment, verifying 48 hours effectiveness. To show that it not only deodourises but also detoxifies (meaning the odourous bacteria do not return to colonise).
1. The deodourisation is immediate and effective.
2. The detoxification has immediate effect and is long-lasting for up to 48 hours.
To measure the 2 washed bins with and without MMD treatment on 8th Nov 2021 before noon.
To spray the MMD manually once into one bin and measure to collect the readings and to take another 2 more readings over 24 hours and 48 hours.
Bin A - Without Treatment after Washing
Bin B - Sprayed With MMD Once after Washing
The Problems
It takes 3-4 hours for food waste to begin to rot, decompose, and produce odourous VOC gases. Household rubbish mixed with food waste are thrown into chutes and bins. When left overnight, it produces an unbearable and obnoxious odour as collection happens only the next morning.
The black bins used in rubbish chutes are never washed.
General waste 660L bulk bins used in and around the bin centres are tall and deep. They are not easy to clean and the occasional hosing down with water (without any detergent use or without any scrubbing) is highly ineffective. It’s also not possible to flip the bin over for proper drying as these bins weigh between 55-75kg. The bin itself has become one of the sources of odours, and cleaning the bin with water will not allow for the elimination of VOCs and odorous bacteria.
Failure to clean the floor and overnight food waste that fell on the floor.
Typically, washing means flushing water to clear the debris but the odorous smell still lingers.
Conclusion
While both temperature and humidity are two of the factors affecting the odours strength and intensity of bacteria growth in food waste decay, these factors were not possible to control given the natural environment in which these bins are located. In the 3 days in which the experiment was conducted, it rained during the time of data collection with a low of 28°C at one point.
On the 3rd day of data collection, heavy rain spilt into the black bins kept outdoors. It was unexpected and out of the testing requirement. Nevertheless, this did not compromise the study given that the readings showed a difference and both bins were within the acceptable odour intensity of 2.5.
We are all working towards reducing odourous VOC for a greener working environment, reducing the carbon footprint, and improving the Neighbourhood’s Air Quality.
The Town Council staff involved and Cleaning Contractor’s management and cleaners have put in great efforts in this implementation and study, but more efforts are still needed in ensuring that the odour control is kept in place. This study can form the basis of an SOP for any cleaning contractor and their workers to maintain the standard.
Appendix - Data collected over the 3-day study.
Blue lines = Odour Intensity | Magenta lines = Odour Strength
08-11-2021 Before washing, both bins were equally odourous hitting 3.5 intensity.
Date: 08-11-21, Mon | Interval: 5s |
Time (HR): 09:49 | Time (HR): 10:11 |
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Date: 08-11-21, Mon | Interval: 5s |
Time (HR): 10:00 After Washing Without MMD | Time (HR): 10:53 After Washing & Applying MMD (once only) |
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After 24 hours | |
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Date: 09-11-21, Tue | Interval: 5s |
Time (HR): 15:46 | Time (HR): 15:36 |
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After 48 hours | |
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Date: 10-11-21, Wed | Interval: 5s |
Time (HR): 15:22 | Time (HR): 15:11 |
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