Ultra-high temperature aerobic fermentation pretreatment composting: Parameters optimization, mechanisms and compost quality assessment

Abstract Rapid treatment processing for agricultural waste is of the utmost importance with the boom in China's agriculture sector. Ultra-high temperature aerobic fermentation pre-treatment process assisted composting (HTC) is superior to traditional composting (CCT) with enhanced compost maturity and accelerated organic matter degradation. This research aimed to optimize and investigate the change in the chemical composition of ultra-high aerobic fermentation pre-treatment (UHT-AF) during agricultural waste composting and compare the effects of HTC and CCT on physio-chemical and biological parameters for compost quality assessment. Taguchi analysis based on physio-chemical parameters of pretreated-product provided experiment R5 (75 °C, 15 h, 40 g/kg) as optimal conditions. Comparative results revealed that HTC is superior to CCT with a shortened maturity period of 24 days. HTC showed a very rapid increase in high temperature (96.02 °C on the 3rd day) and a long-lasted thermophile stage (day 1–20 ≥ 60 °C). The C/N ratio reduced from 21.33 to 15.57, moisture content 60.5–35.5%, pH from 7.80 to 8.17, and compost showed GI ≥ 95%. The FTIR analysis of optimal pretreated-product confirmed that the UHF-AF technique could promote lignocellulose degradation and lignin degradation in subsequent composting, and SEM images provided clear morphological evidence of lignocellulose degradation. The study suggested UHT-AF pretreated (HTC) as a promising agricultural waste composting technique for rapid degradation of organic matter and enhanced quality compost production.