Circular 41/2020/TT-BCA: Method for Determining Wastewater Sampling Points

According to Circular 41/2020/TT-BCA, the determination of wastewater sampling points is carried out as follows:

Method of determining wastewater sampling points (Illustration)

- The wastewater sampling point is selected at the discharge outlet (the outlet to the environment). Choose a position at the discharge outlet as the sampling point where: the wastewater stream is well mixed, with high homogeneity, easy access, ensuring safety for personnel and sampling equipment. If the proposed sampling point does not ensure safety, it must be excluded, and another position must be selected to ensure safety.

- After determining the sampling point, the geographical coordinates of the sampling point must be determined using a geographical coordinates device. If it is not possible to determine using a geographical coordinates device, a solid fixed reference object must be chosen to describe the location of the sampling point in the sampling record.

- In cases where the discharge outlet does not have any position with turbulent flow, depending on the characteristics of the discharge stream cross-section, one of the following two sampling methods should be chosen:

+ Spatial sampling by collecting samples at 3 to 5 selected positions in nearly equal amounts within no more than 15 minutes, mixed well in an intermediate container (a plastic bucket with a capacity of 10 to 15 liters);

+ Create a V-shaped or rectangular partition to narrow the cross-section of the wastewater stream to create turbulent flow. The sampling point is the position behind the narrowed section where turbulent flow occurs.

See the full text of the regulation at Circular 41/2020/TT-BCA effective from June 24, 2020.

Thu Ba

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