Emerging Contaminant Information

On July 30, 2020, the New York State Department of Health (NYSDOH) announced the finalization of new contaminant levels for emerging contaminants, which include 1,4 dioxane.  This new standard went into effect on August 26, 2020.  Recognizing that designing and constructing treatment systems was a time consuming and costly endeavor for water suppliers,  NYSDOH allowed water suppliers to apply for a compliance deferral to allow time for these treatment systems to be constructed.  The Town of Hempstead Department of Water like many water suppliers on Long Island, applied for and was granted a deferral for regulation of 1,4 dioxane for two years with the potential for a one year extension to come into full compliance of these new regulations.  This deferral has come with conditions to keep you, the consumer, informed of the work being done, the latest test results for this compound and a proposed schedule for milestones in the design and construction of these systems.

This page and the links below will be regularly updated with information as it becomes available.  Additionally, you annual Water Quality Report which is sent out every May will contain additional information on this contaminant. 

Work to date

In December of 2019 the Department of Water hired professional engineers proficient in the latest treatment technologies to begin design work at a number of sites.  Their work to date includes performing small scale pilot testing of treatment systems to verify the effectiveness of the systems and to determine the optimized operating levels for the systems.  The data and water quality samples collected are analyzed and Basis of Design reports are written for review by both the NYSDOH and Nassau County Health Department.  Concurrent with this process, detailed design drawings and specifications are developed to allow the work to be bid through a public procurement bid process.  A detailed schedule of the work completed and future contract milestones can be seen at the Project Schedule link below.

While these projects progress, the Department of Water will make every effort to limit the time that wells with elevated levels of this compound run to the system by placing them in a last on-first off manner.  Residents can help with this effort by conserving water, especially in the summer months.  Reducing sprinkler run times by just a few minutes will keep your landscape green, reduce your water costs and reduce the amount of time wells have to be run.

Proposed Treatment

The only proven treatment method for removing 1,4-dioxane from drinking water is the Advanced Oxidation Process (AOP).  AOP treatment blends raw groundwater with a low concentration of an oxidant, most commonly hydrogen peroxide, that then goes through a sophisticated ultraviolet light reactor that then destroys 1,4 dioxane molecules.

Once the groundwater goes through the AOP process it is then piped into Granular Activated Carbon (GAC) vessels to remove any remaining hydrogen peroxide from the water after which the water runs through a series of sophisticated monitoring systems before being sent to the distribution system for the consumer.

Funding these projects

The AOP systems and GAC vessels are costly to construct and operate.  AOP systems utilize a large amount of electricity and oxidizing chemicals and the carbon in GAC vessels must be removed and replaced periodically.  In December of 2020 the Town Board approved bond resolutions totaling over $90 million to fund these construction projects. 

The Town is doing everything it can to ensure residents do not have to bare this financial burden.  To this end the Department has applied for grants from New York State and was awarded a grant in the amount of $3.4 million.  We will continue to pursue all grant opportunities which become available.  Recognizing that the neither Department of Water nor our residents are responsible for the contamination being detected, we have been aggressively pursuing damages against the manufacturers of 1,4 dioxane and the companies that used it in their products.  While litigation can take years, our hope is to be successful in these lawsuits and use the compensation to fund these projects and pay down the associated bond debt. 


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Page Modified: 04/08/2021 16:02:43