Orthos Liquid Systems Equipment

Denitrifying Deep Bed Filter (DDBF™)

Orthos Liquid Systems

Product Brochure

Wastewater Equipment

Denitrifying Deep Bed Filter (DDBF™)


The Denitrifying Deep Bed Filter (DDBF™) is a wastewater treatment process of the Poseidon Filtration System®. It provides fixed‑film biological denitrification in a downflow filter configuration.  With proper chemical treatment, the DDBF™ is capable of meeting stringent effluent limits of total nitrogen as low as 3 mg/l, total suspended solids to 2 mg/L, and total phosphorus to 0.3 mg/L or less.

How it works

In the DDBF™, denitrifying organisms attach to the filter media. Supplemental carbon is augmented to the filter influent to drive the denitrification process. Wastewater flows around nitrogen gas bubbles that accumulate in the media and reduce the space between sand grains, which improves biomass contact and filtration efficiency.

Orthos’ Centurion™ structurally-superior filter underdrains feature nozzles with solid-expelling slots, specifically‑sized to retain the DDBF™ media and prevent biological fouling.  No gravel layer is necessary, which reduces hydraulic profile and eliminates related horizontal short‑circuiting.\


  • Biological removal of nitrate-nitrogen (NO3-N) from clarified wastewater to as low as 3 mg/L
  • Effluent suspended solids, total phosphorus, and BOD reduction
  • Structurally-superior Orthos Centurion™ underdrain with no gravel layer required
  • Compound-loop feedback control of carbon addition
  • Run-time and backwash optimization


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