| Autor: |
Xu J; Department of Civil, Structural and Environmental Engineering , University at Buffalo, the State University of New York , Buffalo , New York 14260 , United States., Kralles ZT; Department of Civil, Structural and Environmental Engineering , University at Buffalo, the State University of New York , Buffalo , New York 14260 , United States., Dai N; Department of Civil, Structural and Environmental Engineering , University at Buffalo, the State University of New York , Buffalo , New York 14260 , United States. |
| Abstrakt: |
This study examined the effects of sunlight irradiation on the trichloronitromethane formation potential (TCNM-FP) of wastewater effluents and the roles of nitrite and nitrate in this process. Using disinfected secondary effluents from four treatment plants, we observed that sunlight irradiation (320 W/m 2 ) for 8 h attenuated the TCNM-FP by 17-47% for 9 of 14 samples but increased the TCNM-FP for two of the other samples. A longer irradiation time (≤36 h) further reduced the TCNM-FP in a non-nitrified effluent with low nitrite and nitrate concentrations but increased the TCNM-FP in two nitrified effluents by 2-3-fold. When nitrite (0.1-2 mg N/L) was spiked into effluent samples, an increase in the TCNM-FP after irradiation was observed. The higher the nitrite concentration, the greater the increase in the TCNM-FP. In the presence of ∼1 mg N/L of nitrite, sunlight irradiation for 8 h increased the TCNM-FP of four wastewater samples by 0.3-3.6 μg/mg C. In contrast, the spike of nitrate up to 20 mg N/L had no effect. The nitrite-sunlight effect was also observed for four model precursors (humic acid, tryptophan, tyrosine, and phenol). Humic acid and tryptophan featured larger increases in the TCNM-FP compared to those of tyrosine and phenol after sunlight irradiation. |
