Wastewater treatment tests are performed by collecting wastewater samples prior to treatment and after treatment; the samples are then analyzed physically and chemically either at the site by the collector or at an approved analytical laboratory. The National Permit Discharge Elimination System, or NPDES, determines the chemical and physical parameters to be tested depending on the type of wastewater being discharged.
Physical parameters such as flow rate, temperature, color and odor are measured by instruments such as thermometers or flow meters or by observation by the wastewater operator. Chemical characteristics of the wastewater are measured by the appropriate meters or test kits. The Hach Company provides a wide variety of easy-to-use, inexpensive chemical and physical parameter test kits and gauges that are generally accepted by state regulators for wastewater testing.
Some testing parameters are considered too sensitive for in-field test kits to provide definitive results. One common example is the test for petroleum constituents, which include benzene, toluene, ethylbenzene and total xylenes or BTEX. If BTEX is known or suspected to be present in wastewater, collectors must gather samples at the site and transport them to an accredited laboratory for analysis. The NPDES website provides many resources for wastewater treatment operator training, as qualification requirements vary from state to state.