Thursday, July 30, 2015

Update on the composting systems


Its been now 9 months that the indoor worm composting experiment has started. During these 6 months the small Styrofoam (very) mini box grew to a slightly bigger composting crate, then expanded into a soy sauce bucket for the Bronx Writing Academy, and 3 (very) mini worm bin. All of that, in an apartment, with no odour, escapees or inconvenience.
In 9 months, 50 kg (110lbs) of food scraps, 16kg (35 lbs) of paper-cardboard and wood dust (dry weight) have been diverted from landfills and transformed on 20 kg (44 lbs) of compost.

We actually do not put all the food waste into the composting system, as it may be too small to process all of our food scraps, so we take the remaining food waste to the farmer's market, where it is collected and composted by GrowNYC. Close to none of our food waste ends up in landfills.
Food waste in the landfill when "washed down" with rain, can pollute the water in the surrounding, costing in treatment to make it safely drinkable. Food in landfills also produces CO2, CH4, NO2 and other greenhouse gases. It is important to note that CH4 and NO2 a much more potent greenhouse gases. While composting - worm composting- will emit C02 as well, and may emit other greenhouse gases, it is emitting less of the CH4 and N02 - if the compost bin is kept aerobic - which is the case as worm are tunneling though, keeping space for air to circulate.
The compost progressively changed aspect, as I have used compressed wood chips in the bedding, and the wood chip do take much longer to degrade. I think it also may have rendered the compost tea less rich, as the compost tea powered hydroponics has shown some deficiencies recently. Another thing I have noticed, is that with the heat of the summer, in a non air conditioned apartment, is that the food scraps heat up quite a lot after addition, which has lead to a dryer compost coming out of the bottom. It also may have reduced the overall worm population. So I have been able to put less food scraps lately, as the input seem not to be transformed as fast. I also recently stopped putting the food scraps in our old food processor to see if it heats up less.
Overall, the compost from the composting bucket for the school is much (very much) wetter, even with numerous holes. It is also darker than the compost form the home composting bucket. In the school bucket, no (or very little) compressed wood chip are used in the bedding, only paper and cardboard is used.

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