Waste to energy analysis of shakarganj sugar mills; biogas production from the spent wash for electricity generation Abdullah Yasar n,1 , Aleena Ali 1 , Amtul Bari Tabinda 1 , Aleena Tahir 1 GCU Lahore, Sustainable Development Study Center, GCU Lahore, Pakistan article info Article history: Received 7 January 2014 Received in revised form 2 September 2014 Accepted 1 November 2014 Keywords: Spent wash Biogas Electricity CDM Renewable energy abstract Waste to energy analysis of a large scale sugar industry was performed. Biogas Power plant of Shakarganj Sugar mills is generating its own electricity from biogas produced by the waste (spent wash). The analysis of the spent wash indicates that it contains high Chemical Oxygen Demand (95000 mg/l) which reduces to 18000 mg/l during biogas production. Biogas is produced by using the anaerobic digestion of the spent wash. The biogas is passed through desulphurization and dehumidification units to remove the sulfur contents from 30000 ppm to 250 ppm. The results indicate that the total biogas production from 0.5 million M 3 of spent wash was 20.34 million M 3 during October to September. The total electricity production was 37.7 million kWh and the total steam (28260 t) generated was used by the mill. The electricity production efficiency by using new biogas boilers was 92%. The estimated CO 2 emission reduction during the year was 28032 (tCO 2 e). Due to CDM the emission factor was zero. The total revenue generated from the utilization of sugar industrial waste during the study period was USD 3.56 million. & 2014 Elsevier Ltd. All rights reserved. Contents 1. Introduction ........................................................................................................ 126 2. Methodology ....................................................................................................... 127 2.1. Study area ................................................................................................... 127 2.2. Sample analysis ............................................................................................... 127 2.3. Process description ............................................................................................ 127 2.4. Net electricity generation ....................................................................................... 127 3. Results and discussions ............................................................................................... 129 3.1. Spent wash analysis in digesters.................................................................................. 129 3.2. Efficiency of anaerobic digester in terms of waste water treatment ...................................................... 129 3.3. Comparison of biogas, steam and electricity production during spent wash treatment ...................................... 129 3.4. Cost benefit analysis ........................................................................................... 130 3.5. Clean development mechanism (CDM) ............................................................................ 130 3.6. Technological risks and uncertainties .............................................................................. 131 4. Conclusions ........................................................................................................ 131 References ............................................................................................................. 131 1. Introduction Renewable energy is gaining attention for energy production. In Pakistan its demand is increasing to fulfill the present and future energy demands of the country [1]. The factors that cause country switching on renewable and alternative energy sources are energy prices, population increase and climate change issues Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/rser Renewable and Sustainable Energy Reviews http://dx.doi.org/10.1016/j.rser.2014.11.038 1364-0321/& 2014 Elsevier Ltd. All rights reserved. n Corresponding author. Tel.: þ923004293718. E-mail addresses: yasar.abdullah@gmail.com (A. Yasar), ravian363@yahoo.com (A. Ali), amtulbaritabinda64@yahoo.com (A.B. Tabinda), aleena_tahir@yahoo.com (A. Tahir). 1 GC University, Katchery Road, Lahore. Postal Code: 54000, Pakistan, Fax no: þ92–42–99213341. Renewable and Sustainable Energy Reviews 43 (2015) 126–132