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Technology

Selenium Ferro-Reduction Process

The Selenium Ferro-Reduction Process, jointly developed by Hokuriku Electric Power Company and Chiyoda Corporation, is an innovative process that uses high-activated Steel wool.

Overview of the Selenium Removal Method

The Selenium Ferro-Reduction Process is a process that reduces selenium by steel wool and stabilizes it as Iron (lll) hydroxide. The Iron (lll) hydroxide generated on the surface of steel wool can be easily separated by air. This allows the filled steel wool to be completely consumed, enabling continuous and stable operation.

Process Flow

The Selenium Ferro-reduction Process is the simple process flow allowing selenium to be reduced and stabilized with a single reactor.

Reaction Cycle of Steel Wool

Process Flow

High Selenium Removal Efficiency

The high contact efficiency of the reactor caused by a large surface area of steel wool can achieve Selenium removal efficiency of more than 99%.

Low Construction and Operating Costs

The 10 to 20% of construction cost can be reduced compared to typical iron reduction methods, because selenium is reduced, neutralized, and oxidized in a single reactor and the number of auxiliaries can be reduced. And, 30 to 40% of operating cost can be reduced compared to typical iron reduction methods, depending on the 40% reduction of steel wool consumption, reducing the amount of sludge and not using acid additive and heating wastewater

Non-resoluble Selenium Sludge

The operation at a near-neutral pH promotes the conversion into Iron(lll) hydroxid. And selenium is reliably stabilized in sludge.

Easy Operation Management

Selenium can be removed from wastewater only passing through the reactor with steel wool.

Reliable load following capability

Reliable load following capability can be achieved by the adjustment of the retention time in reactor and air flow rate control.

Easy Application to Existing Facilities

The simple system with a small number of auxiliaries can be easily applied to existing facilities.