TREATMENT OF N-NITROSODIMETHYLAMINE (NDMA) BY PULSED-ULTRAVIOLET (UV) IRRADIATION AND PULSED-UV/HYDROGEN PEROXIDE (H2O2) PROCESSES

摘要

Bench-scale experiments were conducted to determine the effectiveness of pulsed-ultraviolet (UV) irradiation and pulsed-UV/hydrogen peroxide (H_2O_2) processes for the destruction of N-nitrosodimethylamine (NDMA). Pulsed-UV and pulsed-UV/H_2O_2 processes were investigated at various UV doses, H_2O_2 doses, and initial NDMA concentrations. The presence of compounds that interfere with UV light (e.g., nitrate) and the formation of total trihalomethanes (THMs) after pulsed-UV treatment were also studied. Pulsed-UV technology was demonstrated to be highly effective for destroying NDMA, with reductions in the range of 69 to 100 percent, depending on the conditions. The pseudofirst- order rate constants were calculated to be in the range of 1.4 to 12.2 min~(-1). This technology offers other benefits (e.g., disinfection) and can be applied directly to drinking water treatment. However, one of the major concerns in pulsed-UV photolysis of NDMA is the formation of undesirable chemicals as reaction intermediates, as well as the reformation/regeneration of NDMA after chlorination of pulsed-UV treated effluent. Advanced oxidation processes such as pulsed-UV/H_2O_2 could serve as a solution to address these issues.