Mass Loading Calculations

The mass loading of a discharge is a useful tool in selecting and sizing treatment equipment. The calculation is completed by comparing the daily flow rates with values obtained from water quality sampling and analysis.

Often times, concentrations of parameters from water quality sampling provide results in mg/L. The flow measurements are recorded in L/min; the official designation for flow in calculations is ‘Q’. With the addition of the time period of the water, all the variables to calculate mass loading are present.

There are multiple methods to reach the final number; two of the possible ways are presented to the right.

​Calculating the mass loading of a water stream is vital stage of water characterization. It will be important when creating a treatment system, deciding how to handle the waste stream, and discharging or re-purposing the final water.

More information on measuring flows is available in 'Monitoring Discharge Flows'. Instructions on sampling procedures can be found in Factsheet #006 Water Sampling & Proper Procedures.