Wastewater treatment requires more aggressive chemicals—and in larger amounts—than municipal drinking water treatment. As a result, it is vital to properly store the chemicals used in the wastewater treatment process.
Let’s look at the chemicals used in each of the stages of wastewater treatment. We’ll also provide important chemical storage considerations.
Neutralization, adjusting the pH levels of wastewater by adding an acid or base, is common in wastewater treatment. Sulfuric acid or sodium hydroxide are typically used to achieve pH balance. Both sulfuric acid and sodium hydroxide are highly corrosive and present serious storage challenges that require specialized chemical storage systems.
2. Removing Solid Particles
Wastewater often contains solid particles that need to be removed. Usually, chemicals such as ferric chloride, polymers, and alum are used to produce positive charges. As a result, the solid particles clump together, making it easy to remove the material.
Since more solids exist in wastewater than municipal water, more chemicals are required for this coagulation process. To ensure safe storage, ferric chloride, aluminum chloride, and polymers require specialized chemical storage tank solutions.
3. Odor Control
Collecting and treating industrial wastewater produces unpleasant odors. These odors are also controlled using chemical treatment. Activated carbon and wet scrubbers are often used to reduce odors. It’s common to see sodium hydroxide, calcium nitrate and hydrochloric acid used in the scrubbers.
To prevent the spread of disease, pathogenic microorganisms must be destroyed or removed from the wastewater. A common, relatively safe and inexpensive disinfecting chemical is sodium hypochlorite, or chlorine.
Sodium hypochlorite presents several major chemical storage challenges. It breaks down under UV light exposure, contains transition metals that accumulate in the tank and create off-gassing exposure, and it aggressively oxidizes. A chemical storage system solution specifically engineered to handle sodium hypochlorite is required.
5. Sludge Treatment and Removal
Finally, a polymer chemical may be used to remove water from the sludge. This reduces volume and makes transporting the sludge to the landfill easier and less expensive.
Storage Solutions for Wastewater Treatment Chemicals
The chemicals that are used during the five stages of wastewater treatment are hazardous to humans, the environment and your equipment. It is of the utmost importance to protect your workers, the public, the environment and your property. Properly storing these chemicals is an ethical responsibility.
That's why Poly Processing Company has developed the IMFO®, Sloped-Bottom IMFO® and SAFE-Tank® Systems. We’ve been in the wastewater chemical treatment business for more than 40 years, and our storage solutions are trusted by wastewater facilities across the nation.
A True Full-Drain System
Most full-drain tanks don’t actually give you a 100 percent drain, because the outlet flange is located above the knuckle radius. It’s about two inches above the true bottom of the tank, which means you’ve still got to manually drain the tank.
Poly Processing’s Integrally Molded Flanged Outlet (or IMFO) system provides 100 percent full drain, because the flange is below the lowest point of the sidewall of the tank. The flange is molded as part of the tank during manufacturing, so that the lowest portion sits below the bottom knuckle radius. This specialized design eliminates the need to enter the tank for cleaning.The IMFO tank is also more reliable over time. Because the flange is molded as part of the tank and not added on later, the structural integrity of the tank sidewall isn’t compromised.
Poly Processing also has a sloped-bottom version of the IMFO tank, which we recommend for chemical storage in wastewater applications. The additional gravity feed allows these chemicals to drain more easily, so there is no sediment or sludge that builds up. And that makes cleaning even simpler, because there’s no need for a confined-space entry. Poly Processing Company is the only manufacturer of crosslinked polyethylene sloped bottom tanks in the country.
A Better Secondary Containment Solution
Poly Processing’s SAFE-Tank is a tank-within-a-tank. The double-wall containment system provides a minimum of 110% secondary containment. The system works by allowing the leaked chemical to equalize in the interstitial space between the two tank walls. If your primary tank develops a leak, the liquid is captured by the outer sealed secondary tank.
The footprint is only slightly larger than a single-wall tank, and you can continue to use the leaked chemical until the primary tank is drained. There is no cleanup needed, and no danger of exposure to workers or equipment.
For more information on the chemicals used in wastewater treatment, download our guide .