STUDY OF N-NITROSODIMETHYLAMINE (NDMA) FORMATION POTENTIAL AND ITS REMOVAL IN TREATED EFFLUENT BY UV/H2O2 PROCESS

Abstract

NDMA formation from treated wastewater is one of the concerns in water reuse. This study focused on NDMA formation potential (NDMAFP) in wastewater treated effluent and NDMAFP removal by UV/H2O2 technology. NDMAFP was measured and NDMA organic precursors were characterized. UV/H2O2 system was tested on the removal effect on both organic precursors and NDMAFP. Activated sludge process (ASP) effluent and membrane bio-reactor (MBR) effluent were tested. Results showed similar NDMA formation kinetics between two effluents. Weak correlation (R2 = 0.45) was observed between dissolved organic nitrogen (DON) in molecules with small molecular weight and NDMAFP. Experiment on UV/H2O2 system showed efficient dissolved organic carbon (DOC) removal (70%). DON removal was less efficient (30%). 80% of NDMAFP in ASP effluent was removed within one hour. However, no NDMAFP removal was discovered in MBR effluent. This indicated that UV/H2O2 system on NDMAFP removal was water specific.