Pulp and Paper mills produce large volumes of wastewater and residual sludge waste, presenting a number of issues in relation to wastewater treatment, discharge, and sludge disposal. However, increasingly advanced treatment technologies, including innovative strategies geared towards water reuse and resource recovery, present viable solutions for Pulp and Paper manufacturers in terms of wastewater and solid waste management. Treatment options include primary treatment, secondary biological treatment and tertiary treatment technologies. In this chapter, water reuse, waste water treatment and closed cycle operation in paper mills utilizing recycled fibres is presented.