剩余污泥中无机组分对其厌氧消化的影响机制研究

Anaerobic sludge digestion has been widely regarded as an main technology for recycling sludge resources, as it has the characteristics of recycling biomass energy, reducing the amount of sludge and stabilizing the sludge. However, the low efficiency of anaerobic sludge digestion has become the bottleneck in the application. It thus is imminent to recognize and break through the bottleneck. According to the previous studies and the result of engineering practice, there was a negative correlation between the inorganic substances in sludge (IS / total solid (TS)) and the biodegradability rate of sludge organic matter, indicating that a significant effect which caused by the inorganic substances of sludge was found in the anaerobic bioconversion of sludge organic matter. The main objective of this study was to explore the key scientific problem that the interactions between the organic and inorganic in sludge affect the anaerobic bioconversion of the sludge organic matter. Specifically, from the standpoint of material structure, the key inorganic components that can influence the efficiency of anaerobic sludge digestion are firstly identified. The effects of key inorganic components in sludge on the occurrence of the key sludge organic substances are explored, and the anaerobic digestion performances of different occurrences of the sludge organic substances are then evaluated by biochemical methane potential assays, which also can reveal the influence mechanism of the occurrences of the sludge organic substances. Finally, the influence model that the key inorganic components affect the performances of anaerobic sludge digestion is proposed. These findings, however, will lay the foundations for controlling the bioconversion of sludge organic matter and improve the theoretical system of anaerobic sludge digestion, which also can provide a scientific basis for the improvement of anaerobic digestion efficiency and the maximum recovery of biomass energy.

污泥厌氧消化具有回收生物质能源、减少污泥量、实现污泥稳定等特点，是现代污泥资源化利用的主流技术。然而，污泥有机质转化效率低是限制污泥厌氧消化技术推广应用的瓶颈问题。前期研究及工程实践表明，污泥中无机物质占污泥总固（IS/TS）的比值与污泥有机质厌氧降解效率呈负相关，污泥复杂系统中无机物的存在对污泥有机质厌氧转化具有较大的影响。本项目旨在围绕污泥中无机组分和有机物转化间相互作用及机制的关键科学问题，从物质结构角度明确剩余污泥中影响污泥有机质转化的关键无机组分，探索污泥中关键无机组分对关键有机质赋存形态的影响，并进行不同赋存形态的污泥有机质的厌氧消化性能评估，从而深入揭示赋存形态对污泥颗粒厌氧消化性能的影响，最终构建无机组分影响污泥厌氧消化的机制模型，为污泥中有机物的定向转化调控奠定基础；完善污泥厌氧消化理论体系，为污泥厌氧消化的效率提升和生物质能的最大化回收提供理论支撑。

污泥厌氧消化具有能量回收高、环境影响低等特点，被认为是现代污水处理厂的资源回收利用的重要组成部分。污泥有机质转化效率低是限制污泥厌氧消化技术的推广应用的瓶颈问题之一。本项目围绕污泥中无机组分和有机质间存在相互作用这一客观事实，从物质结构角度识别了剩余污泥中影响污泥有机质厌氧生物转化的关键无机组分和有机质分别是微米级无机砂粒、多价态金属和胞外有机质；探究了污泥中关键无机组分对关键有机质赋存形态的影响，发现了微米级无机砂粒和多价态金属在污泥中的含量越高，胞外有机质的空间构象越紧密，结构稳定性越高；揭示了不同赋存形态的污泥有机质对污泥厌氧消化性能的影响机制，发现了微米级无机砂粒主要是通过吸附作用稳定胞外有机质，从而限制胞外有机质的厌氧生物转化性质，而多价态金属主要是通过络合桥连作用稳定胞外有机分子，从而降低胞外有机质的可生物降解性。研究结果为污泥中有机物的定向转化调控奠定了理论基础，为污泥厌氧消化的效率提升和生物质能的最大化回收提供了理论支撑。