Check Rejection Criteria

A check on rejection criteria avoids developing a standard that is not fit for purpose, and includes a reasoned assessment of the costs relative to the benefits of the 

Environmental and Human Health Standards for Water and Soil 

In short, stakeholders (especially policy makers) must agree with the following  

If these criteria cannot be met, it will be necessary to return to earlier steps in the problem formulation process. 

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To be sure, the first criterion, of conforming with all experimental results, is hardly ever met in practice. Where deviations show up, the design of the experiments, their evaluation, and the reproducibility of the results must be checked. Often, the disagreement can be traced to an artifact, an equipment malfunction, a calculation error, an incorrect entry in a lab record book, or some other extraneous source, and can then be safely disregarded. However, if a divergent result is confirmed, the proposed model is inadequate and must be refined or entirely rejected. 

If the error criterion (4.1.27) is not met, the step is rejected and will be recomputed with a smaller step size. If on the other hand this criterion is fulfilled, it will be checked if it would have been fulfilled even with a larger step size. If so, and if the gain is significant, the larger step size is taken for the next step. 

Even if there is no gross error measurement, any balance will not be exactly equal to zero due to the random noise on the measures. The most simple test for checking if the balance is acceptable is to compare it with the input. This gives the fraction of the feed that is missing or that is in excess. It can be compared with the estimated accuracy on the measurements and gives a first criterion for evaluating a balance. Recoveries should be comprised between 98-102%. Nevertheless, this method does not provide an absolute threshold value to reject or accept the balance. Statistics are more suitable to detect errors. Several authors... 

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