A review on strategies to optimize metabolic stages of anaerobic digestion of municipal solid wastes towards enhanced resources recovery

Table 3 Summary of organic fraction municipal solid wastes optimizing pretreatment conditions

Strategy	Substrates	AD conditions	Results	Ref.
Mechanical (Bead milling at 1000 rpm)	OFMSW (Food Wastes)	Batch, 37 °C	Particle size reduction from 0.8 to 0.7 mm improved hydrolysis step and increased methane yields by 28% at 1000 rpm	[34]
Thermal pre-treatment (at 65 °C)	OFMSW, sewage, and leachates	Batch, 37 °C	Thermal pre-treatment at 65 °C accelerated hydrolysis stage and increased biogas yields by 7%	[35]
Thermal pre-treatment (Steam explosion)	OFMSW and citrus wastes	Batch, 55 °C	The steam pretreated citrus wastes co-digested with MSW had a higher methane yield of 0.53 m³ kg⁻¹ VS^− 1 which was 426% higher than the corresponding untreated substrates	[36]
Chemical (5 N NaOH and 5 N KOH at pH 13 and temp 80 °C)	OFMSW (kitchen wastes)	Batch, 35 °C, 90 rpm	The pretreatment of OFMSW with 5 N NaOH and 5 N KOH at a retention time of 10 d increased the solubility of OFMSW and enhanced the biogas increase by 18 and 30% respectively as compared with the untreated OFMSW	[37]
Microbial (wood-rotting fungi)	chestnut and hay leaves	Batch, 37–38 °C	The biogas production was enhanced by 15% as compared to the untreated substrates	[38]
Microbial (white-rot fungi at 60 °C) moisture content)	Yard trimmings	Batch, 37 °C	Pre-treatment of yard-trimmings with Ceriporiopsis subvermispora, white-rot fungi at 60% moisture content enhanced methane production by 106%	[39]

ISSN: 2468-2039