Water Quality Monitoring, Sampling, and Laboratory Analysis
Know the core parameters: turbidity, disinfectant residual, pH, temperature, alkalinity, hardness, conductivity, nitrate, iron/manganese, DBP precursors, and microbiological indicators (total coliform, E. coli). Understand sampling basics: representative sites, clean technique, proper bottles and preservatives, holding times, chain of custody, and QA/QC (blanks, duplicates, spikes, calibration, control charts). Distinguish process monitoring (frequent, operational) from compliance monitoring (specified frequency and method).
Traps: grabbing a sample without flushing or after disinfection changes; missing holding times; confusing presence/absence with count methods; assuming a single good result proves compliance; and forgetting that turbidity and residual readings must be from approved methods and calibrated instruments.
Rule of thumb: sample where the water is representative, preserve and ship within holding time, and document everything. Worked example: a total coliform-positive routine sample triggers repeat sampling and, if confirmed, public notice steps; the operator's job is correct technique, timely analysis, and accurate records-not interpreting away the result.