A Consistent, Economical Downspout Filter

The stormwater that flows off roofs often carries a significant load of dissolved zinc and copper. The ongoing oxidation of galvanized roofing materials, roof-mounted HVAC systems and copper gutters can all contribute to elevated zinc and copper concentrations in runoff water. When your stormwater plan calls for treatment of roof runoff, the TurnAbout™ Upflow Downspout Filter™ (UDF) offers consistent, economical treatment in an attractive, user-friendly design.

The TurnAbout UDF is powered by all-natural, responsibly sourced peat media from American Peat Technology. Position the TurnAbout under the building’s gutter and downpipe system where the runoff is directed to the TurnAbout’s bottom distribution manifold. From there, the water is forced to travel upwards through a bed of the peat media. As the water
passes through the treatment bed, the peat attracts and bonds dissolved ionic metals such as zinc and copper. By the time the water exits the TurnAbout, all or nearly all of the zinc and copper has been removed. Effective treatment with no power requirements and very little maintenance. It’s that simple.

Proven treatment

Each TurnAbout UDF is sized to treat up to a half acre of roof area with a design flow rate of up to 22 GPM. Multiple downpipes can be directed into a single unit, or additional units can be plumbed in parallel to treat larger surfaces. When operating within the design parameters and with scheduled maintenance, the TurnAbout will provide years of headache-free service.

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Zinc Removal with the TurnAbout UDF 

Ease of Use

The TurnAbout UDF easily connects to your existing downpipes and underground collection systems, using readily-available PVC and flexible pipe. We use durable, double-wall polyethylene to construct each unit, so the TurnAbout will hold up even after years of UV sunlight, weather and traffic.

Simple Maintenance

A built-in interior screen captures solids and sediment that can plug other treatment units. To clean the screen, simply remove the top of the UDF and reach into the water chamber to remove the screen. Wash the screen and then reinsert it into the water chamber. If your location is prone to accumulate solids and debris, we can add a pre-screen designed to remove additional coarse solids.

Scheduled Maintenance

When it is time to replace the spent peat media, a vactor truck will remove the media, and the bottom manifold will be cleaned of fine sediment. Once you install new peat media, the TurnAbout is ready to go back to work, protecting you and your site from exceedances due to roof-borne zinc and copper.

Built-in Bypass

When rainfall exceeds the design flow rate, the TurnAbout’s overflow directs water into the bypass outlet without overspilling.

Buy Direct from the Manufacturer

The TurnAbout UDF is available directly from American Peat Technology and supported by our external team of environmental engineers. Our team of experts can help size your system correctly, advise on engineering reports, and provide performance assurances through our in-house treatability testing.

The APT TurnAbout simplifies water treatment. This easy-to-use, economical solution uses natural peat to remove metals like zinc and copper that are concentrated in roof runoff. Using an innovative upflow design, the TurnAbout removes both solids and sediments in one attractive, efficient unit. Meeting water quality regulations and ensuring clean water returns to the environment has never been easier.

Easy to install

When your TurnAbout arrives, it’s fully loaded with APT’s APTIVATOR peat-based sorption media. Installation is simple: connect it to your downspout collection system, and it’s ready to collect and treat runoff water at the next storm event.

Highly adaptable

The TurnAbout’s compact size packs a lot of treatment capacity into a small footprint. The unit can be customized with right, left and rear outlets.


The TurnAbout treats at the source and can eliminate the need for expensive and complicated end-of-pipe systems. In the Pacific Northwest, one device can treat almost 22,000 ft2 of roof. And in most instances, it only requires maintenance every six months. On-site maintenance is as easy as opening the top and removing large debris from the inlet chamber.

Made in the USA
The TurnAbout is an American-made product. Some components are sourced internationally, but the assembly is carried out in central Minnesota. It is powered by all-natural peat treatment media, APTIVATOR, that is a green alternative to petroleum-based resins. The peat used in the manufacture of APITVATOR is responsibly sourced under a state-issued permit and the manufacturing process uses Earth-friendly biomass energy whenever possible. You can feel good about using the TurnAbout in your stormwater treatment system.

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The TurnAbout is designed to treat 22 GPM before going into bypass mode or, depending on storm parameters, up to 0.5 acre of roof surface area. Multiple units can be plumbed into a distribution manifold to treat greater surface areas.

The unit contains enough APTIVATOR media to capture over 2 pounds of zinc and copper between maintenance cycles. APTIVATOR is a sorption media, which means that the dissolved metals are firmly attached to the surface of the media. The metals will not be desorbed in normal operations.

The interior inlet chamber captures large debris, while smaller particulates are directed to the bottom of the distribution manifold. Sediment and fine solids that can plug other kinds of downspout filters are sequestered below the media and cannot plug the active treatment bed.

The TurnAbout footprint is about 15 ft2 (50” x 44”) and the unit is 51” tall. Forklift pockets allow for safe and easy positioning. The fully loaded unit, less water, weighs about 1300 pounds.

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The TurnAbout is designed to provide months of consistent performance with minimal maintenance. The unit’s straightforward design means the site owner can perform periodic maintenance to manage large debris that will find its way into the inlet chamber. Simply remove the lid to pull out the filter fabric, wash or brush off, and replace.

Over time, smaller particulates will accumulate in the distribution manifold. Those fine sediments are removed during regular scheduled maintenance. For most users, a 6-month maintenance cycle will be sufficient for media change-out and to maintain the unit’s hydraulic characteristics.

At each maintenance event, the spent media will be vacuumed out of the TurnAbout with a vac truck. The vac truck will also clean the bottom distribution manifold of fine sediments. The unit will be inspected for wear and breaks, and new APTIVATOR media will be installed.

Maintenance can be performed by the site owner or by a stormwater professional. Each 6-month maintenance event takes about an hour of time.

As with all treatment products, disposal of spent media must comply with local laws and regulations regarding potentially hazardous materials. For most applications, the spent APTIVATOR media will need to be tested to determine if the loaded metals and other contaminants are readily leached off the media. For many disposal sites, a test such as EPA’s 1311 Toxicity Characteristic Leaching Procedure (TCLP) will be required.

Because APTIVATOR is a sorption media that captures dissolved metals using chemical bonds, the metals are usually tightly bonded to the media surface and are not easily leached. For many applications, the spent media does not meet the definition of hazardous waste. If you have additional questions about disposal, contact us to talk to one of our experts.

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