城市污泥中有机酸在厌氧消化过程中的稳定性差异

Organic Acid Sources in Shenzhen Municipal Sludge and Their Stability During Anaerobic Digestion

研究了厌氧消化作用对深圳污泥中有机酸的降解作用.消化过程中有机酸的稳定性受分子结构决定：羟基酸＜烯酸＜正烷酸＜芳香酸＜甾酸．具有稠环、苯环和共轭双键结构者稳定性较高，而含有羟基和孤立双键者稳定性较低，且羟基基团越多，结构越不稳定．厌氧消化对能选择降解高碳数羟基酸而选择保存低碳数羟基酸．某些情况下，有机酸的稳定性也可能受生物代谢因素的影响．

The source and distribution of organic acids in Shenzhen municipal sludge and their relative stabilities during anaerobic digestion were investigated. Organic acids of bioorigin from domestic wastewater discharge and from indigenous microbe is found to be the main source responsible for the abundant organic acids present in the original sludge. The stability order of organic aids with different structure during anaerobic digestion is found to be: hydroxy acid < unsaturated acid < saturated acid < aromatic acid < steroid acid, which is roughly parallel to their chemical stability order, indicating that the anaerobic digestion of organic acids is mainly a structure-controlled degradation. Organic acids having aromatic ring, conjugated C = C bond and fused ring within their structure are normally more stable. Short chain hydroxy acids are selectively preserved against their long chain counterparts during anaerobic digestion. Anaerobic digestion may, under some circumstances be influenced by microbial metabolism, particularly the preference of carbon source.