The Carrousel® denitIR® System (for denitrification with Internal Recycle) is a two-stage biological treatment system designed to provide a simple, cost-effective method of biological nitrification and denitrification without the need for expensive internal recycle pumps. The combination of the anoxic basin and Carrousel® aeration basin allows for the continuous recycle of nitrified and denitrified mixed liquor between the two basins. Internal recycle from the Carrousel basin to the anoxic basin is achieved by means of a side channel adjacent to the inlet to the aeration zone. Flow is forced into this channel by means of the velocity head generated in the Carrousel® channels. At the entrance of the recycle channel, a control gate allows for adjustment of the MLSS recycle flow. Flow is returned to the Carrousel® basin by means of another side channel adjacent to the outlet of the aeration zone. By combining the operating flexibility and energy economy of the Carrousel® System with a separate, dedicated anoxic basin, and providing high mixed liquor recycle rates at virtually no additional cost, the Carrousel® denitIR® System presents a simply superior solution to the needs of biological denitrification.

Features & Benefits

• All benefits of the Carrousel® System
• Dedicated volumes for aerobic and anoxic conditions – maximum reaction rates
• High efficiency aeration system with maximum power turndown capability
• Power savings due to denitrification oxygen credit
• Alkalinity recovery
• No internal recycle pumps required
• Internal Recycle Rates up to 10 to 15 times the forward flow for “free”
• Up to 90% nitrogen removal efficiency

info.ewt@glv.com