Chapter 10 - Waste to biomethane: advent of circular economy

Abstract

Biotechnologies are the future hub for circular economy. The transition from linear economy model to circular economy model is one of the indications that the biogas plants and the bio-based biorefineries are efficient examples of circular economy wherein the waste is converted to bioenergy, biofertilizer, and many value-added products for its utilization as a raw material for industry. Optimum and responsible usage of resources and the design of technologies following 3R (Reduce, Reuse, and Recycle) approach has led to the transition of developed and developing countries from linear economy to the circular economy model. Recent advancements in the conversion of raw biogas to biomethane makes the biogas technology ensure its place in the circular economy. The necessity for the upgradation of biogas to biomethane is envisaged to meet the standards for its usage as a vehicular fuel or injection to the natural gas grid. The raw biogas can be upgraded to biomethane comprising of 95%–99% of CH4, 1%–5% of CO2 with no traces of any other gases using various adsorption, absorption, separation, and liquefaction technologies. A biogas plant is a well-suited example that fits in the sustainable bio-based circular economy model. The higher the recycling and re-usage of wastes, more the system comes in-line with the concept of the circular economy while being less harmful to its surroundings and more profitable. However, we are still in the advent of circular economy. The products from the biogas plants and the biorefineries will find their way in the global market demand in the coming years. The flexibility of the biomethanation systems/biorefinery and its ability to digest a variety of feedstocks (organic) for the generation of a spectrum of products ensures the role of biogas plants and biorefineries in the circular economy.