A review of high-solid anaerobic digestion (HSAD): From transport phenomena to process design

Mass Transfer Enhancement in High-Solids Anaerobic Digestion of Organic Fraction of Municipal Solid Wastes: A Review

“…Continuous monitoring and appropriate measures are necessary to manage toxic compounds such as ammonia, sulfides, heavy metals, and antibiotics that inhibit microbial activity and lead to process failure [ 4 ]. In addition, temperature is a crucial factor in AD, and it can be classified into three primary ranges: psychrophilic (10–30 °C), mesophilic (35–40 °C), and thermophilic (55–60 °C) [ 1 ]. The metabolic activity of microorganisms is temperature-dependent, with higher temperatures generally resulting in faster digestion.…”

“…The design choice, implementation scale, and operation modes in digesters have a significant impact on the spatiotemporal hydrodynamics, biokinetics, as well as heat and mass transfer [ 1 ]. In the field of HS-AD, various reactor configurations have been developed to accommodate different operational requirements.…”

“…The BEKON system in Germany, Biocel system in Netherlands, and BIOFerm system (single-stage, mesophilic) were shown to be able to treat wastes with a feed TS of 25% to 35% at HRT = 28 days, but the process stability (incomplete mixing and accumulation of VFAs) of the batch-mode digesters remained [ 39 ]. More in-depth information can be found in previous studies [ 1 , 30 , 40 ].…”

“…The formation of dense microflora restricts the diffusion of substrates and hinders the penetration of nutrients and gases into the core of these aggregates. Similarly, the diffusion of gases, such as CO 2 and hydrogen, in HS-AD could be restricted, leading to gas accumulation in specific areas and hampering their utilization by microorganisms [ 1 ].…”

“…With the exponential population growth, economic development, and rapid urbanization, the increased generation of municipal solid wastes has become a pressing concern for waste management [ 1 ]. The inherent complexity and heterogeneity of organic solid wastes demand the fine-tuning of process design for optimal waste utilization and the minimization of environmental impact.…”