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SolidwastemanagementinSaudiArabia:A
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Journal of Applied Agriculture and Biotechnology 2016 1(1): 13−26
ISSN: xxxx-xxxx
Review article
Solid waste management in Saudi Arabia: A review
Muzammil Anjum1*, Rashid Miandad1, Muhammad Waqas1, Ijaz Ahmad1, Ziad Omar Ahmad Alafif1,
Asad Siraj Aburiazaiza1, Mohamed Abou El-Fetouh Barakat1, Tasneem Akhtar2
HIGHLIGHTS
Municipal solid waste is generated in huge amount in Saudi Arabia
The current practices of MSW management are causing negative environmental impacts
A shift from waste to energy approach can decrease the burden on fossil fuel
Anaerobic digestion of food waste generates methane while pyrolysis of plastics produces liquid fuel oil
Authors’ affiliation
1Department of Environmental
Sciences, Faculty of Meteorology,
Environment and Arid Land
Agriculture, King Abdulaziz
University, Jeddah-21589, Saudi
Arabia
2Department of Arid Land
Agriculture, Faculty of Meteorology,
Environment and Arid Land
Agriculture, King Abdulaziz
University, Jeddah-21589, Saudi
Arabia
*Corresponding author
Muzammil Anjum
Email: muzammilanjum@gmail.com
How to cite
Anjum, M., R. Miandad, M. Waqas, I.
Ahmad, Z.O.A. Alafif, A.S.
Aburiazaiza, M.A. Barakat and T.
Akhtar. 2016. Solid waste
management in Saudi Arabia: A
review. J. Arid Agri. Biotechnol., 1(1):
xx-xx
ABSTRACT
he problem of municipal solid waste (MSW) management is
critical to the Kingdom of Saudi Arabia (KSA). MSW contains two
major components, organic waste and plastics. The organic
waste is generated due to the extensive use of food, while the
massive use of disposable stuff is the main source of plastic waste,
especially during the visit of a large number of pilgrims every year. In
the current scenario, the management of waste by conventional
methods such as dumping causes significant environmental impacts,
including greenhouse gas (GHG) emissions, leachate production and soil
contamination. The problems associated with the uncontrolled dumping
can be avoided by shifting to waste-energy approaches, leading to
economic and environmental sustainability. This review focuses on the
current status of the waste disposal system in KSA and its environmental
impacts. Based on the overall current situation and types of solid waste
production in KSA, waste treatment methods such as anaerobic
digestion and pyrolysis processes have been proposed. The anaerobic
digestion could be used for treating the organic fraction of municipal
solid waste, wherein the methane produced during the process can be
used as fuel after up-gradation or converted to liquid fuels. On the
other hand, pyrolysis is highly suitable for the treatment of plastic waste
because of non-biodegradable nature and pyrolysis of plastics can result
in the production of a variety of value- added products, such as fuel oil,
char and gases. Keeping in view the positive aspects of anaerobic
digestion and pyrolysis, there is a great potential to use these
technologies in KSA to make waste management practices highly
effective and eco-friendly.
Key words: Solid waste, Saudi Arabia, Anaerobic digestion, Pyrolysis, Landfill
T
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
1. Introduction The Kingdom of Saudi Arabia (KSA)
is located in the South Western Asia, encompassing
Red Sea at west to the Arabian Gulf at east and lies at
16o 22’, 32o 14 N and 34o 29’, 55o 40’ E longitudes.
The country dwells a population of 30.8 million
according to World Bank data (WB, 2015). The KSA
witnesses a rapid population growth, industrialization
and urbanization in the last few decades, resulting in
the production of a huge amount of solid waste
(Gajalakshmi and Abbasi, 2008). The average increase
in population growth over the last four decades was
recorded 3.4%, while the urbanization increases from
50 to 80% of the total population in 1970 to present.
This scenario has raised the problem of enormous
amount of unchecked solid waste generation (Ouda et
al., 2013), where most of the waste is produced in
some of eight main cities of KSA (Table 1). The rate of
municipal solid waste (MSW) generation in KSA is 15.3
Mt/y with the average rate of 1.4 kg/capita/d (Nizami
et al., 2015a). The produced MSW is generally
regulated by the Local Affair and Ministry of
Municipalities, while the management is carried out
by the local municipalities, which include the
collection, transportation and disposal of waste to
landfill or dump sites without material or energy
recovery (Ouda et al., 2013). The waste is usually
disposed through landfill dumping and combustion.
Some compost facilities have also established for
conversion of organic waste into compost. However,
the prevailing waste disposal practices are posing
serious threats to the environment. The disposal of
wastes without proper treatment can trigger problems
like malodors and pollution of ground and surface
waters (Al-Sabahi et al., 2009). Furthermore, these
waste management practices are liable for second
highest share of GHG emissions (CO2, CH4, N2O) after
fossil fuels (Rahman and Khondaker, 2012). The
majority of the dumping sites in KSA are expected to
reach their capacities in coming few years (Ouda et al.,
2013). Thus, there is a need to shift from prevailing
waste management practices to some advance
technologies such as waste to energy approaches.
The waste produced in KSA contains large amount of
organic wastes (about 40%). Organic waste is
comprised of food waste from different sources like
hotels, restaurants, canteen, homes etc. (Adhikari et
al., 2008). In order to transform these organic wastes
to valuable product, composting is one of the
economical and environment friendly methods (Zhang
et al., 2010).
Table 1: Solid waste production in different cities of
KSA (Ouda et al., 2013; Tolba and Saab, 2008; CDSI,
2004).
The process of composting is based on aerobic bio-
conversion of waste into fertilizer due to the activity of
microorganisms (Alruqaie and Alharbi, 2012). In the
case of food waste which are too wet, can also be
treated through anaerobic digestion. During anaerobic
digestion, methane is produced due to the
decomposition of organic content in the absence of
oxygen and energy is released as a biogas (Svensson et
al., 2004). In other technologies such as incineration,
the energy is produced through combustion of solid
waste (Kameswari et al., 2007). In many countries,
incineration remained the most important part of
MSW management. During this process, waste is
mixed thoroughly to maintain a more constant heating
value and then delivered to furnace for combustion
process (Psomopoulos et al., 2009). The wastes are
then burnt in excess of oxygen at about 800 oC
temperature.
