Leave a Nest Co., Ltd. (Group CEO: Yukihiro Maru) and Galdieria Inc. (CEO: Hajime Tanimoto) have launched the Galdieria Microalgae Wastewater Resource Recovery Project as part of the LVNS Water Cycle Project. The project aims to use Galdieria microalgae to treat industrial wastewater while recovering valuable resources.

Galdieria is a microalga that can grow in high-temperature, strongly acidic environments such as acidic hot springs. It can adsorb precious metals including gold and palladium, even from very dilute solutions. This characteristic could be applied to precious-metal recovery from urban mines and small-scale mines.

Artisanal and small-scale gold mining (ASGM) still uses toxic mercury to smelt gold ore in many parts of the world and is estimated to account for 20–30% of global gold production. At these sites, mercury amounts ranging from several times to more than 100 times the amount of gold being smelted are used. Some of the mercury flows into aquatic environments or is released into the atmosphere as vapor, causing extensive health damage.

Replacing this process with safer Galdieria-based gold processing could protect the health of people involved in gold mining and help protect the environment, including the water sphere.

The project will develop methods for cultivating Galdieria using wastewater containing organic matter discharged from food, sugar, distillery, and textile factories. By using the resulting algal biomass for precious-metal recovery and other applications, the project aims to build a new circular model that connects wastewater treatment with resource recovery while contributing to environmental conservation.

As a first step, the project will work with Filminera Resources Corporation at a gold mine in the Philippines to recover and analyze ore samples and conduct gold-extraction tests in Japan. If the technology proves applicable, the project is expected to proceed to a demonstration at the mine.

Feasibility studies are also underway in India and Southeast Asia to establish Galdieria cultivation models using industrial wastewater.

Through the cycle “Industrial wastewater and waste → Galdieria cultivation → water-environment improvement → resource recovery,” the project will transform wastewater from a treatment target into a resource that creates new value and contribute to the sustainable development of water environments and industry.

Related page: Galdieria Microalgae for Wastewater Treatment and Resource Recovery