Page 194 - Advances in Eco-Fuels for a Sustainable Environment

158 Advances in Eco-Fuels for a Sustainable Environment

mounted and the volume of solid matter in sewage was reduced by anaerobic digestion.
At the same time, the science community was focusing on finding new alternate fuels
proportional to the population growth to fulfill the society’s growing energy demand.
Waste generation is always proportional to the population, with some waste fractions
being difficult to recycle. These fractions should be further investigated for energy pur-
poses (StatisticalReview of World Energy, June2016). Waste materialscan beofmany
types, mainly biodegradable such as biomass, food wastes, etc., and nonbiodegradable
such as plastics, waste oils, and metallic wastes. Many countries such as the United
Kingdom (UK) and Germany have used this idea to produce flammable gas for lighting
street lampsintheearly1900s bytreatingsewage [1].Thefirst sewage plantwasbuiltin
Bombay (currently known as Mumbai), India, in 1859. In the 1930s, the practice of
grange waste to generate flammable gas was developed, again in Bombay [2]. In the
early 1960s, KVIC (Khadi and Villages Industries Commission) developed biogas
plants that were used by Indian villagers. Soon after, the success of the design, which
used a floating drum, shaped the foundation of an ongoing Indian government outreach
program to provide Indian villagers with cooking fuel [3].
In the early 1630s, Jan Baptista Van Helmont, a Belgian chemist, established that
combustible gases could be obtained from decomposing organic matter. In the year
1776, the amount of inflammable gas produced was found to be directly proportional
to the quantity of decaying organic matter by Count Alessandro Volta’s experiment. In
1808, Sir Humphrey Davy investigated whether methane gases were produced during
the anaerobic digestion of cattle waste [4]. In 1875, Wouter Sluys, a Dutch farmer,
first used methane for illumination purposes. England in 1895 when biogas was recov-
ered from a “carefully designed” sewage treatment facility and used to fuel street
lamps in Exeter. The first biogas plant in India was constructed in 1897 in Bombay [5].
China installed 5 million plants based on a septic tank design by taking a similar
initiative in the early 1960s through the 1980s. The dome-shaped designs were rep-
laced by the original rectangular tank. India developed similar designs and formed
the basis of an active program in Nepal with the participation of various groups, a pro-
gram that is now called BSP (Biogas Sector Partnership). China, India, and Nepal have
developed this program steadily. This program has increased interest more recently in
Europe and UK. Due to the oil price spikes, certain groups in the UK started on-farm
energy generation through biogas as an alternative; this was motivated by Indian pro-
gram in the early 1980s [6]. When the soaring prices of oil pushed people to seek alter-
natives. The fall of the oil price, and thus of the electricity, which returned the
installations of not very profitable biogases to the farm, allowed the 200 installations
built at that time to survive [7].
Anaerobic digestion is one of the most extensively applied technologies, but it is
still not yet completely understood because of the complicated digestion process,
which mainly depends on the performance of the microorganisms. Also, the perfor-
mance of these microorganisms largely depends on the environment in which they
reside. Many mathematical models have been developed to study the behavior of
the process and the ongoing optimization of new models. These mathematical models
cannot be directly implemented in industry because of the “biological factor,” which
hampers a process that is not easy to realize and makes anaerobic digestion highly
nonlinear [8]. Similarly, in a year more than 130million tons of food is wasted