The use of sewage sludge on agricultural land provides an alternative for its disposal. Therefore, the aim of the present study was to evaluate the feasibility of using industrial sewage sludge produced in Pakistan, a...The use of sewage sludge on agricultural land provides an alternative for its disposal. Therefore, the aim of the present study was to evaluate the feasibility of using industrial sewage sludge produced in Pakistan, as an agricultural fertilizer. The agricultural soil amended with 250 g kg^-1 sewage sludge with or without lime treatment was used for the growth of the common local grain crop, maize （Zea maize）. The mobility of the trace and toxic metals in the sludge samples was assessed by applying a modified BCR sequential extraction procedure. The single extraction procedure was comprised of the application of a mild extractant （CaCl2） and water, for the estimation of the proportion of easily soluble metal fractions. To check the precision of the analytical results, the concentrations of trace and toxic metals in every step of the sequential extraction procedure were summed up and compared with total metal concentrations. The plant-available metal contents, as indicated by the deionized water and 0.01 mol L^-1 CaCl2 solution extraction fractions and the exchangeable fraction of the sequential extraction, decreased significantly （P 〈 0.05） with lime application because of the reduced metal availability at a higher pH, except in the cases of Cd and Cu, whose mobility was slightly increased. Sludge amendment enhanced the dry weight yield of maize and the increase was more obvious for the soil with lime treatment. Liming the sewage sludge reduced the trace and toxic metal contents in the grain tissues, except Cu and Cd, which were below the permissible limits of these metals. The present experiment demonstrates that liming was an important factor in facilitating the growth of maize in sludge-amended soil.展开更多
The primary goal of this study is to examine the flow of non-Newtonian Sutterby fluid conveying tiny particles as well as the induced magnetic field in the involvement of motile gyrotactic microorganisms.The flow is c...The primary goal of this study is to examine the flow of non-Newtonian Sutterby fluid conveying tiny particles as well as the induced magnetic field in the involvement of motile gyrotactic microorganisms.The flow is configured between a pair of circular disks filled with Sutterby fluid conveying tiny particles and gyrotactic microorganisms.The impact of Arrhenius kinetics and thermal radiation is also considered in the governing flow.The presented mathematical models are modified into nonlinear ordinary differential equations using the relevant similarity transformations.To compute the numerical solutions of nonlinear ordinary differential equations,the differential transform procedure(DTM)is used.For nonlinear problems,integral transform techniques are more difficult to execute.However,a polynomial solution is obtained as an analytical solution using the differential transform method,which is based on Taylor expansion.To improve the convergence of the formulated mathematical modeling,the Padéapproximation was combined with the differential transformation method.Variations of different dimensionless factors are discussed for velocity,temperature field,concentration distribution,and motile gyrotactic microorganism profile.Torque on both plates is calculated and presented through tables.展开更多
文摘The use of sewage sludge on agricultural land provides an alternative for its disposal. Therefore, the aim of the present study was to evaluate the feasibility of using industrial sewage sludge produced in Pakistan, as an agricultural fertilizer. The agricultural soil amended with 250 g kg^-1 sewage sludge with or without lime treatment was used for the growth of the common local grain crop, maize （Zea maize）. The mobility of the trace and toxic metals in the sludge samples was assessed by applying a modified BCR sequential extraction procedure. The single extraction procedure was comprised of the application of a mild extractant （CaCl2） and water, for the estimation of the proportion of easily soluble metal fractions. To check the precision of the analytical results, the concentrations of trace and toxic metals in every step of the sequential extraction procedure were summed up and compared with total metal concentrations. The plant-available metal contents, as indicated by the deionized water and 0.01 mol L^-1 CaCl2 solution extraction fractions and the exchangeable fraction of the sequential extraction, decreased significantly （P 〈 0.05） with lime application because of the reduced metal availability at a higher pH, except in the cases of Cd and Cu, whose mobility was slightly increased. Sludge amendment enhanced the dry weight yield of maize and the increase was more obvious for the soil with lime treatment. Liming the sewage sludge reduced the trace and toxic metal contents in the grain tissues, except Cu and Cd, which were below the permissible limits of these metals. The present experiment demonstrates that liming was an important factor in facilitating the growth of maize in sludge-amended soil.
文摘The primary goal of this study is to examine the flow of non-Newtonian Sutterby fluid conveying tiny particles as well as the induced magnetic field in the involvement of motile gyrotactic microorganisms.The flow is configured between a pair of circular disks filled with Sutterby fluid conveying tiny particles and gyrotactic microorganisms.The impact of Arrhenius kinetics and thermal radiation is also considered in the governing flow.The presented mathematical models are modified into nonlinear ordinary differential equations using the relevant similarity transformations.To compute the numerical solutions of nonlinear ordinary differential equations,the differential transform procedure(DTM)is used.For nonlinear problems,integral transform techniques are more difficult to execute.However,a polynomial solution is obtained as an analytical solution using the differential transform method,which is based on Taylor expansion.To improve the convergence of the formulated mathematical modeling,the Padéapproximation was combined with the differential transformation method.Variations of different dimensionless factors are discussed for velocity,temperature field,concentration distribution,and motile gyrotactic microorganism profile.Torque on both plates is calculated and presented through tables.
