Study on the characteristics of dissolution and acid production in waste activated sludge: Focusing on the pretreatment of thermal-alkali with rhamnolipid

Abstract

This paper studied the effect of thermal-alkali with rhamnolipid coupling pretreatment waste activated sludge (WAS) on the dissolution and acid production of organic matter. The results showed that when the dosage of rhamnolipid (RL) was 40 mg/g vs, the dissolution rate of soluble Chemical oxygen demand (SCOD) and soluble carbohydrate (SC) was the highest, and the concentration of soluble protein (SP), biopolymer and neutral low molecular substances was the highest. Three-dimensional fluorescence parallel factor analysis found that the addition of rhamnolipid promoted the formation of fulvic acids. When the dosage of rhamnolipid was 60 mg/g vs, the highest peak concentration of volatile fatty acids (VFAs) reached 3.5 days. The type of fermentation acid was butyric acid. The higher cracking rate and higher acid production rate showed that thermal-alkali with rhamnolipid had better acid production performance than thermal-alkali pretreatment sludge, but the amount of rhamnolipid affected the fermentation type.