In MSW, plastic is the second most abundant waste
produced in KSA. During the holy month of Ramadan
and Hajj, large amount of plastic waste is produced
due to use of disposable plastic containers and bags
for drinks and food stuff (Abdul Aziz et al., 2007). Only
15–20% of all produced plastic waste is recycled by
sorting method whereas the disposal of plastics
wastes to landfill results in the environmental and
Region /City
Population
(millions)
Amount of waste
(x 103 tons per year)
Saudi Arabia
30.8
15,300
Major cities
of KSA
14.12
8633
Riyadh
5.328
2871
Jeddah
3.456
1888
Makkah
1.675
915
Madina
1.180
645
Al-Taif
0.987
540
Dammam
0.903
1093
Al-Hassa
0.60
681
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
operational overburden to the landfill due to slow
degradation process. In this context, the pyrolysis
process can be used for treating plastic wastes
material with generation of energy in the form of fuel
oil and valuable products like char (Sharma et al.,
2014). During this process, plastic material is
decomposed thermo-chemically in the absence of air
(oxygen) at temperature up to 500 oC. The products
produced are liquid (fuel oil), solid (charcoal) and a
small gaseous fraction. The oil has similar
characteristics as diesel having high cetane and lower
sulphur content (Sharma et al., 2014). Although,
numbers of technologies are available having their
own environmental and economic implications, the
selection of waste treatment method is most
important step. Figure 1 describes an overview of the
waste management hierarchy for various technologies
with respect to their environmental and economic
outcomes.
In the present review, the existing practices in KSA for
waste management and their concerning
environmental effects are discussed. Furthermore, the
feasibility of modern waste treatment methods has
been suggested for the effective management of solid
waste with respect to its production in KSA.
2. Current practices of waste management
in KSA
2.1. Waste collection and dumping
The current management system of MSW in KSA is a
simple practice i.e. collection and dumping in landfill
sites (Ouda et al., 2013). Most of the solid waste in big
cities is disposed through the same way e.g., the waste
dumped at Makkah landfill is about 1800-2000
tons/day in normal days, while during Ramadan the
amount of waste increased to 3000 tons In Jeddah,
solid waste is collected through large bins placed all
around the commercial and residential areas. The
collected waste is first taken to the transfer stations
and then ultimately sent to the dumping site. The
landfill facility located at Buraiman, Jeddah receives
about 1.5 million tons of solid waste every year (Zafar,
2015) and 4500 tons/day during Hajj (AbdulAziz et al.,
2007).
Waste
Dumping
Economy
Incineration
Composting
Anaerobic
Digestion
Pyrolysis
Environment
High operational cost
with no economic
outcome
Ground water
pollution, odor
Produce Thermal Energy
Organic fertilizers
Degrade biodegradable
organic waste only
Air Emissions: Fly ash
Bottom ash
Bioenergy
(Methane)
Crude oil: liquid
fuel, Char
Degrade plastic waste,
Few air emissions
Degrade organic waste
Decrease GHG emissions
Solid
Waste
Figure 1: Solid waste management hierarchy for
various technologies.
Composition of MSW received at waste dumping sites
depends on the source and community and varies
greatly from city to city. On average, MSW consists of
organics as a major fraction (40%), out of which food
waste is the prominent waste stream (50.6%) (Abdul
Aziz et al., 2007). Food waste contains rice (38.7%),
meat (25%), bakery products (18.7%), and fats (13%)
as major fraction (Adhikari et al., 2008). Plastic is the
second largest stream found in the MSW which is
about 5-17%. However, some other components are
also found in waste stream, which include textile
(6.4%), glass (4.6%) and minerals (8.1%) (Khan and
Kaneesamkandi, 2013). Table 2 shows the overall
composition of municipal solid waste generated in
KSA.
At present, most of the dumping sites in KSA are
matured landfills, which imply that a substantial
amount of waste has been dumped and will reach to
the capacity of the landfills in coming few years. The
dumping of other waste types, such as wastewater
sludge are also posing problems of leachate, methane
generation, odor and other health hazards (Ouda et
al., 2013). In general, the dumping of waste without
engineered landfill system is an old practice as
followed in KSA. It causes number of environment risk.
For example, lack of gas collection systems cause
methane emissions directly into the air, when landfill
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
sites reach to its capacity (closed landfill) it cannot be
used for other purposes like construction of building,
etc. because dumping land takes many years for
settlement due to continuing degradation of organic
waste under the ground.
2.2. Makkah waste dumping site: A case study
A survey was conducted to Makkah waste dumping
site in April, 2015 to observe the present conditions
and practices at dumping site. The interview from site
manager, labors and officer worker was conducted. An
overview of results obtained during our survey is
presented in Table 3, showing some facts regarding
Makkah waste dumping site. The Makkah landfill is
located 21o15’44.48” N and 39o48’26.04”E. The waste
is collected by Makkah municipality and landfill
operation is operated by the Dala Company. The
area features desert climate conditions. The land area
is porous and has high chances of percolation of
landfill leachate. The site is only used as dumping of
waste, so may be termed as non-engineered landfill.
Total area covered by the waste dumping site is 4 km2.
Table 2: Composition of municipal solid waste produced in KSA (Tolba and Saab, 2008; Ouda et al., 2013; Khan and
Kaneesamkandi, 2013)
S #
Waste Categories
Fraction (%)
Components
1
Organic materials
65.5
Food waste and paper materials
Food Waste
37.0
Food stuff, fruits and vegetable refuse, peel etc.
Paper
28.5
Wasted Papers, cardboard, box board, bags, magazines, tissue
papers, newspapers, toilet papers,
2
Plastics
5.2
Disposable glass, spoons, plates, wrapping films, wrapping film,
bags, plastic bottles and polythene
3
Glass
4.6
Bottles, glassware, bulbs, ceramics etc.
4
Wood
8.0
All products comprised of wood
5
Textile
6.4
Cloths, dippers etc.
6
Metals/minerals
8.3
Cans, knives, wires bottles , aluminum cans, foils
7
Others
2.0
Leathers, rubber, fibers, rubber, yard waste, soils, tyres,
appliances and electronics and appliances
Table 3: Description of Makkah landfill site and operational facilities
Features
Description
Location
21o15’44.48” N and 39o48’26.04”E
Climate
Desert climate condition
Total area
4 km2
Waste received
4000 - 6000 t/d
Waste received during Hajj and Ramadan
10,000 t/d
Waste Origin
Makkah city
Waste Source
Domestic and commercial entities
Waste Categories
Non-hazardous
Operational Time
24 h
Total machinery (Compactor, Bulldozers etc.)
11
Field Labors
60
Office workers
5
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
The area is under operation for last 10 years and has
capacity to receive waste further for only three more
years. The landfill receives 4-6 thousand tons of waste
on daily basis and the amount is increased up to 10
thousand tons during peak seasons of Hajj and
Ramadan month. The site received the waste
throughout the week and 24 hours of a day. The
waste is produced by domestic and commercial
entities of the Makkah city and consisted of food
wastes, plastic, paper and aluminum cans. The area
also receives the old tyres of the vehicles which are
placed above the ground. About 4 million tyres are
currently thrown at the dumping site. For the dumping
of waste, landfill utilizes the different types of
machinery and vehicles. The solid waste is received by
trucks and processed by different machineries i.e.
bulldozers, shovels, graders, and compactors. The
compactors are used to compress the waste to reduce
its volume, whereas, bulldozers are used for leveling
of the land after waste dumping. Total working staff is
sixty five, with sixty people as labor and five as office
bearer. The labors perform various duties like digging,
waste compressing and dumping through machines.
