Center for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
Center for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia; School of Civil Engineering, Central South University, Changsha, Hunan Province, 410075, China.
J Environ Manage. 2022 Mar 15;306:114463. doi: 10.1016/j.jenvman.2022.114463. Epub 2022 Jan 7.
Water treatment sludge was successfully thermally converted to obtain biochar as a stable material with resource potential. This research explored the application of sludge biochar as a supplementary cementitious material. The cement paste samples incorporating different amounts of sludge biochar were prepared, hardened, and analyzed for performance. The results show an improvement in hydration kinetics and mechanical properties of cement paste incorporating biochar, compared to raw sewage sludge. The mineralogical, thermal and microscopic analyses show evidence of pozzolanic activity of the biochar. The samples with 2% and 5% biochar showed higher heat release than the reference material. Specimens with 1%, 2% and 5% biochar showed a slightly higher compressive strength at 28 days compared to the reference material. Sludge conversion to biochar will incur an estimated cost of US$398.23/ton, which is likely to be offset by the substantial benefits from avoiding landfill and saving valuable cementitious materials. Therefore, this research has demonstrated that through conversion to biochar, water treatment sludge can be promoted as a sustainable and alternative cementitious material for cement with minimum environmental impacts, hence contributing to circular economy.
污水处理厂污泥经过热转化成功制备出具有资源潜力的稳定生物炭。本研究探索了将污泥生物炭作为辅助胶凝材料的应用。制备了掺入不同量污泥生物炭的水泥浆样品，并对其性能进行了分析。结果表明，与原生污水污泥相比，掺入生物炭的水泥浆的水化动力学和力学性能得到了改善。矿物学、热分析和微观分析表明生物炭具有火山灰活性。掺有 2%和 5%生物炭的样品的放热量高于基准材料。掺有 1%、2%和 5%生物炭的样品在 28 天时的抗压强度略高于基准材料。将污泥转化为生物炭的估计成本为 398.23 美元/吨，这很可能会被避免填埋和节省宝贵的胶凝材料带来的巨大好处所抵消。因此，本研究表明，通过转化为生物炭，污水处理厂污泥可以作为一种可持续的替代胶凝材料，用于水泥生产，对环境的影响最小，从而有助于循环经济的发展。
