Wastewater treatment techniques for application in fat recovery from waste ice cream.

Ice cream is a popular dairy food in the United States. Unfortunately, substantial loss of product occurs during production, despite it being of acceptable quality. There are many valuable components in waste ice cream (WIC) that can be utilized if separated. To investigate the potential of wastewater treatment techniques as a means of recovering fat from WIC, a variety of flocculants were tested on 5 ice cream varieties. The flocculation procedure was able to concentrate 89% to 100% of the total fat in 50% to 70% of the original volume. The amount of fat recovered was consistently superior to that recovered from previous centrifugation techniques. Increasing ice cream temperature was effective in reducing the need for flocculant, but was not economical under current cost estimates. Additionally, the remaining aqueous stream was shown to support the growth of Streptococcus thermophilus B59671 and production of its broad-spectrum bacteriocin, thermophilin 110, as well as Saccharomyces cerevisiae Y45, resulting in the production of ∼10% ethanol. This study demonstrates the potential for utilizing flocculation strategies to efficiently concentrate fat from WIC for recovery and generate a defatted stream for use in ethanol and bacteriocin production.