Spiral-Electrocoagulation
(S-EC)

Introducing
Spiral-Electrocoagulation (S-EC)

Looking for a highly effective and sustainable solution for industrial wastewater treatment?

Spiral-Electrocoagulation (S-EC) by Spiraltec GmbH offers cutting-edge technology designed with your needs in mind. This technology is engineered to treat a diverse range of contaminants across a multitude of industries.

What makes our S-EC system special is its unique spiral electrode configuration, which optimizes flow hydrodynamics, thereby saving energy and improving contaminants removal efficiency.

Moreover, the system operates automatically and features a built-in monitoring system, enabling you to easily track key parameters such as pH, conductivity, temperature, etc. both before and after treatment.

How does Electrocoagulation (EC) work

In EC, when an external direct current voltage is applied, then different electrochemical reactions may take place at the anode and cathode of an electrolytic cell. EC involves the generation of in-situ metal coagulant by electrolytic dissolving sacrificial anode materials (aluminium or iron).
In case of aluminium, the anodic process, involves the oxidative dissolution of aluminium into aqueous solution which is presented in reaction (1). In the cathode, the reductive dissociation of water would also take place, see reaction (2).

Anode	Al_(s)→Al³⁺_(aq) + 3e⁻	(1)
Cathode	2H₂O + 2e⁻ → H₂_(g) + 2OH⁻_(aq)	(2)

Aluminium ions (Al3+) produced by electrolytic dissolution of the anode, which act as coagulant reagent, hydrolyze and form mono-nuclear complexes according to the following sequence:

Al³⁺ +H₂O → Al(OH)²⁺ +H⁺	(3)
AlOH²⁺ + H₂O → Al(OH)⁺₂ + H⁺	(4)
Al(OH)⁺² + H₂O → Al(OH)₃ + H⁺	(5)
Al(OH)₃ + H₂O → Al(OH)^-₄ + H⁺	(6)

Reference: Jafari et al., 2023

Figure 1. Sketch of Eq. 1 and Eq. 2 inside the EC reactor.
The inert electrode is usually the same material as anode

Applications

Electrocoagulation is a versatile method for wastewater treatment that finds applications across various industries, encompassing, but not limited to:

Oil refinery, gas exploration, and production

Petrochemical industry

Textile industry (e.g dyeing)

Food and beverage processing

Pulp and paper manufacturing

Mining and metal processing

Chemical and pharmaceutical production

Slaughterhouse

Landfill leachate treatment

Electronics and semiconductor manufacturing

Contaminants Removal

Electrocoagulation can effectively treat a wide range of contaminants found in various wastewater streams. Some common types of contaminants that can be treated through electrocoagulation include:

No.	Contaminant	Compounds
1	Suspended Solids	particles, colloids, and sediments
2	Heavy Metals	lead, chromium, cadmium, arsenic, and mercury
3	Organic Compounds	oils and Fats, Surfactants, Phenols, Dyes and Pigments
4	Phosphorous	orthophosphates, Polyphosphates, Organic Phosphorous Compounds
5	Bacteria and Pathogens	bacteria, viruses
6	Turbidity and Color	caused by suspended particles and dissolved substances
7	Inorganic Ions	sulfate (SO₄), fluoride (F)

Process optimization through innovative electrode configuration

Process optimization through innovative electrode configuration

Optimized flow hydrodynamic
Optimized energy consumption

Three processes were integrated into one system

Flow hydrodynamic optimization

An efficient EC configuration would preferably provide a uniform flow distribution between the electrodes. To compare the flow hydrodynamic of the spiral electrocoagulation (S-EC) with the conventional EC (vertical plates), a fluid flow simulation using Computational Fluid Dynamics (CFD) with similar dimensions and conditions was performed (see Fig 2).

As it can be seen, the uniformity and increased velocity in the spiral EC have been enhanced than the conventional EC. In the conventional EC, the vertical plate electrodes serve as a barrier against flow circulation, so then flow cannot be circulated and distributed evenly between the electrodes. This is a condition under which, fouling is anticipated to occur under the passivation of electrodes. Under such circumstances, fouling potential increases on the anode electrode and reduces the mass transfer coefficient.

Energy consumption optimization

Fig. 3, compares the voltage rise between the conventional EC and spiral EC configurations. To reduce energy consumption, the voltage should be reduced as much as possible. In general, two reasons can be expressed for increasing voltage in ECF. First, the development of a passive film on the anode, and second, the generation of hydrogen gas on the cathode.

These issues increase electrical resistance and hinder optimal removal results, requiring excessive energy consumption. To address these problems and prevent voltage rise, enhancing flow hydrodynamics around the electrodes is crucial, pushing out bubbles and improving mass transfer near the anode. The spiral EC configuration, depicted in Figure 3, shows promising results with lower voltage experienced across all concentrations, suggesting a potential solution to mitigate these challenges.