Search

In order to make a better understanding of the characteristics of N 2 O emission in A/O wastewater treatment plant, full-scale and pilot-scale experiments were carried out and a back propagation artificial neural network model based on the experimental data was constructed to make a precise prediction of N 2 O emission. Results showed that, N 2 O flux from different units followed a descending order: aerated grit tank > oxic zone ≫ anoxic zone > final clarifier > primary clarifier, but 99.4% of the total emission of N 2 O (1.60% of N-load) was monitored from the oxic zone due to its big surface area. A proper DO control could reduce N 2 O emission down to 0.21% of N-load in A/O process, and a two-hidden-layers back propagation model with an optimized structure of 4:3:9:1 could achieve a good simulation of N 2 O emission, which provided a new method for the prediction of N 2 O emission during wastewater treatment. [ABSTRACT FROM AUTHOR]

In order to investigate the heterotrophic nitrification and aerobic denitrification ability of Acinetobacter harbinensis HITLi7 T at 2 °C, both the growth parameters and substrates utilization characteristics were tested and appropriated kinetic models were obtained in this study. Under the initial concentration of 5 mg/L, the maximum NH 4 + -N and NO 3 - -N degradation rates were 0.076 mg NH 4 + -N/L/h and 0.029 mg NO 3 - -N/L/h, respectively. At the simultaneous presence of 2.5 mg/L NH 4 + -N and NO 3 - -N, the maximum nitrate removal rate increased to 0.054 mg NO 3 - -N/L/h (1.86 folds), while a slight decrease was observed in NH 4 + -N removal. Two double-substrate models, Contois-Contois (1) for NH 4 + -N and TOC, Monod-Contois (2) for NO 3 - -N and TOC matched well with the experimental data. The kinetic parameters were determined as μ max1  = 0.095 h -1 , B A1  = 0.012 mg/L, B T1  = 0.784 g TOC/g biomass (R 1 2  = 0.9997), and μ max2  = 0.032 h -1 , K N2  = 0.375 mg/L, B T2  = 1.108 g TOC/g biomass (R 2 2  = 0.9731) by multiple regression equation., (Copyright © 2018 Elsevier Ltd. All rights reserved.)