Research on Drying Sludge in Brick Making
Dried sludge could be used for brick production by firing with shale or clay, which would reduce clay resource exploitation and realize sludge resource utilization. Physical and mechanics parameters of fired shale-sludge brick and clay-sludge brick are tested to examine technical feasibility, and heavy metal leaching concentrations are tested to examine brick safety. The results show that after municipal sludge in Changsha Wastewater Treatment Plant is dried with water content no more than 30%, it can be used for shale-sludge brick and clay-sludge brick firing and qualified produces can be produced. Compressive strength of brick is 10-20 MPa, there is no scum and lime crack on brick body. Under high firing temperature, heavy metal in sludge can be solidified, and leaching concentrations can meet the requirements. By doing so, calorific power of sludge can be utilized and energy saving can be realized.