Developing waste biorefinery in Makkah: A way forward to convert urban waste into renewable energy A.S. Nizami a,⇑ , K. Shahzad a , M. Rehan a , O.K.M. Ouda b , M.Z. Khan c , I.M.I. Ismail a , T. Almeelbi a , J.M. Basahi a , A. Demirbas d a Center of Excellence in Environmental Studies (CEES), King Abdulaziz University, Jeddah, Saudi Arabia b Department of Civil Engineering, Prince Mohamed Bin Fahd University, Al Khobar, Saudi Arabia c Environmental Research Laboratory, Department of Chemistry, Aligarh Muslim University, Aligarh, Uttar Pradesh 202 002, India d Faculty of Engineering, Department of Industrial Engineering, King Abdulaziz University, Jeddah, Saudi Arabia highlights  Waste biorefinery is proposed to convert waste in Makkah into renewable energy.  Total revenue of 758 million SAR can be achieved from waste biorefinery.  1.95 million barrels of oil and 11.2 million MCF of natural gas can be saved.  Reduction in global warming potential of 1.15 million Mt.CO 2 eq. can be achieved. article info Article history: Received 22 December 2015 Received in revised form 22 March 2016 Accepted 27 April 2016 Available online 25 May 2016 Keywords: Waste-based biorefinery Waste-to-energy (WTE) Municipal solid waste (MSW) Renewable energy Recycling Anaerobic digestion (AD) abstract The city of Makkah in the Kingdom of Saudi Arabia (KSA) hosts millions of Muslim worshippers every year. As a consequence, the municipal solid waste (MSW) quantities become enormous. City landfills receive about 2.4 thousand tons of MSW every day, whilst during the months of fasting (Ramadan) and Pilgrimage (Hajj), these quantities become 3.1 and 4.6 thousand tons per day respectively. Currently, there is no waste-based biorefinery or waste-to-energy (WTE) facility existing in KSA to treat different fractions of MSW as a source of renewable energy production and a solution to landfill waste problems. Therefore, the waste-based biorefinery, if developed in Makkah city, including WTE technolo- gies such as anaerobic digestion (AD), transesterification, pyrolysis and refuse derived fuel (RDF) can be able to treat around 87.8% of the total MSW. The remaining 12.2% of MSW fraction can be recycled. The waste-based biorefinery, along with the recycling approach, can generate savings of about 87.6 million Saudi Arabian Riyal (SAR) from carbon credits. Similarly, a total net revenue of 758 million SAR can be generated from landfill diversion (530.4 million SAR) and electricity generation (288.5 million SAR). Moreover, 1.95 million barrels of oil and 11.2 million MCF of natural gas can be saved with a cost savings of 485.5 million SAR. Collectively, the waste-based biorefinery and recycling can reduce the global warm- ing potential (GWP) of 1.15 million Mt.CO 2 eq. Ó 2016 Elsevier Ltd. All rights reserved. 1. Introduction Muslim Pilgrimage to the Kingdom of Saudi Arabia (KSA) is one of the oldest and largest religious gatherings in the world [1]. Millions of Muslims from all over the world gather every year in KSA to perform worship at Al-Haram (Holy Mosques in Makkah and Medinah) and Al-Masha’ir (Mina, Arafat and Muzdalifah). The area of Al-Haram mosque in Makkah, including indoor and outdoor prayer space, is around 356,800 square meters. More than 2 million Muslims can worship at a time, especially during the Ramadan (9th month of the Islamic lunar calendar) and Hajj (12th month of the Islamic lunar calendar) [2]. The number of pil- grims visiting KSA has been significantly increased over the past few decades, with an annual rate of 1.15% from 1993–2014 (Fig. 1) due to expansion in the Holy Mosques, improved http://dx.doi.org/10.1016/j.apenergy.2016.04.116 0306-2619/Ó 2016 Elsevier Ltd. All rights reserved. Abbreviations: AD, anaerobic digestion; CH 4 , methane; GHG, greenhouse gas; HHV, high heating value; IPPC, Intergovernmental Panel on Climate Change; KSA, Kingdom of Saudi Arabia; LCA, life cycle assessment; MPW, municipal plastic waste; MSW, municipal solid waste; OFMSW, organic fraction of municipal solid waste; RDF, refuse derived fuel; SAR, Saudi Arabian Riyal; VAP, value-added product; WTE, waste-to-energy. ⇑ Corresponding author. E-mail address: nizami_pk@yahoo.com (A.S. Nizami). Applied Energy 186 (2017) 189–196 Contents lists available at ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy