Biological Treatment is the recycling of humus, nutrients and/or energy from biological waste by means of aerobic (composting) or anaerobic (digesting) processing. Biological treatment is an important and integral part of any wastewater treatment plant that treats wastewater from either municipality or industry having soluble organic impurities or a mix of the two types of wastewater sources. Biological wastewater treatment is an important and integral step of wastewater treatment system and it treats wastewater coming from either residential buildings or industries etc. It is often called as Secondary Treatment process which is used to remove any contaminants that left over after primary treatment. Organic waste is material that is biodegradable and comes from either a plant or animal. Organic waste is usually broken down by other organisms over time and may also be referred to as wet waste. Most of the time, it's made up of vegetable and fruit debris, paper, bones and human waste which quickly disintegrate. Wastewater treatment is a process used to convert wastewater, which is water no longer needed or suitable for its most recent use, into an effluent that can be either returned to the water cycle with minimal environmental issues or reused. Expenditure on water and wastewater infrastructure in India is set to increase by 83% over the next five years, hitting an annual run rate of $16 billion by 2020. The utility market is set to top $14 billion within five years, while annual spending in the industrial sector will approach $2 billion. Spending on water supply will grow from $5.56 billion to $9.4 billion over the next five years.