Biotech

• “Polyelectrolytes were investigated for flocculation of a corn whole stillage stream to improve solid-liquid clarification operations and reduce downstream utility requirements for evaporation and drying within a bioethanol process.”

Researchers from South Dakota School of Mines and Technology, Department of Chemical and Biological Engineering, in Rapid City, South Dakota, USA; have presented an article titled: “Polyelectrolyte flocculation of grain stillage for improved clarification and water recovery within bioethanol production facilities.” ¹

The researchers from South Dakota School of Mines and Technology, have also noted:

• “Despite a negative zeta potential for the stillage solids, an anionic polyelectrolyte was found to provide the best flocculation.”
• “At the optimal dosage of 1.1mg polymer/g dry suspended solids, an anionic flocculant provided a clarified stream with only 0.15% w/w suspended solids (equivalent to a total dissolved solid to total suspended solid ratio greater than 40, and a viscosity reduction of 39% compared to an unflocculated “clarified” stream).”
• “The resulting solids cake had greater than 40% w/w solids, and more than 80% water recovery was found in the clarified stream.”
• “Addition of flocculant improved filtration flux by six fold and/or would allow for up to a 4-times higher flow rate if using a decanting centrifuge for clarification of corn stillage.”

(1) Menkhaus TJ, Anderson J, Lane S, Waddell E: Polyelectrolyte flocculation of grain stillage for improved clarification and water recovery within bioethanol production facilities. Bioresour Technol. 2009 Dec 4; (Article in Press)