Nitrification and denitrification in the Community Land Model compared to observations at Hubbard Brook Forest

2022 ◽  
Author(s):  
Cynthia Nevison ◽  
Christine Goodale ◽  
Peter Hess ◽  
William R. Wieder ◽  
Julius Vira ◽  
...  
Keyword(s):  
Hubbard Brook ◽  
Community Land Model ◽  
Nitrification And Denitrification

Process evaluation of HASP with IMET system through SNR and SDNR for the efficient management of Sewage Treatment Plant

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Young H. Yoon ◽  
Jae R. Park ◽  
Sang W. Ahn ◽  
Kwang B. Ko ◽  
Kyung J. Min ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Linear Regression Analysis ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Reaction Rates ◽  
Nitrification Rate ◽  
Activated Sludge Process ◽  
Type Experiment ◽  
Batch Type ◽  
Nitrification And Denitrification

Hybrid Activated Sludge Process (HASP) with IMET was developed and applied to an activated sludge process for the advanced nutrient treatment in Korea. The characteristics of nitrogen removal from the HASP were investigated through a kinetic study by batch-type experiment. Online DB analysis produced from the IMET was conducted for the nutrient removal performance in the field demonstration plant treating 10,000 m3/day in G city of Korea. In this paper, we aimed to determine the effect of increasing NHM4+-N load on the specific nitrification rate (SNR) and the specific denitrification rate (SDNR) through a batch-type experiment, and to estimate the net reaction time for the phase-transfer rate using online DB analysis in the HASP operation. Experimental results include: (1) both the nitrification and denitrification followed first-order kinetics; (2) the maximum SNR and SDNR were 4.0301 mgN/gVSS·hr and 2.785 mgN/gVSS·hr, respectively; (3) comparison of reaction rates between nitrification and denitrification from the non-linear regression analysis found that nitrification rate was higher than denitrification.

Theoretical and practical identifiability of a reduced order model in an activated sludge process doing nitrification and denitrification

1998 ◽  
Vol 37 (12) ◽  
pp. 309-316 ◽  
Author(s):  
S. Julien ◽  
J. P. Babary ◽  
P. Lessard
Keyword(s):  
Activated Sludge ◽  
Reduced Order Model ◽  
Actual Behavior ◽  
Activated Sludge Process ◽  
Order Model ◽  
Identifiability Analysis ◽  
Reduced Order ◽  
3 Dimensional ◽  
Nitrification And Denitrification ◽  
Line Oxygen

This paper deals with the structural identifiability and the identification of the parameters of a reduced order model used for control of a single reactor activated sludge process doing nitrification and denitrification. This reduced order model is splitted into two submodels, one 3-dimensional state submodel in aerobic conditions and one 2-dimensional state submodel in anoxic conditions. The identifiability analysis is based on on-line oxygen and nitrate concentrations data. It has been shown that the reduced order model is structurally identifiable. The parameter identification has been carried out by using the simplex method of Nelder and Mead. Simulation results performed over a range of six hours (two aerobic/anoxic cycles), show that there exists a good fit between the simulated solution and the actual behavior of a lab scale pilot plant.

scholarly journals Quantifying the Responses of Evapotranspiration and Its Components to Vegetation Restoration and Climate Change on the Loess Plateau of China

2021 ◽  
Vol 13 (12) ◽  
pp. 2358
Author(s):  
Linjing Qiu ◽  
Yiping Wu ◽  
Zhaoyang Shi ◽  
Yuting Chen ◽  
Fubo Zhao
Keyword(s):  
Climate Change ◽  
Loess Plateau ◽  
Dominant Role ◽  
Vegetation Restoration ◽  
Vegetation Coverage ◽  
Ecological Planning ◽  
The Loess Plateau ◽  
Canopy Interception ◽  
Community Land Model ◽  
Spatiotemporal Trends

Quantitatively identifying the influences of vegetation restoration (VR) on water resources is crucial to ecological planning. Although vegetation coverage has improved on the Loess Plateau (LP) of China since the implementation of VR policy, the way vegetation dynamics influences regional evapotranspiration (ET) remains controversial. In this study, we first investigate long-term spatiotemporal trends of total ET (TET) components, including ground evaporation (GE) and canopy ET (CET, sum of canopy interception and canopy transpiration) based on the GLEAM-ET dataset. The ET changes are attributed to VR on the LP from 2000 to 2015 and these results are quantitatively evaluated here using the Community Land Model (CLM). Finally, the relative contributions of VR and climate change to ET are identified by combining climate scenarios and VR scenarios. The results show that the positive effect of VR on CET is offset by the negative effect of VR on GE, which results in a weak variation in TET at an annual scale and an increased TET is only shown in summer. Regardless of the representative concentration pathway (RCP4.5 or RCP8.5), differences resulted from the responses of TET to different vegetation conditions ranging from −3.7 to −1.2 mm, while climate change from RCP4.5 to RCP8.5 caused an increase in TET ranging from 0.1 to 65.3 mm. These findings imply that climate change might play a dominant role in ET variability on the LP, and this work emphasizes the importance of comprehensively considering the interactions among climate factors to assess the relative contributions of VR and climate change to ET.

Study on nitrified liquor recycling process operations using polyurethane foam sponge cubes as a biomass support medium

1994 ◽  
Vol 30 (6) ◽  
pp. 143-149 ◽  
Author(s):  
H. Deguchi ◽  
M. Kashiwaya
Keyword(s):  
Experimental Study ◽  
Polyurethane Foam ◽  
Type A ◽  
Denitrification Rate ◽  
Rate Coefficients ◽  
Type B ◽  
Recycling Process ◽  
Support Medium ◽  
Suspended Growth ◽  
Nitrification And Denitrification

An experimental study was carried out to find a way of using sponge cubes as a biomass support medium to reaction tanks for nitrified liquor recycling process. Type-A, in which biomass fixed cubes are contacted with both anoxic and oxic stages and Type-B, where biomass fixed cubes are contacted with either anoxic or oxic stages, were selected as experimental cases. The results showed that the amount of CO2-C generated which was related to sludge production for Type-B exceeded the amount for Type-A by between 12 to 21%. The nitrification and denitrification rate coefficients at 20°C in Type-A were 1.5 and 1.6 times respectively higher than the coefficients for suspended growth. The rate coefficients in Type-B were 1.5 and 2.0 times respectively higher than the coefficients for Type-A.

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