Frequently used evaluations for effluents

Abstract

Heavy elements inevitably contaminate the effluents from surface finishing industries. Determination of the elements is important to estimate the level of contamination and thus proceeds for treatment of the effluents. We offer two types of instruments; ICP-AES, and ICP-MS for determination of the elements. The atomic absorption spectrometer requires an individual lamp for each element to be determined, whereas the ICP-MS offers multi-elemental analysis. For both, ICP-AES and ICP-MS, the apparatus required is to be cleaned in 5 % sodium hydroxide, 5 % nitric acid, and ultrapure water sequentially. Samples of effluents are taken in clean bottles, previously washed three times. All reagents and water are purchased at the ultrapure level. Standard solutions are also bought commercially, and appropriate dilutions are prepared for ICP-AES or ICP-MS. Measurements of the concentration of elements by using the ICP-AES and ICP-MS are repeated at least three times and a blank is checked simultaneously. A calibration line is calculated using 3 or 4 standard solutions and r (the slope) is ascertained, which should be near 1 to achieve accurate determinations. The concentration of elements is calculated from the calibration line and errors are estimated. From this procedure, the concentration of elements is obtained for effluents. The concentration levels are compared to wastewater quality standards in the respective designated area (Japan or states in the United States). From the results obtained, the concentration of heavy elements can be controlled or monitored.