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What is Chitosan-Enhanced Sand Filtration?


At Washington Stormwater, we use chitosan-enhanced sand filtration (CESF) units daily to filter water effectively and compliantly on construction sites across Washington. However, if you’ve never heard of CESF units before, you may be wondering: what are these filtration systems, and how do they work?

We’ve created this guide to help you learn everything you need to know about CESF systems. Read on to learn more about chitosan, how these systems work, and their benefits over other filtration methods.

Chitosan: The Basics

Water filtration systems typically use some sort of physical barrier to block or separate contaminants from water, leaving the water clean and clear. One of the most effective filters, especially for large-scale use, is chitosan.

Chitosan is a substance derived from the outer shell of crabs, lobster, shrimp, and other shellfish. One of its primary uses is in medicine and drug manufacturing, as the substance can help reduce your body’s absorption of fat and cholesterol in your diet.

However, chitosan can also enhance the efficiency of filtration equipment. When submerged in water, chitosan acts like a magnet to hold together the tiny particles and pollutants contaminating the water. This process allows the filtration system to filter the water more effectively, making it safe to discharge into the ecosystem.

How Does Chitosan-Enhanced Sand Filtration Work?

Water on construction sites is typically turbid or cloudy. However, adding even a small amount of chitosan to the water causes those particles to stick to the chitosan, making them easy to separate from the water. In many ways, the resulting filtered water is even cleaner than drinking water.

Chitosan-enhanced sand filtration systems use a three-step process to filter water in industrial settings:

  1. Monitor and test stormwater: CESF systems continually test incoming stormwater to determine its pH and turbidity. These systems then adjust the water to a neutral pH.
  2. Treat with chitosan: Then, CESF systems use controlled dosages of chitosan to attract and separate suspended particles from the water.
  3. Remove suspended sediments: Finally, these systems use pressurized sand filtration to remove sediments from the water and restore it to acceptable turbidity.

Chitosan enhanced sand filtration systems use a continuous flow-thru process that directly discharges the water rather than needing to test it further in surface ponds.

These water treatment systems can remove a range of contaminants from construction stormwater and wastewater, including heavy metals, hydrocarbons, sediment, organics, and more.

Why Is Water Filtration Necessary On Construction Sites?

You may be wondering: why do construction sites need to filter their water?

The short answer is that water that touches construction sites becomes contaminated with pollutants and particles. For example, when rain falls on a construction site, the rainwater picks up contaminants from surfaces throughout the site. Letting this water drain into the natural ecology can cause it to contaminate the larger body of water it enters.

The Environmental Protection Agency (EPA) and the Washington State Department of Ecology (WSDOE) have strict regulations that prevent construction companies from dumping water back into the ecosystem without first filtering out contaminants. As a result, construction sites need adequate filtration systems to catch, filter, and release water safely.

Benefits of CESF Systems

Chitosan-enhanced sand filtration systems offer numerous benefits over other stormwater treatment technology. A few of the most significant include:

  • Efficiency: The primary reason we choose to utilize CESF systems in our daily water filtration processes is efficiency. These systems can filter significant amounts of construction stormwater quickly and effectively, making them suitable for large-scale industrial sites and projects.
  • Lower project costs: CESF systems filter water faster than many other industrial filtration systems. As a result, you can install smaller tanks on your project site and save money.
  • Versatility: CESF systems are ideal for various construction and industrial uses. These systems work for all soil types and are self-contained, allowing us to install them on construction sites with limited space.
  • Eco-friendliness: Chitosan enhanced sand filtration is also eco-friendly. This process uses biodegradable chitosan to filter stormwater rather than harsh chemicals or treatments. Additionally, CESF systems comply with current EPA and WSDOE environmental regulations for construction water filtration.

If you’re planning a construction project or industrial build, incorporating chitosan enhanced sand filtration into your water treatment system is an excellent idea. Contact our Washington Stormwater team today at (360) 625-8366 to schedule your onsite consultation.

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Planning a construction project or industrial build?

Contact our Washington Stormwater team today at (360) 625-8366 to schedule your onsite consultation.


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