Remediation of muddy tidal flat sediments using hot air-dried crushed oyster shells

► Hot air-dried crushed oyster shells (HACOS) were applied to a muddy tidal flat. ► HACOS was effective to remove hydrogen sulfide from organically enriched sediments. ► HACOS led to an increase in the number of benthic organisms. ► The HACOS mixing is a promising technology to create a new habitat for organisms.