Methane digestion residues composted in 7 days, even with high-temperature fermentation in winter!

Overview of Composting at Biogas Plant in Biman, Shimizu Town

The Shimizu Town Biman Biogas Plant is a methane power plant that collects 50,000 to 60,000 tons of dairy cow manure annually and is capable of providing electricity for about 1,600 households for one year.

View of Shimizu Biman Biogas Plant

The residues from methane power generation are composted, and the challenges faced during the facility design were the following two points:

1. Large amounts of residues are generated, so we want to compost them as quickly as possible to save space.

2. In winter, temperatures can drop to -25°C, so we want to ensure high-temperature fermentation even during severe cold to kill pathogens in the compost.

Introduction of “Easy Jet”

Therefore, in planning for the facility, MIRAIE cooperated with the plant manufacturer to conduct a demonstration test in Hokkaido during winter. It was shown that using Easy Jet recorded fermentation temperatures of 70-80℃ on the second day, about 20℃ higher than conventional piling methods, and eliminated 99.999% of pathogens, leading to its introduction.

At this facility, the residues after power generation are separated into solid and liquid, and the solid part is composted using Easy Jet.

Separated solid residues from power generation

Easy Jet Machine Room

When materials are piled in the composting facility, temperatures reach over 70°C by the next day, completing composting in about 7 days.

Since turning is not required, odors are also minimized, and space-saving processing contributes to improved facility efficiency.

Inside the composting facility

Exterior of the composting facility