Applications of lignite semi-coke on modifying and deep concentrated dewatering of sludge.

In order to solve the current difficulty of sludge dewatering, the sludge was modified by semi-coke which was the pyrolysis product of lignite. The lignite semi-coke's effect on modifying and deep concentrated dewatering of sludge was explored by the method of gravity concentrated dewatering. The results show that the dewatering property, the settling property and the mechanical dewatering property of sludge are improved greatly through adding semi-coke into the sludge. When 2 g semi-coke was added into 100 g sludge, the water content of concentrated sludge is reduced from 91. 13% to 78.05% after modified treatment. What's more, the water content of filter cake is reduced from 65. 00% to 49. 50% by vacuum filtration. In 20 minutes, the average sedimentation rate of sludge is increased from 2. 67 mL/min to 3. 25 mL/min. This study explored the mechanism of semi-coke on the modifying and deep concentrated dewatering of sludge. The mechanism mainly manifest in semi-coke's adsorption on sludge and weakening hy-drophilic properties of sludge. [ABSTRACT FROM AUTHOR]