Fox Metro’s Laboratory

1) Total Kjeldahl Nitrogen

Total Kjeldahl Nitrogen (TKN) is the combined measure of organic nitrogen and ammonia in a sample. Excess nitrogen can harm aquatic ecosystems by lowering dissolved oxygen levels and becoming toxic to aquatic life. In analysis, organic nitrogen is first converted to ammonium through Kjeldahl digestion. The ammonium is then distilled into a boric acid solution and measured via titration with sulfuric acid. The solution contains a red pH indicator, changing from green to red as ammonia is neutralized. The amount of titrant needed to lower the pH to 4.5 allows us to identify the amount of Nitrogen in the sample.

2) Phosphorus

Phosphorus serves as a vital nutrient for aquatic plants, but excessive levels can trigger algae blooms, diminishing dissolved oxygen and releasing toxins. At Fox Metro, phosphorus analysis commences with an acidic digestion. Subsequently, the pH is slightly adjusted and a color developer is introduced. Under favorable conditions, this developer reacts with phosphorus, yielding a vivid blue color. The intensity of this blue hue directly corresponds to the phosphorus concentration.

3) Inductively Coupled Plasma

Some contaminants, including certain elemental metals, pose challenges for effective treatment and can be harmful even at very low concentrations. At Fox Metro, we employ “Inductively Coupled Plasma-Mass Spectrometry” (ICP-MS) to analyze these metals. In this process, a sample is injected into a high-temperature argon plasma. The plasma atomizes most molecules, and the resulting atoms are directed into a mass spectrometer. Here, particles are sorted based on their mass and identified using their mass-to-charge ratio. This technique allows for the identification of numerous elements with an accuracy of 10 parts per billion.

4) Microscope

Various techniques are employed to remove pollutants and treat influent wastewater before safe discharge into nature. Physical debris is removed by bar screens and settling tanks, while chemical treatment targets problematic “bad” bacteria. Biological nutrient removal (BNR) relies on beneficial “good” bacteria to absorb and retain nutrients like nitrogen and phosphorus until they can be physically separated from the water. These bacteria reside in activated sludge, and Fox Metro routinely examines samples from aeration tanks to assess sludge health. Our Microscope Lab allows us to view the nutrient-removing bacteria, observe their behaviors, and gain insight into their well-being.

5) Field Data

The Fox River is continuously monitored for temperature, dissolved oxygen, and pH using field instruments called sondes. These sondes utilize electrochemical and optical probes for measurements and are strategically positioned at various locations along the river. They collect data snapshots at regular intervals, storing them until field scientists retrieve and download the data during site visits. Sondes are purpose-built for continuous deployment in the dynamic and challenging environments of rivers and sewer systems. Their sturdy construction ensures reliable performance even in rough waters.

6) Hexane Extractable Material

Fats, oils, and greases (FOG) are viscous, sticky, and semisolid substances that pose a threat by clogging wastewater pipes and equipment in treatment plants. Some FOG components can also be toxic to plants, animals, and humans. Fox Metro employs a technique called hexane extractable materials (HEM) to monitor these pollutants. In this process, the non-aqueous portion of a sample is collected on a filter and placed into a Soxhlet apparatus. Hexane is then refluxed over the solid sample, dissolving fats, oils, and greases into the solvent. Subsequently, when the hexane solvent is evaporated, the FOG residue remains for analysis.