Case of composting garbage in a cold region – Hokkaido (Introduced to: Kimobetsu Town) - Deodorization and Composting equipment - Miraie

CASE STUDY

Construction example

2021.10.22 EASYJET

Case of composting garbage in a cold region – Hokkaido (Introduced to: Kimobetsu Town)

PlaceKimobetsu Town, Abuta District, Hokkaido Prefecture
Processed Material and AmountGarbage (general waste) 330 tons per year
OverviewThis facility recycles garbage (industrial and general) from Kimobetsu Town and Rusutsu Village as compost.

Measures and Effects

Reduce foul odorsThere was in the past a foul odor problem at a neighboring compost center, so a system that does not make foul odors was desired for this facility.
Reduce foul odors 2This facility is in a cold area, so it was designed to not have condensation or foul odors accumulate.
Raise fermentation temperatureA system was needed that would ensure the temperature rises even in winter.
Reduce costsBy using a return compost system, they reduced their spending on auxiliary materials by more than half.
Reduce costs 2Labor was saved, so the facility can be operated with a small number of staff.

In this case, we delivered a garbage recycling facility to Kimobetsu Town, Hokkaido.

This facility collects and recycles garbage generated by town residents in order to produce high quality compost.

The deciding factor to use our system was our record of achievements in other cold regions and the lack of odor.

This facility has three distinguishing features, the first of which is that it has almost no odor (so even people who work all day in the building do not get an odor on their clothes).

The second feature is that it can do fermentation at high temperature even in winter. The third feature is that the compost made can be used as return compost.

With regard to odors, they eliminated turn over work by using the high pressure aeration method, which reduced foul odors. Odor problems are the most common part of garbage composting to cause trouble.

Garbage carried to the compost center is acidic, with a pH value of about 4 (because garbage decomposes), so it has a peculiar sour odor and ammonia that combine to form a complex odor.

When composting this kind of material, it is important to maintain the aerobic state while quickly turning the materials alkaline, and to reduce generation of gas during turn over. This facility uses a high pressure aeration system that supplies oxygen to every part of the material, and reduces the number of turn overs, suppressing the causes of foul odors.

By maintaining aerobic conditions, they can also quickly raise the fermentation temperature simultaneously.

Also, condensation often forms in regions with low air temperatures, and this can easily cause foul odors. Therefore, they have introduced a ventilation system with sensors in order to automatically control proper ventilation in the facility.

Processing starts with the collection of garbage generated in the town, which is then weighed on a truck scale, and carried to the facility.

Next, the garbage is placed in the garbage storage area of the facility, then mixed with auxiliary materials (bark chips and return compost) using heavy machinery.

The mixed materials are then put on the EasyJet (high pressure aerator) and subject to primary fermentation.

Materials become compost after a fermentation period of 6 weeks.

With EasyJet, there is almost no turning over compost.

Fermentation temperatures rise over 60˚ C the day after they are deposited, and get close to 80˚ C on the 2nd or 3rd day.

There is almost no odor.

We plan to regularly analyze the materials and compost, and also monitor odor levels, in order to maintain proper operation long term.