We compared two methods of fluid medical waste disposal from an environmental point of view. Incineration of a full suction bag and using Serres Nemo for disposal. The biggest differences in environmental impact come from the incineration. In transportation, there is significant CO2 reduction potential too.
First, we have a full suction bag. When it comes to disposal, both incineration and Serres Nemo are viable ways for disposing of fluid waste. But how do they compare from an environmental perspective?
Disposal by incineration
After a procedure, the suction bag is collected with the hospital’s waste, measured by weight and paid for accordingly. Then, the bag is transported to incineration. In our example, the incinerator is 100km away from the healthcare facility.
Disposal by Serres Nemo
After a procedure, the suction bag is carried to a nearby washroom. There the suction bag is placed into Serres Nemo, the lid is clicked shut, a button is pressed and 20 seconds later the only waste left is the now empty bag. The bag is then transported to incineration.
When incinerating waste, a full suction bag of fluid medical waste will be transported to the incinerator. When using Serres Nemo, only the empty bag is transported to incineration. Here’s the impact on carbon emissions.
- One full 2l Serres Suction Bag generates 12g of CO2 emissions / 100 km.
- One empty 2l Serres Suction Bag generates 1g of CO2 emissions / 100km.
Finally, the waste is incinerated.
- One full 2l Serres Suction Bag generates 150g of CO2 emissions
- One empty 2l Serres Suction Bag generates 5g of CO2 emissions
Now, let’s look at the carbon emissions in a facility that uses 7,000 bags per month.
- Disposal of full Serres Suction Bags amounts to 1,134kg of CO2 emissions.
- Disposal of only empty Serres Suction Bags amounts to 42kg of CO2 emissions.
Annual footprint: 13,014 kg of CO2 emissions per year saved with Serres Nemo
This is the equivalent of the energy used to heat 1.6 homes for a year. It is also comparable in savings to the impact of recycling 4.5 tons of waste instead of transporting it to a landfill.
How did we calculate this?
Calculating the energy expended for incinerating the full suction bag, we had to take into account that the fluid waste is largely water. Incinerating the plastic and vaporizing the liquids requires more energy than incinerating an empty Serres Suction Bag.
Heating the full 2kg bag of fluid waste from 20°C to 100°C and evaporating the fluids takes approximately 5MJ of energy. We took into consideration the fossil materials burned using natural gas (CH4) which is primarily methane. Then, thermal efficiency was taken into the equation to arrive at 367g of CO2 emissions generated from incinerating a full suction bag. We assumed a 50% average heat recovery rate for incinerators and therefore our conservative estimate is in average 150g CO2 reduction per bag.
For transportation, we calculated that 60g of CO2 is saved per 1 ton per 1km. Using 100km as the average distance from hospital to incineration, the CO2 emissions for a 2kg bag are 0,002[tkg] x 100[km] x 60g = 12g CO2 per 2kg bag.