Research of microbial flocculants in dredging sediment dewatering

The high water content and large volume of dredging sediment made it uneasy to transport,storage and reutilize.Thus,the volume reduction was very important in dredging sediment treatment.A high-efficiency microbial flocculant-producing strain F22 was screened and cultured in the lad,the optimal culture conditions were obtained as follow: glucose as carbon source,yeast extract and urea as nitrogen source,culture at 32 ℃ for 60 h.The experiment was carried out to use F22 for rapid dehydrate of dredging sediment.The results shown that,when the water content rate of the dredging sediment was 93%,the volume was 100 mL and pH ranged 8-10,optimum dosage of CaCl2 was 4-5 mL,and the optimum dosage of F22 fermentation liquid was 3 mL.After adding the F22 fermentation liquid in dredging sediment,the floc was sedimentated to the bottom in about one minute.The results indicated that the F22 had perfect dewater capacity;saccharide played an important role in the flocculation process of microbial flocculants;the flocculating mechanism was hydrogen bonding.