【Paper】
An Estimation of Required Sampling Weights of Multicomposition Wastes and a Statistical Determination Method of Test Results Considering Variability
Tomohiro Tasaki* and Kohei Urano**
* Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
** Graduate School of Environmental and Information Science,
Yokohama National University, Yokohama, Kanagawa, Japan
† Correspondence should be addressed to Tomohiro Tasaki:
Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
（16-2 Onogawa, Tsukuba, Ibaraki, 305-8569 Japan）


Abstract
Conventional equations to estimate sampling variability are insufficient because they are based on the assumption that wastes consist of a single composition. In this paper, we applied sampling equations for multicomposition wastes obtained theoretically in the previous paper to four wastes, containing many compositions. However, the coefficient of variation of the test results under the sampling conditions was estimated to be 1.1. It was concluded, therefore, that wide variations under practical sampling conditions must be accepted. We also then examined a statistical determination method of test results that take variability into consideration. The examination showed that test results would exceed the standard values with more than 10％ probability if the average test value is not less than 0.6 times the standard value.


Key words: sampling, multicomposition wastes, sampling weight, leaching test, statistical determination method