By integrating the flotation tank, micro-bubble air saturation system, automatic surface sludge scraper, sludge hopper, and PLC control system into a single skid-mounted package, this unit delivers reliable clarification prior to discharge or downstream biological treatment.

Typical Removal Efficiencies

Parameter	Typical Removal / Reduction Efficiency
Total Suspended Solids (TSS)	90% - 98% removal
Fats, Oils, & Grease (FOG)	90% - 95%+ removal
Chemical Oxygen Demand (COD)	40% - 75% reduction (particulate fraction)
Biochemical Oxygen Demand (BOD)	40% - 70% reduction

Technical Specifications & Sizing Parameters

Parameter	Standard Range / Option	Design Significance
Hydraulic Loading Rate	4 - 12 m3/m2/h	Determines surface area requirement based on rise velocity
Micro-Bubble Size	20 - 50 microns	Ensures optimal bubble-particle attachment ratio
Recycle Ratio	15% - 50%	Sized according to solids concentration and air requirements
Operating Pressure	4.0 - 6.0 bar	Maintained in the air saturation vessel for dissolved air generation
Tank Materials	SS304 / SS316L / Coated Carbon Steel	Selected based on wastewater pH and chloride levels
Control Integration	Manual / Automatic / PLC (Siemens or Allen-Bradley)	Controls recycle pump, chemical dosing, and scraper timing

How the Packaged DAF System Works

Chemical Conditioning (Optional): Coagulants and flocculants are dosed to destabilize particles and form larger flocs.

Bubble Attachment: A recycled stream of clarified water is saturated with air under pressure and released into the flotation zone at atmospheric pressure. Micro-bubbles attach to the flocculated particles.

Surface Separation: Floating solids form a dense sludge blanket at the water surface.

Automatic Scraping: The top scraper transfers the sludge blanket into the collection hopper without disturbing the lower clarified water zone.

Key System Components

Flotation Separation Tank: Engineered geometry in 304/316 Stainless Steel or Coated Carbon Steel designed for optimal surface hydraulic loading.

Dissolved-Air Recycle System: Includes multi-stage recycle pump, air saturation vessel, pressure release valves, and micro-bubble distribution headers.

Automatic Surface Sludge Scraper: Heavy-duty chain-and-flight or continuous blade drive with variable speed control.

Integrated Sludge Hopper: Bottom-sloped design with direct connections for gravity drainage or progressive cavity sludge pumps.

Integrated Control Panel: IP65/NEMA 4X enclosure with manual/auto modes, variable frequency drives (VFDs), and optional PLC integration.

Industry Applications

Industry	Primary Contaminants Removed	Typical Pretreatment Requirements
Food & Beverage Processing	Organic solids, starch, vegetable oils, FOG	Coagulation + Flocculation
Meat & Poultry Processing	Proteins, blood solids, animal fats, grease	PH adjustment + Flocculation
Dairy Processing	Milk solids, butterfat, whey particulates	Coagulation + Flocculation
Edible Oil Refining	Free oil, emulsified oils, soapstock	Acid cracking / Coagulation
Industrial Manufacturing	TSS, emulsified hydrocarbons, metal hydroxides	Polymer dosing

Verified Field Case Studies

Case Study 1: Poultry Processing Facility

Challenge: High FOG (>1,200 mg/L) causing downstream biological reactor fouling.

Solution: 50 m3/h Packaged DAF System with integrated polymer dosing unit.

Results: Outlet FOG consistently reduced to <45 mg/L (>96% removal); TSS reduced from 1,800 mg/L to <80 mg/L.

Case Study 2: Dairy Wastewater Pretreatment

Challenge: Fluctuating peak hydraulic loads and high suspended organic solids.

Solution: 30 m3/h Stainless Steel DAF skid with dual-speed sludge scraper and automatic PLC controls.
Results: Reduced downstream municipal sewer surcharge fees by 85%.

Supplier Comparison Checklist

Scope Completeness: Confirm if the offer includes the recycle pump, micro-bubble release valves, chemical dosing headers, internal piping, and electrical control panel.

Material Specifications: Differentiate between wetted parts material (e.g., SS304 vs. SS316L) and structural frame materials.

Scraper Durability: Verify drive motor power, chain material, flight blade wear strips, and mechanical overload protection.

Factory Testing: Request Factory Acceptance Test (FAT) records, weld inspection documentation, and wet testing photos or videos prior to shipment.

FAQ

Q: How do I determine if my wastewater requires chemical pre-treatment before the DAF?

A: Free oils and coarse solids often float naturally with micro-bubbles. However, if your wastewater contains emulsified oils, colloidal particles, or fine suspended solids, coagulants (such as PAC or Ferric Chloride) and polymers (PAM) are required to build larger flocs for efficient bubble attachment.

Q: What is the main advantage of an automatic sludge scraper over manual skimming?

A: An automatic sludge scraper continuously removes the floating sludge layer at a controlled speed. This maintains consistent separation efficiency, prevents sludge from sinking back into the clarified water, controls sludge dry-solids content, and eliminates manual labor.

Q: How is a DAF system sized correctly?

A: DAF systems must be sized based on both hydraulic flow rate (m3/h) and total solids loading rate (kg TSS/h). Selecting a unit based on flow rate alone can lead to undersized equipment if the wastewater has high TSS or oil concentration.

Q: Can the DAF system handle variable flow rates and pollutant loads?

A: Yes. Packaged DAF systems equipped with Variable Frequency Drives (VFDs) on the recycle pump and adjustable scraper speed control can handle fluctuations in flow and loading. Integrating a upstream Equalization Tank (EQ Tank) is also recommended for severe surges.

Q: What daily maintenance is required for a packaged DAF system?

A: Daily maintenance is minimal: monitor pressure gauges on the air saturation vessel, inspect micro-bubble distribution uniformity, check chemical dosing storage, and visually confirm scraper alignment and chain tension.

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