6 Questions to Ask About Stormwater Filtration Systems

Aqua-Filter Model AF-8.8 Ready for Installation. 8-ft swirl chamber plus 8 rows of filter media.

When considering a stormwater filtration system, engineers have an array of choices. So, it’s important to first consider these short and long-term outcomes and options when drafting a project’s specifications.

1.     What flow rates are available with the system? This can vary widely. At first glance it may appear that the highest flow rate is the best; after all, it can better handle high water rates in storms and floods. However, it’s not that simple, which leads us to the next question.

2.     80 percent removal of what? Too often, stormwater filtration systems are not tested consistently, lacking apples to apples comparisons. This leads to challenges for engineers trying to meet regulations that can differ broadly across the country. The specs may state that a filtration device meets the 80% removal rate, but if lab testing relied on a larger particle size than another system, you might not be getting the whole picture. Make sure you ask about the particle size that was used in the product’s testing to confirm that it meets your desired filtration expectations. Don’t skip out on quality just to achieve a higher flow rate.

3.     What field tests were used? Best-case scenario is to select a product that has been tested by a third party, outside the lab under real world conditions. Stormwater runoff contains all sorts of material from tree branches, to sediment to car oil. Product performance can’t truly be measured by lab testing alone.

4.     What are the installation requirements? Engineers walk a tightrope while juggling installation timelines, client demands and budgets. Ask early about what equipment will be required for installation, especially if special circumstances exist. Will shipping require road closures? How long until it is ready?  What about backfilling?

5.     What are the storage capabilities? Compare the sediment storage as well as the oil and debris storage, then consider what this means for maintenance and long-term life of the equipment. Can your client save more over 5 years by investing now?

6.     What filter media options are available to my client? Take the time to ask extra questions about the filter media, how easy is it to use, what filter options are available for site-specific contaminants of concern, and how often it requires replacement.

By analyzing the stormwater filtration system up front, engineers can bring added value to their clients by helping address concerns before they happen, and helping achieve progressive stormwater management for the long term. Do you have questions? Reach out to us to discuss your stormwater filtration needs. We’re ready to answer your toughest questions.