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| Effects of pharmaceuticals on the removal of NDMA and NDMA total precursors in an anaerobic/ anoxic/ oxic system |
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Abstract Chlorpheniramine and ranitidine were added to an anaerobic/anoxic/oxic (A/A/O) nutrient removal system, and the influences of these two pharmaceuticals with dimethylamine group on the removal of N-nitrosodimethylamine (NDMA) and NDMA total precursors were investigated. The results show that the removals of chlorpheniramine and ranitidine in the A/A/O system were low (32% and 58%, respectively), and they were mainly removed by anaerobic processes. Total nitrogen removal efficiency decreased from 58% to 24% due to chlorpheniramine addition, and concentration of ammonia in the effluent increased obviously. Ranitidine addition caused obvious inhibition of NDMA removal, resulting in its decrease from 90% to 66%. However, the removal of NDMA had no necessary correlation with the removal of total nitrogen in A/A/O system. Due to their high NDMA formation potentials, addition of chlorpheniramine and ranitidine resulted in a significant increase in the concentration of NDMA total precursors; correspondingly, removal efficiencies of NDMA total precursor declined obviously (from 70% to 31%~33%).
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Received: 30 September 2014
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