How Does Water Recycling Work and Why is Water Recycling Important?

Water reclamation and recycling is increasingly an essential element in the sustainability plans of many cities. It makes sense. By recycling water—particularly for irrigation and industrial uses—we can reduce the demand for water sourced for drinking water. But how is water reused? And how does water recycling work? As you can read below, there are different processes used to produce different types of water.
What city service did the project improve or what municipal budget challenge did it overcome?
In 2020, Bayonne Water—operated by SUEZ under a public-private partnership—faced two critical challenges. The first, the removal of a 30-year-old, 4,000-gallon diesel fuel underground storage tank at the city’s largest pump station, demanded immediate action. The second, replacement of an enormous storm water bar screen system, required longer-term planning. Both would have severe environmental and financial repercussions if not remedied.
 
The projects came in the throes of the COVID-19 pandemic. But action could not be delayed. Those who were required to be on-site for the tank removal and above-ground replacement donned PPE and employed enhanced pandemic tactics (e.g., social distancing); those who could work remotely did so.
 
In the first instance, SUEZ discovered in early 2020 as part of its oversight of Bayonne Water’s wastewater system, that the insurance policy covering the underground storage tank was set to expire. If the tank was not removed by May 6, the insurance deductible would soar from $10,000 to $250,000.
 
In the second instance, a large metal bar screen system that removes solids and debris from combined sewer overflows, had not been operating efficiently for years. The mechanism, as well as the electronics control panel, was severely corroded. While Bayonne Water technically has remained in environmental compliance because of secondary screening devices, only replacement of the screening system and the attendant electronics offers a viable long-term solution. However, the project is forecast to cost at least $2.5 million, nearly the entirety of the $2.7 million 2020 municipal budget.

Recycling Water Conserves Resources

As the available water supply is decreasing, the demand for water is increasing. To ensure that we have enough water to meet our present and future needs, we need to conserve water and expand the use of recycled water. In essence, by expanding the use of recycled water, we are actually helping to conserve our drinking water supplies.


There’s also an added big bonus. Recycled water is good for the environment. Without recycling, secondary treated, nitrogen-rich sewage water would be discharged directly into our oceans—affecting the marine life. By recycling, less water is discharged, improving the environmental condition of our coastal waters.

What Can Recycled Water Be Used For?

  • Irrigation water for common greens: large turf areas, like golf courses and parks. Reclaimed water can be used for many other non-potable uses, as well, such as washing down equipment and tanks; dust control or surface cleaning of roads, construction sites, and other trafficked areas; concrete mixing and other construction processes; and indoor uses, such as flushing toilets.
  • Low-pressure boiler feed: Recycled water is used for generating steam to be used within the refining process. Additional treatment steps, including microfiltration and reverse osmosis are utilized to reduce the total dissolved solids and other inorganic constituents such as total hardness and silica, to levels acceptable for steam generation.
  • High-pressure boiler feed: This water, used by refineries and other industries, is produced in much the same way that low-pressure feed water is, but in this instance the low-pressure boiler feed output is treated with a second pass of reverse osmosis. The low-pressure boiler feed treatment system reduces the total dissolved solids in the recycled water to approximately 35 mg/l, whereas the high-pressure boiler feed treatment system reduces the total dissolved solids ever further, to approximately 3 mg/l.
  • Seawater barrier: To prevent seawater intrusion, a seawater barrier was constructed. A seawater barrier is a series of injection wells positioned like a dam between the ocean and the groundwater aquifer. These wells inject water along the barrier to ensure that the water level near the ocean stays high enough to keep the seawater from seeping into the aquifer.
  • Recharging aquifers: If wastewater is properly treated, it can be used to recharge inland and coastal aquifers and municipal water wells.

Is Recycled Water Safe to Drink?

Reclaimed and recycled water is not typically used directly for drinking water. However, SUEZ can treat water to the point where it can be injected underground to augment groundwater supplies used for drinking water. SUEZ’s LEAP*mbr (membrane bioreactor) technology is used in the process. At its core, the LEAPmbr uses the ZeeWeed membrane, an advanced ultrafiltration technology that separates solids, bacteria and viruses from water or wastewater.


MBR effluent is then further treated using reverse osmosis membranes and an advanced oxidation process before being injected into the aquifer.


