56
3 Advanced Technologies (Biological and Thermochemical) …
challenges that limit its commercialization, e.g., the rigorous pre-treatments needed,
the high cellulase costs and structural hindrances of lignin and hemicellulose, and
high capital costs of such complex processes, etc. The biorefinery is a promising
approach in which biomass such as lignocellulose could be converted into multiple
high-valued biochemicals and biomaterials in addition to bioethanol.
Keywords Waste-to-energy conversion · Advanced technologies ·
Thermochemical conversion · Combustion · Pyrolysis · Hydrothermal
liquefaction · Gasification · Biochemical conversion · Anaerobic digestion ·
Mechanical biological treatments · Fermentation · Biological methods ·
Biorefinery
As discussed in the previous chapter, incineration and landfilling are the two most
common ways of treating municipal solid waste by far. However, they are associated
with potential environmental and health hazards such as leachate generation, air
pollution and soil contamination. Concerns over the negative impact of solid waste
on the environment and the idea of improving resource conservation resulted in a
growing interest in the diversion of wastes by such as recycling and composting. The
next best option of waste management is Waste-to-Energy (WTE) conversion. WTE
conversion is the process of recovering energy in the form of electricity, heat or steam
from the conversion of the organics in the waste streams to provide an alternative
source of renewable energy. It reduces the mass and volume of waste as well as
greenhouse gases and carbon emissions released from the landfills or incinerators,
thus provides an environmentally friendly way to deal with wastes.
Biomass resources are all forms of organic materials from waste streams or dedicated energy crops. Examples of waste biomass are wood and forestry residues/byproducts (sawdust, bark, treetops, lignin), agricultural crops and crop residues
(wheat/rice straws, corn stover), marine products, MSW, wastewater sludge, and
waste streams from animal farms (manure) and food processing [1–3]. Energy from
the waste biomass can be captured using two main types of technologies, namely,
biological and thermochemical conversions. These technologies are considered as
advanced technologies since they convert wastes into a renewable energy resource
such as biogas, biofuels, syngas and ethanol. Biological conversion refers mainly
to the fermentation of carbohydrate materials into bio-ethanol and biogas. Thermochemical conversions mainly include incineration (combustion), gasification, pyrolysis and hydrothermal liquefaction [3–5]. The above-mentioned biomass conversion
methods and their products are illustrated in Fig. 3.1.
Some of these technologies such as pyrolysis and gasification have been already
used in Europe and North America for the management of special wastes, however,
their application to municipal solid waste does not have a history of commercial
application so it is still a new concept in waste management. A number of WTE technologies exist in concept form, bench- or pilot-scale demonstration units. Generally,
they involve thermal or mechanical treatments combined with the use of chemical
3 Advanced Technologies (Biological and Thermochemical) …
challenges that limit its commercialization, e.g., the rigorous pre-treatments needed,
the high cellulase costs and structural hindrances of lignin and hemicellulose, and
high capital costs of such complex processes, etc. The biorefinery is a promising
approach in which biomass such as lignocellulose could be converted into multiple
high-valued biochemicals and biomaterials in addition to bioethanol.
Keywords Waste-to-energy conversion · Advanced technologies ·
Thermochemical conversion · Combustion · Pyrolysis · Hydrothermal
liquefaction · Gasification · Biochemical conversion · Anaerobic digestion ·
Mechanical biological treatments · Fermentation · Biological methods ·
Biorefinery
As discussed in the previous chapter, incineration and landfilling are the two most
common ways of treating municipal solid waste by far. However, they are associated
with potential environmental and health hazards such as leachate generation, air
pollution and soil contamination. Concerns over the negative impact of solid waste
on the environment and the idea of improving resource conservation resulted in a
growing interest in the diversion of wastes by such as recycling and composting. The
next best option of waste management is Waste-to-Energy (WTE) conversion. WTE
conversion is the process of recovering energy in the form of electricity, heat or steam
from the conversion of the organics in the waste streams to provide an alternative
source of renewable energy. It reduces the mass and volume of waste as well as
greenhouse gases and carbon emissions released from the landfills or incinerators,
thus provides an environmentally friendly way to deal with wastes.
Biomass resources are all forms of organic materials from waste streams or dedicated energy crops. Examples of waste biomass are wood and forestry residues/byproducts (sawdust, bark, treetops, lignin), agricultural crops and crop residues
(wheat/rice straws, corn stover), marine products, MSW, wastewater sludge, and
waste streams from animal farms (manure) and food processing [1–3]. Energy from
the waste biomass can be captured using two main types of technologies, namely,
biological and thermochemical conversions. These technologies are considered as
advanced technologies since they convert wastes into a renewable energy resource
such as biogas, biofuels, syngas and ethanol. Biological conversion refers mainly
to the fermentation of carbohydrate materials into bio-ethanol and biogas. Thermochemical conversions mainly include incineration (combustion), gasification, pyrolysis and hydrothermal liquefaction [3–5]. The above-mentioned biomass conversion
methods and their products are illustrated in Fig. 3.1.
Some of these technologies such as pyrolysis and gasification have been already
used in Europe and North America for the management of special wastes, however,
their application to municipal solid waste does not have a history of commercial
application so it is still a new concept in waste management. A number of WTE technologies exist in concept form, bench- or pilot-scale demonstration units. Generally,
they involve thermal or mechanical treatments combined with the use of chemical