CDFU Versus Conventional DAF, MACT Versus Plain Carbon: A Parameter-by-Parameter Look
Oily firefighting wastewater is an awkward stream to treat: it arrives in bursts, it carries suspended solids alongside the oil, and any adsorbent used at the tail has to survive a hard duty. Rather than argue about it in general terms, it is more useful to line the two core pieces of equipment in the SINOKLE process - CDFU, the cyclonic dissolved air flotation unit, and MACT - against their conventional counterparts and read off the numbers.
Part One: CDFU Against Conventional DAF
CDFU is a patented product of SINOKLE. Building on internationally advanced technology, it organically combines cyclonic centrifugal separation with flotation separation, and was developed into its present form through CFD optimization. The comparison table tells the story:
- Treated water quality: both handle oily wastewater with suspended solids.
- Retention time: 15~40min for conventional DAF against <5min for CDFU.
- Single-stage oil removal efficiency: 60%~85% conventional versus above 90%.
- Single-stage suspended-solids removal rate: 50%~70% conventional versus above 80%.
- Removal particle size at above 80% efficiency: >5μm conventionally against <3μm.
- Bubble diameter: 5μm~100μm with only moderate uniformity conventionally, versus 5μm~30μm with good uniformity.
- Operation mode: manual and open type conventionally; automatic and enclosed here.
- Structure type: reinforced concrete conventionally; a pressure-vessel skid-mounted package here.
Three structural design features support that performance. Dual tangential inlets deliver greater rotational speed and a more stable swirling flow, which adds resistance to fluctuation and lets the unit absorb large turndown swings of up to 50%. Dual flotation zones divide the tank into an inner and an outer zone via the central tube, which refines the flow and keeps oil droplets from being entrained in the effluent. And the cyclonic desanding design steers heavier particles along the inner tube wall into a conical zone for periodic fluidized sand discharge, so clogging is far less likely.
Part Two: MACT Against Conventional Activated Carbon
MACT is also a patented product of SINOKLE. It begins with conventional activated carbon and modifies it specifically to improve the adsorption effect and rate on PFCS pollutants, then achieves recycling through a patented microwave high-efficiency regeneration technology.
- Treated water quality: oily firefighting wastewater on both sides.
- Retention time: 20min conventionally against 10min for MACT.
- COD removal rate: 60% conventionally versus 80%.
- PFOA removal rate: 10% conventionally versus 80%.
- Performance efficiency: 60%-70% conventionally versus 85%-90%.
- Effluent stability: medium conventionally against high.
- Sludge volume: low conventionally against very little, with regeneration.
- Reuse rate: 90% conventionally versus 95%.
- Regeneration energy consumption and time: high and long conventionally; low and short here.
Activated carbon modification mainly involves physical surface modification - adjusting specific surface area and pore size distribution - and chemical surface modification such as oxidation, reduction, loaded-atom and surface acid-base treatment, all aimed at obtaining targeted adsorption performance.
The microwave regeneration step deserves a note of its own. Set against conventional high-temperature, biological, ultrasonic and solvent regeneration, it needs no chemicals, consumes little energy, uses zero water, reaches a high regeneration rate and completes in a short cycle. The mechanism is straightforward: polar molecules adsorbed on the carbon undergo dipole reorientation polarization in the microwave field, which converts microwave energy into heat, so the carbon heats rapidly and its pores recover quickly, reaching over a thousand degrees Celsius within minutes. As a physical regeneration method it requires no backwashing and produces no additional wastewater.
Overall Process Indicators
The complete CDFU plus MACT train achieves an oil removal efficiency of no less than 90%, with low energy consumption (only 10%) and low gas consumption (1%~3% of throughput). Performance is stable and the equipment can meet a flow fluctuation range of 10%~120%. Compared with conventional technology, the footprint is less than 10% and the operating cost less than 30%, with ozone consumption at 20~25%, while the effluent can stably meet the Class I A standard or better.
What the Two Comparisons Add Up To
The two halves of the train solve different problems, and it is worth being clear about which is which. The flotation stage decides how much oil and solids leave the water in the first place; the adsorption stage decides how clean the water can become after the bulk is gone. A project that upgrades only one of them tends to hit a ceiling, because the other becomes the limiting step. Reading the two tables together is therefore more informative than reading either alone.
The Takeaway
Neither comparison is a wash. On the flotation side, the retention-time and removal-efficiency gaps are large enough to change how much tankage a project needs. On the adsorption side, the jump in PFOA removal from 10% to 80% is the difference between a token step and a working one. Read together, the numbers explain why the combination is offered as a package rather than as two independent equipment choices, and they also set a fair expectation: the case rests on measurable gaps, not on the label "advanced".