Grab sampling involves collecting a single sample at a specific time and location to analyze instantaneous water quality conditions, such as pH or dissolved oxygen.
Composite sampling combines multiple samples collected over a specified period (e.g., 24 hours), providing a better picture of fluctuating water quality conditions and pollutant loads.
A DO probe or meter measures the concentration of dissolved oxygen in water, which is critical for assessing the performance of biological treatment processes.
TSS is measured by filtering a known volume of water, drying the residue on the filter, and weighing it. This quantifies the amount of suspended solids in the sample.
Accurate flow measurement ensures compliance with NPDES permit limits, which often specify allowable pollutant loads based on the volume of treated wastewater discharged.
