The addition of sulfamic acid to the wastewater effectively removes sodium nitrite by reducing the nitrites to form sodium bisulfate, diatomic nitrogen, and water. The addition of sodium hydroxide to the wastewater results in the formation of a precipitate effectively removing heavy metals. The treatment process generates sludge from the initial settling and heavy metal flocculation, which must be dewatered and disposed as a hazardous waste. The unit removes sodium nitrite to a level below the NPDES level of 1 mg/L. Therefore the wastewater can be discharged to the sanitary sewer system. The centralized unit began operating in August 1996 at Naval Air Station North Island.

The system consists of mixing tanks, metering pumps, filters, and chemical sensors. The influent enters a feed settling tank for gravity settling of large suspended particles. The wastewater then undergoes nitrite reduction through the addition of a 15% solution of sulfamic acid (NH₂SO₃H). For heavy metal precipitation, sodium hydroxide is added to the wastewater. The sodium hydroxide forms a precipitate that removes heavy metals through coagulation and flocculation. An anionic polymer is added to aid in the precipitation of the heavy metals. The final addition of sulfuric acid neutralizes the wastewater prior to discharge. Filters, as small as 5 microns, clean the effluent subsequent to its discharge to the sanitary sewer system. Sludge produced from the settling tank and the heavy metal precipitation is dewatered prior to disposal.

The compliance benefits listed here are only meant to be used as general guidelines and are not meant to be strictly interpreted.  Actual compliance benefits will vary depending on the factors involved, e.g., the amount of workload involved.

Consult your local Industrial health specialist, your local health and safety personnel, and the appropriate MSDS prior to implementing any of these technologies.

• This system demonstrates an effective process to convert nitrite to nitrogen gas. It will allow for treatment of wastestream produced by the marine steam boiler maintenance which had gone to contractors for disposal. This will result in an substantial costs savings. This technology will potentially be available in stationary and mobile treatment units.  

• Effective only on waste stream generated from boiler steam cleaning.

Based on a 50 mg/L initial toxic concentration, the cost to operate the LIPOD range from $0.01/L to $0.02/L ($0.03/gal. to $0.07/gal.). The cost reflects the complete conversion of toxic organic compounds to carbon dioxide and water.

The 600-gallon transportable unit is currently under development by NFESC and will be implemented by the Naval Surface Warfare Center, Carderock Division. The projected annual cost savings Navy-wide will be $10 million. The unit should reduce disposal costs by approximately 95% (from $3.25 per gallon contracted disposal, to $0.15 per gallon treatment costs). Six units have been built to date at a cost of $60,000 each.

*There are multiple MSDSs for most NSNs. The MSDS (if shown above) is only meant to serve as an example. To return from the MSDS, click the Back arrow on the Tool Bar.

National Concrete Products
P.O. Box F
Greenwood, DE 19950
Phone: (302) 349-5528
FAX: (302) 349-9435
Contact: Mr. Mac McCombs