Wastewater analysis is important because wastewater comes from manner of sources, including runoff water from washing your car and clothes as well as water discharged manufacturing processes, such as water cooling tools that shape metal parts.
These varied sources of wastewater include many different types of contaminants.
Before wastewater treatment plants discharge wastewater into surrounding waters such as rivers, lakes and streams, wastewater analysis is required to identify contaminants that need to be removed or reduced.
The 1972 U.S. Clean Water Act (CWA) and its amendments allow the Environmental Protection Agency (EPA) to implement pollution controls. The National Pollutant Discharge Elimination System (NPDES) issues permits that specify the types and quantities of pollutants that wastewater plants are allowed to release into open waters.
Which contaminants are regulated by the NPDES?
The NPDES agency regulates released levels of biochemical oxygen demand, total suspended solids, pH, coliforms and nutrients. Also, metals, total dissolved solids, pharmaceuticals and endocrine disruptors limits might or might not be included in the permits. However, they, too have negative effects of humans and the environment. Scientists currently are studying the effects of those contaminants. Let’s take a closer look.
Biochemical Oxygen Demand (BOD)
BOD is a measure of organic compounds in the water. Wastewater analysis determines the quantity of dissolved oxygen in the water that’s needed by air-breathing (aerobic) organisms. If BOD levels are too high, microorganisms are forced to use existing water oxygen. Depleting the supply can, over time, kill fish and encourage invasive weeds.
Total Suspended Solids (TSS)
TSS includes both organic and inorganic solids suspended in water that don’t pass through a filter. As TSS increases, water captures sunlight, eventually raising water temperatures and destroying fish habitats.
pH measures acidity in water. Pure water is pH neutral, and most aquatic life requires an almost neutral pH for reproductive health.
Coliform bacteria are always present in soil, but levels need to be measured with wastewater analysis and limited in waters. When released into water, the presence of coliform bacteria can indicate the presence of dangerous disease causing pathogens that pose immediate human health problems.
Nutrients, especially nitrates and phosphorus, can encourage excessive growth of plants in open waters (eutrophication), and aquatic animals can die from oxygen deprivation.
What are other contaminants that may or may not be required to test?
Metals in water are by-products of industrial manufacturing and household pipes. Heavy metals, such as lead, mercury, chromium and cadmium, can get into waters. Concentrations of heavy metals are dangerous to humans and harmful to the environment when present in irrigation water.
Total Dissolved Solids (TDS)
TDS materials are inorganic salts such as magnesium, chloride, potassium and sulfates. Water with high levels of TDS can’t be used for irrigation or even landscaping.
Synthetic chemicals can be endocrine disruptors. When humans absorb them, they alter hormone levels throughout the body. These harmful materials enter wastewater through the use of pesticides and industry and manufacturing processes. Researchers have shown the disruptors’ negative environmental effects as well.
When people take the medicine that their bodies need, some of that medicine passes through into the wastewater. People also sometimes throw unwanted medicine into the toilet, flush it, and that goes into the wastewater. Researchers currently are investigating the effects of released pharmaceutical chemicals on humans and wildlife.