Degremont水处理手册(第7版)-3

Degremont水处理手册(第7版)-35METHODSANDMEANSOFANALYSIS1GENERALAnalysisisabsolutelynecessarytodesignawatertreatmentinstallationprojectaswellastomonitoritsoperationandtoevaluatethequalityofthetreatedwater(plantoutlet,systems,naturalenvironment).Therelentlessprogressofanalyticaltechniquesmakesitpossibletoimproveourknowledgeoftheconstituentsofthedifferenttypesofwaterandtheireffects.Qualitystandardsareincreasinglyrigorous,treatmentsareincreasinglysophisticatedandmonitoringneedstobeallthemorepreciseandreliable.1.1PRECISIONTheprecisionofamethodincludesseveralcriteria.Accuracyisthedifferencebetweentruevalueandtheaverageoftheresults.Itdependsonsystematicerrors(interferences,sampling,calibrating).Reliabilityisdeterminedbyrepeatability(sameproceduralconditionsforthesameoperator)andreproducibility(differentproceduralconditionswithdifferentoperators).Thestatisticalexpressionoftechniquesmakesitpossibletoimproveourknowledgeoftheconstituentsofthedifferenttypesofwaterandtheireffects.Qualitystandardsareincreas