Amathmaticalmodel for cadmium removal using asulfate reducing educing bacterium: desulfovibrio alaskensis 6SR

In this work, an unstructured-type mathematical model was developed to simulate cadmium [Cd[2+]] removal by Desulfovibrio alaskensis 6SR, which is a recently described sulfate reducing bacterium, whose capacity for removing heavy metals are being studied. Three processes are considered in the model: 1] the sulfate reduction process, 2] the consumption of lactate as carbon source, and 3] the metal removal. The model was tested with different initial Cd[2+] concentrations [50, 100, 170, and 190 mg/L], and it accurately predicted the behavior of experimental data with satisfactory correlation coefficients [R[1]>0.97]. In addition, the model showed that the H2S production rate and initial concentration of Cd[2+] are key operating variables in a bioreactor. Desulfovibrio alaskensis 6SR was able to remove more than 99.9% of cadmium in a batch process, where the in itial concentration was 170 mg/L. The model, applied to a continuous process, predicted a maximum Cd[2+] removal of 99.1% with the same initial concentration. Also, the model predicted the inhibitory effect of initial Cd[2+] concentrations above 190 mg/L. The mathematical model developed can be used for optimization and control purposes

Regulation of an activate sludge wastwater plant via robust active control design

The main task of this work is related with the design of a class of SISO robust control law for the regulation of substrate concentration [CDO] of an Industrial Activated Sludge Wastewater Plant. The control design is related with an uncertainty estimator [reduced order observer] based Active Control. Departing from the tracking error between the desired and the current substrate concentrations trajectories a control law is designed and the plant is regulated to the corresponding set point of the COD concentration. To be realizable the controller needs model information related with the kinetic term of COD consumption which is provides with a reduced order observer, these coupled structure [observer based controller] is robust against model uncertainties. The performance of the proposed control law is illustrated with numerical simulations employing a mathematical model of an Industrial Activated Sludge Wastewater Plant tuned with industrial data