The scientific and managerial challenges around the multiple processes, i.e., reclaimed wastewater, green energy, etc., are so similar in many countries. Many countries, including Egypt, countenance great challenges consequent the limited water and energy resources. These limitations have boosted the benefit in finding alternative water and renewable energy origins to output biofuels on one side and to reuse wastewater in agriculture. Conventional aerobic wastewater treatment plants require intensive oxygenation; a large numeral of chemicals and the implementation and maintenance are energy demanding. By using green technologies, i.e., integrating developed oxidation processes and microalgae-based systems, removal of biological pathogens and nutrients, i.e., ammonium and phosphate, can be recovered by microbial assimilation and operational cost of oxygenation avoided by in situ production via photosynthesis. Thus, the microalgae biomass should be harvested and utilized as the substrate for anaerobic digestion. Integration wastewater treatment, algal biomass production, and valorization via anaerobic digestion have the potential to raise the economic feasibility of providing the new provenance of energy and amendment of water quality in water bodies. This chapter discusses the wastewater treatment process challenges and opportunities for reusing unconventional water.