Bioremediation of Lead‐Contaminated Wastewater Using Isolated Lead‐Resistant Bacteria: Growth Kinetics and Continuous Packed Bed Reactor Studies

ABSTRACT Lead is widespread throughout our environment for extensive industrial applications, modern agricultural practices, municipal landfills, and sewage disposal. In order to restrict the emanation of lead‐containing waste from industries eco‐friendly cost‐effective bioremediation process has to be conducted with the chemically treated lead‐containing industrial waste. The current study deals with comprehensive experiments on bioremediation of lead under different operating conditions using the isolated lead‐resistant bacterium Acinetobacter sp. (isolated in‐house from a native source). Two substrates, viz., glucose and lead, have been utilized to understand the cell growth kinetics of the bacteria under lead microenvironment. An attempt has also been made to quantify the cell growth kinetics in the form of mathematical model equations with a proper explanation of the procedure to find out intrinsic kinetic parameters from experimental data. Rigorous modeling and simulation exercises reveal that a multiplicative noncompetitive relationship is present between glucose and lead with respect to bacterial cell growth. Bioremediation of lead using the isolated strain has also been carried out in a continuous mode packed‐bed bioreactor with an intention to extend the process in large‐scale mode. Initially, the isolated biomass has been immobilized on an inert matrix using the attached growth technique. The conjugate biocatalyst so formed has been used as a packing in a specially designed packed‐bed reactor. From the comprehensive experimental runs, it was observed that at superficial velocity 1.4 m/h, lead was eliminated up to 80.4% from the wastewater stream having 0.04 g/L initial concentration of lead.