In addition to organic matter, sludge usually contains 20% to 30% of inorganic substances, mainly calcium, silicon, iron and aluminum. Sludge building materials are an effective method for making full use of inorganic substances in sludge.
The research team incorporated 10% to 30% of the sewage sludge into clay bricks and burned it into an ordinary “ecological brick” for construction at 900 °C. This method not only treats the sludge, but also seals the toxic heavy metals in the sludge during the firing process, kills all harmful bacteria, decomposes toxic organic matter, and the brick does not have any odor. Professor Weng Huanxin of Zhejiang University, when presiding over the provincial key project “Study on the development and utilization of sludge resources in wastewater treatment”, based on a large number of experimental studies to obtain various technical parameters, the use of sludge has the characteristics of high calorific value and light texture. Successfully developed a lightweight brick. The main index of this kind of lightweight brick reaches the national standard of ordinary sintered brick, and has the advantages of high compressive strength, energy saving of 10%, light weight of ordinary bricks of the same volume, and saving 10% to 15% of clay resources. . Therefore, the use of sludge for burning bricks not only achieves waste utilization, but also relieves the pressure of sludge treatment, opening up a new path for the comprehensive utilization of sludge.