Figure 2 shows some images of the Makkah waste
dumping site captured during the visit. We found that
current landfill is an example of uncontrolled dumping
of waste (non-engineered landfill). This uncontrolled
dumping can pollute groundwater and soil, and
responsible of attracting disease-carrying insects and
rats. The continuous flow of leachate was observed at
downstream area from old dumping sites. The
leachate from landfill usually is composed of four
types of compounds: inorganic macro components,
dissolved organic matter, xenobiotic and heavy metals
(Kjeldsen et al., 2002). The improper collection and
management of leachate may cause soil and water
pollution (USEPA, 2002). As climate of the area is hot,
it increases evaporation of leachate and hence may
add volatile organic compounds in the air, causing air
pollution. Besides the leachate problem, another
Leachate accumulation
(downstream area) Waste dumped mountain
(upstream area)
Figure 2: Pictography of Makkah waste dumping site.
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
major issue is bad odor which is produced due to
biological degradation of the solid waste heaps.The
compaction of landfill layers and biodegradability of
organic waste creates anaerobic conditions which is
responsible for production of methane gas (Kjeldsen et
al., 2002). As, there is no gas collection system exist,
the gases are directly released into the atmosphere
from old dumping cells, increasing GHG potential. The
gas released from the landfill may catch the fire and
could be responsible for major accident (USEPA,
2002).
2.3. Composting of organic waste
In KSA, there are many facilities constructed for the
conversion of waste like food waste, manures and
plant residues to compost for agricultural purpose (Al-
Turki et al., 2013). The composting is a process of
aerobic degradation of organic waste which can be
helpful to reduce negative environmental impacts of
organic waste and produce organic fertilizers (Simandi
et al., 2005). KSA has desert climate and only 835,000
ha of land is associated with agriculture (GIZ, 2012),
thus composting of waste for agriculture application
would not be very effective. However, various
initiatives have been taken to promote the organic
agriculture and use composted products from organic
waste. The introduction of the 1st National Regulation
and Standards for Organic Agriculture in 2011 is one
on the clean examples of raising focus on developing
strong organic farming system (GIZ, 2012).
Composting is an efficient technology for recirculation
of waste to valuable products and can reduce
problems originating from waste disposal sites
(Svensson et al., 2004). The soil application of
compost can positively influence the water holding
capacity, organic matter status, cation exchange
capacity of soil and provide maximum availability of
the nutrients to plants (Alzaydi et al., 2013).
Conversely, the low quality compost has a negative
impact on soil properties and plant growth. The
chemical properties that indicates the compost quality
are pH, organic matter, carbon to nitrogen ratio,
electrical conductivity (EC), nitrate and ammonium
levels and heavy metal contents (Bernal et al., 2008).
In order to assess the quality of compost, several
private and official authorities established standards
and regulations to check the compost quality for
agricultural application and environmental protection.
Recently, some of the Arabic Gulf Countries also
document regulations for the quality of imported and
local made compost (GCST, 2006).
Composting is an economical and ecofriendly
approach for waste management, but the quality of
the compost produced in KSA is not coinciding with
the international standards. Research study has been
done by Al-Turki et al. (2013) in which they
investigated the chemical characteristics of twenty
five composts produced in Saudi Arabia. Their aim was
to investigate and compare the quality of compost to
international and local standards of compost quality.
They found that there exists a large variation between
the standards and chemical properties of locally
produced compost. They concluded that most of the
locally produced composts were immature. The
variability among the standards and compost quality
shows that there is a need for quality assurance
procedures and proper regulations to be applied in
order to convert waste to quality compost in KSA.
3. Modern approaches in waste
management practices
Municipal solid waste is considered as a significant
source of valuable products and energy. There are
enormous profits associated with solid waste and are
indisputable for countries such as KSA and Gulf region.
As the current practices in KSA are not very effective
for recovery of resources from solid waste, a few
initiatives at small scale have been taken in the
Eastern Province of Saudi Arabia (Ouda et al., 2013).
Waste to energy approach is emerging all around the
world. About 600 waste to energy facilities are
currently working in various parts of the world,
producing electricity and heat from 130 million tons of
waste (Young, 2010; Cheng, 2010). There are a
number of wastes to energy technologies available
such as incineration, gasification, pyrolysis, anaerobic
digestion and fermentation. Under the consideration
of waste composition and energy demand in KSA, the
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
emphasis has been given to the technologies such as
anaerobic digestion and pyrolysis. The extensive food
consumption and wastage cause high organic content
in municipal solid waste for which anaerobic digestion
is most feasible technology. Similarly, pyrolysis is
efficient method for conversion of plastic waste to
liquid fuel, because plastic waste is the second largest
component of municipal solid waste due to high
consumption of disposable items especially in the holy
cities of Makkah and Madina where thousands of
pilgrims come every year from other countries. The
problems associated with current technologies and
overall advantages of shifting from old practices to the
new technologies are summarized in Fig. 3.
3.1. Anaerobic digestion: shifting from dumping to
engineered landfill systems
Recently, the attention has been increased towards
use of anaerobic digestion technology for treatment of
solid organic waste. This is due to the development of
new and strict regulations for safe disposal of organic
waste and need for alternative resources of energy to
depleting fossil fuels (Lettinga, 2001; Esposito et al.,
2012). Anaerobic digestion is defined as “the microbial
degradation and stabilization of organic materials
under oxygen free conditions, which leads to the
production of stable biomass and biogas (mixture of
H2, CO2 and CH4)’’ (Chen et al., 2008). It is highly
attractive for treatment of solid organic waste as it
provides an option of safe environmental disposal of
Municipal Solid Waste Management in KSA
Current Practices in KSA
Waste
Dumping Incineration Composting Land Settlement
GHG Emission
Leachate
Ground water pollution
Required Energy
to run
Produce Energy
(Heat)
Fly Ash
Bottom Ash
Slow Process Only Organic waste
Treated
Organic fertilizers
Anaerobic Digestion Pyrolysis
Engineered Landfill Bioreactors Digestate
Catalytic Pyrolysis
Biogas
Thermal Pyrolysis
Biogas Un-used Land
utilization
Large amount of
waste treated
Upgradation
(Pure CH4 production) Liquid Fuel
(Methanol)
Supply to
Industries
Electricity
Production
Electricity
Production
Transportation
Fuel
Liquid
Fuel
Gases
Char
Produce liquid fuel has
high quality.
