Dredged materials are a mixture of cobble, garbage, bottles, cans and sand etc. Those materials are crushed into particles and classified into useless garbage, aggregates, sand and slurry. Sand and aggregates are directly re-used for construction materials, and crushed garbage and slurry are re-manufactured into a dewatered solid cake through hyper-press filter, then re-used for roadbed and embankment etc. Daiho has an extensive record of recycling use of dredged materials.

Daiho has developed a special technology to remediate dioxin found in contaminated soil for recycling use, through a combination of a high press de-watering treatment method, and a chemical resolution treatment method. This technology has been proven to satisfy Japan's current stringent safety standards for soil and exhaust after treatment.

To minimize damage to tunnel structure by fire, Daiho has developed insulating materials for tunnel lining which provides protection from severe heat in case of fire. This material is light, cost-saving, and has proven to be effective for fire-proofing for up to 1200 degrees centigrade heat for 60 minutes.

To reduce by-products from tunneling work by TBM including shield method, Daiho has developed an effective use of excavated material for construction of tunnel invert structure. Consolidation additives are mixed with excavated material produced by tunnel excavation and placed at the bottom part of invert after checking specified strength of the consolidated mixture. This consolidated mixture of excavated material and additives has been actually used for several subway projects in Japan.