Co-composting Of Wine Grape Pomace With Pig Manure For Humification And The Effect Of The Products On Copper And Zinc Passivation

Recycling agricultural waste contributes to the sustainable and healthy development of the ecological environment while promoting the layout,optimization,and scale expansion of agricultural industrialization.As livestock and poultry farming rapidly develop,proper treatment of the waste generated by these industries is crucial.Aerobic composting has received attention as a low-cost,simple,and environmentally friendly method for solid waste treatment.However,conventional composting presents potential risks,such as low product humification and low migration of bioavailable heavy metals(HMs).In this study,pig manure(PM)was composted with varying proportions of polyphenol-rich wine grape pomace(WGP)to investigate the humification process and the morphological changes of Cu and Zn in the composted pig manure product.The research aimed to improve the quality of compost humification products and examine the influence of the morphological transformation and distribution of inherent heavy metals in pig manure on the ecological availability of compost products.The findings are as follows:The addition of WGP promoted the humification process of the compost.WGP enhanced the humic acid(HA)content and humification by effectively prolonging the thermophilic period of the compost and strengthening microbial interactions.Moreover,a40% WGP mixture facilitated carbon and nitrogen fixation and increased the seed germination index by 21.09% compared to the control group.Excitation-Emission Matrix(EEM)combined with Parallel Factor Analysis(PARAFAC)and Self-Organizing Mapping(SOM)revealed that WGP aided the conversion of protein-like material to HA-like material in the compost pile.Furthermore,structural equation modeling identified polyphenol content and temperature as key factors influencing humification products.The polysaccharides and aliphatic functional groups of HA facilitate complexation with Cu and Zn.Additionally,the inclusion of 60% and 40% WGP increased the passivation of Cu and Zn by 47.24% and 25.82%,respectively.The study identified polyphenol conversion and the dominant bacterial genus as the primary factors influencing the passivation of Cu and Zn.In summary,the co-composting of WGP and PM allows for the efficient utilization of phenolic-rich biomass,enhances the composting process of PM,and improves the quality of organic fertilizer products.This approach is of significant importance in enhancing the quality of organic fertilizers and contributes to the reduction of pollution and carbon sequestration in agricultural solid waste.