The relationship between extent of hemoglobin purification and the performance characteristics of a blood‐based flocculant

BACKGROUND Whole blood is a highly complex substance. Hemoglobin, the most abundant blood protein, can function as a flocculant; most of the other blood components exhibit poor flocculant activity. For the purpose of processing raw whole blood into a flocculant product, the practical value of hemoglobin purification is uncertain. RESULTS This study compares the flocculant performance of whole blood to that of three different semi‐purified hemoglobin preparations. The whole blood is processed to remove the plasma proteins, the solid cell components, or both. The flocculant performance of whole blood and each hemoglobin preparation is compared over wide ranges of flocculant dose and suspension pH. The clarified liquids are examined for increases in chemical oxygen demand and Kjeldahl nitrogen. Hemoglobin preparations that excluded plasma gave peak flocculation performance at approximately 30 mg solids per gram of suspended kaolin, and gave greatly reduced performance at higher doses; preparations that included plasma gave very similar peak performance, but also maintained relatively high performance at doses up to at least 200 mg g−1. CONCLUSION It is shown that removal of the plasma and the cell solids does not improve the flocculant performance or lessen the residual pollutants in the treated water. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.