Electrocoagulation DAF Unit
Faced with complex wastewater from electroplating, printing and dyeing, petrochemical, landfill leachate and other industries—characterized by high salinity, high turbidity, oil content and poor biodegradability—traditional chemical coagulation often falls into the dilemma of high chemical consumption, large sludge volume and unstable compliance. Wushi Environmental officially launches the Electrocoagulation-Dissolved Air Flotation Integrated Unit (EC-DAF), which integrates electrolytic coagulation, electroflotation and free radical oxidation into a single unit. With no or only a small amount of chemical dosing, it simultaneously achieves coagulation, flotation separation and partial oxidative degradation, providing a cleaner and more compact technical route for the pretreatment and advanced treatment of difficult wastewater.
I. Product Positioning
The Electrocoagulation-DAF Integrated Unit is a deeply coupled device combining electrocoagulation (EC) and dissolved air/electroflotation (DAF). It uses sacrificial metal (iron/aluminum) anodes to dissolve multivalent metal ions under direct current as an "in-situ coagulant", while hydrogen gas is evolved at the cathode to form micron-sized microbubbles. The buoyancy of these bubbles carries flocs, oil droplets and colloidal particles to the water surface to form scum that is scraped off, while the lower clear water is discharged to meet standards. The unit adopts a modular integrated design, integrating reaction, separation, scum collection and electrical control, and can be installed above ground and put into use immediately.
II. Working Principle (Brief)
Raw water inlet: The wastewater to be treated enters the reaction zone of the unit, is evenly distributed and begins electrolytic treatment.
Electrocoagulation reaction chamber: Under the direct current electric field, the iron/aluminum sacrificial anode dissolves multivalent metal ions, which act as an "in-situ coagulant" to form flocs with pollutants in the water; meanwhile, the cathode continuously evolves hydrogen gas, forming microbubbles of tens of microns.
Flotation separation chamber: The microbubbles attach to flocs, oil droplets and colloidal particles, causing them to float to the surface to form scum, which is periodically removed by a scraper; the lower clear water sinks and collects.
Clear water outlet: The separated clear water is discharged from the bottom, and the scum is transported out for disposal, completing the synergistic purification of "coagulation + flotation + oxidation".
Process schematic: Raw water → Electrocoagulation reaction chamber (in-situ coagulation + hydrogen evolution microbubbles) → Flotation separation chamber (scum floats / clear water sinks) → Treated water outlet
The entire process is continuously completed in the same reactor: the metal hydroxide flocs generated by electrolysis have stronger entrapment and adsorption capacity than chemical coagulation, while the hydrogen microbubbles continuously evolved at the cathode (typically tens of microns) provide ample buoyancy carriers for the flocs; some organic matter is also electrochemically oxidized near the anode and indirectly oxidized by free radicals (·OH, etc.), achieving a triple synergy of "coagulation + flotation + oxidation".
III. Core Advantages
① Electricity instead of chemicals, sludge reduction at source In-situ generation of coagulant, no or minimal dosing of PAC/PAM, sludge production can be reduced by about 30%–50% compared with traditional coagulation.
② Dual action of bubbles + oxidation Synergy of hydrogen microbubble flotation and free radical oxidation, simultaneous removal of colloids, emulsified oil and color.
③ Compact integrated, ready to use Modular steel tank, small footprint, above-ground installation, suitable for land-constrained or retrofit projects.
④ Intelligent control, anti-passivation Constant current/constant voltage mode + automatic polarity reversal, slowing electrode passivation, stable operation and simple maintenance.
⑤ Wide water quality adaptability Good adaptability to high salinity, high turbidity, oily and heavy metal-containing wastewater, resistant to shock loads.
⑥ Clean and safe No introduction of large amounts of external chemicals, low secondary pollution, more controllable hazardous waste properties.
IV. Main Technical Parameters (Reference Range)
Item | Parameter Range / Description | Remarks |
|---|---|---|
Single unit capacity | 0.5 – 50 m³/h (modular parallel expansion available) | Customized by model |
Electrode plate material | Iron alloy / aluminum alloy (switchable according to water quality) | Sacrificial anode |
Power supply mode | DC stabilized, constant current or constant voltage operation | Equipped with automatic polarity reversal |
Current density | Approx. 10 – 60 A/m² | Adjusted with water quality |
Electrode gap | Approx. 5 – 20 mm | Affects energy consumption and mixing |
Hydraulic retention time | Approx. 8 – 30 min | Including reaction and separation |
Microbubble size | Tens of microns (cathodic hydrogen evolution) | Flotation carrier |
SS / turbidity removal rate | Approx. 80% – 95% | Depends on raw water |
COD removal rate | Approx. 30% – 70% | Higher range for refractory water |
Oil removal rate | Above 90% | Also applicable to emulsified oil |
Color removal rate | Approx. 60% – 90% | Significant for printing and dyeing wastewater |
* The above are typical reference ranges. Actual removal performance varies with raw water quality, electrode combination and operating conditions. Specific values should be determined by bench tests or on-site parameter adjustment.
V. Typical Application Scenarios
Industry / Wastewater Type | Main Removal Targets |
|---|---|
Electroplating / surface treatment wastewater | Heavy metal ions, cyanide, suspended solids |
Printing and dyeing / textile wastewater | Color, COD, colloids |
Paper mill wastewater | Suspended solids, colloids, partial COD |
Petrochemical / machining wastewater | Emulsified oil, floating oil, SS |
Food / aquaculture wastewater | Organic matter, grease, colloids |
Landfill leachate / high-concentration refractory wastewater | Pretreatment for turbidity removal, COD reduction, biodegradability improvement |
Hospital / bacteria-containing wastewater | Coagulation flotation + electrolytic auxiliary sterilization |
VI. Selection Recommendations
The Electrocoagulation-DAF Integrated Unit is more suitable for pretreatment for turbidity and oil removal, advanced decolorization and destabilization of refractory wastewater. For scenarios with extremely low concentration tail water or requiring extremely high removal rates, it is recommended to combine with biochemical, Fenton, ozone and other processes to form a cascade treatment. In water with low conductivity, electrolytes can be appropriately supplemented to improve electrolysis efficiency; for high hardness water, attention should be paid to electrode scaling and polarity reversal strategy.
Let difficult water be "electrified" first
We can provide bench-scale test units, water quality adaptation solutions and integrated equipment selection. Welcome to call or leave a message to obtain process configuration recommendations for your water quality.
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