Wastewater (WW) reuse in agriculture is a sustainable technique for developing agrarian countries like Pakistan. Despite the various WW treatment technologies are available but their selection and application for agricultural purposes involve some complications. So, because of their WW treatment status, the present paper provides a fundamental review on different aspects of WW treatment technologies regarding their description, abilities, merits and, demerits to assess their application potential. It recommends complete WW treatment system by a comprehensive review of different aspects of selected treatment technologies from primary to advanced level along with sludge processing. It mainly focuses on their treatment principles, factors affecting treatment, application potential, designing and performance calculations. The recommended WW treatment technologies such as sedimentation, trickling filter, adsorption filter, anaerobic digestion have critical fundamental status under the domain of WW treatment. Thus, this paper will provide a foundation approach towards the development of WW treatment systems for developing countries.