A renewable flocculant from a poultry slaughterhouse waste and preliminary estimate of production costs

Authors: Piazza, George; Garcia, Rafael; McAloon, Andrew

Submitted to: Resources Conservation and Recycling
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2011
Publication Date: 7/1/2011
Citation: Piazza, G.J., Garcia, R.A., Mcaloon, A.J. 2011. A renewable flocculant from a poultry slaughterhouse waste and preliminary estimate of production costs. Resources Conservation and Recycling. 55:842-848.

Interpretive Summary: Flocculants are used in a wide variety of industrial processes such as wastewater clarification, paper manufacture, concentration during chemical operations, and dewatering in mineral operations. They are also used as aids in filtration and centrifugation and also applied directly to soil to prevent erosion in agricultural and construction areas. The most widely used polymeric flocculant is anionic polyacrylamide which is manufactured from chemicals that are made from natural gas. The purpose of this research was to determine if biodegradable fractions prepared from chicken blood have potential nonfood use as renewable flocculants. Heat treated and centrifuged fractions of chicken blood and their freeze dried and spray dried counterparts were prepared and tested as clay flocculants. It was found that some of the fractions were flocculants at low concentration when the media was slightly acidified. This research will benefit chicken abattoir operators by providing a market for chicken blood which is currently treated as a waste product.

Technical Abstract: Chicken blood (CKB) is a waste product of large processing plants. CKB fractions (frozen and dehydrated) were tested as renewable flocculants, and their actions were compared to that of anionic polyacrylamide, a commercial, polymeric flocculant made from natural gas. The CKB frozen fractions were (A) blood, freed of coagulated blood; (B) blood plasma, i.e., blood centrifuged to remove blood cells; and (C) heated blood, centrifuged to remove solids. These blood fractions were dehydrated two ways: freeze drying and spray drying at elevated temperature. Flocculation performance (FP) was quantified by determining the weight of flocculant needed to settle a constant amount of suspended clay particles in 1 h or 5 h. Good FP by the blood fractions required the addition of pH 5.5 buffer. At 5 h, never dehydrated CKB fractions A and B exhibited FP that was similar to that given by PAM at typical treatment rates. At 1 h, the FP of CKB fractions A and B was superior to that given by PAM. In addition, CKB fractions A and B functioned well without the addition of calcium chloride, but PAM was not a flocculant without the addition of calcium chloride. The FP of freeze dried CKB fraction B was no different than that of fraction B. The FP of freeze dried CKB fraction A was as good as that given by fraction A at 5 h, and at 1 h with calcium chloride added. The FP of spray dried samples A-s and B-s was worse than that of their frozen counterparts (A and B), and twice the mass of these samples was required. CKB fraction C and its dehydrated counterparts exhibited relatively poor FP.