Globally water requirements for potable and non-potable applications are getting higher with the scarcity of water, increasing human consumption, and industrialization (Ezugbe and Rathilal 2020). Currently, only less than 4% of the total wastewater in the world has been utilized for reuse (Yang et al. 2020). Therefore, it is essential need to upgrade existing wastewater treatment plants to reuse water to generate enough potable and non-potable applications. Considering industrial wastewater, physicochemical characteristics of wastewater may get varied from one industry to another (Edzwald 2011). Therefore, it is always recommended to investigate appropriate water treatment plant design strategies while estimating capital expenditure, operational and maintenance expenditure, saving energy, improving process control, recovering chemicals, minimizing waste, and maintaining good housekeeping (Mohsen and Jaber 2003).
Physicochemical characteristics of wastewater need to be conducted after water quality testing at a licensed laboratory. Characteristics of wastewater may vary due to various factors such as seasonal changes, changes in plant operations, floor washing, cleaning, and many other considerations. The final treated water should comply with country-specific or area-specific drinking water standards. Typical unit operations of drinking water recovery from wastewater are given below.
- Intake wells — store water that is sufficient for treatment and equalizes wastewater characteristics (Lagrega and Keenan 1974).
- Coagulation — is the process of adding a chemical coagulant to wastewater to destabilize colloidal suspensions and increase aggregations (Teh et al. 2016).
- Flocculation — is the process of slow mixing in which destabilized particles are induced and form larger particles(Teh et al. 2016).
- Softening — is a special chemical treatment process which used to remove hardness-causing cations (Alexander and Mcclanahan 1975).
- Clarifiers — are typically cylindrical tanks operated at very low velocities for settling down-solid/floc mixture from the wastewater using gravity settling (Engelhardt 2010).
- Re-carbonation — Carbon dioxide is added to reduce the pH which was…