In September 2019, the City of Morro Bay Water Reclamation Facility Project in central California partnered with SUEZ to adopt this process to make recycled water safe to drink. Though there are more than 50 operating MBR projects in California that produce recycled water for irrigation and industrial use, when permitted, the City of Morro’s facility will be the first to use MBR technology in a process to recycle wastewater to augment groundwater supplies used for drinking water.

What was the impact of this successful water concession?
SUEZ and Bayonne Water were able to save the City of Bayonne nearly a $250,000 in insurance costs, while protecting the health and safety of its residents. Just as important, SUEZ’ responsiveness amid the pandemic illustrates the strength of water PPPs (with focuses in water and wastewater sectors): Bayonne Water was able to leverage SUEZ’ technical expertise and its supply-chain prowess to successfully complete the emergency project on time and within local water budget. A key advantage of the water concession, executed under SUEZ’ SOLUTIONSM business model, is that it provides mechanisms for one-off capital needs (termed “Agreed Modifications”) should circumstances demand additional amounts that exceed the annual municipal budget. In this case, failure to replace the decrepit bar screen system—already about 30 years old—could result in costly environmental fines and represent a health and safety hazard to residents and plant workers.
 
As of this writing, the 4,000-gallon diesel fuel underground storage tank had been replaced with an above-ground, double-hulled unit, and the bar-screen project had been put out to bid. It is expected to be completed in 2021.
What areas did the successful execution of the project impact?

Service delivery improvement: Installation of a new bar screen mechanism to remove solids and debris from entering the stormwater discharge outflow. Removal of a 30-year-old, 4,000-gallon diesel fuel underground fiberglass storage tank with an above-ground, double-hulled unit. Both projects ensure environmental protection for residents and physical protection for workers.


Innovation: The two projects typify the flexibility of the innovative SOLUTION model framework and agreement, which have encouraged investment in a system that had long been neglected.  Since closing the transaction (i.e., inception of the PPP) in late 2012, more than $25M has been invested in the city’s water and sewer system to ensure service reliability and environmental compliance. SUEZ has undertaken novel approaches to addressing many other challenges in operating the city’s water & sewer system. For example, during the second quarter of 2020—through the height of the pandemic—SUEZ was able to continue with the inspection of over 14,000 feet of sewer main using innovative acoustic inspection technology in order to meet its contractual obligations.


Municipal budget savings: The public-private partnership between the City of Bayonne and Bayonne Water Joint Venture, an entity that includes SUEZ and private investors managed by Argo Infrastructure Partners LLC, allowed the City of Bayonne to immediately avoid a $240,000 increase in its insurance deductible. Moreover, by proactively detecting—and remediating crumbling infrastructure—SUEZ and Bayonne Water Joint Venture saved large environmental fines that inevitably would have been levied.


Environmental impact: Removal of an underground storage tank saved contaminants from leaking into the soil and groundwater. The new bar screen mechanism will remove debris from CSOs before entering the city’s waterways.


Impact on city economy: Since 2013, the public-private-partnership between SUEZ and the city has led to positive changes in the city’s overall financial health.  An immediate result of the partnership was the defeasance of all the system-related debt ($150 million) and the subsequent decision by Moody’s Investor Service to change the rating on the city’s outstanding obligations from Baa1 with a negative outlook to a stable outlook for the first time in five years. Three years after the partnership began, Moody’s further upgraded Bayonne’s credit to A3, reflecting—among other factors—the financial stability the city demonstrated as a result of the upfront payment the partnership provided as well as the long-term stability provided by our SOLUTION.


Business benefits: The commitment to guaranteeing reliable, safe, and clean drinking water has become imperative to attract new business and build a smart city for future generations. As SUEZ continues to improve infrastructure, the city continues to grow its customer base and expand its economic development program without finding additional sources of supply.


Tourism benefits: Fishing, boating and other outdoor activities in and along Bayonne’s waterways has increased in recent years. Replacement of the mechanical bar screen will help ensure the trend increases.

Water Recycling Facility, Nassau County, NY | SUEZ North America

Credit: SUEZ North America

Wastewater Reuse Facility for Sewage, Burbank, CA | SUEZ North America

Credit: SUEZ North America