Effects of aging and transformation of anatase and rutile TiO2 nanoparticles on biological phosphorus removal in sequencing batch reactors and related toxic mechanisms

List of abbreviations: 

CER, cation exchange resin; CLSM, confocal laser scanning microscopy; COD, 

chemical  oxygen  demand;  EDS,  energy-dispersive  X-ray  spectrometer;  EPS, 

extracellular  polymeric  substances;  GAOs,  glycogen-accumulating  organisms; 

HRTEM,  high-resolution  transmission  electron  microscopy;  LDH,  lactate 

dehydrogenase; NPs, nanoparticles; PAOs, phosphate-accumulating organisms; PCA, 

perchloric  acid;  PHAs,  poly-β-hydoxyalkanoates;  PPK,  poly-P  kinase;  PPX, 

exopolyphosphatase;  SAED,  selected  area  electron  diffraction;  SBR,  sequencing 

batch reactor; SOP, soluble orthophosphate; TEM, transmission electron microscopy; 

TiO

2

-A,  anatase;  TiO

2

-R,  rutile;  VFAs,  volatile  fatty  acids  (VFAs);  WWTPs, 

wastewater treatment plants