Properly treating wastewater is an important, but often misunderstood process. If wastewater isn’t treated correctly, it can be extremely harmful to our environment, including the people and animals that live in it.
There are several different elements involved in treating wastewater, including physical treatment that removes particles and debris. However, the chemical treatment of wastewater is especially important.
Let’s take a look at the most important things you should know about chemically treating wastewater — including the most common chemicals and the best practices for storing these chemicals.
The Roles of Chemicals in the Wastewater Treatment Process
Chemicals are essential in treating wastewater. In fact, wastewater treatment requires even more aggressive chemicals than municipal drinking water treatment. So it’s always important to properly and safely store the chemicals that are used in the treatment process.
Poly Processing Company's Chemical Storage Guide for Wastewater Treatment addresses common chemical storage challenges found in wastewater treatment and provides sensible storage solutions. In the first section, you’ll find out about the five steps of a wastewater treatment process, as well as the common chemicals involved in each step. In the second section, you’ll learn more about each chemical, along with its appropriate storage considerations.
The chemicals used in wastewater treatment have five important roles.
1. Removing Solid Particles
To remove the solid particles in wastewater, chemicals such as ferric chloride, polymers, and alums are used to produce positive charges. The positive charges neutralize negatively charged solid particles. As a result, the solid particles clump together, making it easier to physically filter out and remove the material.
Since more solids exist in wastewater than municipal water, more chemicals are required for this coagulation process.
Neutralization is the adjustment of the pH levels of water. In wastewater treatment, an acid or a base is added, depending on the pH level of the water being treated. Usually, either sulfuric acid or a base chemical such as sodium hydroxide is added to the water to achieve optimal pH balance.
3. Odor Control
When industrial wastewater is collected and treated, you get some strong, unpleasant, and harmful odors. These odors need to be treated, as well. Specific chemicals help to control odor at the treatment facility. In addition to activated carbon, wet scrubbers are used to reduce the stench. It’s very common to see sodium hydroxide and calcium nitrate used. Hydrochloric acid is also used in conjunction with media in the scrubbers.
Pathogenic microorganisms thrive in wastewater, making the water dangerous to humans. To prevent the spread of disease, these microorganisms must be destroyed or removed from the wastewater. A common, relatively safe and inexpensive disinfecting chemical is sodium hypochlorite.
5. Sludge Treatment and Removal
At this point, wastewater still contains sludge that needs to be disposed of. A polymer chemical is typically used to remove water from the sludge, which reduces its volume. This makes it easier and less expensive to transport the sludge to the landfill.
Creating a Safe Storage Solution for Wastewater Chemical Treatment
The chemicals used in wastewater treatment are extremely hazardous and aggressive. Five of the most frequently used chemicals include:
Sodium Hypochlorite — more commonly known as bleach, this chemical is often used to eliminate viruses and bacteria during the disinfection stage.
Sulfuric Acid — sulfuric acid is the most commonly used acid in the world. It is frequently used to bring the pH level of wastewater back to normal.
Ferric Chloride, Aluminum Chloride, and Polymers — these chemicals are used during the process of flocculation and the de-watering of digestive cake, to make it easier to transport waste materials to a landfill.
Sodium Hydroxide — like sulfuric acid, this chemical is often used to neutralize the pH of wastewater.
Hydrochloric Acid — this highly corrosive acid is used to control odors in wastewater.
Chemicals that are used for wastewater need to be stored very carefully so that their quality is not compromised. The key to this process is making sure that the storage solutions are designed based on the specific chemical that will be stored in them.