One of the busiest border crossings in the U.S. will soon welcome visitors with a stroll through a new wastewater treatment plant. That sounds a bit, well, unfriendly, but there’s a twist. The “treatment plant” will be disguised as a beautifully landscaped, man-made wetland environment that purifies wastewater through natural processes. Visitors using the Otay Mesa Land Port of Entry in California will amble to the U.S. through the wetlands on a curved, meandering pedestrian walkway. It’s still sewage, but it sure sounds a lot more pleasant than a TSA pat-down!
The Living Machine Constructed Wetlands
The new treatment plant/wetlands is called Living Machine, produced by the company Worrell Water Technologies. The concept is based on the decomposition that takes place in tidal wetlands, in which two kinds of bacteria digest organic matter. These are anaerobic bacteria, which thrive in the absence of oxygen, and aerobic bacteria. The man-made Living Machine wetland is designed to maximize the efficiency of these processes within the smallest possible space. Though the resulting water is not suitable for drinking or cooking, it has a wide variety of other uses including recharging aquifers, irrigation, toilet flushing, cleaning, filling fountains and ornamental ponds, and various industrial uses. The Living Machine at Otay Mesa will be capable of treating up to 1,500 gallons of high-strength “black water” (from toilets) and “gray water” (from sinks).
A New Direction for Wastewater Treatment
Constructed wetlands like the Living Machine obviously cannot be applied to every situation. For example, they would be difficult to site within cities and other congested areas, although mini-wetlands using cattails are one possibility. Where sufficient land is available, constructed wetlands are becoming a mainstream means of treating and recycling wastewater, as evidenced by the fact that at least one very fancy private golf club has begun to irrigate its grounds with reclaimed wastewater. Constructed wetlands also play a key role in the U.S. EPA’s green remediation strategies, which are designed to reduce the carbon footprint involved in cleaning up Superfund and brownfield sites.
Image: Living Machine constructed wetlands courtesy U.S. GSA.
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. You can also follow her on Twitter @TinaMCasey and Google+.