Nitrogen-Nutrient-Reduction-Septic-Systems- The basics.

Why is nitrogen removal important? Nitrates and nitrites are known to have adverse effects on our health. They also effect ecosystems such as lakes and oceans. In Florida, there is a rising concern for the health of our natural springs. Although onsite-systems constitute a small part of the overall nitrogen problem, it is necessary, and relatively easy, to reduce the total-nitrogen emitted from septic-systems to affect the long term health of our springs and waterways.

The removal of nitrogen is accomplished through the biological oxidation of nitrogen from ammonia (nitrification) to nitrate, followed by denitrification, the reduction of nitrate to nitrogen gas. Nitrogen gas is released to the atmosphere and thus removed from the water.

In nitrogen-nutrient-reducing-septic-systems, nitrogen is removed from wastewater through a process called nitrification-denitrification. Nitrification itself is a two-step aerobic process, each step facilitated by a different type of bacteria. The activated sludge process is a common method to accomplish the task. The nitrification process begins when wastewater flows from an anoxic zone to an aerobic zone (from the septic tank or trash tank to the aeration chamber of an ATU). In the aeration chamber, conversion of ammonia-nitrogen to nitrate-nitrogen occurs biologically by bacteria present in the effluent.

Denitrification requires anoxic conditions to encourage the appropriate bacterial communities to form. Since denitrification is the reduction of nitrate to dinitrogen gas, an electron donor is needed. This is usually organic matter (from feces)  but can be a commercially available food grade carbon source additive that is pumped into the system.

In nitrogen-nutrient-reducing-septic-systems this is typically accomplished by recirculating a portion of the aerated effluent back to the septic tank or trash tank of the system.

Click on the images below to view information on the different nitrogen-nutrient-reducing systems that we utilize in our designs.