Sewage sludge can be mixed in a short time, shortening the composting period!

Background of equipment introduction

Hamada City has only one sludge treatment facility, and that facility has been operating smoothly and normally despite repeated expansions and renovations.

However, with the increasing trend of sludge treatment each year, the facility has been operating beyond its processing capacity (106㎥/day) without consideration, maintaining an optimistic attitude of “We’ll consider it when the facility starts experiencing issues,” so we revisited the “Livestock Composting Facility” plan, initially considered for other projects since the former Misumi Town era, thinking that creating a facility to process both the sludge from agricultural community sewage treatment and livestock manure together would be a win-win solution, resolving both issues.

Reasons for choosing MIRAIE

In planning, it is unavoidable to compare economic aspects, so we considered the following four cases:

1. Transporting and processing sludge at the current facility.
2. Construction of a resource recycling facility.
3. Transporting the sludge to a recycling facility after dewatering at the processing site.
4. Dewatering and drying at the processing site.

After comparing the 10-year maintenance costs for these four cases, we concluded that constructing a resource recycling facility would be the most cost-effective. Based on this result, we evaluated the facilities and decided on one that met the following five criteria.

1. The facility does not need to secure a large area.
2. The equipment used is easy to handle.
3. The construction cost is low.
4. The facility allows for agricultural land return and produces a product as close to odorless as possible.
5. The cost of using auxiliary materials is low.

Evaluation After Installation

In the western region of Shimane Prefecture, this was the first area to have such equipment installed, and despite the company’s headquarters being in Matsue, they provided thorough support at every step, from startup and operation of the equipment to product management.

The product took 42 days to complete, and apart from the thorough management of fermentation temperature, the results significantly exceeded our initial expectations at the time of selection.

The strange odor generated from the product immediately after mixing the sludge and sub-materials and during fermentation is a phenomenon that cannot be helped, but since it is impossible to seal the building itself, it would be better if you could think of improvements to eliminate the odor during mixing.