My answer is yes if this system is run at the size of a town/city and it could run as a rental service.
A medium-sized facility will be the center of this operation.
First it collect organic wastes from major producer of this town.(Supermarkets, coffee shops, food factories, parks)
And these waste will be made into fresh compost piles in correct C:N ratio.
Most of compost is put into reactors and sent to "subscribers" who needs heating:
This will reduce the space needed for storing the compost in the facility.
A compost pile can be "revived" or "boosted" by adding fresh material while turning the pile.
This means the thermal output of a compost pile can be maintained at high level for a long time.
I did a experiment on my prototype reactor and proved this.
Here's the record I collected so far:
A stands for steam temperature in upper area of the reactor.
B is the core temperature of the heap.
Average ambient temperature = 30 degrees Celsius
This experiment started at 2022.06.12(Day 0) and on Day 1 the core temperature already reached 64 degrees Celsius.
I boosted it on day 5 and day 17, and you can see the core temperature remained above 50 degrees most of the time.
Another important result is that it is an efficient way to shrink the volume organic waste.
Here's the record of volume change of the pile:
Total volume of the reactor is considered 100%.
From day 1 to day 5, it lost 25 percent.
From day 6 to day 17, it lost 30 percent.
From day 18 to day 23, it lost 20 percent.
It's 75 percent in total.
This is quite normal since the raw material is only grass, which has high water content.
The compost pile shrinks quickly due to dehydration.
If food waste, which usually contains even more water, is added into the mix, the shrinking will be even greater.
If we process organic waste in a town in this way, a large amount of diesel/gas will be saved since the waste will not be carried by garbage trucks and travel to distant incineration plant.
Instead, it stays locally and produces useful heat and fertilizer.
Moreover, the compost can be swiftly turned into a possible fuel source: black soldier fly oil.
This insect grows fast( 14 days to get mature)
There are 12–34% percent of fat by weight in this insect's larvae( see reference 1).
They have no problem thriving on my finished grass-based(manure-free) compost pile as long as it's wet and shaded.
After all, manure from herbivores is just a pile of well fermented grass.
BSF oil, as a heating fuel, can be sent to extremely cold areas where hot composting might fail and have limited electricity supply.
It can also be converted into biodiesel for diesel engines.
This operation creates a series of valuable products which are illustrated in the following picture:
Advantages:
1.Reduce gasoline/diesel consumption of waste transportation and fuel for incineration.
2.Reduce natural gas usage in heating.
3.Reduce natural gas usage in chemical fertilizer synthesis.
4.Carbon fixing effect from compost usage and no dig farming.(reference 4,5)
5.Create a fast shortcut from waste to protein and fertilizer
6.From 1 to 5 combined. This system can help securing national food and energy safety by reducing imported resources from other countries)
7.Create new jobs
Potential income sources:
1.Sell compost / vermicompost
2.Provide rental service of heating
3.Charge for organic waste disposal
4.Sell BSF derived products(animal feed, fuel for heating)
Challenges:
1.No one ever tried this approach and it's unclear if it can generate enough income to sustain its operation.
An article(reference 2) which proposes a medium-scale BSF based facility which looks quite promising.
2.Its operation is complicated and requires a lot of workforce to handle it:
a.Mini truck drivers to transport organic waste and compost
b.Professionals who can sort organic waste, turn them into good compost piles, and determine a compost pile is ripen or not.
c.BSF farmers
d.Engineers who can maintain equipment in the facility
e.Managers who take care of financial issues and supervise operations of the facility.
--------References---------
ref 1. Review of Black Soldier Fly (Hermetia illucens) as Animal Feed and Human Food Foods 2017, 6(10), 91; https://doi.org/10.3390/foods6100091
ref 2.Opportunities and constraints for medium-scale organic waste treatment with fly larvae composting. October 2015
Conference: 15th International Waste Management and Landfill Symposium, Sardinia,At: S. Margherita di Pula, Italy.
ref 3.Comparison of the Effect of Vermicompost and Inorganic Fertilizers on Vegetative Growth and Fruit Production of Tomato ( Solanum lycopersicum L.)
January 2015Open Journal of Soil Science 05(02):53-58
DOI:10.4236/ojss.2015.52006
ref 4.No-dig gardening https://en.wikipedia.org/wiki/No-dig_gardening
ref 5.Koplowicz, Sarah R., "Utilizing Compost for Carbon Sequestration: A Strategy for Climate Goals and Land Use Management" (2019).
Master's Projects and Capstones. 945.
