Water Resources Engineering (WRE) connects engineering hydrology and hydraulics with global, economic, environmental, and societal issues.  Our student Alex Johnson makes this connection here:

The news entitled, “North Minneapolis’ Webber pool, the country’s first natural public swimming pool, to hold another open house” was reported on the website MinnPost on July 30th, 2015.  The news relates to the WRE domain of hydrology as the issue covers water management.  This article celebrates the opening of the Webber Natural Swimming Pool in Minneapolis, MN, which the nation’s first all-natural public swimming pool.  Rather than using chemicals (e.g. chlorine) for disinfection, the water is recycled every 12 hours to a “regeneration basin” consisting of 7,000 aquatic plants and layers of limestone and granite to filter the water.  This article mainly recites pool specifications from the designer’s webpage so in relation to design aspects to WRE the article is accurate.  However, since the pool just opened in July, the effectiveness of the treatment mechanisms listed in the article remains to be seen.  It should be noted that this article did not explain how the plants or the microbiology of the basin contribute to water treatment.  From my engineering knowledge, the regeneration basin is an example of a phytoremediation technique.  The aquatic plants have the ability to extract pollutants or reduce their bioavailability from the system (Salt et. al, 1995).  Beneficial microbes would also be responsible for removing chemical species such as nitrogen, sulfur, etc. from the water in the regeneration basin.  For example, denitrifers would remove nitrogen from the system as nitrogen gas through denitrification (Pepper et. al, 2015).  It would also be expected that the pool is monitored for water quality, but this effort is not mentioned.

The Webber pool relates to WRE through a broader context as it is an example of environmental management.  Rather than draining the water and diverting it to a wastewater treatment plant, the water is conserved by treating it on-site.  Additionally, no outside chemicals are delivered to the pool, which require fossil fuels to manufacture and transport them to the site.  These chemicals can also pose risks to human and environmental health and introduce disinfection by-products such as trihalomethanes (THMs).  Jin Lee and others (2009) showed that the incremental lifetime cancer risk can be exceeded for frequent swimmers (e.g. athletes) from exposure to THMs through oral ingestion and skin contact in traditional swimming pools.  As such, new techniques are needed to design and manage swimming pools to reduce water consumption and minimize environmental and health risks to society.  The introduction of the Webber pool may be a first step in achieving this.

IMAGES:

Figure 1: Photograph of the completed Webber Natural Swimming Pool.  The color of the water has a natural greenish-hue.  Picture adapted from original news article.

WebberParkNaturalSwimmingPool

URL: https://www.minnpost.com/community-sketchbook/2015/07/north-minneapolis-webber-pool-countrys-first-natural-public-swimming-po

References:

Salt D, Blaylock M, Kumar N, Dushenkov V, Ensley B, Chet I, Raskin I.  Phytoremediation: A Novel Strategy for the Removal of Toxic Metals from the Environment Using Plants.  Nature Biotechnology.  1995:13: 468-474.

Pepper, I. L., Gerba, C. P., Gentry T. J.  Environmental Microbiology, Third Edition.  Academic Press, San Francisco, 2015.

Lee J, Ha K, Zoh K.  Characteristics of trihalomethane (THM) production and associated health risk assessment in swimming pool waters treated with different disinfection methods.  Science of the Total Environment.  2009;407(6): 1990-1997.

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