Sludge granulation in PN/A enhances nitrogen removal from mainstream anaerobically pretreated wastewater.

Treating anaerobically pretreated wastewater using partial nitritation/anammox (PN/A) process faces severe challenges because of the complex syntrophic and competitive relationship among various bacteria. Results of this study suggested a continuous low dissolved oxygen (DO) concentration failed to sustain NH removal (<80 %), whereas moderate DO concentrations with high aerobic periods suppressed anammox reaction. Through implementing a moderate DO concentration with low aerobic periods (MDO-LA), NH and total nitrogen removal efficiency reached 91.

[Evaluation of floc strength based on morphological analysis and optical online monitoring].

Based on morphological analysis and PDA online monitoring, a method was established for the evaluation of floc strength. In order to calculate the binding force of flocs formed under a given flocculation condition, a jar test was conducted. The morphological characteristics of flocs were studied by image analysis and the particle image velocimetry technology.