底物和中间产物对餐厨垃圾厌氧消化污泥表面张力、黏度和发泡潜能的影响

餐厨垃圾厌氧消化(Anaerobic digestion,AD)系统中含有大量具有表面活性的物质,这些物质的存在会改变厌氧消化污泥的表面张力及发泡潜能,甚至诱发严重的泡沫现象.了解这些物质对污泥表面性质和发泡潜能的影响,对预防厌氧消化系统泡沫的产生和过程恢复具有重要意义.因此,本文以餐厨垃圾中温厌氧消化污泥为研究对象,分别考察不同浓度的底物和中间代谢产物的单组分及其组合对污泥表面张力、黏度、发泡趋势(Foam tendency,FT)和泡沫稳定性(Foam stability,FS)的影响.结果表明,污泥的表面张力、黏度与污泥的发泡趋势、泡沫稳定性之间并没有一致的相关性,确定污泥发泡潜能的最佳方法是测定污泥的发泡趋势和泡沫稳定性.在餐厨垃圾厌氧消化反应体系中,油酸和明胶可以大幅提高污泥的发泡趋势和泡沫稳定性,因此,认为这两种物质的存在是潜在的主要泡沫诱发因子.玉米油的存在能够降低污泥的表面张力和发泡趋势,可能对系统产生的泡沫具有抑制作用.乙酸、淀粉、蛋白胨也能提高污泥发泡趋势,但却不能强化污泥的泡沫稳定性.研究结论可以为实际工程提供理论支撑,并为餐厨垃圾厌氧消化遇到泡沫问题提供解决思路.

Effect of substrates and intermediate compounds on surface tension, viscosity and foaming potential of anaerobic digestion sludge

An anaerobic digestion system for treating food waste contains a large amount of compounds with surface activity. The presence of those substances can decrease the surface tension and increase the foaming potential, even resulting in serious foaming. Therefore, understanding the effects of those substances on surface properties and foaming potential of the system is of great significance in foaming prevention and process recovery. This paper studied the sludge of a mesophilic anaerobic digestion system. The effects of different concentrations of substrate and intermediate compounds of one-component and their mixtures on sludge properties, such as surface tension and viscosity, were investigated and compared with the effects on foaming tendency and foam stability. The results showed that there was no consistent correlation between foaming potential and surface tension or the viscosity of the tested sludge. A preferred way to determine the foaming property was to directly measure foaming tendency and foam stability. During the digestion process, oleic acid and gelatin showed the highest foaming tendency and stability, which could be considered as the main potential foaming problem. The corn oil can not only decrease the surface tension, but also reduce the foaming tendency of the sludge. Thus, it might have an inhibited effect on the foam generation. Acetic acid, starch and peptone can also intensify foaming tendency. However, they could not induce stable foams. Those results can be applied to practical application and provide a theoretical support for handling the foaming problems of anaerobic digestion system when treating food waste.