A sampling of each storage point, Zhuang, and mixed. This sample is representative of the waste water from the production process, all of the factories in the same time interval.
Sampling a plunge of the store, then mix well. The sample is representative of the entire production process effluent from the plant during the same period.
Sampling counter of each collection points were mixed. Sample collection that represent bath leave from the production process of factory in the same period.