Effects of rice husk powder and thermal hydrolysis on sludge characteristics

Abstract

To reduce the water content and improve the incineration characteristics of sludge, rice husk and thermal hydrolysis were employed in this study. Effects of rice husk and thermal hydrolysis on the characteristics of the sludge were investigated. The results showed that synergistic thermal hydrolysis with rice husk could effectively destroy sludge particles and release more bound water. For rice husk with a particle size of 50-mesh and an additional amount of rice husk at 1:0.2, the solid content of the sludge was reduced from 17.4 to 16.2%, and the sludge particle size was reduced by 6%. Filtration time and specific resistance to filtrate (SRF) were shortened by 88.9 and 98.7%, respectively. The organic matter content of the filtration cake increased by 14%, compared with the sludge treated by thermal hydrolysis without rice husk. Furthermore, it could be shown that the most optimal conditions were rice husk of particle size 50-mesh and an additional amount of rice husk at 1:0.2, which could lead to effective thermal hydrolysis and higher organic matter content of the filtration cake. HIGHLIGHTS The optimal process of collaborative thermal hydrolysis of rice husk was selected by changing the grain size and the additional amount of rice husk.; Good drainage channels can be formed in the dehydration process of rice husk after the thermal hydrolysis of sludge to improve the efficiency of dehydration.; Rice husk combined with thermal hydrolysis can improve the organic matter content of sludge-dehydrated filter cake.;

Keywords

• rice husk
• sludge characteristics
• sludge dewatering
• thermal hydrolysis