Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/30/2009
Publication Date: 9/5/2009
Citation: Piazza, G.J., Garcia, R.A. 2009. Meat & bone meal extract and gelatin as renewable flocculants. Bioresource Technology. 101:781-787.
Interpretive Summary: Flocculants are used in a wide variety of industrial processes such as wastewater clarification, concentration during chemical operations, and dewatering and thickening in mineral operations. The purpose of this research was to determine if biodegradable agricultural proteins have potential nonfood use as renewable clay flocculants to replace polyacrylamide, a widely used flocculant derived from petroleum. A laboratory test for clay flocculation was developed. This test was validated using a commercial polyacrylamide flocculant. Two commercial soy proteins, a whey fraction, porcine gelatin, and protein in a meat & bone meal extract, were tested for their flocculation activity. It was found that porcine gelatin and protein in a meat & bone meal extract had flocculation activity, while the other proteins had no activity. The results of this research show that some agricultural proteins can potentially replace petroleum-derived flocculants. This research may benefit producers of these proteins by providing new market opportunities and also reduce US dependence on imported petroleum.
Technical Abstract: The purpose of this research was to determine whether proteins have a nonfood use as renewable clay flocculants to potentially replace polyacrylamide (PAM), a flocculant derived from petroleum. A laboratory test for clay sedimentation was developed as a measure of flocculation ability. This test was validated using commercial anionic PAM. When calcium chloride was present, anionic PAM promoted clay sedimentation, but PAM was not effective without calcium chloride. Two soy proteins, a whey fraction, a porcine gelatin, and a meat & bone meal (MBM) extract were used in the sedimentation test. It was found that MBM extract and porcine gelatin promoted clay sedimentation. With the addition of calcium chloride, 88, 99, and 97% of the clay was settled after 24 h in the presence of optimal amounts of PAM, gelatin, and MBM extract, respectively. Without the addition of calcium chloride, gelatin and MBM extract were still effective, and 99 and 97% of the clay was settled after 24 h in the presence of optimal amounts of these proteins, respectively. These figures compare favorably to no flocculant controls, in which approximately 50% of the clay had settled with or without the addition of calcium ion after 24 h.