Waste menace is one of the most voiced and unsolved problems in the entire world. The whole world is facing the threat of water pollution, soil pollution/ land pollution, odour pollution from the growing waste. Though we find many missions and programs at international, national, and regional level to solve the waste associated issues, this is mostly in context with the solid fraction of the waste. Very little is being done to manage the liquid part of the waste or what we call the wastewater. The conversion of wastewater has the potential to be converted to energy in the form bioenergy, bio-fertilizers, electricity, nutrient recovery, etc. The use of sludge as biofertilizers solves the problem of sludge management on the one hand and production of organic crops on the other. The biological treatment methods like sludge treatment gives the farmers the source of biofertilizers and organic manure for the plants. In the present scenario, energy crisis is also one of the issues that we are facing particularly in context with the thermal power plants which are environmentally highly polluting. Through various techniques like microbial fuel cells or biohydrogen, we get a source of cleaner energy. So, through this book, we try to produce the content and information to give the audience an understanding of the waste water as one of the environmental and health issues and mitigation strategies. The book gives a sufficient understanding of how waste can be turned into a resource.