These plans — perhaps most notably a net-zero energy target for the city’s 14 wastewater treatment plants by 2050 — position New York as a national leader in water solutions. Catalyzing evolution in New York’s water scene, the various goals are driving stakeholders to explore novel technologies for more efficient, sustainable water treatment and supply.
The net-zero goal, for instance, has led NYC’s Department of Environmental Protection (DEP) to develop energy conservation measures across all 14 of the city’s WWTPs, including evaluation of opportunities for solar photovoltaic (PV) installations.
By the end of December 2017, construction had begun on a 12 MW cogeneration system at the North River Wastewater Treatment Plant. And at the Newtown Creek Wastewater Treatment Plant, waste-to-energy technology has been deployed as part of a codigestion demonstration project ramping up to process 250 tons food waste per day by June 2019, from 60 tons per day achieved in 2017.
“DEP is simultaneously meeting the ambitious OneNYC energy reduction goals and new energy-intensive water/wastewater quality regulatory mandates, while integrating and not sacrificing state-of-good-repair needs,” said Tara Deighan, DEP deputy press secretary, describing the utility provider as “becoming a progressive leader in sustainable operations and resource recovery, seeking the best investments for environmental and social solutions.”
There’s a “robust capital program” financing the aspirations too: N.Y. Governor Andrew Cuomo has made funding of blue infrastructure a priority, with $2.5 billion pledged for 2017-2018 alone.
Still, there is another aspect to the evolution of New York’s water scene, one characterized less by state-of-the-art technology and more by its approach to planning water assets.
Arcadis, a leading engineering firm heavily involved in NYC’s urban development scene, is contributing in no small part to this. “With changing climates, the new normal can be pretty extreme, and with the associated risks urban spaces must be designed to address these circumstances in a proactive, rather than reactive, manner,” said Edgar Westerhof, flood risk and resilience lead at Arcadis.
“Resiliency is about developing assets with an eye towards the future and recognizing how multiple urban systems are connected. It involves raising the bar wherever possible and assuring we’re building for this new normal while safeguarding asset functions of the past.”
A textbook example of Arcadis’s application of this systems-based mindset is evidenced in its development of the Big U and Waterfront Resiliency Plan of Manhattan, which after much anticipation is slated to break ground on an initial 2.5-mile stretch of sea level defense around lower Manhattan later this year.
Alongside private actors embracing the new ways, so too are public bodies. DEP’s Office of Integrated Water Management is taking an active role in responding to these new circumstances. Leading the office is Alan Cohn, who told WaterWorld: “Resilience involves optimizing the system to absorb shocks more readily. Anything we can do to reduce demand on the system whilst optimizing our resources makes us more resilient to otherwise harmful events.”
Cohn explained that the office’s twofold focus prioritizes demand management (including water conservation) and climate resiliency: “We see the two as very much intertwined, as demand management is a central tool in our climate resilience toolbox when it comes to drinking water supply and sewage.”
Since New York operates a majority combined sewer system, water asset resiliency hinges upon recognition of relationships between combined sewer overflow, stormwater management and water quality.
A prime example of the value of this mindset in action presents itself in the increasingly critical context of tackling New York’s susceptibility to extreme rainfall, or ‘cloudburst’ events. Such events can overwhelm sewers and associated infrastructure, and create localized flooding. With the potential consequences as severe as they are, the circumstances prompted the DEP’s Cloudburst Resiliency Planning Study to assess risks and management strategies, and develop new solutions.
“With Cloudburst we recognized we cannot just upgrade infrastructure and build bigger pipes. Even if we did, there would always be a larger storm above the design standard,” said Cohn.
He continued: “The new perspective is that this isn’t a DEP problem but an issue we need to collectively understand and solve as a city. City agencies with property, streets or parks, need to ask how we can use groundwater management to address flooding and reduce discharge from sewers to harbor.”
Inspired by a program of cloudburst mitigation undertaken in Copenhagen, Denmark — and working with the city under a three-year MoU on cloudburst management that commenced in 2015 — DEP is applying a resiliency lens to address the threat.
Although not at the same scale as in Copenhagen, DEP has multiple cloudburst pilot projects underway. Here, in place of traditional engineering measures to manage stormwater runoff, investment is made in public spaces and so-called blue-green infrastructure. Examples include permeable pavement, rain gardens, and stormwater green streets — assets that can absorb high volumes of water in order to reduce damage to and stress on traditional assets where water would otherwise go.
Remarking on Arcadis’s experiences with similar infrastructure in Pittsburgh, Westerhof said: “We’ve seen that rather than large pumps and extended sewers to prevent flooding or handle water, success is possible through large-scale green infrastructure implementation and holistic solutions.”
Within a DEP demand management program, Cohn explained that incentives for retrofitting building plumbing geared towards reducing loads on sewer system and simultaneously saving on potable water is another kind of solution in play.
These novel solutions can necessitate interagency partnering and carry challenges of their own, but they bring positive consequences across all sorts of metrics high on the city’s political, social and environmental agendas.
A DEP Water-Energy Nexus study that quantified benefits associated with four of DEP’s programs during 2015 — green infrastructure, water demand management and conservation, wetland restoration and water supply forestland protection — reports:
• 687 million gallons per year (MGY) of stormwater input to NYC’s 14 WWTPs was avoided via green infrastructure;
• 528 MGY of reduced water demand and associated wastewater treatment via conserving fixtures;
• 133 MGY of reduced water demand via repairs to leaking water mains.
Associated with the programs, the study calculated an estimated reduction in total emissions for 2015 of 178,000 metric tons (MT) of CO2 (which is equivalent to removing approximately 53,000 passenger cars from the road).
