1.0 Introduction

Nowadays, ‘energy from waste’ is getting popular worldwide, and the concept is specifically relevant to the countries like Saudi Arabia due to its inclination towards reducing dependence on conventional fuel energy. In addition, for the Kingdom of Saudi Arabia, energy from waste has become the need of the time due to its ambitious government policy ‘Vision 2030’, which is primarily focused on renewable energy sources due to massive gathering of religious community gathering in the City of Mecca and Madinah for Hajj and Umrah that creates a massive amount of waste generation (Omar et al., 2017). Therefore, this paper mainly focused on the potential of Madinah city to produce biodiesel from waste. Further, the paper also explains the method incorporated for transforming the waste to biodiesel and achieving the initiative by the authority.

2.0 Madinah City

The assessment for ‘energy from waste’ for the Kingdom of Saudi Arabia started in the year 2012. According to (Minghau et al., 2009), MSW production was assumed to be 1.4 kg/capita/day. For the City of Madinah, the population is 1.2 million. Figure 1 shows three major cities of Saudi Arabia. The population growth has been estimated to grow according to its historical trend of 3.4% until the year 2032.

Figure 1: Major cities in the Kingdom of Saudi Arabia, including Madinah

Potential fuel saving by transforming waste to biodiesel is approximately 0.83 million bbl and 3.85 million Mcf of natural gas. With the increasing population and pilgrims to Madinah, the projected fuel savings in coming years are 1.72 million bbl. From the collected MSW, the City has targeted to produce 130 thousand tonnes of biodiesel, glycerol up to 13 thousand tonnes, and 244 thousand tonnes of MBM as biofuel.

3.0 Method to convert used-cooking oil to biodiesel

Figure 2 shows the schematic representation of biodiesel production adopted by Madinah city transforming fat fraction of Municipal Solid Waste (MSW), mainly used cooking oil and slaughtering waste.

Figure 2: Major cities in the Kingdom of Saudi Arabia, including Madinah (Shahzad et al., 2017)

Biodiesel production is a hi-tech, well-developed process with high productivity estimated up to 98%, producing glycerol as a by-product due to fatty acid inputs (Tits et al., 2012). The process used to convert the MSW to biodiesel is transesterification. The biodiesel produced from animal fat is known as tallow methyl ester (TME). Sulphuric acid (H2SO4) is used in the first step to convert free fatty acids to biodiesel through esterification. This is followed by the reaction of tallow by methanol (CH3OH) in the ratio of approximately 1:6. The reaction takes place in the presence of potassium hydroxide (CH3OH), which acts as a catalyst (Shahzad et al., 2013). The quality of the produced biodiesel mainly depends on the fraction of unsaturated fatty acids present in the raw material. Higher biodiesel quality when an unsaturated fraction of fatty acids in the raw material is higher. The produced biodiesel has lower quality when the raw material has a higher amount of saturated fatty acid (Kettl et al., 2011).

4.0 Results of City’s initiative

The initiative by the City is ongoing and estimated to save 533 Saudi Riyal in the form of fees from landfills, up to 96 million Saudi Riyal in terms of carbon credits which saves emission of CH4, 569 million Saudi Riyal by using biofuel for the generation of electricity. Implementing this technology has added revenue of 611 million Saudi Riyal, increasing progressively and is expected to reach 1274 million Saudi Riyal by 2050.

References

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