Surface water is channelled into the unit through a kerbside inlet, through an inlet pipe or directly from the surface and flows through the mulch, plant and soil filter media, providing high-performance, high-flow filtration that targets sediment, hydrocarbons, heavy metals and nutrients.

Targeted Pollutants
	Very fine particles
	Dissolved, liquid and sediment bound hydrocarbons
	Gross pollutants
	Sediment bound heavy metals
	Sediment bound nutrients
	Dissolved pollutants

Applications

Hydro Filterra™ engineers in nature’s way to enhance any urban environment even where space is at a premium or where a retrofit surface water treatment solution is required. Suitable for residential or commercial settings, car parks and highways.

Attractive and Space Saving

Hydro Filterra™ contributes to attractive urban areas and street scenes and supports local biodiversity. Its compact design makes it ideal for both new build and retrofit applications.

Versatile

The treated water is discharged via the under drain system to a drainage outflow, watercourse, or onwards for infiltration if soil conditions allow. It can also be integrated with a secondary attenuation or infiltration such as Hydro’s Stormcell® or Stormbloc®.

Low-Cost Maintenance

Maintenance is similar to landscaped areas and each unit is supplied with a 12-month maintenance agreement.

Easy, Cost Effective Installation

While the chemical and biological processes behind Hydro Filterra™ are complex, installation is simple. The filter media and ready-fitted internal components are pre-packaged in the concrete chamber to facilitate easy drop-in-place construction.

A Proven Track Record

Hydro International’s Hydro Filterra™ has a proven track record with regulatory agencies around the world, including:

• Massachusetts Stormwater Technology Evaluation Project (MASSTEP)
• State of Washington Department of Ecology
• Maryland Department of the Environment
• Maine Department of Environmental Protection
• Oregon Department of Transportation
• New York State Department of Transportation
• Texas Department of Transportation
• Virginia Department of Transportation

Treatment Processes

•  Sedimentation

•  Inert filtration

•  Reactive filtration

•  Media recharge

Operation

Similar in application and concept to a traditional bioretention system, the Hydro Filterra™ has been optimised for high volume flow whilst retaining high pollutant removal efficiencies.

Contaminated surface water runoff drains from the impermeable surface through the kerb inlet slots incorporated into the Hydro Filterra™ cover slab or through an inlet pipe on to the mulch layer, where energy dissipater stones are applied to prevent erosion of the mulch and engineered media. The runoff then flows through the mulch and media layers where pollutants are captured and immobilised. Treated water is collected in an underdrain carrier pipe, which exits the chamber via a standard pipe coupler cast in to the wall of the chamber.

Frequently asked questions

Q. When do I use an Up-Flo™ Filter instead of a Hydro Filterra™?

The Up-Flo™ Filter is very resistant to high contaminant loading associated with pollutant hotspots. It also fits easily within a traditional drainage system. However, the Hydro Filterra™ can fit to the landscaped environment and provides biological treatment. Try our Surface Water Treatment Selection Tool to help you decide on an appropriate treatment package for your given application or contact our Design Support Team on 01275 337 955.

Q. What sizes are available? Which size should I use?

The Hydro Filterra™ is available as a 1.2m x 1.2m; 1.2m x 1.8m or 1.2m x 2.4m unit. The size of unit required is dependent on the rainfall characteristics, catchment type and pollutant loadings. Contact our Design Support Team on 01275 337 955 for site specific sizing.

Q. What size outlet pipe is acceptable?

All units are fitted with a Rigidrain CRD100 socket coupling.

Q. Can the plant be omitted from the Hydro Filterra™ System?

No. The plant is a critical component in bioretention technology and is necessary for the Hydro Filterra™ to operate as intended. Phytoremediation studies have shown that plants are effective at cycling the pollutants captured by the system. The plants can accumulate metals in the cell tissue to make them less toxic, utilise nitrogen and phosphorous for cell growth and process organic matter for energy. While the engineered media alone would still be effective at removing pollutants, the inter-event recovery and system recharge would not be facilitated by the plant and therefore the media would require periodic replacement.

Q. What kind of plant can I use?

Guidance on plant selection can be read here. Many UK native species are, unfortunately, not suited to the free draining conditions experienced within a bioretention system. Therefore, it is often more appropriate to use carefully selected, non-invasive ornamental species. If it is desirable to use a particular type of plant to suit local aesthetic or biodiversity plans, then this can often be accommodated.

Q. Whats in the soil mixture?

The filter media has been specially engineered to facilitate a high through flow rate, while retaining effective pollutant removal efficiency.

Q. What is removal efficiency of the different size units?

Removal efficiency is dependent upon the particle size and specific gravity of the pollutant, in addition to the water quality and peak flow rate of the runoff. Contact our Design Support Team on 01275 337 955 for technical advice.

Q. What is the maintenance procedure? Is confined space entry required? How often is maintenance needed?

The unit is supplied with a 1 year maintenance contract included.

Maintenance is safe and easy and can be carried out from the surface using standard landscaping tools. No confined space entry is required. Maintenance consists of removing sediments and litter, replacing the mulch, ensuring that all inlets and outlets are clear and care of the plant. Maintenance is typically carried out twice a year. Irrigation may be required to maintain healthy plant growth during prolonged periods of dry weather.

Q. Does installation of the Hydro Filterra™ require any special equipment or experience?

The Hydro Filterra™ is supplied as a complete chamber unit, with the engineered media and pipework already installed to prevent system failures that can be associated with conventional bioretention or biofiltration installations. Full installation guidelines can be obtained from our Design Support Team on 01275 337 955.

Q. Is the Hydro Filterra™ an equivalent to an oil interceptor?

Yes. PPG3 recommends that SuDS are used in place of an oil interceptor for sites where there is a risk of light contamination and a low risk of spills (e.g. car parks, residential roads). The Hydro Filterra™ is verified as delivering hydrocarbon removal to Class I interceptor required performance.