Preparation and characterization of a novel sludge conditioner by Microbial flocculant (MBF) extracted from waste yeast with nano SiO2 particles

Microbial flocculant (MBF) was extracted from waste yeast and used as a sludge conditioner with nano SiO₂ particles. The effects of the new composite material on sludge dewatering characteristics were investigated. The equivalent concentration of MBF was defined as the mole number of adsorbed Cu²⁺ per volume solution. An equivalent concentration of 712 μmol/L MBF can be extracted under optimal conditions (i.e. pH = 10 and 100 °C water bath for 60 minute). The results showed that MBF (20mL/L) and nano SiO₂ (0.8g/L) conditioner improved settling performance of the sludge by decreasing the ratio of sludge settlement from 0.79 to 0.65, and shortened sludge filtration time by reducing the specific resistance of sludge by 11.57 percent. The effects of different sludge conditioners on filtration constant and compression index in sludge dewatering process were discussed to guide design of industrial process. The drying moisture balance was reduced in sludge conditioned by this conditioner.