June 15, 2015
In a May 8, 2015 article published by the New York Times, John Schwartz touches on the sticky issue of rebranding recycled wastewater, or “black water”, into drinking water. He explains how wastewater from a treatment plant in Orange County, CA is converted to purer H20 than bottled water and is completely safe to drink. While the idea has been embraced by conservationists, about 13% of Americans remain staunchly opposed to the concept of black water treatment across the board. However, the technology that offers the potential to recycle more than half of the water used in the United States is not quite so black and white an issue.
The treatment of black water has been gaining attention in recent years, but the technology is hardly new. In 2005, The Durst Organization called for a way to cut down water consumption and increase efficiency by constructing the largest known black water treatment plant within a residential building. In response, Dagher Engineering, PLLC developed a state-of-the-art design for The Helena that does just that. For ten years now, The Helena, a 597-unit upscale residential building located in Midtown Manhattan, has been reusing the wastewater it produces allowing it to conserve about 50,000 gallons of water a day.
The plant, which the American Council of Engineering Companies awarded the Diamond Award, is designed to convert black water into potable quality water through a purification process so that it can be safely reused for cooling towers, toilets, and irrigation for the roof garden. This adds up to about 35% to 40% of potable water consumption which The Helena reclaims without sending to the city’s sewage system.
The Helena does not reuse treated water for drinking or bathing purposes, which is about 65% of water use in residential buildings. Therefore, it continues to champion water conservation in the face of growing urbanization while avoiding the current controversy over drinking treated black water.
Just how do Helena residents feel about sharing an apartment wall with the black water treatment plant? Dagher Engineering achieved an innovative design that concealed the system entirely from residents, eliminating noise and odor through modularizing the treatment process and enclosing the tiered membrane bioreactors. This design, created to fit into a compact space, proves that black water treatment plants can be effectively and economically incorporated into urban development.
The benefits of black water treatment only begin there. California’s imminent and serious drought is now gaining widespread attention. While residents in urban and suburban areas are asked to drastically cut back their water usage, farmers in the state continue to use potable water to irrigate water-rich crops like almonds and alfalfa. In “Our Water-Guzzling Food Factory,” New York Times reporter, Nick Kristof, illuminates us on the nation’s myriad plant and livestock commodities that are consuming the lion’s share of potable water; the 10 gallons of water required to produce one handful of almonds pales in comparison to the 450 gallons required to produce a ¼ lb. beef hamburger.
Agriculture is too valuable an industry for California, or other dry states, to consider abolishing, relocating, or limiting production. As reservoir and aquifer levels plummet consistently each year, politicians in the state are looking at desalination or piping in (costly to both energy and monetary resources) as solutions to water supply shortages. Desalination continues the process of withdrawing water, treating it, using it, then treating it again before returning it to natural water system. Similarly, piping in water from Alaska offers a palliative solution to an endemic problem.
Meanwhile, black water treatment eliminates the need for extraction and redundant treatment of waste water, and for extravagant out-sourcing of fresh water from distant locations, offering monumental opportunities for dry states like California to continue supplying up to 80% of total water use for agriculture and livestock needs.
By incorporating black water treatment plants into urban and suburban buildings, treated black water can be reused for non-drinking purposes, conserving the potable water supply. Black water can even be pulled from municipal sewage systems, treated and supplied to farmers, retaining waste water potential that would otherwise be treated before being dumped back into the Pacific Ocean only to be extracted again by a desalination plant. Black water treatment offers an affordable, effective, and long-lived answer to water conservation without yet asking to be swallowed in the literal sense.
In New York City alone, it is estimated that about half of all water used is consumed toward non-potable means, mainly by cooling towers. Integrating a non-potable water utility, consisting of treated black water – the same treated water that is currently discharged to the Hudson and East Rivers – would be an effective way to radically reduce our water consumption.
Dagher Engineering, PLLC continues to look at opportunities for leadership in sustainability, owing that the future of our cities and civilization depends on effective and immediate action in the face of climate change. The Helena is a milestone in the company’s movement toward a sustainable future.