Metal Concentrations In Wastewater Research Articles

Metal removal by wetland mesocosms subjected to different hydroperiods

Scirpus californicus (giant bulrush) wetland mesocosms were subjected to four hydroperiods (pulsed-discharge regimes). The most frequently pulsed treatment (twice per day) was the most efficient at removing metals from synthetic wastewater. This was attributed to the formation of iron oxyhydroxides, which complex with the metals. The continuously flooded treatment had slightly lower removal rates. After a year of metal additions, mean removal efficiencies were 75–78% for cadmium, chromium, and zinc, 84% for lead, and 55% for mickel. Most of the metals were retained in the soil. The fine roots accumulated roughly 35% of the added cadmium, 6% of the copper, and 13% of the zinc. The shoots, rhizomes, and coarse roots each accumulated about 1% or less of the added metals. Indications are that wetland treatment, especially with hydroperiod manipulation, can reduce metal concentrations in wastewater and, therefore, in downstream ecosystems.

A comparison of DCP‐AES and AAS analysis in determining Cu, Cd, C, Pb, Ni and Z concentrations in municipal wastewater

A Direct Current Plasma Spectrometer, DCPS, was used successfully to determine the concentrations of Cu, Cn, Cd, Ni, pb and Zn in the wastewater of the City of Windsor. There were no problems due to the spectral interferences from unknown elements in the wastewater when background corrections were made and linear relationships were obtained. Furthermore, excellent repeatability of the results existed, giving confidence in the analysis. Finally, by comparing the results obtained with the DCPS to those obtained with an Atomic Absorption Spectrometer, AAS, on the same samples, it was seen that the values were in good agreement. The DCPS provides small laboratories the option of using a relatively inexpensive method which is precise and accurate in determining metal concentrations in wastewater.