Soil Pollution Remediation Project for a Steel Casting Plant

Site Background

This site, located  in Keelung City, was formerly a steel casting plant that produced cast steel and iron products using steel plate trimmings and casting sand in electric arc furnaces. After the plant ceased operations in 2003, the site was used for storing scrap materials from shipbuilding. On-site soil contamination was caused primarily by heavy metals waste, with localized petroleum contamination caused by fuel oil leaks from storage equipment that spread through wells and underground conduits.

Pollution Status

In 2006, the Keelung City Government designated the site as contaminated with heavy metals and TPH*, including arsenic, chromium, copper, nickel, lead, and zinc. The site covered approximately 12,500m².

Remediation Approach

ApolloTech was contracted in 2006 to manage the remediation project, completing the work within three years, including comprehensive treatment for complex heavy metal contamination. The site received de-listing approval from Keelung City Government in 2009. This remediation effort enabled the successful revitalization of the land for development and productive use.

Bioremediation

For the TPH contamination, ApolloTech applied a bioremediation process using local soil bacteria strains capable of degrading TPH. These strains, introduced through bioaugmentation, accelerated TPH degradation in the soil. The process achieved a 38% reduction in TPH within three weeks.  With continuous operation, it effectively accelerated progress toward remediation goals.

Specialized Wet Magnetic Separation Process

To address heavy metals contamination, ApolloTech implemented a tailored wet magnetic separation process, utilizing the site's existing tank pits. This approach marked Taiwan’s first application of wet magnetic separation for soil, leveraging soil dispersion in water to enhance the separation of arsenic-laden slag from the soil and significantly improving remediation outcomes.

Note: *Total Petroleum Hydrocarbons (TPH)