Expert Interview Series: Alan Weene of BioNova® Natural Pools About the Appeal of Natural Swimming Pools

Natural swimming pools
Alan Weene is the CTO for BioNova® Natural Pools, the North American leaders in planning and construction of eco-friendly Natural Swimming Pools which use plants instead of chemicals to purify the water. We had a chance to speak with Alan about NSPs and learn more about how they work and what it takes to build them.

What exactly is a BioNova Natural Swimming Pool?

A Natural Swimming Pool or Natural Swimming Pond (NSP) is a constructed body of water in which the conditions found in naturally occurring ponds or lakes are replicated and optimized for water quality and for bather heath and safety. The vessel is contained by an isolating membrane and operates as a closed-loop system. The system is completely chemical-free, with no devices that disinfect or sterilize the water (e.g., UV, ozone, ionizers, etc.). An NSP is cleaned and clarified purely with the controlled and directed flow of water through biological filters and aquatic plants rooted hydroponically in a specially-constructed wetlands regeneration zone.

An NSP has a clearly defined area for swimming and/or bathing that is physically separated from the planted section of the pool. These energy-efficient, sustainable, eco-friendly watershapes are always specifically designed, engineered, and permitted as a swimming pool.

From an owners’ standpoint, what are some of the differences between an NSP and a traditional pool?

Primarily, the biggest difference is that a Natural Swimming Pool is not sterilized or disinfected in any way. It is a biologically active living ecosystem which promotes biodiversity and helps to restore native wildlife habitats. An NSP can be built to look just like a traditional pool, with the plants located in an autonomous chamber adjacent to or completely separate from the swimming area. Alternatively, an NSP can be built to look like a naturally occurring body of water such as a pond or a lake. Nearly any traditional swimming pool can be converted into an NSP with some modifications to the plumbing and hydraulics as well as the installation of a wetlands regeneration zone.

Are there any myths about NSPs that you can dispel for us?

Myth: An NSP will have mosquitoes.
The water in an NSP is in constant motion, so mosquitoes will not be an issue. Furthermore, many of the aquatic plant species which live in the pool’s regeneration zone will attract dragonflies and other predators of mosquitoes.

Myth: An NSP will not work in my climate; it’s too hot or too cold where I live.
With a proven record of success in 45 countries around the world, and North American installations from Toronto to Texas and Connecticut to California, a BioNova® Natural Swimming Pool can be built in any normally habitable climate zone.

Myth: An NSP will be full of algae.
The function of the aquatic plants in a Natural Swimming Pool is to outcompete algae for available resources. When constructed correctly, an NSP will be a nutrient-poor body of water (oligotrophic to mesotrophic), with only enough nutrients to sustain healthy plant growth. To accomplish this, careful attention is given to aquatic plant selection and planting density, laboratory testing is conducted for all materials and substrates which will come in contact with the water, and measures are taken to eliminate outside sources of nutrients (e.g., surface runoff, wildlife, etc.). It should be expected that some algae will be present on the floor and walls of an NSP, since algae is a part of any freshwater ecosystem. Algae and sediment can be easily removed from the swimming area with a pool vacuum or an automatic pool cleaning robot.

Myth: I can have fish in my NSP.
Although an NSP is a perfect habitat for fish, it is not recommended to keep fish in an NSP. Fish will consume beneficial microbes and zooplankton that the system relies on to stay clean. Fish also add an undesirable amount of waste and biological load to the system. These pools are designed for humans to swim in, not fish.

Myth: I can’t heat the water in my NSP.
The water in a Natural Swimming Pool can be mechanically heated up to 86F using any conventional method for heating a swimming pool (e.g., electric heat pump, propane or natural gas, solar thermal, etc.). It’s OK if the water warms up beyond 86F on a hot day, because that’s what you would expect to find at a naturally occurring pond or lake.

Why are Natural Swimming Pools attractive to municipalities who are looking to build a new pool in their community?

Natural Swimming Pools are attractive to municipalities and commercial facilities because they help to distinguish communities as leaders in environmental sustainability and demonstrate their commitment to community engagement and ecological activism. Webber Park Natural Swimming Pool in Minneapolis, Minnesota, the first public NSP in North America which opened in 2015, is a prime example. It’s the product of innovative science and engineering made possible through years of grassroots neighborhood advocacy, creative fundraising, and political maneuvering.

All BioNova® Public NSPs are built to exceed the European FLL Guidelines for natural bathing waters. Adopted by most of the countries of the European Union, the FLL Guidelines are stricter than most of the state health departments in the United States, the Environmental Protection Agency, and World Health Organization standards for public bathing waters.

Given that BioNova has a dealer training program, what types of businesses or contractors are a good fit to provide NSP installation and maintenance?

Anybody who shares our passion for sustainability in the built environment might be a good fit to provide NSP design, planning, and installation services. But generally speaking, the majority of our licensed dealers are landscape architects, landscape contractors, or pool contractors.

What additional knowledge or instruction must a contractor have in order to design and build Natural Swimming Pools?

Designing and building a Natural Swimming Pool is far more complex than building a pond, water feature, or a traditional chemically-treated swimming pool. An NSP is a balanced wetlands ecosystem based on the principles of limnology, hydraulics, hydroponics, and modern pool construction methods. For the end product to have the ecological stability to be a long-term success providing optimal water clarity, quality, and bather enjoyment, all of these principles must be incorporated. BioNova® offers world-class training and support to qualified firms who are interested in bringing the state-of-the-art in Natural Swimming Pool design, planning, construction, and maintenance to their local communities.

What are some of the important things to know about building and installing the water garden that accompanies each NSP?

There are many factors that influence the design and construction of the water garden (regeneration zone) for a BioNova® NSP, and each one is unique to the Natural Swimming Pool it accompanies. Climate, substrate selection, hydraulics, flow rates, water depth, aquatic plant selection and hardiness, planting density, expected bather load, minimum footprint requirements, and site grading all must be considered.

Are you seeing a bigger demand for green construction projects – not just of structures like homes and buildings, but also of amenities and property additions (like NSPs)?

Like any green or sustainable product, NSPs have taken some time to gain a foothold in the North American market. But we’ve observed a steady rise in the interest and demand for these watershapes each year since we introduced the technology to the US in 2008. In German-speaking Europe, nearly 17% of all new swimming pools are constructed as NSPs, and we expect that it is only a matter of time before the same trend emerges here in the United States.

NSPs are not for everyone. But for consumers who are environmentally-conscious and desire to lead a chemical-free lifestyle, then a BioNova® Natural Swimming Pool may be the right choice for their landscape and outdoor living space.

Looking for PE-approved courses pertaining to water treatment and green construction? Click here for more information.

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