Environmental Engineering Reference
In-Depth Information
forestry and agriculture, along with industrial and municipal residues and
wastes, are the biomass types used as feedstock for energy generation.
Biomass resources suitable as biogas feedstocks, usually named anaerobic
digestion (AD) feedstock are represented by a large variety of organic
materials available on a renewable basis, ranging from simple compounds to
complex high-solid matters. They usually have a high content of sugar,
starch, proteins or fats, and a common feature is their ability to be easily
decomposed through AD.
2.2
Categories of biomass appropriate as feedstocks
for biogas production
Historically, AD has been associated with the treatment of animal manure
and slurries and with stabilization treatment of sewage sludge from
wastewater plants. During the 1970s, organic wastes from industry and
municipal wastes were introduced as biogas feedstocks. This was due to
increasing environmental awareness and demand for adequate waste
management strategies and was possible because of the development of
high-rate reactor configurations and sophisticated process control techni-
ques (Steffen et al., 1998). The cultivation of crops such as maize, grasses,
cereals, beets, potatoes and sunflowers, specially dedicated to be used as
feedstock for biogas, was developed in the 1990s in countries like Germany
and Austria, although the idea is much older - the methane potential of
various crops was investigated in the 1930s by Buswell (Murphy et al.,
2011).
The biomass resources amenable to biogas production can be grouped
into categories according to various criteria. According to the taxonomic
rank (Latin regnum) of their origin, they can be vegetal (plantae) and animal
(animalia). According to the sector generating them, they can be agricultural
(animal manures and slurries, vegetable by-products and residues, energy
crops), industrial (organic wastes, by-products and residues from agro-
industries, food industries, fodder and brewery industries, organic-loaded
wastewaters and sludges from industrial processes, organic by-products
from biofuel production and biorefineries, etc.), municipal (source-separated
household waste, sewage sludge, municipal solid waste and food residues).
Across these sectors, wastes, residues and by-products of different biomass
value chains are the most sustainable materials now used as AD feedstocks
(Table 2.1).
Over the last decade, the potential of aquatic biomass as a feedstock for
biogas has received increasing attention and has become the focus of
research efforts around the world in attempts to develop cost sustainable
and technically feasible full-scale applications for the culture, harvesting and
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