Improve the economic of
process by reducing
temperature and
retention.
New Technologies Suggested Shifting to New
Technologies
(Eco-Friendly)
Shifting to New
Technologies
(Economical)
Figure 3: Shifting from ongoing to new technologies of solid waste management.
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
waste with additional economic benefits (Barton et al.,
2008).As the methane content of biogas is up to 70%
(Sheets et al., 2016), so it can be used as renewable
energy source which is inexpensive as compared to
the conventional fossil fuels. Moreover, energy
recovered from solid waste is environmentally safer,
as no additional GHG emissions are associated with
anaerobic digestion (Esposito et al., 2012).
In KSA, MSW is managed by a simple practice i.e.
collection and dumping into landfill. These landfills are
not an engineered landfill systems and lack leachate
and gas collection infrastructure, as observed in the
case of Makkah landfill site. The dumping of waste
into these landfills creates various problems such as
bad odors and leachate which may cause naissance
and ground water pollution. Further, due to anaerobic
degradation in landfill, the release of methane may
add extra global warming potential in the
environment. In 2009, it was observed in Europe that
the dumping of only 38% of total solid waste in landfill
has generated over 140 million tons of GHG emission
(measured as CO2 equivalent of CH4) (Eurostat, 2013).
This shows that, if the potential of anaerobic digestion
in landfill is not utilized for energy recovery, it may be
bad to the environment rather improving the
environmental quality. The landfill offers an
unmatched resource of energy in the form methane
gas, if this potential is utilized it can replace the
demand of fossil fuels and decrease CO2 emissions
(Starr et al., 2015).
KSA has the total area of 2,250,000 km² and most of
the land is fallow and desert. So, there is no scarcity of
land to use for development of landfill system. Given
the large amount of solid waste production every year
(Ouda et al., 2013), it is a worthwhile to examine the
potential of methane as a possible addition to the
current energy mix. The biogas produced during
anaerobic digestion cannot be used as a fuel in its
actual form. This is due to low calorific value of the
biogas (Al Mamun et al., 2015). Different technologies
are applied to get the full benefit of biogas and used
as a fuel. Some of the techniques such as biogas
upgradation and transformation of biogas to liquid
fuel (methanol) are described as follows.
3.1.1. Biogas up-gradation
The methane from anaerobic digestion does not
comes alone, it contains other gases such as carbon
dioxide, nitrogen, hydrogen sulfides etc. On an
average, the major portion of biogas contains CH4 and
CO2 which are present in the range of 30-70% and 15–
50%, respectively (Dirkse, 2009; Petersson and
Wellinger, 2009). The calorific efficiency of biogas is
proportional to the concentration of CH4, more the
methane content more will be the calorific value and
vice versa. The presence of large volume of CO2
reduced the calorific value of biogas which leads to
the increased compression and transportation costs.
Therefore, minimizing the CO2 concentration is
necessary step to use full potential of methane for
fuel, electricity generation and heating purpose (Zhao
et al., 2010; Al Mamun et al., 2015; Starr et al., 2015).
The process of removing the CO2 to increase the
calorific value of biogas is called biogas up-gradation.
There is a high feasibility to use the upgraded biogas
as a fuel for vehicles or supply to the grid for
electricity generation. This option has been
implemented in more than a hundred cities around
the world (Petersson and Wellinger, 2009). Similar to
that, it can be opted in the big cities of KSA. There is a
huge demand of electricity and extensive amount of
solid waste is available. The energy demand in KSA is
55000 MW (Ouda et al., 2013) which is fulfilled by
fossil oil and natural gas. Biogas up-gradation provides
an opportunity to reduce the pressure on natural gas
and dependency on fossil fuels (Starr et al., 2015), if it
is integrated in landfill biogas system to get purified
methane gas. The upgraded biogas cannot substitute
natural gas consumption completely but can
contribute its share in overall energy production and
can decrease the pressure on depleting fossil fuel
resources.
There are various methods developed for up-
gradation of biogas, such as physical and chemical
adsorption, membrane based separation, pressure
swing adsorption, chemical and biological fixation of
CO2 and cryogenic separation, etc. (Farooq et al.,
2012; Abatzoglou and Boivin, 2009; Yang et al., 2008).
According to Starr et al. (2015) two widely applied
technologies are; high pressure water scrubbing and
chemical scrubbing with amine. These technologies
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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are based on absorption of CO2 using water and amine
solution (such as monoethanolamine), respectively, to
separate the CO2. The additional benefit of these
methods is that the captured CO2 can be regenerated
and sold to the industries, instead of releasing into
environment (Global CCS Institute, 2011; Parsons
Brinckerhoff, 2011). Al Mamun et al. (2015) found
that the water scrubbing system was efficient to purify
CH4 up to 100% in counter current flow water and gas.
Flow rate plays a crucial role in water scrubbing
system. The flow rate of water and gas as 0.465 and
1.8 m3/h can decrease the CO2 content by 93%.
Similarly, the water flow rate as 2 m3/h can remove
CO2 up to 87.6% (Shyam, 2002). In chemical
purification method of biogas, various solvents are
used such as mono-ethanolamine (MEA), tri-
ethanolamine, di-ethanolamine and aqueous solution
of alkaline (sodium, calcium) salts, etc. (Farooq et al.,
2012; Tippayawong and Thanompongchart, 2010).
New purification process i.e. treating biogas with
some purifying agent such CaO solution, solid CaO and
activated carbon can be applied for CO2 removal from
biogas at highly effective level. As mentioned, biogas
up-gradation methods are well studied, however,
there is a need to find out some viable and non-
expensive methods which can be integrated to landfill
to get high economic benefit of biogas (Al Mamun et
al., 2015).
3.1.2. Conversion of methane into liquid fuel
(methanol)
The biogas can be utilized as fuel using up-gradation
techniques, however, these process are usually
expensive and make the application of methane
uneconomical (Sheets et al., 2016). Similarly, other
problem associated with methane includes difficulties
to store and transportation because methane exists in
gaseous state at ambient temperature (Ge et al.,
2014). These issues can be resolved by converting
methane to methanol, which is a valuable product and
can be used as a liquid fuel by converting into olefins
and gasoline (Sheets et al., 2016).
Various methods have been reported for conversion of
methane to methanol, including thermo-chemical
(Riaz et al., 2013), biological conversion using
methanotrophs (Sheets et al., 2016), partial oxidation
(Krisnandi et al., 2015), and nonthermal plasmas
(Mahammadunnisa et al., 2015), etc. In
thermochemical process, methane can be efficiently
converted to methanol but the process is expensive
due to the requirement of metal catalysts and high
temperature up to 900 oC (Riaz et al., 2013).
