Many people confuse the terms wastewater and sewage. According to Wikipedia, wastewater is any water that has been corrupted by human waste, but can also include industrial pollutants, as well as surface, storm or sewer runoff.
Sewage is a specific type of wastewater from human waste.
How Is Wastewater Treated?
Municipal wastewater is treated in municipal wastewater treatment plants. Once treated, wastewater is released back into water systems.
In some communities storm drains run directly back into moving waterways such as creeks, rivers and bays.
In other communities where there is a high level chemical runoff or where the storm drains combine with sewage and are sent to sewage treatment plants.
Sewage treatment is simply the process of removing contaminants from wastewater so it can be safely released back into the environment. The solids that are removed from sewage, often referred to as sludge or slurry, often undergo further treatment before being burned or even used as fertilizer.
There are both physical, chemical and biological processes involved in wastewater treatment.
The Three Main Types Of Municipal Wastewater Treatment
- Physical wastewater treatment. Physical or mechanical treatment of municipal wastewater removes the heaviest solids from raw sewage and municipal runoff. The process includes screening, sedimentation (allowing solids to sink) and often removes as much as 50-60% of the solids.
- Biological wastewater treatment. In this second phase, live microbes are added to consume the dissolved organic matter that escaped the physical treatment stage. Microbes consume the organic matter as food and then convert it to carbon dioxide gas, water and other less harmful waste. Additionally, much of the remaining organic material recombines or binds together. So an additional sedimentation and screening may occur. At this point, as much as 85% of the solid waste will be removed from the wastewater.
- Chemical wastewater treatmentis the final step that will ensure the removal of more than 99 percent of all the impurities from wastewater. Chlorine disinfection is the most common chemical treatment. Other processes attempt to remove levels of phosphorus and nitrogen. Additionally, carbon filtering may be used in this final stage before clean water is released back into the environment.
What About Septic Systems?
According to some estimates, as much as 20% of the United States is currently treating their own sewage through the use of onsite septic systems.
Septic systems take all the water flow out of the home including the human and household waste. The wastewater flows into a septic tank where solids sink to the bottom and oils float to the top. These solids and oils are then removed on a regular basis. The remaining water flows into a drain field where the remaining liquids dissipate into the surrounding soil.
We’ll cover more on that in an upcoming article.
Chemtech’s Wastewater Treatment
Chemtech’s Wastewater Treatment options include Histosol and Dry Bacteria Formulations for the effective and economical treatment of odorous compounds and breakdown of waste/organic matter.
OdorGone, a product that naturally removes odors common in wastewater treatment using a specially formulated combination of natural oils such as peppermint, lemon and eucalyptus.
Chemtech also offers storm water safety products for storm drains and erosion control.