Dry Washing vs. Water Washing for Biodiesel: A Comprehensive Comparison

Dry and wet washing refer to the purification of biodiesel, or diesel fuel from vegetable or animal fats. Dry washing uses magnesium silicate while wet washing uses water, according to "Biodiesel Magazine."

Wet Washing

• Wet wash purification is more traditional and more expensive. A water mist is sprayed over the diesel, removing impurities as the water sinks to the tank bottom.

Dry Washing

• Dry washing is faster, cheaper, uses less equipment and is less toxic to the environment. The addition of magnesium silicate powder neutralizes the contaminants in the biodiesel, and the final product is ready within a shorter time, according to "Biodiesel Magazine."

Product Quality

• Dry washing produces higher quality biodiesel with a water content of less than 500 parts per million (ppm) compared to 1,000 ppm when wet washing is used. In addition, the magnesium silicate in dry washing can be recycled as compost and an animal feed additive.