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

Polymeric flocculants are widely used in industrial and municipal applications to remove solids from waste water and to inhibit soil erosion. Currently used polymeric flocculants are prepared from non-renewable materials. Recent research has revealed that some proteins can be excellent flocculants. The purpose of this research was to determine if protein-rich, but low value chicken blood can be used as a renewable flocculant. Fractions of chicken blood (CKB) were assayed for flocculation activity, and the magnitude of the activity exhibited by these fractions was compared to that of anionic polyacrylamide (PAM), the most widely used polymeric flocculant. Activity of the CKB fractions was found to be equivalent to that of PAM at slightly acidic pH values. Since, commercial viability requires retention of activity after dehydration, flocculation trials were conducted with reconstituted samples of freeze and spray dried CKB fractions. Some of the reconstituted samples retained satisfactory flocculation activity. Citric, phosphoric and sulfuric acids were tested to determine if their addition stimulated the flocculation activity of a CKB fraction by slightly decreasing the media pH value. All of the acids were effective, but sulfuric acid is the least costly. A preliminary costs estimate of preparing an active spray dried CKB fraction was completed. The cost of an appropriate amount of sulfuric acid is included in the estimate. The estimate shows that spray dried flocculant prepared from CKB is cost competitive to PAM.

► Kaolin flocculation by chicken blood and blood fractions was demonstrated.
► Flocculant activity was observed under slightly acidic conditions.
► Flocculant activity was reduced 2-fold or more with reconstituted freeze or spray dried blood fractions.
► Analysis showed that flocculation by spray dried chicken blood is cost competitive with flocculation by a synthetic flocculant.