Biogas Production Through Co-digestion of Date Palm Seed And Wastewater Treatment Sludge W. Radeef, A. Shanableh and T. Merabtene Department of Civil and Environment, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates (wradeef@sharjah.ac.ae ; shanableh@sharjah.ac.ae; tmerabtene@sharjah.ac.ae) ABSTRACT The production of bio-fuel from locally available organic waste products is an attractive option as it combines waste management and useful energy recovery. The production of bio-fuel in the form of methane biogas requires readily biodegradable organic feedstock. Growing energy crops for bio-fuel production in the United Arab Emirates may not be a feasible option due to climate aridity and low soil fertility. On the other hand, wastewater treatment sludge, organic solid waste and date palm biomass are locally available. In this study, wastewater treatment sludge and two types of date palm seeds were co-digested to produce biogas. The study involved assessing the impact of date seeds on biogas production from the sludge. Date palm seeds are rich in biodegradable organic matter, including proteins, carbohydrates, and lipids. On the other hand, date seeds may contain inhibitory substances that may negatively affect biogas production. The results indicated that co-digesting date seeds with sludge at dry weight ratios less than 20% (wt/wt) can enhance biogas production. However, within three weeks of incubation, higher ratios of date seeds mixed with sludge do not significantly contribute to biogas production with signs of inhibition observed. Keywords: Khalas Date Seeds, Khudari Date Seeds, Wastewater Sludge, Biogas Production 1. INTRODUCTION The production of bio-fuel from wastewater treatment sludge is considered a suitable energy recovery option [1]. Bio-fuel production from waste products has been a subject of intensive research efforts over the past decade due to challenges associated with fuel production. The challenges include: suitability and sustainability of locally available organic waste resources; slow rate of bio-fuel production; and cost of bio-fuel production and processing. Although producing bio-fuels from locally available organic resources has some limitations, recent worldwide developments in relation to global warming and future energy strategies suggest that the time is favorable for developing appropriate renewable energy sources. In particular, the United Arab Emirates is a leader in advancing the cause of alternative and renewable energy options and is committed to achieving significant renewable energy utilization by 2020. The production of bio-fuel in the form of methane biogas requires readily available and biodegradable organic feedstocks [2-5]. There are generally two sources of organic matter that are suitable for bio-fuel production, which are: energy crops; and organic waste products. Growing energy crops for bio-fuel production may not be a feasible option in the UAE due to low soil fertility and dependence on desalination for water. The available organic waste streams in the UAE include wastewater treatment sludge; organic solid waste; and date palm biomass. In this study, wastewater treatment plant sludge and date palm seeds were co-digested to produce biogas. With the population in the UAE exceeding 8 million, wastewater treatment plants generate large quantities of sludge that can be used for bio-fuel production. The date palm production in the UAE is significant. According to the Food and Agriculture of the United Nation [6], the UAE’s export of dates has jumped from zero in 1971 to 50,000 metric tons in 1998. In 2011, the UAE became the fourth palm dates producing country in the world, with annual production of approximately 900,000 metric tons [6]. Date palm seeds, scientifically called Phoenix dactylifera, are rich in biodegradable organic materials, including Protein (5-5.5%), Carbohydrates (81-83%) and Lipids (10-12%) [7]. Date palm seeds provide a source of organic matter that can potentially contribute to and enhance the production of biogas from wastewater sludge. The main focus of this project was the production of bio- fuel in the form of methane gas from locally available organic waste resources, namely: wastewater sludge combined with date palm seed. Following a detailed literature review, only one study was found to report in biogas production from date palm seeds combined with cattle feces rather than wastewater treatment sludge [2]. However, no studies were reported on the co-digestion of date seeds and wastewater sludge.