EliminatIR™ Gate

High nitrate recycles can dilute incoming BOD and reduce hydraulic detention times in that zone, which can suppress nitrogen removal. The EliminatIR™ gate can be closed at certain times of the day to adjust the actual internal recycle real time and/or to develop anaerobic conditions.

In the Carrousel® denitIR® system, internal (nitrate) recycle is conveyed through a slipstream channel that captures a portion of the large recirculating channel flow. This slipstream is often 15-20 times faster than the influent flow, allowing for large amounts of the nitrate recycle to flow back into the anoxic zone. This is one of the primary reasons Carrousel systems remove total nitrogen to such low levels.

Throughout the day, there are times when it is undesirable to have too much recycle go back to the anoxic zone. High nitrate recycles can dilute incoming BOD and reduce hydraulic detention times in that zone, which can suppress nitrogen removal. The EliminatIR™ gate is used to adjust the actual internal recycle real time.

In facilities that require phosphorus removal, the EliminatIR gate may be closed at certain times of the day to develop anaerobic conditions. The Carrousel AlternatIR System operates the EliminatIR gate in this manner using the Oculus control system.

  • Manual or automatic operation
  • Pivoting gate allows for varying positions
  • Controls flow amounts

The EliminatIR™ flow control gate is used in Carrousel® denitIR® systems to control the amount of mixed liquor flow from the Carrousel basin to the upstream anoxic basin. Mixed liquor containing nitrates from the Carrousel basin is recycled to the upstream anoxic basin through a bypass channel.

At the head of this channel is the adjustable EliminatIR™  flow control gate. The components of the gate permit the gate position to be varied in accordance with the amount of internal recycle flow desired. The flow through the bypass channel is controlled by the position of the denitIR gate and the position is selected based on the denitrification requirements of the particular design.

Do I need to control internal recycle?
For maximum nitrogen removal, yes. The internal recycle in a Carrousel® system is free and is not limited by pumping capacity and can approach 15-20Q . While this high recycle rate is good for nitrate delivery to the anoxic zone, this large recycle amount can dilute the incoming BOD and anoxic zone detention times, suppressing overall nitrogen removal. A control system on the internal recycle allows you to have unlimited nitrate recycle capacity and allows you to make adjustments based on ORP measurements to deliver the optimum nitrate recycle at any given time.

contact us

Carrousel® is a trademark of Royal Hasking DHV, B.V., The Netherlands