What kind of sampling method is typically used to monitor wastewater quality over time?

Composite sampling is commonly used to monitor wastewater quality over time because it allows for the collection of multiple individual samples over a specific period, which are then blended into a single sample. This approach provides a more representative view of the wastewater quality since it accounts for variations that might occur in flow rates and pollutant concentrations throughout the sampling period. By averaging the results from multiple samples, composite sampling reduces the impact of transient spikes in pollutant levels that might occur during the monitoring time frame. This method is especially important in wastewater treatment, where conditions can change rapidly, and it ensures that the results reflect typical conditions more accurately than a single grab sample could provide.

Other methods like sequential sampling, random sampling, and systematic sampling have their specific uses, but they might not adequately represent the variations in wastewater quality over time in the same way that composite sampling does.