Effects Of Biochar On Humification Of Pig Manure Composting

The rapid development of large-scale pig farming has produced huge amount of pig manure waste which may cause enormous pressure on the ambient environment. Aerobic composting technology is an effective way to achieve animal manure mineralization and realize harmless and quantity reduction. However, improving composting efficiency with high quality product is still a key issue in traditional composting process.In this thesis, pilot scale experiments were carried out to study3%(w/w) biochar amendment on temperature evolution, nitrogen conservation and humification process. Fourier infrared spectrum (FT-IR), nuclear magnetic resonance (NMR), three-dimensional fluorescence (3D-EEM) and other chemical analysis methods were used to monitor humic substance structure change during large-scale pig manure compost. The main results of this thesis are as following:(1) Through in-vessel pig manure composting, the effects of3%biochar addition on physicochemical property during composting were mainly studied. Results indicated that biochar amendment could accelerate temperature rising, short the composting time, increase dehydration rate and reduce nitrogen loss. Compared to the control, biochar amendment could reduce composting time by6days, increase the last dehydration by9.7%and reduce nitrogen loss by25.1%.(2) The synthesis and decomposition of humic substance simultaneously occurred in pig manure composting followed with the dynamic change of its content. Easily degradable component of humic substance is degraded to form a more stable structure in composting process. During composting, fulvic acid content kept declining in composting; humic acid fist declined then increased through composting while humin content fist increased then remained stable. At the end of the compost, humic substance in biochar amendment treatment showed a significantly higher content than control.(3)3D-EEM,13C-NMR and FT-IR were applied to quantify the changes of chemical composition and structure of the humic substance especially humic acid extracted from samples during the pig manure composting. The EEM contours of EXC from the composting samples of VPSB exhibited a faster increasing in humic substance peaks at Ex/Em of250/400-450nm and350/400-450nm. An increase mainly in the intensity of aromatic C=C and C=O structure occurred at thermophilic phase. Aromaticity in VPSB at the thermophilic phase inferred that3%(w/w) biochar amendment brought about a more intensive humification of pig manure.