Moreover, thermochemical process becomes
ineffective when impurities are present in the
methane biogas (Yang et al., 2014). Conversely,
biological conversion methods are more feasible and
environment friendly. Sheets et al. (2016) isolated a
new methnotroph that could use methane as a
substrate for its growth and multiplication. They
achieved 25% methane to methanol conversion in just
48 h.
In general, the selection of technology is very
important to use the potential of methane either by
up-gradation or conversion to methanol. Both have
their own benefits and potential as energy source. In
the case of KSA, there is a huge consumption of liquid
fuel in transportation. The methanol as a liquid fuel
can easily be handled and converted to other
petroleum fuels for its vast application such as
transportation.
3.2. Pyrolysis: converting plastic waste into liquid fuel
In KSA, municipal waste generation is 15.3 million tons
per year which contains 17.4 % plastic (Nizami et al.,
2015a). Plastic is non-biodegradable, hence it remains
in the environment for long period of time (Achilias et
al., 2007). Plastic waste mostly comprises of
polypropylene (PP), polystyrene (PS), low density
polyethylene (LDPE), polyvinyl chloride (PVC) and
polyethylene (PE). The disposal of these wastes by
landfill or incineration may cause environmental and
health problems (Ashworth et al., 2014). Likewise in
KSA, most of plastic wastes are disposed of with MSW
in landfill. Moreover, conventional recycling
techniques recycle only a small portion of plastic
waste. Under these circumstances, various waste to
energy techniques such as gasification and pyrolysis
are getting more attention of the researcher as an
alternative way for plastic waste treatment (Nizami et
al., 2015a).
Pyrolysis is a tertiary recycling techniques widely used
for thermal conversion of plastic waste at different
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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temperature ranges from 300oC to 900oC (Chen et al.,
2014). However, most of the researcher reported that
optimum temperature for pyrolysis was 450 oC to 550
oC (Miskolczi et al., 2009; Abbas-Abadi et al., 2014).
Plastic waste pyrolysis is carried out in the absence of
oxygen forming vapours and char (Sharma et al.,
2014). Vapours produced during pyrolysis are
converted into liquid fuel by condensation process.
The process takes about 3 to 4 hours to convert plastic
waste into liquid fuel (Fonts et al., 2009). The pyrolysis
process can be optimized by using catalyst to reduce
the temperature and retention time of process
(Miskolczi et al., 2009).
In pyrolysis technology, various kinds of pyrolytic
reactors were used by different researchers.
Generally, there are one-stage and two-stage pyrolysis
reactors. In one-stage reactor, catalyst is added with
the feedstock in the same reactor (Achilias et al.,
2007), while in two-stage reactor, the heating and
catalytic reactors are separated (Syamsiro et al.,
2014). On the basis of substrate feeding, there are two
types of reactor, which are pre-feeding (Lopez et al.,
2009) and post feeding, Moreover, on the basis of
design, there are various types of reactors like fixed
bed-reactor (Wang et al., 2006), rotary kiln reactor (Li
et al., 2005), tubular reactor (Marculescu et al., 2007)
and fluidized bed reactor (Al-Salem et al., 2010).
3.2.1. Value-added products of pyrolysis
Liquid fuel is the main energy product of pyrolysis.
Through pyrolysis, 74-84% plastic (by weight) can be
converted into liquid fuel (William, 2006; Lopez et al.,
2011). Liquid fuel produced from pyrolysis having
nearly same values to that of diesel in terms of
density, viscosity, high heating value (HHV), cold flow
properties, etc. Thus, it has huge potential to be used
as an alternative of conventional diesel. Research on
characterization of pyrolytic liquid fuel showed that
the produced fuel has 0.79-0.87 g cm-3 of density 1-
2.96 mm2/s of viscosity and -18 oC as cold flow
property (Syamsiro et al., 2014; Wongkhorsub and
Chindaprasert, 2013; Isioma et al., 2013). Viscosity is
an important fuel characteristic and depends on the
feedstock composition. Generally, PS produces less
viscous oil as compared to PE and PP, which has
complex branched hydrocarbons (Siddique and
Redhwi, 2007). Moreover, less cold flow properties
makes it more favorable to be used in those parts of
the world where temperature remains very low
throughout the year. In addition, the liquid fuel
produced from PS, HDPE, LDPE and mix plastic has
HHV ranging between 45.86, 38–39, 44.4 MJ/kg
respectively (Sharma et al., 2014; Panda et al., 2010;
Kim et al., 2010).
Char is an unburnt plastic which left over in the
reactor after completion of pyrolysis process. It is a by-
product of the process and can be used as adsorbent
in wastewater treatment. Char adsorption values can
be increased by thermal activation at temperatures of
900 oC for 3 hours. Activation increases its BET surface
area from 10.83 m2/g to 16.77 m2/g, reduces the pore
size (521.30 oA to 496.00 oA) and increases pore
volume (0.1441 cm3/g to 0.2080 cm3/g) (Jindaporn and
Lertsatitthanakorn, 2014). Char with high BET surface
area, pore volume and less pore size has the potential
to be used as adsorbent in different environmental
applications such as removal of heavy metals from
wastewater (Heras et al., 2014). Moreover, the char
produced from PS and HDPE has HHV of 36.29 and
23.04 MJ/kg, have potential to be used as alternative
source of energy (Syamsiro et al., 2013).
Gases produced from pyrolysis are comprised of CO,
CO2, CH4 and H2, while PVC plastic also produces
chlorine gas (Lopez et al., 2011). The use of catalyst
having high BET surface area increases the gases
production during pyrolysis process. Moreover, gases
produced from catalytic pyrolysis have 45.9 - 46.6
MJ/kg HHV, which show that it has potential to be
used as alternative of natural gas (Miskolczi et al.,
2009).
3.2.2. Catalytic pyrolysis: emphasis on Saudi Arabian
natural zeolite
Catalytic pyrolysis is a prominent technique to convert
plastic into high quality liquid fuel and other value-
added products, such as char and gases. Catalyst
enhances the efficiency of pyrolysis process by
lowering the temperature and retention time (Manos
et al., 2002), removing impurities and converting
hydrocarbon into gasoline (Lopez et al., 2011). The use
of catalyst makes the process highly economical and
also improves the quality of the liquid fuel. Catalysts
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
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Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
used for pyrolysis process are acidic in nature
(Jindaporn and Lertsatitthanakorn, 2014). Most
frequently used catalysts are ZSM-5 (Lopez et al.,
2011), HZSM-5 (Miskolczi et al., 2009), FCC (Achilias et
al., 2007), Red mud (Lopez et al., 2012), Natural zeolite
(NZ) (Syamsiro et al., 2014), etc. In Kingdom of Saudi
Arabia (KSA) NZ is found in abundance in the area of
Harrat Shama and Jabbal Shama (Nizami et al., 2015b).
