## 2 Principal Textile Colored WW Characteristics and Composition
### Coagulation-Flocculation Technologies and Its Performances in Colored Textile WWs Treatment
Very effective chemical coagulation-floculation (C-F) methods and the precipitation of phosphorus and existing carbonates in different colored WWs (e.g., textile WWs) have been reported, which reduce the load of the biological treatment, working with relatively high concentrations of inorganic coagulants based on lime, iron, and aluminum salts (e.g., more than 200-300 mg/L); however, very good results were also reported when using a combination of an inorganic coagulant and a polymeric flocculant (coagulation aid), such as for a reference model of textile WWs reported in the scientific literature, such as a poly (aluminum chloride) (PAC) along with an organic polymer [117] or ferrous/ferric chloride and a commercial organic coagulant aid (e.g., sodium alignates) at a pH of 6.7-8.3 (color removal \(>80\%\)) [118], alum at pH = 8.2 (54-81% color removal) with the addition of bentonite (3 g/L) for Remazol Violet dye-containing effluent [119], or ferric chloride and two commercial polyelectrolytes, cationic Prodefloc CRC 301 and anionic Ponilit GT-2 polyelectrolyte at a pH of 7.38-7.83 (turbidity removal of \(>\)86.12%, color removal of 48.22%, and COD removal of \(>\)36.84%) [63]. \begin{table}
\begin{tabular}{p{113.8 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Operating Characteristics** & **Coagulation by Double Layer Compression** & **Coagulation by Charge Neutralization and Adsorption** & **Co-Precipitation with Neutralization and Adsorption** & **Flocculation by Interparticle Bridging** \\ \hline Destabilization chemicals (coagulant/flococulant) & Non-hydrolyzing counter ions & Hydrolyzing salts (Fe\({}^{3+}\), Al\({}^{3+}\) salts); superficial active counter ions, soluble polynuclear compounds & Metal ions and anions, Hybrid materials & Polymers/co-polymer, Polyelectrolytes, Polyelectrolytes, Hybrid materials \\ Electrostatic effects Chemical and adsorption effects & Predominant placed aggregation & Important & Important & Sub-ordinated Predominant \\ Zeta potential for aggregation & Almost zero & Almost zero & Often, different to zero & Frequent, different of zero \\ Physical properties of formed aggregates & Dense and resistant coagulation & Dense, filtrable, easily dehydrated coagulation & Easily filtrable and settable, tridimensional tetrahedral, easy filtrate flocs \\ Addition of agent & Without effect & Re-stabilization because of charge exchange exchange exchange & Re-stabilization because of charge and ionic exchange exchange & Re-stabilization because of complete surface covering \\ Surface covering degree for destabilization & Not observable & \(0<\phi<1\) & \(0<\phi<1\) & \(\phi=0.5\) \\ Critical content of destabilization/re-stabilization agent & Independent of disperse phase concentration. & Stoichiometric towards superficial concentration of disperse phase phase & Dependent on disperse phase concentration and charge & Stoichiometric \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Destabilization characteristics in terms of coagulation–floculation process. In the case of industrial beverage WW treatment applied for the removal of trace metals, such as total Fe (Fe\({}^{2+}\) + Fe\({}^{3+}\)), total Cr (Cr\({}^{3+}\) + CrO\({}_{4}\)\({}^{2-}\)) and Zn (Zn\({}^{2+}\)) ions, the effectiveness of polymer/co-polymer or hybrid material addition to the coagulation-flocculation process was verified, especially when both FeCl\({}_{3}\) (300 mg/L) and an organic polymer (a non-ionic polyacrylamide, 65 mg/L) were added individually, using a FeCl\({}_{3}\)-polymer/co-polymer combination (hybrid material); in the case of the individual use of a ferric-based coagulant, high removals of metal species were reported, such as total Cr(III, VI) ion removal (91%), Zn(II) (72%), and total Fe(II, III) (54%), and the addition of polymer/co-polymer increased the efficiencies of the processes to about 95%, 87%, and 88%, respectively.