A leachate study was conducted at a large, operating, regional municipal solid waste (MSW) landfill near Seattle, Washington, to examine differences in composition and emission rates between old and new areas of the fill. The landfill began operation in 1966, was receiving approximately 2000 tpd of MSW and had 30 × 106 m3 (∼12 × 106 tonnes) waste in place at the time of this study. The two areas studied had average ages of 3.7 and 16 years, and contained 5.7 × 106 and 2.04 × 106 tonnes of MSW, respectively. Variations in flow rate, total dissolved solids (TDS), chemical oxygen demand (COD), total organic carbon (TOC), Fe, and Mn were monitored over a 3‐month period in the winter and spring of 1992. Increases in flow driven by precipitation caused gradually increasing leachate mass emissions from the aged fill. The rate of mass emission increase with increasing flow from the new fill was more than three times higher than that from the old fill. Leachate flow through the old fill appeared more channelized, resulting in diluting effects with increasing percolation. In leachate from the new fill concentrations were essentially independent of flow. Overall, mass emissions per unit waste mass in place decreased with increasing waste age for TDS and Mn, indicating that these components were leachable independent of degradation processes. Mass emissions per unit waste mass in place increased with increasing waste age for COD, TOC, and Fe, which typify components that increase in availability for leaching with increasing age and progressing stage of decomposition.
the samples being analyzed, by making up standards in a synthetic matrix similar to the average major composition of the materials being analyzed, or by using either of the previous methods and buffering samples and standards by dissolving in them a fairly large amount of an element with a low ionization potential, such as potassium or lithium (16,26).Applicability to Other Elements. Without any further sample preparation, the spectrometer/spectrograph was employed to estimate the major compositions of IAEA S-5 and Kieselguhr which are included in Table VII. The synthetic blank solution and the solutions of NBS-91, VS-N, NBS 613, and GSB were used as calibration standards in these determinations. This same approach was used to estimate concentrations of iron and copper in three samples of diatom ash. The results of these analyses are included in Table IV.A detailed consideration of the use of the dc argon plasma jet to perform multielement emission spectrometric analyses of siliceous materials of diverse major compositions will be presented elsewhere.ACKNOWLEDGMENT We thank V. T. Bowen and R. R. L. Guillard for helpful suggestions, .
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