What type of samples should a facility collect to test how the treatment system is operating (grab vs. composite)?
The type of samples collected to determine the efficiency of an operating treatment system depends on whether the unit operation is a batch or continuous operation. Generally, grab samples are collected for batch operations and composite samples are collected for continuous operations. Samples collected to characterize raw waste streams are typically grab samples because of the batch nature of wastewater generation. Samples collected during treatability testing are typically grab samples.
