Giwa Abdulmoseen Segun, Maurice Ndungutse Jean, Luoyan Ai, Liu Xinxin, Yunlong Yang, Hong Zhao
School of Environment and Civil Engineering, Nanchang Institute of Science and Technology, Nanchang, 330108, China.
Institute of Environmental Science, Shanxi University, Taiyuan, 030006, China.
Heliyon. 2023 Sep 4;9(9):e19765. doi: 10.1016/j.heliyon.2023.e19765. eCollection 2023 Sep.
Sewage sludge (SS) is an environmental issue due to its high organic content and ability to release hazardous substances. Most of the treatments available are biological, thermal hydrolysis, mechanical (ultrasound, high pressure, and lysis), chemical with oxidation (mainly ozonation), and alkali pre-treatments. Other treatment methods include landfill, wet oxidation, composting, drying, stabilization, incineration, pyrolysis, carbonization, liquefaction, gasification, and torrefaction. Some of these SS disposal methods damage the ecosystem and underutilize the potential resource value of SS. These challenges must be overcome with an innovative technique for the improvement of SS's nutritional value, energy content, and usability. This review proposes plasma pyrolysis and anaerobic digestion (AD) as promising SS treatment technologies. Plasma pyrolysis pre-treats SS to make it digestible by AD bacteria and immobilizes the heavy metals. The addition of Char to the upstream AD process increases the quantity and quality of biogas produced while enhancing the nutrients in the digestate. These two processes are integrated at high temperatures, thus creating concerns about their energy demand. These challenges are offset by the generated energy that can run the treatment plant or be sold to the grid, generating additional cash. Plasma pyrolysis wastes can also be converted into biochar, organic fertilizer, or soil conditioner. These combined technologies' financial sustainability depends on the treatment facility's circumstances and location. Plasma pyrolysis and AD can treat SS sustainably and provide nutrients and resources. This paper explains the co-process treatment route's techno-economic prospects, challenges, and recommendations for the future application of SS valorization and resource recovery.
由于污水污泥（SS）有机含量高且具有释放有害物质的能力，它成为了一个环境问题。现有的大多数处理方法包括生物处理、热水解、机械处理（超声、高压和裂解）、化学氧化处理（主要是臭氧化）以及碱预处理。其他处理方法还包括填埋、湿式氧化、堆肥、干燥、稳定化、焚烧、热解、碳化、液化、气化和烘焙。这些SS处置方法中的一些会破坏生态系统，并且未充分利用SS的潜在资源价值。必须通过创新技术来克服这些挑战，以提高SS的营养价值、能量含量和可用性。本综述提出等离子体热解和厌氧消化（AD）作为有前景的SS处理技术。等离子体热解对SS进行预处理，使其可被AD细菌消化，并固定重金属。在上游AD过程中添加炭可以增加沼气的产量和质量，同时提高消化液中的养分。这两个过程在高温下整合，因此引发了对其能源需求的担忧。这些挑战被产生的能量所抵消，这些能量可以运行处理厂或出售给电网，从而产生额外的收入。等离子体热解废物还可以转化为生物炭、有机肥料或土壤改良剂。这些联合技术的财务可持续性取决于处理设施的情况和位置。等离子体热解和AD可以可持续地处理SS，并提供养分和资源。本文解释了共处理路线的技术经济前景、挑战以及对未来SS增值和资源回收应用的建议。
