ENVE 201 Environmental Engineering Chemistry 1 Sampling – Sampling Types Dr. Aslıhan Kerç

Sampling Adequate sampling is as important as true analysis. Sample types: - Grab samples - Composited samples

Grab Samples Taken more or less instantaneously and analyzed separately. Decision of frequency of sampling ? Number of sufficient samples vs cost e.g. Deep well  water quality is uniform  Single grab sample would be enough

Composited Samples Mainly used in evaluating the efficiency of wastewater treatment facilities. 24 h composite sample, 1-2 hrs. and collect in a container. The mixed sample is analyzed. Each sample volume should be proportional to flow at that time.

Composited Samples Some parameters (pH, alkalinity) may be analyzed in individual samples and then pooled into 2, 4, …24 h composites for other analysis. Detention times in the treatment plant should be considered in the sampling.