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Removal of cephalexin residues from wastewater is one of the most concerned issues in treatment plants due to the growing of the antibiotics consumption level around the world. In this study, the impact of the initial concentration of cephalexin residues on its removability by lemna minor was investigated by developing a grau model accounting for the cephalexin initial pH value. In the model, the second-order kinetic constants of adsorption were linked linearly with the influent pH values. Results showed that using lemna minor along with phytoremediation process increased the removal efficiency value to 86.5% and dropped chemical oxygen demand (COD) to 0.012 mg/L in effluent, making the removability of cephalexin from the polluted water easier. In addition, it was found that changing the grau model kinetic constants linearly (positively or negatively) with pH affects the removal efficiency. Based on the results, the best removability can be noticed at the pH level of 7 with a value of 71%.

Removal of cephalexin residues from wastewater is one of the most concerned issues in treatment plants due to the growing of the antibiotics consumption level around the world. In this study, the impact of the initial concentration of cephalexin residues on its removability by lemna minor was investigated by developing a grau model accounting for the cephalexin initial pH value. In the model, the second-order kinetic constants of adsorption were linked linearly with the influent pH values. Results showed that using lemna minor along with phytoremediation process increased the removal efficiency value to 86.5% and dropped chemical oxygen demand (COD) to 0.012 mg/L in effluent, making the removability of cephalexin from the polluted water easier. In addition, it was found that changing the grau model kinetic constants linearly (positively or negatively) with pH affects the removal efficiency. Based on the results, the best removability can be noticed at the pH level of 7 with a value of 71%. [ABSTRACT FROM AUTHOR]

Abstract: Studies have been undertaken to explore the applicability of different kinetic models for the performance appraisal of upflow anaerobic sludge blanket (UASB) reactors treating wastewater in the range of 300–4000mg COD/l. Three kinetic models namely, Monod, Grau second-order, and Haldane model are considered for the analysis. Both linear and nonlinear regressions have been performed to examine the best-fit among the kinetic models. In this process, five error analysis methods have been used to analyze the data. Apart from optimization of kinetic coefficients with minimization of associated errors, prediction of effluent COD has also been undertaken to verify the applicability of kinetic models. In both the cases, Grau second-order model is found to be the best class of fit for wide range of data sets in UASB reactor. [Copyright &y& Elsevier]

The lab-scale upflow anaerobic biofilm reactor was successfully operated for the treatment of synthetic wastewater with high nitrogen load by Anammox (anaerobic ammonium oxidation) process. During the entire period of operation, the reactor temperature was kept at 35±1°C. The operational strategy consisted of both increasing the ammonium and nitrite concentrations from 60 to 700mgN/L and from 80 to 920 mgN/L, respectively and decreasing the hydraulic retention time from 24 to 6 h, at each step. The highest achieved removal efficiency of ammonium and nitrite were 91 and 93%, respectively. Consequently, due to their acceptable performance for nitrogen removal in previous researches, modified Stover-Kincannon and Grau second-order models were used in this study. According to the experiment results, the model validity testing showed that the Stover-Kincannon model was a little more appropriate for the description of nitrogen removal in the reactor, even though both models gave high correlation coefficients (R(2)=0.999).