A December 26, 2011 Associated Press article discussed challenges faced by many cities to control overflows due to wet weather from combined municipal stormwater and wastewater systems. The article references a USEPA memo released in late October, 2011 describing an integrated planning approach that EPA will implement with municipalities to look for opportunities to solve multiple water quality problems. EPA’s announcement of the planning approach touts “[g]reen infrastructure, such as green roofs, rain gardens, planter boxes, and permeable pavement, [as] an example of an integrated solution that can reduce, capture, and treat stormwater runoff at its source before it can reach the sewer system. Green infrastructure provides a cost effective way to reduce overflows and add green space in communities.”
Some of the technologies mentioned by EPA fall into the patentECO Industry ecosystem (e.g., green roofs, rain gardens, planter boxes) while others are transportation-related (permeable pavement). Is there other, more advanced patented clean technology that can be brought to bear on reducing stormwater runoff or pollution in towns and cities, thereby also reducing the potential for overflowing sewage from their combined treatment facilities?
The “greenest” technologies to accomplish this would use living, green plants. It has long been known in ecology that wetlands have a tremendous capacity for buffering storm runoff (and wave action in the case of tidal wetlands) and absorbing and/or converting water pollutants to less toxic or available forms. Early work to apply this knowledge to the treatment of polluted water occurred in Germany in the 1950s. In the US, a number of patents using this knowledge have been granted to John H. Todd:
5,087,353: “Solar aquatic apparatus for treating waste”
5,389,257: “Methods for treating water”
5,486,291: “Ecological fluidized bed method for the treatment of polluted water”
5,618,413: “Ecological fluidized bed system”
Todd’s patents were purchased in 1999 by Worrell Water Technologies of Charlottesville, VA. Worrell has updated the technology and received additional patents.
Patent number 7,320,752, “Integrated hydroponic and wetland wastewater treatment systems and associated methods”, was issued on January 22, 2008 to David C. Austin, David J. Maciolek, and J. Rob von Rohr. The invention is classified in the US system as 210/602; this places it with technology that uses plants or animals of a higher order (i.e., not bacteria) to purify or separate liquids.
Claim 1 states:
“A method for achieving advanced treatment of wastewater comprising:
removing from water to be treated at least some organic compounds and solids in a first module;
at least intermittently exposing the water to be treated to oxygen in the first module;
achieving at least partial denitrification of the water to be treated in the first module;
channeling the water from the first module to a second module comprising an aerated hydroponic reactor;
and channeling water exiting the hydroponic reactor to a top of a third module comprising a vertical-flow wetland adapted to maintain a population of aquatic invertebrates therein, for achieving BOD removal, nitrification, denitrification, and removal of TSS.”
Worrell’s other patents for this technology include:
7,347,940: “Nitrogen removal system and method for wastewater treatment lagoons”, issued March 25, 2008.
7,378,021: “Tidal vertical flow wastewater treatment system and method”, issued May 27, 2008.
The upshot of these patents is that if you are a building owner interested in reducing the environmental impact of your property, and you desire to improve water quality, the technology to do that with constructed ecosystems exists. It would even make a fascinating addition to your building’s lobby.