Attached Growth Design: baf
baf design downflow sunken to baf dnf loading continuous backwash max
Attached growth biological treatment design parameters — trickling filter (low rate, high rate, partial BOD, nitrification), TFSC, TFAS, IFAS, MBBR carrier properties and removal/volumetric fluxes, and BAF volumetric loadings, oxygen transfer, denitrification loadings, and backwash rates. Source: Metcalf & Eddy Wastewater Engineering 5th Ed., Chapter 9.
| process type | parameter id | description | parameter name | unit | value min |
|---|---|---|---|---|---|
| baf | baf design downflow sunken | Primary effluent applied above bed of heavy media at 1.6-2.0 m depth. Typical media: 3.0-5.0 mm expanded clay or shale (SG ~1.6). Downflow velocity 2.4-4.8 m/h. Backwash: air scour ~90 m³/m²·h then water ~15 m³/m²·h. Products include Biocarbone and Biodrof. | BAF design description - downflow sunken media | — | — |
| baf | baf design fluidized bed | Wastewater fed upward to fluidized bed of 0.3-0.7 mm sand or 0.6-1.4 mm activated carbon. Bed depth 3.0-4.0 m. Upflow velocity 30-40 m/h for 0.5 mm silica sand. Recycle 2-5× influent flowrate. HRT 10-20 min. | BAF design description - upflow fluidized bed bioreactor | — | — |
| baf | baf design upflow floating | Floating bed of spherical media lighter than water. Biostyr: 3.0-6.0 mm polystyrene (SG ~0.5); Biobead: 2.3-2.7 mm polyethylene (SG ~0.95). Typical bed height 3-4 m. Upflow velocity 4-6 m/h. Other products: Biopure and Biolest. | BAF design description - upflow floating media | — | — |
| baf | baf design upflow floating anoxic | Biostyr variation with anoxic zone for nitrification and denitrification in same reactor. Air header ~2 m below top; bottom portion is nonaerated preanoxic zone. Nitrified effluent recycled to influent; BOD in primary effluent provides electron donor. | BAF design description - upflow floating media with anoxic zone | — | — |
| baf | baf design upflow sunken | Primary effluent applied through nozzles in plenum floor. Typical media: expanded clay or shale 3.5 or 4.5 mm spherical (SG 1.6). Bed depth 3 m (range 2-4 m). Upflow velocity 4-6 m/h. Backwash water flush rate 10-30 m³/m²·h. Product: Biofor. | BAF design description - upflow sunken media | — | — |
| baf | baf dnf loading anoxfbbr max | — | DNF volumetric loading - AnoxFBBR maximum | kg NO3-N/m³·d | 5 |
| baf | baf dnf loading anoxfbbr min | — | DNF volumetric loading - AnoxFBBR minimum | kg NO3-N/m³·d | 3 |
| baf | baf dnf loading anoxmbbr max | — | DNF volumetric loading - AnoxMBBR maximum | kg NO3-N/m³·d | 0.5 |
| baf | baf dnf loading anoxmbbr min | — | DNF volumetric loading - AnoxMBBR minimum | kg NO3-N/m³·d | 0.25 |
| baf | baf dnf loading continuous backwash max | — | DNF volumetric loading - continuous backwash maximum | kg NO3-N/m³·d | 2 |
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