FORT COLLINS, Colo.–In-Situ® Inc. announced today that the United States Environmental Protection Agency has granted nationwide approval to three In-Situ RDO® optical dissolved oxygen methods under the Alternate Test Procedure, or ATP, process.

The In-Situ RDO methods are the only optical- or luminescence-based DO methods to pass the rigorous ATP approval process for measuring Biochemical Oxygen Demand (BOD), Carbonaceous Biochemical Oxygen Demand (CBOD) and Dissolved Oxygen (DO) under the Clean Water Act.

The comprehensive ATP process validated three methods using the In-Situ RDO optical (luminescent) DO sensor as the determinative technique. Results from the validation establish the In-Situ RDO methods as the most widely tested and applicable optical DO methods available for compliance monitoring.

Ten federal- or state-certified laboratories performed testing in nine water and wastewater sample matrices. Over 1,300 samples were tested in municipal wastewater (influent and effluent), industrial wastewater from significant and categorical dischargers, ambient surface water, drinking water and other categories. No significant matrix interferences were observed in any of the 1,300 samples tested.

Entities holding National Pollution Discharge and Elimination System (NPDES) permits must use EPA-approved methodologies for BOD, CBOD and DO testing.

The EPA Office of Science and Technology will recommend the In-Situ RDO methods for inclusion at 40 CFR Part 136.3. In the interim, NPDES permit holders can begin monitoring with the In-Situ RDO methods after seeking approval from their regional USEPA authority.

In-Situ RDO sensors measure DO using the principle of “dynamic luminescence quenching.” Unlike other optical sensors, RDO sensors do not require hydration. In addition, RDO sensors exhibit minimal sensor drift over extended periods of use and are not subject to matrix interferences that plague electrochemical sensors (e.g., sulfides, oils, greases, ammonia).

RDO sensors eliminate a variety of reliability concerns and maintenance costs inherent in older technologies. Now with wide-ranging, nationwide approval, In-Situ Inc.’s RDO technology can effectively replace the antiquated membrane-based DO technology.

Complete and accurate names of the In-Situ methods are:

– In-Situ Inc. Method 1003-8-2009 Biochemical Oxygen Demand (BOD) Measurement by Optical Probe (ATP Case No. N09-0020)

– In-Situ Inc. Method 1004-8-2009 Carbonaceous Biochemical Oxygen Demand (CBOD) Measurement by Optical Probe (ATP Case No. N09-0021)

– In-Situ Inc. Method 1002-8-2009 Dissolved Oxygen Measurement by Optical Probe (ATP Case No. N05-0014)

The In-Situ RDO sensor and sensing foil are manufactured entirely by In-Situ Inc. in Fort Collins and Boulder, Colo. RDO sensors are available for process, laboratory and field applications. For laboratory applications, the In-Situ RDO sensor is available exclusively with Thermo Scientific Orion Star series meters.

Visit www.in-situ.com/news and click on “Press Room” to download the EPA letters; the In-Situ RDO methods for BOD, CBOD and DO; and photos.

ABOUT IN-SITU INC. In-Situ Inc. designs, manufactures, distributes, and rents environmental equipment for monitoring the quantity and quality of groundwater and surface water. From advanced aquifer characterization, to long-term monitoring, to economical data collection, In-Situ instruments provide accurate results and reliable operation even in harsh conditions. In-Situ Inc.’s headquarters are located at the foot of the Rocky Mountains in Fort Collins, Colo., USA. In-Situ offers world-class technical support 24 hours a day, 7 days a week through its global network of regional offices and distributors. Please visit www.in-situ.com.

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