Optimal Operation Modes for a Fixed-Bed Bioreactor Used in Wastewater Treatment

1996 ◽  
Vol 29 (1) ◽  
pp. 6832-6837
Author(s):  
C. Benthack ◽  
B. Srinivasan ◽  
D. Bonvin
2016 ◽  
Vol 285 ◽  
pp. 562-572 ◽  
Author(s):  
C. Cortés-Lorenzo ◽  
A. González-Martínez ◽  
H. Smidt ◽  
J. González-López ◽  
B. Rodelas

2015 ◽  
Vol 266 ◽  
pp. 233-240 ◽  
Author(s):  
C. Cortés-Lorenzo ◽  
M. Rodríguez-Díaz ◽  
D. Sipkema ◽  
B. Juárez-Jiménez ◽  
B. Rodelas ◽  
...  

2003 ◽  
Vol 47 (1) ◽  
pp. 113-120 ◽  
Author(s):  
D.S. Chaudhary ◽  
S. Vigneswaran ◽  
V. Jegatheesan ◽  
H.H. Ngo ◽  
H. Moon ◽  
...  

Wastewater treatment has always been a major concern in the developed countries. Over the last few decades, activated carbon adsorption has gained importance as an alternative tertiary wastewater treatment and purification process. In this study, granular activated carbon (GAC) adsorption was evaluated in terms of total organic carbon (TOC) removal from low strength synthetic wastewater. This paper provides details on adsorption experiments conducted on synthetic wastewater to develop suitable adsorption isotherms. Although the inorganics used in the synthetic wastewater solution had an overall unfavourable effect on adsorption of organics, the GAC adsorption system was found to be effective in removing TOC from the wastewater. This study showed that equation of state (EOS) theory was able to fit the adsorption isotherm results more precisely than the most commonly used Freundlich isotherm. Biodegradation of the organics with time was the most crucial and important aspect of the system and it was taken into account in determining the isotherm parameters. Initial organic concentration of the wastewater was the determining factor of the model parameters, and hence the isotherm parameters were determined covering a wide range of initial organic concentrations of the wastewater. As such, the isotherm parameters derived using the EOS theory could predict the batch adsorption and fixed bed adsorption results of the multi-component system successfully. The isotherm parameters showed a significant effect on the determination of the mass transfer coefficients in batch and fixed bed systems.


2004 ◽  
Vol 50 (2) ◽  
pp. 47-53 ◽  
Author(s):  
P. Cornel ◽  
B. Weber

Irrigation periods are usually limited to vegetation periods. The quality requirements for treated wastewater for disposal and for reuse are different. The reuse of water for irrigation allows partly the reuse of the wastewater's nutrients (N and P). Outside the irrigation period the water must be treated for disposal, thus nutrient removal is often required in order to avoid detrimental effects on the receiving surface water body. Only wastewater treatment plants with different operation modes for different seasons can realise these requirements. The nitrification is the most sensitive biological process in the aerobic wastewater treatment process. At low water temperatures the nitrifying bacteria need several weeks to re-start full nitrification after periods without NH4-removal. Therefore it is necessary to develop options for waste water treatment plants which allow a fast re-start of the nitrification process. Based on theoretical considerations and computer simulations of the activated sludge treatment process, one possibility for implementing a wastewater treatment plant with different seasonal operation modes is evaluated.


Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 673 ◽  
Author(s):  
Juan Rueda Márquez ◽  
Irina Levchuk ◽  
Mika Sillanpää

Catalytic wet peroxide oxidation (CWPO) is emerging as an advanced oxidation process (AOP) of significant promise, which is mainly due to its efficiency for the decomposition of recalcitrant organic compounds in industrial and urban wastewaters and relatively low operating costs. In current study, we have systemised and critically discussed the feasibility of CWPO for industrial and urban wastewater treatment. More specifically, types of catalysts the effect of pH, temperature, and hydrogen peroxide concentrations on the efficiency of CWPO were taken into consideration. The operating and maintenance costs of CWPO applied to wastewater treatment and toxicity assessment were also discussed. Knowledge gaps were identified and summarised. The main conclusions of this work are: (i) catalyst leaching and deactivation is one of the main problematic issues; (ii) majority of studies were performed in semi-batch and batch reactors, while continuous fixed bed reactors were not extensively studied for treatment of real wastewaters; (iii) toxicity of wastewaters treated by CWPO is of key importance for possible application, however it was not studied thoroughly; and, (iv) CWPO can be regarded as economically viable for wastewater treatment, especially when conducted at ambient temperature and natural pH of wastewater.


2022 ◽  
pp. 66-83
Author(s):  
Qingjiao Zhu ◽  
Xintong Guo ◽  
Yanan Guo ◽  
Jingjing Ma ◽  
Qingjie Guo

With the acceleration of industrialization and urbanization in China, wastewater treatment is increasing yearly. As a by-product of wastewater treatment, the gasification of sludge with coal in chemical looping process is a clean and efficient conversion technology. To explore the reaction behavior of cogasification of sludge and coal with iron-based oxygen carriers (OCs) for producing hydrogen-rich syngas, the experiment of cogasification using Fe2O3/Al2O3 as OC in a fluidized bed reactor was conducted. The result showed that the volume percentage of hydrogen (H2) and syngas yield is proportional to the amount of sludge added. The optimal operation conditions were: temperature at 900 °C, the mass ratio of OC to coal at 5.80 and mass ratio of sludge to coal at 0.2. Under this operating condition, the volume percentage of H2 and syngas yield in the flue gas was 75.6 vol% and 97.5 L·min-1·kg-1, respectively. Besides, the OC showed a stable reactivity in the sixth redox cycle with added sludge. However, the reactivity of OC significantly declined in the seventh and eighth redox cycles. It was recovered when the ash was separated. The decrease in the specific surface area of the OC caused by ash deposition is the main reason for the decline in its reactivity. The kinetic analysis showed that the random pore model describes the reaction mechanism of sludge/coal chemical looping gasification (CLG). The addition of sludge can reduce the activation energy of coal CLG reaction, accelerate the gasification reaction rate and increase the carbon conversion.


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