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Meet EPA limits with simple, safe Evoqua solutions

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Nitrate contamination in groundwater sources is becoming an increasing concern everywhere, but especially in areas affected by drought. In many of these areas, municipalities with water shortages have been forced to consider reopening wells that had been closed due to high concentrations of nitrates. As these conditions persist, many municipalities are turning to Evoqua for nitrate removal solutions.

What are nitrates?
Nitrates (NO3-) is a naturally occurring compounds of nitrogen and oxygen found in air, soil, and water.  Much of the nitrate in our environment comes from decomposition of plants and animal wastes.  Nitrates have no detectable color, taste or smell at the concentrations involved in drinking water supplies, and can occur both naturally and from man-made sources. Because they do not evaporate, nitrates are likely to remain in water until consumed by plants or other organisms. Manmade nitrate contamination originates mainly from agricultural operations including farm runoff and fertilizer usage, septic system failure and improper discharge of industrial and food processing waste and wastewater, but can also come from munitions and fireworks operations. Since they are very soluble and do not bind to soils, nitrates have a high potential to migrate to ground water.

Why is nitrate contamination a public health concern?

Long exposure to high levels of nitrates in drinking water has been shown to cause serious health problems in infants and the older population, especially those who drink formula made with well water or untreated municipal water. In a child's body, nitrates can be converted into toxic nitrites that interfere with the oxygen-carrying capacity of a child's blood. This condition can cause serious illness and death from a condition called Methemoglobinemia (“blue baby syndrome”).​

What are the safe maximum contaminant level goals of nitrates and nitrites?
The US Environmental Protection Agency (EPA) has set a Maximum Contaminant Level (MCL) for nitrates of 10 parts per million (ppm) as nitrogen.

What methods are typically used to remove nitrates and nitrites from groundwater?
The best available technologies as determined by the EPA for removing nitrates and nitrites from potable water are ion exchange and reverse osmosis (RO).

Another growing trend for removing nitrates from both potable and non-potable applications is biological remediation.  California has granted several systems with conditional use permits for biological treatment of nitrate for drinking water.  

Evoqua is a leader in all of these technologies - with more than 100 years of experience in meeting the clean water needs of municipalities and water users throughout the United States. We can provide solutions in forms that meet the chemistry, process and budget needs of your nitrate removal application.

Products and Services:

Evoqua Ion Exchange - Nitrate Re​moval Service that Grows and Changes with Your Needs
Ion exchange is the most frequently used tre​at​​ment for ni​trate removal. Ion exchange is a simple, robust process that can be automated.

How does it work?

Ion exchange removes nitrate ions from the aqueous phase by passing contaminated water through a bed of ion exchange resin. As contaminated water is passed through the resin, contaminant ions are exchanged for other ions, most often chlorides, in the resin.  

The ion exchange resin is regenerated with a salt solution.  There is a resultant brine waste stream.  Evoqua can provide either onsite or offsite re-generable ion exchange systems for nitrate removal. Each application is analyzed to determine the system configuration that best meets current and future needs.

If the site can discharge brine to the sewer or tie into a brine line, onsite automated regeneration is an excellent choice for treatment. 

Evoqua also offers an off-site regeneration service-based treatment option that integrates equipment and service combinations.  Mobile vessels can be rented or purchased, and are selected based upon available manpower, space requirements, access requirements and the specific water quality.   Once the media is exhausted, the exchange vessels are removed, replaced with freshly regenerated vessels and returned to service. Exhausted vessels are transferred to our central treatment and processing facility wher​e the resin is regenerated.  The benefit is that there is no brine waste stream or chemical handling on the customer site.  Offsite regeneration can also offer the flexibility to add or remove treatment capacity. If needs change, Evoqua can simply change type of number of tanks, thereby saving you significant capital expense.

Reverse Osmosis (RO) for Nitrate Removal
​Nitrate removal by reverse osmosis (RO) uses a semi-permeable membrane to selectively remove various inorganics from the water. 

How does it work?  

Pressure is applied to the water to force it through the membrane. As the water passes through the membrane, it effectively leaves the impurities behind. Membranes do not exhibit varying selectivity for any given contaminant, and therefore the RO process removes many contaminants, including nitrates. Roughly 85 to 95 percent of the nitrates can be removed with reverse osmosis, depending on initial water quality, system pressure and water temperature. Because RO has a significant waste stream, as w​ell as higher operating costs and complexity, it is not as commonly used as Ion Exchange for this application.  

Biological Removal of Nitrates
​​​​Though a relatively new technology offering, naturally occurring bacteria in most groundwater can be used to provide denitrification (i.e. remove nitrates) and release the nitrogen as a gas. 

​How does it work?  

Biological reduction of nitrates to nitrogen gas and water is a natural process.  Evoqua enhances this natural process and then adds ultrafiltration on the back end to ensure compliance to drinking water standards.  Biological remediation offers easier waste handling and lower operating costs than IX or RO.

The patented two-stage continuously stirred Hall reactor and carrier media provide a high concentration of active bacteria in a small space.  This allows for a smaller overall footprint, and the ability to handle nitrate spikes due to process upsets.  The Evoqua system requires less chemical addition resulting in lower waste production and lower overall operating costs.  Finally, the bacteria in the Evoqua system does not go into sulfate reduction, which means this system does not have hydrogen sulfide gas odors typically associated with bioremediation.  

Memcor® ultrafiltration
provides an absolute barrier to suspended solids.  Subsequent disinfection integration provides a turnkey solution to nitrate treatment.

This system has been given California State Water Resources Control Board’s Department of Drinking Water conditional approval for use in drinking water.  

 Count on Evoqua for cost-effective, reliable nitrate removal

Whether it be ion exchange, reverse osmosis, or biological treatment technology - Evoqua can help you define the nitrate technology right for you.  You can count on Evoqua for dependable, responsive service, with 65 customer support centers nationwide and 24/7 dispatch through a convenient service hotline. We look forward to working with you on your next nitrate treatment system. Find your local service branch.

Read the below case studies to learn how Evoqua has helped customers​​​ with nitrate removal: