For the remarkable advantages,such as safety to human health,biodegradability and cheapness on producing,the study of microbial flocculants (MBFs) has attracted wide attentions in water treatment research,and MBFs are widely used in wastewater treatment,such as food and industry wastewater processing.The concept of the compound bioflocculant (CBF) was first proposed by Ma Fang etc in 2003.CBF was widely studied with its criteria as high efficiency,safety and non-toxicity.