Wastewater treatment utilizes a huge amount of energy which we get from the grid. From last many years many researches have been done to reduce or minimize the energy consumption and to increase the renewable energy from the waste water treatment. This review presents the aspects which can guide technologists to move towards low energy or no energy waste water treatment. This review is to present systematic approaches to achieve energy neutral condition in waste water treatment. This review contains methods for reducing energy consumption and increasing the energy recovery to supplement with the extra external renewable energy.