What is the Aerobic Composting
Method by Urban Compost Bali?

Urban Compost provides pickup services including reliable bin collection and scheduled pickups up to 3x a week.

All the organics collected (food scrap and garden trimmings) are send to Urban Compost Bali composting facilities to be properly composted. The finished product (the compost) is then given back to the subscribers as part of the service. A yearly report regarding the composting achievement is provided too.

“We make sure that all the organics that we collect are 100% composted instead of going to landfill or being burned. By doing so, subscribers divert the 60% of daily waste they produce. Through composting, we also reducing the GHGs and offsetting the carbon footprint. The compost itself is excellent for soil conservation, plantation and sustainable farming program.”

3 Phases of the Aerobic
Composting Method by Urban
Compost Bali.


Once the food scrap (source of N, Nitrogen) and garden trimmings (source of C, Carbon) arrive into the composting facility, they both will be put into the composting cell. The shredded garden trimmings are part of the first layer (about 10cm thick). The food scrap is then added as a second layer (also 10cm thick) creating a 50/50 proportion of shredded garden trimmings and food scrap by volume. It keeps going that way until reaching 1m height.


After 1 week (or no more than 10 days), the materials in the cell must be tossed out to the front area (which has been topped up with 10 – 20 cm thick of shredded garden trimmings, acting as bedding) to go through the aeration process.

The aeration process means to activate the aerobic native bacteria in the pile. This must be done by moving the pile little by a little, either using hand tools (shovel or pitch folk) or excavator machine – this way all the surfaces of the pile is exposed to the oxygen.

After moving, the pile goes back upside down to the previous position (the top now become the base, and vice versa) – this is turn no.1.

After 3 days, the bacteria become active as the pile heats up to 70°C. After 5 – 7 days, the pile can heat up to more than 80°C and it should be moved again (turn n.02) so that all the microorganism, except the thermophilic actinomycetes bacteria die.

This step is repeated a minimum 5 times or when the pile looks darken, soil-like form, and no heat up (no more than 40°C). Sometimes, when the ambient temperature is hot and dry, every time the pile is turned, watering the pile is necessary to keep the humid condition of the pile.


After 5 weeks of aeration process, the pile will be left on the surface in the specific area for the maturity process.

At this stage, the pile will not exceed 35°C – so that many creatures such as worms, micro insects, grubs, nymphs, and other billions beneficial soil bacteria and fungi will thrive inside the pile, creating diverse micro ecosystem, improving the compost texture and binding the essential macro and micro nutrient.

After 2 weeks of observation – making sure that the temperature doesn’t heat up anymore, the compost can be harvested and applied to recondition the soil or feed the plants. Sieving is sometimes necessary in order to get the finer compost product and filter any big chunk – it can be tossed back to the active pile in the Phase 2nd.