Polyelectrolytes have been used in wastewater treatment processes to destabilize colloidal suspensions of proteins, cells and other biological compounds, resulting in flocculation. When a solution containing a single model protein, bovine serum albumin (BSA), is treated with a polyelectrolyte, carboxymethyl cellulose (CMC), large and strong flocs are formed, which are easily retained by a 20 mu m pore size filter. However, when a mixture of proteins, cells, and fats from an actual wastewater sample is treated in the same manner, smaller and weaker flocs are observed. An adsorption and filtration process for the recovery of valuable biological compounds using cellulose-based fibrous materials has been developed. When used simultaneously with CMC, cellulose acetate and triacetate fibrets (CAF and CTF) resulted in high recovery of biomolecules from solution at very low dosages of both polyelectrolyte and fibrets. CMC interacts with biomolecules by electrostatic interactions and polymer bridging, while CTF/CAF facilitate flee growth by adsorption and bridging of primary particles and by entrapment of small aggregates within their highly fibrillated microstructure.