Cation exchange resin coupled with bacterial pretreatment to promote waste activated sludge reduction: Performance and mechanism

Abstract

Due to the rapid advancement of industrialization and urbanization, there has been a significant rise in the generation of industrial wastewater and domestic wastewater, which results in the rapid increase of waste activated sludge (WAS). However, the complex structure and slow hydrolysis of sludge limit aerobic digestion of WAS. This study evaluated the effect of lysozyme-secreting strain Proteus mirabilis sp. SJ25 and the new isolation of surfactant-secreting strain Enterobacter cloacae sp. WH11 on the promotion of sludge hydrolysis, and introduced cation exchange resin (CER) to enhance the promotion effect. The reduction efficiencies of suspended solids (SS) and volatile suspended solids (VSS) enhanced by 25.0 and 24.9 %, respectively, and the soluble chemical oxygen demand (SCOD) release was increased by 2370.27 mg/L when the inoculum of strain SJ25 and strain WH11 were 3 % and 6 %, and the dosage of CER was 2.0 g/g SS against the control. The fluorescence region integral (FRI) results showed a significant quantity of dissolved organic matter (DOM) was let out, and the biodegradability of the sludge was improved. The alterations in several physicochemical characteristics of the sludge also suggested that the extracellular polymeric substances (EPS) were disrupted and an enormous quantity of sludge cells were lysed. In addition, functional gene prediction from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database indicated that CER coupled with bacterial pretreatment enhanced microbial metabolic capacity. This work suggests a novel pathway for the development of novel pretreatment methods to promote sludge hydrolysis.