This document discusses various ways that whey, a byproduct of cheese production, can be utilized. It is commonly used as animal feed but can also be concentrated, dried into powder, or processed into protein concentrates. Further processing can produce refined lactose, ethanol, organic acids, yeast products, biogas, hydrogen, or electricity through microbial fuel cells. The highest value applications involve separation or fermentation processes to extract high value components from whey for use in foods, pharmaceuticals, or energy production.