Journal of Energy Technologies and Policy www.iiste.org ISSN 2224-3232 (Paper) ISSN 2225-0573 (Online) Vol.5, No.12, 2015 70 Energy from Domestic Wastewater and Recovering the Potential Energy of Sewage Sludge Abdul Wahid Amiri, June-ichiro Giorgos Tsutsumi, Ryo Nakamatsu Graduated School of Engineering and Science, University of the Ryukyus, Okinawa Japan Senbaru-1, Nishihara-cho,Okinawa, 903-0213, Japan Abstract This paper gives a concept overview of energy from sludge in term of anaerobic digestion method. Wastewater is grossly undervalued as a resource of energy. The sludge production is a function of the wastewater treatment system used for liquid phase. In principal, all the biological treatment process generate sludge. Nevertheless, waste and wastewater treatment have been a neglected problem in Afghanistan, where 80 % of our energy importing from neighborhood countries. As world going toward renewable energy, sewage treatment plants can retrieve valuable resources such as water, green energy and fertilizers. Developing and implementing renewable energy systems such as biogas from anaerobic digestion (AD), based on national and regional biomass resources, will increase security of national energy supply and diminish dependency on imported electricity and gases. In Afghanistan there is a lot of opportunities to capture affordable energy and heat from biomass and biogas and it enable every individual households to generate their own energy demand, but unfortunately people don not aware about this valuable resource and it is utilization. So in this study struggled to provide basic information about the value of waste and biomass and then promulgate to local people and governments to consider on their financing institutions operating in the future. Therefore, the objective of this study focused on the concept of resource efficiency in sewerage sludge to convert into green energy. The methodology was based on anaerobic process which is widely used for treatment of municipal waste sludge and has excellent potential for treatment of many industrial waste; and the design criteria are based on a volumetric organic load (kgBOD/m 3 ·d). In particular, calculation and simulation results from treated flow of 2000 m 3 /d, resulting from amount of yielding gas is 109 m 3 /d which is huge amount of capturing energy at small treatment plant. In consequence, the production of energy from sewage sludge through anaerobic digestion has been able to effectively offset energy demand for wastewater treatment plant and methane is a useful end product. Developing source of clean, renewable energy will boost local and regional economics strengthen our national energy security as well decrease our energy dependency. Keywords: Domestic Wastewater, Sludge, and green energy. 1. Introduction Efficient municipal wastewater treatment produces vast amounts of sludge. Sludge management is an integral part of any modern municipal wastewater treatment plan [1]. Sewage sludge generated in wastewater treatment plants, comprising primary sludge from mechanical pre-treatment as well as surplus from biological treatment, requires further treatment for a number of reasons [10]. At a time of heightened concern about waste, climate change and the need for cleaner energy; an anaerobic digestion of organic waste provides many benefits: its includes the generation of renewable energy, a reduction of greenhouse gases, a reduced dependency on fossil fuels [3]. After digestion the sludge has a much lower volatile content and the odour has changed [4]. Calorific value of biogas produced in the digesters during anaerobic stabilization amounts to approximately about 6 kWh/m 3 – this corresponds to about half of diesel oil. Likewise, generation of energy and waste heat in a combined heat and power plant, the energy needs for a typical domestic wastewater treatment plant employing aerobic activated sludge treatment and anaerobic sludge digestion is 0.6 kWh/m 3 of wastewater treated, about half of which is for electrical energy to supply air for the aeration basins [9]. With conventional approaches involving aerobic treatment a quarter to half of a plants energy needs might be satisfied by using the CH 4 biogas produced during anaerobic digestion, and other plant modifications might further reduce energy needs considerably [5]. On the other word, waste is a source of energy which is a good alternative of fossil fuel in order to mitigate the climate change and greenhouse gas emission. Production of biogas from sewage sludge is already applied worldwide on small, medium, and large scales, the reason, anaerobic digestion technology is attractive because of its role in organic waste emphasizing these benefits and implementing certain policies [7]. 2. Methodology CORE Metadata, citation and similar papers at core.ac.uk Provided by International Institute for Science, Technology and Education (IISTE): E-Journals