Addition/Correction Cite This: Environ. Sci. Technol. XXXX, XXX, XXX-XXX
pubs.acs.org/est
Correction to Formation of Low-Molecular-Weight Dissolved Organic Nitrogen in Predenitrification Biological Nutrient Removal Systems and Its Impact on Eutrophication in Coastal Waters Heonseop Eom, Douglas Borgatti, Hans W. Paerl, and Chul Park* Environ. Sci. Technol. 2017, 51, 3776−3783. DOI: 10.1021/acs.est.6b06576 and 2014 compared to the average TSS in 2010 and 2011 (3.3 ± 1.5 mg/L) indicates that the increase in effluent TON was attributed mainly to an increase in dissolved organic N (DON).
We discovered errors in the data presentation for Figure 2 in our original paper. These errors took place during the data
Figure 2. Concentrations of TON and DIN in effluents from the Amherst WWTP before and after upgrading to a predenitrification BNR. Error bars represent the standard deviations. The number of effluent samples for N analysis were 24, 62, 172, and 105 in 2010− 2011 (CAS), 2012 (transition), 2013 (BNR), and 2014 (BNR), respectively.
transferring between our analyses. In addition, we realized from the recent meeting with the Amherst Wastewater Treatment plant (WWTP) personnel that this facility changed its process to predenitrification biological nutrient removal (BNR) in September 2012 not in early 2013. Trials for changing the process to decrease N discharge took place during the year of 2012. Hence, the facility’s treatment mode in 2012 was neither conventional activated sludge (CAS) nor BNR. Even after correction of these errors, our original conclusions in the study were not affected and thus remain unchanged. The original paper’s Results and Discussion on Figure 2 (i.e., the changes in effluent N in the Amherst WWTP before and after retrofitting to BNR) should be revised with those shown below. To evaluate the changes in effluent total organic N (TON) before and after the upgrade of the Amherst WWTP to predenitrification BNR, we analyzed the effluent N data for 2010−2011 (CAS), 2012 (trial and transition period), and 2013−2014 (BNR). The average effluent TON concentration during the 2010−2011 CAS period was 1.66 ± 0.96 mg N/L. The effluent TON for the years 2013 and 2014, when the facility was operated in predenitrification BNR, was 2.52 ± 1.40 mg N/L. These results show that effluent TON of the Amherst WWTP increased by 0.86 mg N/L after the upgrade, which is significant increase (p-value