It has high BET surface area with crystalline structure
and has potential to be used as catalyst in different
waste to energy field. In general, the use of Saudi
Arabian natural zeolite could be an excellent option
for enhancing the efficiency of pyrolysis process for
treatment of huge amount of plastic waste. The use of
NZ will not only improve the liquid fuel quality but also
make the process highly economical due to local
abundance.
In order to improve the catalytic activity of catalyst,
there are different modification techniques available
by which the catalytic efficiency of natural zeolites can
also be increased. Modification can be carried out by
thermal activation (Syamsiro et al., 2014), acid
leaching (Sriningsih et al., 2014) and doping of metal
via wet impregnation (Adnan and Jan, 2014). Thermal
activation of catalyst at 550 oC removes the volatile
compounds from the catalyst (Syamsiro et al., 2014)
while acid leaching increases acidity of catalyst and
removes internal impurities of the catalyst. Likewise,
catalyst can be modified by doping of metals, such as
Ni, Co, Mo, Zn, etc. Presence of metal sites can
accelerate hydrogenation and dehydrogenation
reactions (Panda et al., 2010). Hence, dual functions
make it more prominent to be used as catalyst in the
catalytic pyrolysis (Ciobanu et al., 2008).
4. Conclusion
KSA has a high potential to recover the resources from
huge amount of solid waste generated in the country.
The current practices of municipal solid waste in KSA
are not very effective, thus shifting toward new
approaches of resource recovery not only provides
environmental safety, but also add the value in the
economy in terms of energy and value added
products.
The major portion of municipal solid waste is organic
(40%), thus the anaerobic digestion process is highly
feasible to recover methane as an energy resource.
For this purpose, there is a need to develop new
landfill systems which should be properly designed,
engineered, and managed. This could be an effective
alternative to current practice of uncontrolled waste
dumping system, where no gas recovery systems are
available. To get the full potential of methane biogas,
the landfill system should be equipped with gas
collection and further integrated with biogas up-
gradation system to get methane with high calorific
value.
As plastic waste is the second largest proportion of
municipal solid waste, initiative should be taken for
proper segregation and recycling this waste. The other
ways include the use of pyrolysis technology which has
capability to convert any type plastic into fuel oil. To
get high quality fuel oil, catalytic pyrolysis is an
effective method, where the use of natural zeolite as a
catalyst could be beneficial from economic point as
zeolite is abundantly available in KSA.
There is a huge potential of using waste as a resource,
yet there is a need to improve the existing strategic
planning regarding waste management, especially in
big cities of KSA accommodating most of the country
population.
References
Abatzoglou, N. and S. Boivin. 2009. A review of biogas
purification processes. Biofuel Bioprod. Biorefin.,
3: 42–71.
Abbas-Abadi, M.S., M.N. Haghighi, H. Yeganeh and
A.G. Macdonald. 2014. Evaluation of pyrolysis
parameters on polypropylene degradation
products. J. Anal. Appl. Pyrol., 109: 272-277.
Abdul-Aziz, H., M. Isa, O. Kadir, N. Nordin, W. Daud, A.
Alsebaei and A. Abu-Rizaiza. 2007. Study of
baseline data regarding solid waste management
in the holy city of Makkah during Hajj. The
custodian of the two holy mosques institute of
the hajj research (Unpunished Report).
Achilias, D.S., C. Roupakias, P. Megalokonomos, A.A.
Lappas and E.V. Antonakou. 2007. Chemical
recycling of plastic wastes made from
polyethylene (LDPE and HDPE) and polypropylene
(PP). J. Hazard. Mater., 149: 536–542.
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
24
Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
Adhikari, B.K., S. Barrington, J. Martinez and S. King.
2008. Characterization of food waste and bulking
agents for composting. Waste Manage., 28: 795–
804.
Adnan, J. S. and M. R. Jan. 2014. Polystyrene
degradation studies using Cu supported catalysts.
J. Anal. Appl. Pyrol., 109: 196–204.
Al Mamun, M.R., M.R., Karim, M.M., Rahman, A.M.,
Asiri and S. Torii. 2015. Methane enrichment of
biogas by carbon dioxide fixation with calcium
hydroxide and activated carbon. J. Taiwan Inst.
Chem. Eng. (In press).
Alruqaie, I.M., and B.H. Alharbi. 2012. Environmental
advantage assessment of recycling food waste in
Riyaz, Saudi Arabia. Res. J. Environ. Sci., 6: 230-
237.
Al-Sabahi, E., S.A. Rahim, W.Y. Wan Zuhairi, F. Al-
Nozaily F. Alshaebi. 2009. The characteristics of
leachate and groundwater pollution at municipal
solid waste landfill of Ibb City, Yeme. American J.
Environ. Sci., 5(3): 256-266.
Al-Salem, S.M., P. Lettieri, and J. Baeyens. 2010. The
valorization of plastic solid waste (PSW) by
primary to quaternary routes: from reuse to
energy and chemicals. Prog. Energy Combust. Sci.,
36: 103–129.
Al-Turki, A., Y. El-Hadidy and F. Al-Romian. 2013.
Assessment of chemical properties of locally
composts produced in Saudi Arabia composts
locally produced. Int. J. Curr. Res. 5: 3571-3578.
Alzaydi, A., S. Alsolaimani and M. Ramadan. 2013.
Demand, practices and properties of compost in
the western region of KSA. Aust. J. Basic Appl. Sci.
7(7):768-776.
Ashworth, D.C., P. Elliott and M.B. Toledano. 2014.
Waste incineration and adverse birth and
neonatal outcomes: a systematic review. Environ.
Int., 69:120–132.
Barton, J.R., I. Issaias and E.I. Stentiford. 2008. Carbon-
making the right choice for waste management in
developing countries. Waste Manage., 28: 69–76.
Bernal, M.P., J.A. Albuquerque and R. Moral. 2008.
Composting of animal manures and chemical
criteria for compost maturity assessment: A
review. Bioresour. Technol., 100: 5444-5453.
CDSI (Central Department of Statistics and
Information). 2004. Annual Statistic book.
http://www.cdsi.gov.sa/english/index.php?option
=com_content&view=article&id=84 &It emid=172
Chen, D., L. Yin, H. Wang and P. He. 2014. Pyrolysis
technologies for municipal solid waste: A Review.
Waste Manage., 34:2466–2486.
Chen, Y., J.J., Cheng and K.S. Creamer. 2008. Inhibition
of anaerobic digestion process: a review.
Bioresour. Technol., 99(10): 4044-4064.
Cheng, H. and Y. Hu. 2010. Review municipal solid
waste (MSW) as a renewable source of energy:
current and future practices in China. Bioresour
Technol., 101:3816–24.
