Suhas Dixit - Waste to Energy

Waste to Energy Suhas Dixit, Pyrocrat Systems LLP, Navi Mumbai

Definition ď‚— Waste-to-energy is the process of generating energy in the form

of electricity or heat from the primary treatment of waste. ď‚— WtE is a form of energy recovery. ď‚— Most WtE processes produce electricity and/or heat directly through combustion, or produce a combustible fuel commodity, such as methane, methanol, ethanol or synthetic fuels

Incineration ď‚— Incineration is the process of combustion of waste for energy recovery.

ď‚— Modern incinerators reduce the volume of the original waste by 95-96 percent,

depending upon composition and degree of recovery of materials such as metals from the ash for recycling. ď‚— Incinerators have electric efficiencies of 14-28%.

Gasification  Gasification is a process that converts organic or fossil

fuel based carbonaceous materials into carbon monoxide, hydrogen and carbon dioxide.  The material is reacted at high temperatures (>700 °C), without combustion, with a controlled amount of oxygen and/or steam.

Thermal Depolymerization ď‚— Thermal depolymerization (TDP) is a depolymerization process

using hydrous pyrolysis for the reduction of complex organic materials (usually waste products of various sorts, often biomass and plastic) into light crude oil. ď‚— Under pressure and heat, long chain polymers of hydrogen, oxygen, and carbon decompose into short-chain petroleum hydrocarbons with a maximum length of around 18 carbons.

Pyrolysis ď‚— Pyrolysis is the process of thermochemical decomposition of organic material at

elevated temperatures in the absence of oxygen ď‚— The process is used to convert plastic and tire waste into fuel.

Plasma Gasification ď‚— Plasma gasification is an extreme thermal process using plasma which

converts organic matter into a syngas (synthesis gas) which is primarily made up of hydrogen and carbon monoxide. ď‚— A plasma torch powered by an electric arc, is used to ionize gas and catalyze organic matter into syngas with slag remaining as a byproduct. ď‚— It is used commercially as a form of waste treatment and can be highly useful in treating hazardous waste.

Anaerobic digestion ď‚— Anaerobic digestion is a collection of processes by

which microorganisms break down biodegradable material in the absence of oxygen.The process is used for industrial or domestic purposes to manage waste or to produce fuels. ď‚— Anaerobic digestion is particularly suited to organic material, and is commonly used for industrial effluent, wastewater and sewage sludge treatment.

Fermentation ď‚— Fermentation is the primary means of producing energy by the degradation of

organic nutrients anaerobically. ď‚— Hydrogen production by fermentative bacteria is technically simpler than by photosynthetic bacteria. Also, the fermentation process generates hydrogen from carbohydrates obtained as refuse or waste products.

Mechanical Biological Treatment  A mechanical biological treatment (MBT) system is a type of waste

processing facility that combines a sorting facility with a form of biological treatment such as composting or anaerobic digestion. MBT plants are designed to process mixed household waste as well as commercial and industrial wastes.  The ‘mechanical’ element is usually an automated mechanical sorting stage. This either removes recyclable elements from a mixed waste stream (such as metals, plastics, glass and paper) or processes them.

THANK YOU