A "continuously flowing fixed bed" process is reported as the "first economical way to produce biodiesel from algae oil". According to Ben Wen, vice president of United Environment and Energy LLC (New York, United States), the process costs much less than the conventional because running times are faster (smaller plants are possible), there are no water disposal costs, and a purification step is made unnecessary. The use of a solid catalyst provides the key advantage for the process. In conventional biodiesel production, the biodiesel-yielding reaction between the oil and the alcohol uses a liquid catalyst (usually an alkali solution). A purification step is necessary to separate the liquid catalyst from the biodiesel product. In the new process, the reactants are just run through a fixed column of solid catalysts. Conversion of the reactants into biodiesel proceeds as the liquid stream passes through the column. Hence, the final product can be collected at the end of the column without any purification step to separate the catalyst from the product. A pilot program for the process with a production capacity of nearly 1 million gallons of algae biodiesel per year is being conducted..