Industrial Wastewater DAF Selection | Beta Pramesti

Dissolved Air Flotation (DAF) separates suspended solids, oil, grease, and light floc by attaching fine bubbles to particles and lifting them to the surface for skimming. DAF is worth testing when solids settle poorly or FOG dominates, but unit size and chemical conditioning must come from actual samples, flow, solids loading, and flotation-test results.

PT Beta Pramesti Asia, through beta.co.id, supplies Betaqua DAF units, recycle and saturation systems, skimmers, dosing packages, and testing support for industrial wastewater in Indonesia. Selection covers pretreatment, coagulants, flocculants, sludge routing, construction materials, instrumentation, and the treated-water target.

When is DAF more suitable than a clarifier?

DAF is not a universal replacement for sedimentation. Choose the mechanism from particle behaviour and test evidence: dense solids forming stable floc may settle in a clarifier, while oil, grease, algae, or low-density floc may be better candidates for flotation.

Water or floc condition	First route to test	Evidence for the decision
Free or emulsified oil/grease with TSS	DAF with coagulation-flocculation review	FOG, TSS, pH, emulsion condition, flotation result, and skimmings
Light or slow-settling floc	DAF compared with a clarifier	Separation rate, water clarity, surface loading, and sludge volume
Dense mineral solids that settle readily	Gravity clarifier	Settling test, hydraulic load, and solids load
TDS or dissolved ions limit the water	Dissolved-solids treatment, not DAF	Ion analysis and the reuse or discharge target
Load changes sharply between shifts	Equalisation followed by tests at several conditions	Flow, concentration, pH, temperature, and upset-source profile

Which data determine DAF size and chemistry?

Start with average/peak flow and the load profile, not a catalogue capacity alone. Calculate mass load as concentration (mg/L) × flow (m³/day) ÷ 1,000 = kg/day, then measure the fraction that flotation can actually separate.

Design data	Why it matters	Decision supported
Flow and load profile	Defines hydraulic load and equalisation demand	Unit size, train count, and turndown
TSS, FOG, COD, pH, temperature	Defines contaminant mass and behaviour	Pretreatment, materials, and separation target
Coagulant/flocculant tests	Assesses floc formation and strength	Product, starting dose, injection order, and mixing
Flotation/recycle test	Shows whether bubbles carry the conditioned floc	Saturation, recycle, skimming, and clarified-water conditions
Skimmings character	Defines volume, solids percentage, and pumpability	Sludge tank and dewatering stage
Effluent target	Defines the next process requirement	DAF as biological pretreatment, filtration, or final separation

A chemical programme does not automatically require PAC or a high dose. Screen coagulants and flocculants on the actual water, then check whether floc remains stable through pumps, pipes, and the contact zone. Calibrate pumps and state dose consistently as commercial product or active material.

How should unstable DAF performance be checked?

Symptom	First checks	Evaluation response
Clarified water remains cloudy	pH, dose, mixing, floc size, recycle, and flow distribution	Restore the baseline and test one variable at a time
Oil carries through	Emulsion source, temperature, surfactant, coagulant, and skimming	Test suitable emulsion breaking and flotation conditions
Skimmings are too dilute	Skimmer frequency, bed depth, water carryover, and conditioning	Optimise withdrawal and the sludge route
Pressure or recycle is unstable	Pump, vessel, valve, sensor, leakage, and supply	Correct mechanical function before increasing chemicals
Chemical use rises sharply	Influent quality, stock concentration, calibration, and injection point	Confirm delivery and load change before replacing the programme

Frequently asked questions about wastewater DAF

Does DAF always require coagulants and flocculants?

No. Need and dose depend on particle size, emulsion, pH, surface charge, and the separation target. A test without chemicals and a controlled dose sweep show whether conditioning creates a measurable benefit.

Can DAF be installed before biological treatment?

Yes, when testing shows that FOG and TSS separation reduces downstream disturbance without removing the influent characteristics needed by the next process. Review the result with the design of the aerobic wastewater system.

Which data are needed for a DAF proposal?

Send the flow diagram, normal/peak flow, TSS, FOG, COD, pH, temperature, coagulation/flotation results, water target, material restrictions, utilities, space, and sludge route through the Beta contact page.