High aeration rate enhances flow stratification in full-scale oxidation ditch

2009 ◽  
Vol 33 (2) ◽  
pp. 293-298 ◽  
Author(s):  
Vasileios Diamantis ◽  
Ioannis Papaspyrou ◽  
Parasxos Melidis ◽  
Alexander Aivasidis
Keyword(s):  
Aeration Rate ◽  
Full Scale ◽  
Oxidation Ditch

scholarly journals Study on Sludge and Dissolved Oxygen Distribution in a Full-Scale A2/O Oxidation Ditch

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2776
Author(s):  
Chengyi Li ◽  
Zhao Han ◽  
Yuquan Zhang ◽  
Yuan Zheng ◽  
Hepeng Zhang ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Flow Model ◽  
Rotation Speed ◽  
Full Scale ◽  
Oxidation Ditch ◽  
Bed Height ◽  
Consumption Rates ◽  
The Relationship ◽  
Oxygenation Rate ◽  
Biological Selection

The distribution of velocity, sludge, and dissolved oxygen in a full-scale anaerobic-anoxic-oxic (A2/O) oxidation ditch was numerically simulated under three rotation speed scenarios. The viscosity and settling rate of activated sludge were defined through a user-defined function (UDF), and the sludge phase was calculated using the mixture multiphase flow model. Dissolved oxygen (DO) was set as a user-defined source (UDS) and its generation and consumption rates were defined with UDFs. The relationship between velocity and sludge concentration was found to be contradictory, with dead zones leading to large sludge concentrations at the bottom of the oxidation ditch (OD), but not at the middle-curved wall of the anoxic pool. The flow rate of the reflux slot and aerator oxygenation rate were checked and correlated with DO concentrations in the anaerobic pool. The majority of the large sludge concentrations were concentrated in the biological selection pool and these remained constant with bed height. With reduced propeller and agitator rotation speed, the sludge concentrations reduced in the biological selection pool, but increased in the anaerobic and anoxic pools.

Simulation of liquid-gas flow in full-scale Caroussel oxidation ditch with surface aeration

2012 ◽  
Vol 19 (6) ◽  
pp. 1615-1621 ◽  
Author(s):  
Zhen-liang Li ◽  
Li-sha Guo ◽  
Dai-jun Zhang ◽  
Dan-yu Xu
Keyword(s):  
Gas Flow ◽  
Full Scale ◽  
Oxidation Ditch ◽  
Surface Aeration

scholarly journals Improve the performance of full-scale continuous treatment of municipal wastewater by combining a numerical model and online sensors

2018 ◽  
Vol 78 (8) ◽  
pp. 1658-1667 ◽  
Author(s):  
Qiuwen Chen ◽  
Qibin Wang ◽  
Hanlu Yan ◽  
Cheng Chen ◽  
Jinfeng Ma ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Numerical Model ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Operation Mode ◽  
Oxygen Demand ◽  
Aeration Rate ◽  
Full Scale ◽  
Continuous Treatment ◽  
Online Sensors

Abstract Mathematical models based on instant environmental inputs are increasingly applied to optimize the operation of wastewater treatment plants (WWTPs) for improving treatment efficiency. This study established a numerical model consisting of the activated sludge module ASM3 and EAWAG bio-P module, and calibrated the model using data from a full-scale experiment conducted in a WWTP in Nanjing, China. The calibrated model was combined with online sensors for water temperature, chemical oxygen demand, -N and -P to optimize and dynamically adjust the operation of the WWTP. The results showed that, compared to the original default operation mode, the effluent water quality was significantly improved after optimization even without supplementation of external carbon or alkalinity, and the required aeration rate in spring, summer, autumn, and winter was reduced by 15, 41, 33 and 11%, respectively. The study indicated that there was the potential for application of closed-loop automatic control to regulate operating parameters to improve wastewater treatment processes through the integration of data on influent characteristics and environmental conditions from sensors, and results from simulation models.

Modelling of wastewater treatment plants – how far shall we go with sophisticated modelling tools?

2006 ◽  
Vol 53 (3) ◽  
pp. 79-89 ◽  
Author(s):  
G.C. Glover ◽  
C. Printemps ◽  
K. Essemiani ◽  
J. Meinhold
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Full Scale ◽  
Structure Identification ◽  
Oxidation Ditch ◽  
Computational Fluid Dynamics Analysis

Several levels of complexity are available for modelling of wastewater treatment plants. Modelling local effects rely on computational fluid dynamics (CFD) approaches whereas activated sludge models (ASM) represent the global methodology. By applying both modelling approaches to pilot plant and full scale systems, this paper evaluates the value of each method and especially their potential combination. Model structure identification for ASM is discussed based on a full-scale closed loop oxidation ditch modelling. It is illustrated how and for what circumstances information obtained via CFD (computational fluid dynamics) analysis, residence time distribution (RTD) and other experimental means can be used. Furthermore, CFD analysis of the multiphase flow mechanisms is employed to obtain a correct description of the oxygenation capacity of the system studied, including an easy implementation of this information in the classical ASM modelling (e.g. oxygen transfer). The combination of CFD and activated sludge modelling of wastewater treatment processes is applied to three reactor configurations, a perfectly mixed reactor, a pilot scale activated sludge basin (ASB) and a real scale ASB. The application of the biological models to the CFD model is validated against experimentation for the pilot scale ASB and against a classical global ASM model response. A first step in the evaluation of the potential of the combined CFD-ASM model is performed using a full scale oxidation ditch system as testing scenario.

Bacterial Community Shift during the Startup of a Full-Scale Oxidation Ditch Treating Sewage

2017 ◽  
Vol 27 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Yajun Chen ◽  
Lin Ye ◽  
Fuzheng Zhao ◽  
Lin Xiao ◽  
Shupei Cheng ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Full Scale ◽  
Oxidation Ditch ◽  
Community Shift
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