Ciobanu, G., D. Ignat, G. Carja, S. Ratoi and C. Luca.
2008. Zinc modified forms of Zeolites by wet
Impregnation method. Chem. Bull., 53(67): 1-5.
Dirkse, E. H. M. 2009. Biogas Upgrading using the DMT
TS-PWS technology. Dirkse Milieutechniek, Joure,
Netherlands.
Esposito, G., L., Frunzo, A. Giordano, F. Liotta, A.
Panico and F. Pirozzi. 2012. Anaerobic co-
digestion of organic wastes. Rev. Environ. Sci.
Biotechnol., 11(4): 325-341.
Eurostat, 2013. Climate change–driving forces [WWW
Document]. <http://epp.
eurostat.ec.europa.eu/statistics_explained/index.
php/Climate_change_driving_forces>
Farooq, M., I.A. Chaudhry, S. Hussain, N. Ramzan and
M. Ahmed. Biogas upgradation for power
generation applications in Pakistan. J. Qual.
Technol. Manage., 7(2): 107–18.
Fonts, I., M. Azuara, G. Gea and M.B. Murillo. 2009.
Study of the pyrolysis liquids obtained from
different sewage sludge. J. Anal. Appl. Pyrol.,
85(1-2): 184-191.
Gajalakshmi, S., and S.A. Abbasi. 2008. Solid waste
management by composting: state of the art. Crit.
Rev. Environ. Sci. Technol., 38: 311–400.
GCST (Gulf Countries Standards). 2006. Standards of
fertilizers and soil conditioners in Gulf Countries
(in Arabic).
Ge, X., L. Yang, J.P. Sheets, Z. Yu and Y. Li. 2014.
Biological conversion of methane to liquid fuels:
status and opportunities. Biotechnol. Adv., 32:
1460–1475.
GIZ (2012). Organic agriculture in Saudi Arabia.
Retrieved from https://www.giz .de/en/
downloads/giz2012-organic-agriculture-saudi-
arabia-en.pdf
Global CCS Institute, Parsons Brinckerhoff. 2011.
Accelerating the Uptake of CCS: Industrial Use of
Captured Carbon Dioxide. Global CCS Institute,
Docklands, Australia
Heras, F., D. Jimenez-Cordero, M.A. Gilarranz, N.
Alonso-Morales, J. J. Rodriguez. 2014. Activation
of waste tire char by cyclic liquid-phase oxidation.
Fuel Proc. Technol., 127: 157–162.
Isioma, N., Y. Muhammad, O.D. Sylvester, D. Innocent,
and O. Linus. 2013. Cold flow properties and
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
25
Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
kinematic viscosity of biodiesel. Uni. J. Chem.,
1(4): 135-141.
Jindaporn, J., and C. Lertsatitthanakorn. 2014.
Characterization and utilization of char derived
from fast pyrolysis of plastic wastes. Proc. Eng.,
69: 1437-1442.
Kameswari, K.S.B., B., Velmurugan, K. Thirumaran and
R. Ramanujam. 2007. Biomethanation of
vegetable market waste untapped carbon trading
opportunities. In: Proceedings of the International
Conference on Sustainable Solid Waste Manage.,
P. 415–420.
Khan, M.S.M. and Z. Kaneesamkandi. 2013.
Biodegradable waste to biogas: renewable energy
option for the Kingdom of Saudi Arabia. Int. J.
Innov. Appl. Stud., 4(1): 101-113.
Kim, J.S., H.M. Cho and S.H. Jung. 2010. Pyrolysis of
mixed plastic wastes for the recovery of benzene,
toluene and xylene (BTX) aromatics in a fluidized
bed and chlorine removal by applying various
additives. Energy Fuels, 24:1389-1395.
Kjeldsen, P., M.A. Barlaz, A.P. Rooker, A. Baun, A.
Ledin and T.H. Christensen. 2002. Present and
Long-term composition of MSW landfill leachate:
A Review. Crit. Rev. Environ. Sci. Technol., 32:
297-336.
Krisnandi, Y.K., B.A.P. Putra, M. Bahtiar, I. Abdullah,
and R.F. Howe. 2015. Partial oxidation of methane
to methanol over heterogeneous catalyst
Co/ZSM-5. Proced. Chem., 14: 508-515.
Lettinga, G. 2001. Digestion and degradation, air for
life. Water Sci. Technol., 44: 157–176.
Li, S.Q., L.B. Ma, W. Wan and Q. Yan. 2005. A
mathematical model of heat transfer in a rotary
kiln thermo-reactor. Chem. Eng. Sci., 28: 1480–
1489.
Lopez, A., I.D. Marco, B.M. Caballero, M.F. Laresgoiti,
A. Adrados and A. Aranzabal. 2011. Catalytic
pyrolysis of plastic wastes with two different
types of catalytic: ZSM-5 zeolite and Red Mud.
App. Catal. B: Environ., 104: 211-219
Lopez, A., Marco, I.D., B.M. Caballero, M.F. Laresgoiti
and A. Adrados. 2012. Catalytic stepwise pyrolysis
of packaging plastic waste. J. Anal. Appl. Pyrol.,
96: 54-62.
Lopez, G., M. Olazar, M. Artetxe, M. Amutio, G. Elordi
and J. Bilbao. 2009. Steam activation of pyrolytic
tyre char at different temperatures. J. Anal. Appl.
Pyrol., 85: 539–543.
Mahammadunnisa, S.K., K. Krushnamurty and C.H.
Subrahmanyam. 2015. Catalytic nonthermal
plasma assisted co-processing of methane and
nitrous oxide for methanol production. Catal.
Today, 256: 102–107.
Manos, G., I. Yusof, N. H.Gangas and N. Papayannakos.
2002. Tertiary recycling of polyethylene to
hydrocarbon fuel by catalytic cracking over
aluminum pillared clays. Energy Fuels, 16: 485–
489.
Marculescu, C., G. Antonini, A. Badea and T. Apostol.
2007. Pilot installation for the thermo-chemical
characterization of solid wastes. Waste Manage.,
27: 367–374.
Miskolczi, N., A. Angyal, L. Bartha and I. Valkai. 2009.
Fuel by pyrolysis of waste plastics from
agricultural and packaging sectors in a pilot scale
reactor. Fuel Proc. Technol., 90: 1032-1040.
Nizami A.S, M. Rehan, O.K.M. Ouda, K. Shahzad, Y
Sadef, T. Iqbal and I.M.I. Ismail 2015a. An
argument for developing waste-to-energy
technologies in Saudi Arabia. Chem. Eng. Transac.,
45: (In Press)
Nizami, A.S., O.K.M., Ouda, M. Rehan, A.M.O. El-
Maghraby, J. Gardy, A. Hassanpour, S. Kumar and
I.M.I. Ismail. 2015b. The potential of Saudi
Arabian natural Zeolites in waste-to-energy
technologies. Energy: (In press).
