Table 1: Various processes of wastewater treatment and their advantages and disadvantages.

Process Advantages Disadvantages
Coagulation/flocculation Inexpensive capital cost, Good sludge settling and dewatering characteristics, Significant reduction in the chemical oxygen demand and Bacterial inactivation capability. Requires adjunction of non-reusable chemicals (coagulants, flocculants, aid chemicals). Physicochemical monitoring of the effluent (pH). Increased sludge volume generation (management, treatment, cost), Low removal of arsenic [61].
Membrane filtration Small space requirement, simple, rapid, and efficient, even at high concentrations. No chemicals required. Low solid waste generation. Eliminates all types of dyes, salts, and mineral derivatives. Investment costs are often too high for small and medium industries. High energy requirements. The design of membrane filtration systems can differ significantly [62].
Biological methods Biodegradation of organic contaminants is simple, economically attractive, and well accepted by the public. White-rot fungi produce a wide variety of extracellular enzymes with high biodegradability capacity. High removal of biochemical oxygen demand and suspended solids. Requires management and maintenance of the microorganisms and/or physicochemical pre-treatment. Slow process (problems of kinetics). Low biodegradability of certain molecules (dyes). Poor decolorization, possible sludge bulking and foaming [63].
Ion exchange Wide range of commercial products available from several manufacturers. Technologically simple (simple equipment). Well-established and tested procedures; easy control and maintenance. Large volume requires large columns. Rapid saturation and clogging of the reactors. Saturation of the cationic exchanger before the anionic resin (precipitation of metals and blocking of the reactor) [64].
Photochemical No sludge production. Formation of by-products [65].
Chemical precipitation Technologically simple and integrated physicochemical process. It is economically advantageous and efficient. Very efficient for metals and fluoride elimination. Significant reduction in the chemical oxygen demand. Chemical consumption (lime, oxidants, H2S, etc.). Ineffective in the removal of the metal ions at low concentration, high sludge production, handling, and disposal problems (management, treatment, cost) [61].
Adsorption Technologically simple (simple equipment) and adaptable to many treatments. Target a wide variety of contaminants. Highly effective process. Relatively high investment, non-destructive processes, non-selective methods. Performance depends on the type of material [66].