**Abstract**

This chapter elucidates the technologies of biological and chemical wastewater treatment processes. The presented biological wastewater treatment processes include: (1) bioreme‐ diation of wastewater that includes aerobic treatment (oxidation ponds, aeration lagoons, aerobic bioreactors, activated sludge, percolating or trickling filters, biological filters, ro‐ tating biological contactors, biological removal of nutrients) and anaerobic treatment (anaerobic bioreactors, anaerobic lagoons); (2) phytoremediation of wastewater that in‐ cludes constructed wetlands, rhizofiltration, rhizodegradation, phytodegradation, phy‐ toaccumulation, phytotransformation, and hyperaccumulators; and (3) mycoremediation of wastewater. The discussed chemical wastewater treatment processes include chemical precipitation (coagulation, flocculation), ion exchange, neutralization, adsorption, and disinfection (chlorination/dechlorination, ozone, UV light). Additionally, this chapter elu‐ cidates and illustrates the wastewater treatment plants in terms of plant sizing, plant lay‐ out, plant design, and plant location.

**Keywords:** Wastewater treatment, biological treatment, chemical treatment, bioremedia‐ tion, phytoremediation, mycoremediation, vermifiltration, treatment plant