Ouda, O.K., H.M., Cekirge and S.A. Raza. 2013. An
assessment of the potential contribution from
waste-to-energy facilities to electricity demand in
Saudi Arabia. Energy Conserv. Manage., 75: 402-
406.
Panda, A.K., R.K. Singh and D.K. Mishra. 2010.
Thermolysis of waste plastics to liquid fuel. A
suitable method for plastic waste management
and manufacture of value added products—A
world prospective. Renew. Sust. Energy Rev., 14:
233–248.
Petersson, A. and A. Wellinger. 2009. Biogas
Upgrading Technologies-Developments and
Innovations. IEA Bioenergy, Paris, France.
Psomopoulos, C., A. Bourka and N. Themelis. 2009.
Waste-to-energy: a review of the status and
benefits in USA. Waste Manage., 29: 1718–1724.
Rahman, S.M. and A.N. Khondaker. 2012. Mitigation
measures to reduce greenhouse gas emissions
and enhance carbon capture and storage in Saudi
Arabia. Renew. Sust. Energy Rev., 16(5): 2446-
2460.
Riaz, A., G. Zahedi and J.J. Klemes. 2013. A review of
cleaner production methods for the manufacture
of methanol. J. Clean. Prod., 57: 19–37
Sharma B.K., B.R., Moser, K.E. Vermillion, K.M. Doll
and N. Rajagopalan. 2014. Production,
characterization and fuel properties of alternative
Anjum et al. 2016 J. Appl. Agri. Biotechnol. 2016 1(1): 13−26
26
Copyright© PMAS-Arid Agriculture University Rawalpindi, Pakistan http://jaab.uaar.edu.pk
diesel fuel from pyrolysis of waste plastic grocery
bags. Fuel Proc. Technol., 122: 79-90.
Sheets, J.P., X. Ge, Y.F., Li, Z. Yu and Y. Li. 2016.
Biological conversion of biogas to methanol using
methanotrophs isolated from solid-state
anaerobic digestate. Bioresour. Technol., 201: 50-
57.
Shyam, M. 2002. Promising renewable energy
technologies. AICRP. Tech. Bull. CIAE., 88:47–8.
Siddiqui, M. N. and H. H. Redhwi. 2009. Pyrolysis of
mixed plastics for the recovery of useful products.
Fuel Proc. Technol. 90: 545–552.
Simandi, P., M. Takayanagi and K. Inubushi. 2005.
Changes in the pH of two different composts are
dependent on the production of organic acids.
Soil Sci. Plant Nutr., 61(5): 771 -774.
Sriningsih, W., M.G. Saerodji, W. Trisunaryanti,
Triyono, R. Armunanto and I.I. Falah. 2014. Fuel
production from LDPE plastic waste over natural
Zeolite supported Ni, Ni-Mo, Co and Co-Mo
Metals. Proc. Environ. Sci., 20: 215–224.
Starr, K., G. Villalba and X. Gabarrell. 2015. Upgraded
biogas from municipal solid waste for natural gas
substitution and CO2 reduction–A case study of
Austria, Italy, and Spain. Waste Manage., 38: 105-
116.
Svensson, K., M. Odlare and M. Pell. 2004. The
fertilizing effect of compost and biogas residues
from source separated household waste. J. Agri.
Sci., 142: 461–467.
Syamsiro, M., H. Saptoadi, T. Norsujianto, S. Cheng, Z.
Alimuddin and K. Yoshikawa. 2014. Fuel oil
production from municipal plastic wastes in
sequential pyrolysis and catalytic reforming
reactors. Energy Proc., 47: 180-188.
Syamsiro, M., W. Hu, S. Komoto, S, Cheng, P. Noviasri,
P. Prawisudha and K. Yoshikawa. 2013. Co-
production of liquid and gaseous fuels from
polyethylene and polystyrene in a continuous
sequential pyrolysis and catalytic reforming
system. Energy Environ. Res., 3(2): 121-132.
Tippayawong, N. and P. Thanompongchart. 2010.
Biogas quality upgrade by simultaneous removal
of CO2 and H2S in a packed column reactor.
Energy, 30: 1–5.
Tolba, M.K. and N. Saab (eds). 2008. Arab
environment: Future challenges. Arab Forum for
Environment and Development. ISBN: 9953-437-
24-6.
USEPA. 2002. Solid Waste Management: A local
challenge with global impacts. Retrieved from:
http://www3.epa.gov/climatechange/wycd/waste
/downloads/folder.pdf
Wang, L.H., Y. Zhang and L.N. Song. 2006.
Experimental research on pyrolysis process of
waste rubber. Liaoning Gongcheng, Jishu Daxue
Xuebao (Ziran Kexue Ban)/J.Liaoning Tech. Univ.
Nat. Sci. Edu., 25: 336–338.
WB (World Bank), 2015. http://data.worldbank.org/
indicator/SP.POP.TOTL
Williams, P.T. 2006. Yield and composition of gases
and oils/waxes from the feedstock recycling of
waste plastic. In: Scheirs, J., Kaminsky, W. (Eds.),
Feeds tock Recycling and Pyrolys is of Waste
Plastics: Converting Waste Plastics into Diesel and
Other Fuels. John Wiley & Sons Press, West
Sussex. P. 285–309.
Wongkhorsub, C. and N. Chindaprasert. 2013. A
Comparison of the Use of Pyrolysis Oils in Diesel
Engine. Energ. Power Eng., 5: 350-355.
Yang, H., Z. Xu, M. Fan, R. Gupta, R.B. Slimane and A.E.
Bland. 2008. Progress in carbon dioxide
separation and capture: a review. J. Environ. Sci.,
20: 14–27.
Yang, L., X. Ge, C. Wan, F. Yu and Y. Li. 2014. Progress
and perspectives in converting biogas to
transportation fuels. Renew. Sust. Energy Rev. 40:
1133– 1152.
Young, G.C. 2010. Municipal solid waste to energy
conversion processes: economic, technical, and
renewable comparisons. 1st ed. Hoboken, New
Jersey: John Wiley.
Zafar, S. 2015. Waste Management in Jeddah.
Retrieved from:
http://www.ecomena.org/tag/solid-waste-
management-in-jeddah/
Zhang, Y. M., G. H. Huang and L. He. 2010. Integrated
fuzzy ranking analysis for assessing the quality of
composting products. J. Environ. Eng., 136: 508–
519.
Zhao, Q., E. Leonhardt, C. Mac-Connell, C. Frear, and C.
Chen. 2010. Purification technologies for biogas
generated by anaerobic digestion. Climate
Friendly Farming, Compressed Biomethane
Research Report 2010-001. 9: 1–24.
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