Enhancement of fermentative volatile fatty acids production from waste activated sludge by combining sodium dodecylbenzene sulfonate and low-thermal pretreatment

This study investigated the combination of low-thermal and sodium dodecylbenzene sulfonate (SDBS) as a pretreatment method to improve the volatile fatty acids (VFA) production from waste activated sludge (WAS). The results showed that the maximum VFA yield of 320 +/- 7.7 mg COD/g VS was obtained in the combined pretreatment (0.01 g SDBS/g TS + 70 degrees C for 60 min), which was 1.8, 1.7 and 4.0 times of that from sole low-thermal, sole SDBS and the control test. The mechanism study revealed the combined pretreatment had synergetic effect on enhancement of disintegration of WAS. Moreover, low-thermal exhibited greater performance on releasing organic matters, and SDBS accelerated hydrolysis and acidogenesis, thus contributing to the enhancement of VFA production in the combined pretreatment. The microbial community analysis demonstrated that the combined pretreatment increased the abundance of phyla Firmicutes which might be responsible for the improvement of VFA production.