Thermophilic composting of municipal solid waste D. Elango a , N. Thinakaran b , P. Panneerselvam c , S. Sivanesan c, * a Department of Civil Engineering, Hindustan College of Engineering, Padur 603 103, India b Department of Chemistry, St. Joseph College of Engineering, Chennai, India c Department of Chemical Engineering, Anna University, Chennai 600 025, India article info Article history: Received 17 December 2007 Received in revised form 26 June 2008 Accepted 26 June 2008 Available online 28 August 2008 Keywords: Composting Municipal solid waste Thermophilic reactor Organic wastes abstract Process of composting has been developed for recycling of organic fraction of municipal solid waste (MSW). The bioreactor design was modified to reduce the composting process time. The main goal of this investigation was to find the optimal value of time period for composting of MSW in thermophilic bio- reactor under aerobic condition. The temperature profiles correlated well with experimental data obtained during the maturation process. During this period biological degraders are introduced in to the reactor to accelerate the composting process. The compost materials were analyzed at various stages and the environmental parameters were considered. The final composting materials contained large organic content with in a short duration of 40 days. The quantity of volume reduction of raw MSW was 78%. The test result shows that the final compost material from the thermophilic reactor provides good humus to build up soil characteristics and some basic plant nutrients. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction The collection and disposal of solid waste is one of the major un- solved problems of urban and semi urban areas in India. The amounts of MSW generated in urban and semi urban areas ranges from 400 to 600 g per capita/day [1]. The quantity of MSW gener- ated in Chennai metropolitan city is around 3500–4800 tonnes/ day, and contains more than 70% of organic wastes. The other dis- posal methods like landfills are not suitable because in metropoli- tan cities like Chennai, space is a constraint, where valuable land that can be used for other purposes is wasted. Composting can be defined as the controlled biological decomposition of organic sub- strates carried out by successive microbial populations combining both mesophilic and thermophilic activities, leading to the produc- tion of a final product sufficiently stable for storage and application to agricultural field without adverse environmental effects [2]. Composting time of organic matter varies from ten days to three months [3]. In order to reduce the composting time, new ap- proaches like faster reaction rate, smaller composting area and introduction of bio degrader are essential. Recent research has shown that the growth of aerobic microorganism and fermentation of organic substances accelerates the composting process, and re- duces composting time [4]. The compost materials are used in agricultural fields, are bene- ficial to the plants [5], and at the same time attract higher financial premiums. Compost materials require gradual replacement of chemical fertilizers that are currently extensively used in agricul- tural production, with organic soil amendments. Additionally, or- ganic soil amendments increase the organic matter content and water reserve and reduce runoff and soil erosion from the typical hilly, terrain region [6,7]. A large number of the literatures related to different aspects of composting process, such as introduction of micro organism [8], changes of chemical composition in the com- post [9] have been reported. However, there is scarce information about the prediction of temperature profiles in composting pro- cess. Under these conditions, metabolic heat generation is com- bined with the thermal inertia effect found in compost materials due to their self-insulating properties [10]; in consequence, high thermophilic temperatures are usually maintained during the mat- uration period [11]. Temperature (75 °C) is a crucial parameter in composting since it determines the pathogen kill of the compost prior to its application to soil [12]. The main aim of this study is to evaluate the immense problems in MSW and to evolve engineer- ing and economic solutions. This study proves an eco-friendly, cost effective and nuisance-free solution for the management of MSW. In other treatment methods like incineration and pyrolysis, air pol- lution problems are predominant and also initial investments are very high. 2. Materials and methods 2.1. Feed stock used in composting MSW is collected from the Perungudi yard at the Chennai metropolitan city. The yard has an area of approximately 10 km 2 . 0306-2619/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.apenergy.2008.06.009 * Corresponding author. Tel./fax: +91 44 22203525. E-mail address: sivanesh@yahoo.com (S. Sivanesan). Applied Energy 86 (2009) 663–668 Contents lists available at ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy