scholarly journals Phenol degradation by combined photochemical-biological wastewater treatment system : kinetic modeling and optimization

Author(s):  
Maryam Edalatmanesh

A dynamic kinetic model, for the oxidation of phenol in water by UV/H₂O₂ system is developed. The model is based on elementary chemical and photochemical reactions, initiated by the photolysis of hydrogen peroxide into hydroxyl radical. Numerical values of chemical reaction rate constants and photochemical parameters are taken from literature. The model is validated with data on the oxidation of phenol in the simulated and the actual UV/H₂O₂ system. Using experimental data from literature, kinetic rate constants for the reactions involving phenol oxidation intermediates, catechol and hydroquinone, are estimated. The rate constants for the reactions, where phenol oxidized to catechol and hyroquinone by hydrogen peroxide are 9x10⁸ and 2x10⁸ s⁻¹ M⁻¹, respectively. The reaction rate constants for oxidations of catechol and hydroquinone by hydrogen peroxide are found to be 9x10⁸ and 8x10⁷ s⁻¹ M⁻¹, respectively. Phenol biodegradation is best represented by a two-step Haldane model. Both photochemical and biological models are coupled together to give one single chemical-biological system. The photochemical-biological process is optimized for the retention time, electrical energy consumption, and cost. The optimization approach is solved using the Successive Quadratic Programming (SQP) method. The least retention time for this system is determined to be 99h and the optimal electrical energy consumption occurs at a photochemical retention time of 15h and a biological retention time of 92h. Calculations on the total cost for different retention times show that the incurred cost by the photochemical unit is considerably higher than that by the biological unit. However, the minimum total cost is evaluated to occur at 15.5h of photochemical retention time and 90h of biological retention time.

2021 ◽  
Author(s):  
Maryam Edalatmanesh

A dynamic kinetic model, for the oxidation of phenol in water by UV/H₂O₂ system is developed. The model is based on elementary chemical and photochemical reactions, initiated by the photolysis of hydrogen peroxide into hydroxyl radical. Numerical values of chemical reaction rate constants and photochemical parameters are taken from literature. The model is validated with data on the oxidation of phenol in the simulated and the actual UV/H₂O₂ system. Using experimental data from literature, kinetic rate constants for the reactions involving phenol oxidation intermediates, catechol and hydroquinone, are estimated. The rate constants for the reactions, where phenol oxidized to catechol and hyroquinone by hydrogen peroxide are 9x10⁸ and 2x10⁸ s⁻¹ M⁻¹, respectively. The reaction rate constants for oxidations of catechol and hydroquinone by hydrogen peroxide are found to be 9x10⁸ and 8x10⁷ s⁻¹ M⁻¹, respectively. Phenol biodegradation is best represented by a two-step Haldane model. Both photochemical and biological models are coupled together to give one single chemical-biological system. The photochemical-biological process is optimized for the retention time, electrical energy consumption, and cost. The optimization approach is solved using the Successive Quadratic Programming (SQP) method. The least retention time for this system is determined to be 99h and the optimal electrical energy consumption occurs at a photochemical retention time of 15h and a biological retention time of 92h. Calculations on the total cost for different retention times show that the incurred cost by the photochemical unit is considerably higher than that by the biological unit. However, the minimum total cost is evaluated to occur at 15.5h of photochemical retention time and 90h of biological retention time.


2021 ◽  
pp. 1-15
Author(s):  
Fernanda P. Mota ◽  
Cristiano R. Steffens ◽  
Diana F. Adamatti ◽  
Silvia S. Da C Botelho ◽  
Vagner Rosa

1999 ◽  
Vol 103 (15) ◽  
pp. 2664-2672 ◽  
Author(s):  
Kazuaki Tokuhashi ◽  
Hidekazu Nagai ◽  
Akifumi Takahashi ◽  
Masahiro Kaise ◽  
Shigeo Kondo ◽  
...  

2012 ◽  
Vol 16 (3) ◽  
pp. 131
Author(s):  
Didik Ariwibowo

Didik Ariwibowo, in this paper explain that energy audit activities conducted through several phases, namely: the initial audit, detailed audit, analysis of energy savings opportunities, and the proposed energy savings. Total energy consumed consists of electrical energy, fuel, and materials in this case is water. Electrical energy consumption data obtained from payment of electricity accounts for a year while consumption of fuel and water obtained from the payment of material procurement. From the calculation data, IKE hotels accounted for 420.867 kWh/m2.tahun, while the IKE standards for the hotel is 300 kWh/m2.tahun. Thus, IKE hotel included categorized wasteful in energy usage. The largest energy consumption on electric energy consumption. Largest electric energy consumption is on the air conditioning (AC-air conditioning) that is equal to 71.3%, and lighting and electrical equipment at 27.28%, and hot water supply system by 4.44%. Electrical energy consumption in AC looks very big. Ministry of Energy and Mineral Resources of the statutes, the profile of energy use by air conditioning at the hotel by 48.5%. With these considerations in the AC target for audit detail as the next phase of activity. The results of a detailed audit analysis to find an air conditioning system energy savings opportunities in pumping systems. Recommendations on these savings is the integration of automation on the pumping system and fan coil units (FCU). The principle of energy conservation in the pumping system is by installing variable speed drives (VSD) pump drive motor to adjust speed according to load on the FCU. Load variations FCU provide input on the VSD pumps to match. Adaptation is predicted pump can save electricity consumption up to 65.7%. Keywords: energy audit, IKE, AC


2014 ◽  
Vol 675-677 ◽  
pp. 1880-1886 ◽  
Author(s):  
Pedro D. Silva ◽  
Pedro Dinis Gaspar ◽  
J. Nunes ◽  
L.P.A Andrade

This paper provides a characterization of the electrical energy consumption of agrifood industries located in the central region of Portugal that use refrigeration systems to ensure the food safety. The study is based on the result analysis of survey data and energy characteristics of the participating companies belonging to the following agrifood sectors: meat, dairy, horticultural, distribution and wine. Through the quantification of energy consumption of companies is possible to determine the amount of greenhouse gases (GHGs) emissions indexed to its manufacturing process. Comparing the energy and GHGs emissions indexes of companies of a sector and between sectors is possible to create reference levels. With the results of this work is possible to rating the companies in relation to reference levels of energy and GHGs emissions and thus promote the rational use of energy by the application of practice measures for the improvement of the energy efficiency and the reduction of GHGs emissions.


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