Aerobic composting of animal wastes by using a hyperthermophilc pre-treatment process: patterns and mechanisms

Composting, especially when rapid, is a useful way of transforming organic wastesinto valuable organic amendments for soils. The amounts and chemical structure ofthe humic material constitute are the main indices for assessing the stability andmaturity of the compost. The humic substances play a fundamental role inconditioning soil properties, since they are directly involved in the slow releaseof nutrients, high cation exchange capacity, heavy metals and xenobiotic organicmolecule retention. Rreivious study showed hyperthermophilic (>80℃) pretreatmentof animal wastes for 1 to 2 hours was able to increase composting efficicency andaccelerate the process of composting significangtly, but the regularity andmechanism are not clear. It is hypothesized that hyperthermophilic pretreatmentcould accelerate and enhance the humification process by promoting the productionand transformation of humic precusors and changing the microbial evolution incomposting process. As a result, indoor simulation and compost experiments will becarried out to study the degree of humification during the pretreatment processand the subsequent composting process of pig manure by using advanced analysistechniques including fourier transform infrared spectroscopy (FTIR), 13C nuclearmagnetic resonance (13C-NMR), real-time PCR and MiSeq high throughput sequencing.The reponses of humic precursor, Fe-, Mn-oxides and microbes in the feedstock tothe hyperthermophilic pretreatment will also be investigated. The factorsinfluencing the humification process of pig manure composting by thermophilicpretreatment were explained from the aspects of composition of organic matter andmicrobial evolution. The results obtained will enrich compost theory and providescientific basis for developing low-carbon and high-efficiency compostingtechnology.