## 1 Introduction  
The leather trade can be an economic problem for developing countries that produce a good type of product from animal leather, such as footwear, luggage, and clothing. However, its production has a terribly high environmental footprint [1]. In addition, considering the enormous quantity and low biodegradability of the chemical products present in the productive cycle of tanner work, the wastewater from said process represents a great environmental and technological inconvenience [2]. In [3], the authors mentioned that the Electrocoagulation (EC) is often considered as an alternate treatment methodology with several advantages such as easy instrumentality, simple operation and automation, a brief retention time, low sludge production, and no chemical necessities. Other studies have stated that Electrocoagulation mixtures and alternative technologies have been designed to treat high concentration organic waste material such as the textile trade and mixed industries [4, 5]. In [6], mentioned that the use of EC as the only treatment process could face serious practical limitations, especially if the wastewater is highly contaminated. Therefore, there is a need for an efficient and relatively inexpensive treatment process. Due to this, the use of a post- or pre-treatment process with the ECwill improve its performance, as mentioned by several studies that have described more profitable combined treatment systems [6; 7]. The authors of [8] published a review that includes EC combined with other treatment processes such as: electrocoagulation-ozone, electrocoagulation-adsorption, electrocoagulation-ultrasound, and electrocoagulation-pulses. In his work, the authors also mention about the performance of these combined systems. According to [9] Electrocoagulation (EC) is used in chemical science water treatment techniques where anode electrodes (aluminum, Al, or iron, Fe) area unit are dissolved in place, which promote coagulation and succeeding removals of pollutants and also the concurrent reduction of turbidity from water and wastewater. EC relies on the physical-chemical method of destabilization of mixture systems below the action of a right away current [10]. The electrodes dissolve according to Equations (1) and (2) to provide coagulant metal ions (Al\({}^{3+}\) or Fe\({}^{2+}\)/Fe\({}^{2-}\)) into the water, and these instantaneously carries rapid hydrolysis. Anode reactions:  
\[\mathrm{Al}_{\mathrm{(s)}}\rightarrow\mathrm{Al}_{\mathrm{(aq)}}^{3+}+3e^{-} \quad E^{0}=1.66\;\mathrm{V} \tag{1}\]  
\[\mathrm{Fe}_{\mathrm{(s)}}\rightarrow\mathrm{Fe}_{\mathrm{(aq)}}^{3+}+3e^{-} \quad E^{0}=0.04\;\mathrm{V} \tag{2}\]  
When the anode potential is sufficiently high, secondary reactions may occur, especially oxygen evolution, according to Equation (3)  
\[2\mathrm{H}_{2}\mathrm{O}_{\mathrm{(I)}}\rightarrow\mathrm{O}_{\mathrm{2(g)} }+4\mathrm{H}_{\mathrm{(aq)}}^{+}+4e^{-}\quad E^{0}=1.66\;\mathrm{V} \tag{3}\]  
Simultaneously with the anode reaction, water molecules H\({}_{2}\)O break down at the cathode, producing hydrogen gas H\({}_{2}\) and OH\({}^{-}\) ions, according to Equation (4). Cathode reaction:  
\[\mathrm{H}_{2}\mathrm{O}_{\mathrm{(I)}}+2e^{-}\rightarrow\mathrm{H}_{2(g)}+ \mathrm{OH}_{\mathrm{(aq)}}^{-}\quad E^{0}=1.66\;\mathrm{V} \tag{4}\]  
The electrical energy applied to the anode dissolves the aluminum into the solution which then reacts with the hydroxyl ion from the cathode to form aluminum hydroxy. The most significant advantage of electrocoagulation is avoiding any addition of chemical substances thus reducing the likelihood of secondary pollution; the dosing of coagulator depends on the cell potential (or current density) applied [11]. Other advantages are the simple equipment, so requiring less maintenance and straightforward automation of the method [12]. Standard treatments for cloudiness removal have many disadvantages, such as the use of enormous amounts of chemicals and generating large amounts of sludge that causes disposal issues and therefore the loss of water.