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In this work, the parametric optimization of real domestic wastewater treated in an activated sludge sequencing batch reactor (SBR) was performed by means of the response surface methodology (RSM). The influences of influent organ...
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In this work, the parametric optimization of real domestic wastewater treated in an activated sludge sequencing batch reactor (SBR) was performed by means of the response surface methodology (RSM). The influences of influent organic matter concentration as chemical oxygen demand (CODinf), biomass concentration (X-s) and aeration time (t) on the COD, organic matter removal efficiency as COD (eta) and sludge volume index (SVI) were determined to evaluate the performance of activated sludge SBR. The results showed that organic matter efficiency and maximum SVI were obtained at a t of 12 h, 300 mg L-1 of CODinf and 2000 mg L-1 of X-s. The SBR-activated sludge exhibited a eta of 73% and an SVI of 119 mL g(-1). Both values indicated a very good performance. Furthermore, the COD of the effluent under these conditions complied with Mexican regulations for wastewater discharged into water bodies.
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An isoperibolic combustion calorimeter developed to measure the enthalpy of combustion of organic compounds containing carbon, hydrogen, oxygen, and nitrogen atoms has been assembled, calibrated, and tested. The calorimeter was ca...
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An isoperibolic combustion calorimeter developed to measure the enthalpy of combustion of organic compounds containing carbon, hydrogen, oxygen, and nitrogen atoms has been assembled, calibrated, and tested. The calorimeter was calibrated with benzoic acid NIST 39j, and the resulting energy equivalent was epsilon(calor) = (10116.8 +/- 0.5) J K-1. Salicylic acid, 1,2,4-triazole, and acetanilide were used as test compounds. The main result is that all obtained values of the standard molar enthalpy of formation for the test compound are in agreement with the results available in the literature.
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The energies of combustion of single-walled and multi-walled carbon nanotubes were measured by using an isoperibolic micro-combustion calorimeter. The values of the massic energy of combustion in oxygen at T = 298.15 K and pAA = 0...
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The energies of combustion of single-walled and multi-walled carbon nanotubes were measured by using an isoperibolic micro-combustion calorimeter. The values of the massic energy of combustion in oxygen at T = 298.15 K and pAA = 0.1 MPa of the compounds under study were obtained as: (- 27,635.0 +/- 9.5) and (- 32,347.3 +/- 15.3) J g(-1), respectively. The corresponding standard molar enthalpies of formation were derived as: (4.7 +/- 1.3) and (0.8 +/- 0.9) kJ mol(-1), respectively. The used calorimeter to test the compounds was calibrated previously with benzoic acid NIST 39j, salicylic acid and 1,2,4-triazole.
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In this work, a comparison of the performances of different AOPs in the phenol and 4-chlorophenol (4-CP) degradation at lab and pilot scale is presented. It was found that, in the degradation of phenol, the performance of a couple...
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In this work, a comparison of the performances of different AOPs in the phenol and 4-chlorophenol (4-CP) degradation at lab and pilot scale is presented. It was found that, in the degradation of phenol, the performance of a coupled electro-oxidation/ozonation process is superior to that observed by a photo-Fenton process. Phenol removal rate was determined to be 0.83 mg L−1 min−1 for the coupled process while the removal rate for photo-Fenton process was only 0.52 mg L−1 min−1. Regarding 4-CP degradation, the complete disappearance of the molecule was achieved and the efficiency decreasing order was as follows coupled electro-oxidation/ozonation > electro-Fenton-like process > photo-Fenton process > heterogeneous photocatalysis. Total organic carbon was completely removed by the coupled electro-oxidation/ozonation process. Also, it was found that oxalic acid is the most recalcitrant by-product and limits the mineralization degree attained by the technologies not applying ozone. In addition, an analysis on the energy consumption per removed gram of TOC was conducted and it was concluded that the less energy consumption is achieved by the coupled electro-oxidation/ozonation process.
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