Combining Anaerobic Digestion and Waste-to-Energy

Abstract

A large fraction of the municipal solid wastes (MSW) stream in the U.S. comprises of natural organic compounds (i.e., food and plant wastes) with high moisture content and low heating value. While these properties are undesirable during the combustion of MSW in waste-to-energy (WTE) plants, they are required for anaerobic digestion (AD). During AD, methane gas is produced that can be captured and used for energy generation. The required long residence times limit the throughput of an AD plant but further development may result in increasing the rates of bioreactions. This paper introduces current AD practices and identifies possible synergies between AD and WTE. It is suggested that co-siting of WTE and AD facilities may result in mutual benefits.

Lignocellulosic biomass as sustainable feedstock and materials for power generation and energy storage

“…Ethanol cannot be directly converted to methane and carbon dioxide but is initially transformed to acetate. Hydrogen formed in this step is considered as an inhibitory product owing to its inhibiting effect on the metabolism of acetogenic bacteria [85]. This reaction only proceeds in conditions with low hydrogen partial pressure which allows the conversion thermodynamically.…”

“…Though anaerobic digestion can be thought to occur in these four stages, all processes occur simultaneously and synergistically [85].…”

Big bluestem as a bioenergy crop: A review

“…Hydrolysis is considered the rate-limiting step for high-solid feedstocks such as biomass feedstocks; methanogenesis is the rate-limiting step for high soluble [132]. End products are CH 4 and digestate, a moist solid that is typically dewatered to produce a liquid stream and a dry solid [133]. Anaerobic processes utilize a small part (approximately 14%) of the available energy for microbial growth (10% for fermentative bacteria and 4% for methanogenesis); most energy (approximately 86%) is converted into CH 4 as end product [134].…”

A simple anaerobic system for onsite treatment of domestic wastewater

“…Two types of digesters are used in the anaerobic digestion process which are batch and continuous process. In batch process, all the constituent is put in the reactor in the beginning and is removed completely after the reaction is complete, whereas in continuous process fresh influent is fed into the reactor and effluent is regularly drawn out (Ostrem et al, 2004). Most commonly continuous type reactors are used for domestic wastewater treatment.…”