Combined Toilet, Hot and Vermi Composting

After 12 months of progressive refinements, I would like to present my conclusions on composting generally and specifically on handling the product of a composting toilet.

I started my composting adventures with hot compost using dried sugarcane and horse manure in a conventional bin. Within a few days, the pile temperature exceeds 70oC. Reheating on subsequent turnovers is also rapid. The high sugar content of dried sugarcane is largely responsible for the rapid increase in temperature. The compost works well in the garden and as a seedling mix either on its own or mixed with sand. Recently retired, I am developing a fairly large garden area in thin clay in a hilly, sub-tropical environment. I need a lot of compost so the productivity of hot composting is ideal. As for refinements, I like to add at least 15% by volume of charcoal with the manure and dried sugarcane. Best results are obtained when all components are passed through a garden shredder but the manure has to be reasonably dry.

The composting toilet needed a few iterations to avoid problems of odour and fly infestations. I now have a urine diverting seat and cover that screws onto a 20l container. The local pool shop gives me the containers. Hydromulch fibre of shredded sugarcane and newspaper is an ideal cover material and absorbent. The diverted urine is diluted and applied to about one square metre of soil per day. More care needs to be taken with the solids. My answer is to combine heat treatment in hot compost with worm treatment in a flow-through vermicomposting bin. The partly full 20l container is tipped into a fertiliser/feed bag and buried as in a new bin of compost. The bag is extracted after the first or second turn and emptied into the vermibin.

The vermibin takes kitchen and garden wastes. The relatively small daily supply of these materials does not really suit hot composting. The long residence time in the vermibin and the proven pathogen reducing capacity of compost worms makes me confident that the worm casts may be used safely in the garden.

That's the composting trio in a nutshell. Comments and questions would be appreciated.

For me, I find that humanure composting gets too hot for worms. And my kitchen scraps don't do especially well on the hot compost pile (perhaps because I am often too lazy to cover them completely, or perhaps because they are put on in small increments). My current plan is to start using the kitchen scraps for worms, and let the humanure pile go its own way.

Thank You Kindly.