An Eco Friendly Solution To The Food Waste Disposal

Transcription

1 An Eco Friendly Solution To The Food Waste Disposal G Reddy Babu 1, G Madhav Kumar 2 1 Professor, Department of Civil Engineering, Vishnu Institute of Technology, Bhimavaram, Andhra Pradesh, India 2 Cluster EHS Manager, Hyderabad Cluster, B&F-L&T Construction, Telangana State, India 1 greddybabu66@gmail.com 2 madhavs22@gmail.com Abstract: In recent years, waste disposal at workmen camp is one of the major problems being faced by many nations across the world. In the workmen colony at Chittapur, a series of kitchens were built for cooking purpose and a number of small canteens are also functioning. Considerable quantity of food waste is collected daily from these eateries and disposed at a faraway place. Food waste is highly degradable in nature, if not disposed properly it causes problems related to environmental pollution. Hence, it is very important to identify an environment friendly process rather than opt for land filling or any disposal method. We worked together to find a suitable eco-friendly solution for the food waste disposal at Chittapur site and suggested that biogas production through anaerobic digestion is a solution for the disposal and utilization of food waste for better purpose. This resulted in setting up a 500 kg per day food waste treatment biogas plant at Chittapur. This establishment is the first time in the construction industry at workmen camp in India. Anaerobic Digestion has been recognized as one of the best options that is available for treating food waste, as it generates two valuable end products, biogas and compost. Biogas is a mixture of CH 4 and CO 2 about (55:45). Biogas generated can be used for thermal applications such as cooking or for generating electricity. The digested slurry is a well stabilized organic manure and can be used as soil fertilizer. Plant design is to handle 500 kg of food waste /day. 27 kg LPG is obtained from 500kg of kitchen waste. The Value of 27 kg of LPG is Rs.2700/day. Daily 1000 litres of digested effluent was obtained. It is good organic manure with plant micro nutrients and macro nutrients. This can be used for growing plants and in agriculture. The value of manure per day is Rs.250/-. The annual revenue is Rs lakhs and the annual expenditure is 1.8 lakhs. The net benefit is 8.82 lakhs. Payback period is 2.1 years. This process controls the environmental pollution and fulfilled the concept of reuse, reduce, recycle and renewable Keywords: food waste, anaerobic digestion, biogas, bioenergy, manure, biodegradable waste 1. INTRODUCTION The bio-waste that raises the significant waste material is food waste, which is the main attention of the current study. According to the Food and Agriculture Organization, about one third (around 1.3 billion tonnes) of the food for human consumption is wasted globally [1]. Improper disposal of food waste leads to environmental pollution and climate change and changes the ethical and social aspects of the society. Food waste is the important type of domestic waste and is biodegradable waste [2]. Food waste may raises from collection to cooking and consumption of food materials [3]. It is mainly of cooked and uncooked. Cooked consists of left over in the mess, hotels food joints and dining halls etc. and also spoiled food items. Uncooked food consists of rotten vegetable, fruits and peelings of vegetables etc. It is highly putrescible in nature and need immediate proper disposal system. Food waste is deteriorating the natural ecosystems due to the inefficient use of land and water resources. Also, it emits unpleasant odor and methane which is a major greenhouse gas contributing to global warming. In recent years, waste disposal at workmen camp is one of the major problems being faced by many nations across the world. Anaerobic digestion has the advantage of energy recovery in the form of biogas, which leads to the conservation of non-renewable energy sources [4]. The digested effluents/slurry is well stabilized and can be used as soil fertilizer in agriculture [5,6]. Further, anaerobic digestion is strongly recommended over land filling and aerobic

2 composting options as it take place in closed containers and under controlled conditions, helps in reducing greenhouse gas emissions into the atmosphere [7]. Anaerobic Digestion has been recognized as one of the best options that is available for treating food waste, as it generates two valuable end products, biogas and compost [8]. Biogas is a mixture of CH 4 and CO 2 about (55:45) [9]. Biogas generated can be used for thermal applications such as cooking or for generating electricity [9]. The digested slurry is a well stabilized organic manure and can be used as soil fertilizer [10]. 1.1 Description of the Study Area The workmen colony is located at Chittapur village in the district of Gulbarga, Karnataka state. The total population of workmen colony is 2,500. In the workmen colony at Chittapur, a series of kitchens were built for cooking purpose and a number of small canteens are also functioning. Considerable quantity of food waste is collected daily from these eateries and disposed at a faraway place. Food waste is highly degradable in nature, if not disposed properly it causes problems related to environmental pollution such as surface and ground water pollution through leachate, promotes the breeding of flies, mosquitoes, rats and other disease bearing vectors [11]. Also, it emits unpleasant odour & methane which is a major greenhouse gas contributing to global warming [12]. Hence, it is very important to identify an environmentally responsible way to process it rather than opt for land filling or composting [13]. The Obstacles in the management of waste includes segregation and collection, high organic content and fast degrading nature, changes in composition from season to season and time to time, proper feed preparation and maintaining ideal ph [14]. 2.1 Segregation 2. METHODOLOGY The quantity of food waste is collected from the canteens in the workmen colony. The waste that cannot be treated and to be strictly avoided are coconut shells, egg shells, big bones, plastic/polythene, glass, metal etc. use of surfactants or detergents & Shock loading to be avoided in the Bio gas Plant [15]. The material is segregated according to this manner. 2.2 Process Anaerobic digestion is a solution for the utilization of food waste for better purpose [16]. Anaerobic digestion is a controlled biological degradation process (Fig: 1) which allows efficient capturing & utilization of biogas [17]. Anaerobic digestion of food waste is achievable but different types, composition of food waste results in different reaction kinetics and varying degrees of methane yields [18]. Hence the effects of mixing various types of food waste and their proportions should be determined on case by case basis. Fig 1: Anaerobic digestion Process A two stage anaerobic digestion processes for food waste biomethanation was adopted at Chittapur. Daily Food waste is collected from the colony and delivered at the biogas plant where non degradable contents if any present in the food waste are separated and then masticated into a fine paste form by adding water (fig: 3) and sent to the primary digester. Hydrolytic and acetogenic stages of food waste degradation takes place in the primary digester

3 (fig: 5) the residence time for this slurry is about 4 to 5 days. Partially degraded food waste is taken into a stabilization tank (fig: 9) and ph is adjusted to about 6.5 with the digested effluents (fig: 4) and then pumped to a secondary digester. Food waste is converted into biogas inside the secondary digester (fig: 6). Composition of biogas is methane (50-65%), carbon dioxide (30-40%), nitrogen (2-3%) and water vapor (0.5%). Fig 2. Flow chart showing the process of food waste to biogas. The biogas generated in the secondary digester is collected into the floating gas dome and stored in gas balloon. Provisions are made for releasing excess gas into atmosphere. The biogas is pressurized to about 5 milli bar in a pressure vessel (fig: 7) and supplied to the kitchen for cooking purpose (fig: 12). Biogas Blower, Moisture Trap Tank, Gas Meter are also the important components for this process (fig: 8, fig: 10, fig: 11). The process flow chart is given below (Fig: 2). Fig 3. Feeding Room

4 Fig 4. Effluent Tank Fig 5. Primary Digester Fig 6. Secondary Digester Fig 7. Gas Pressure Tank Fig 8. Biogas Blower Fig 9. Stabilization Tank

5 Fig 10. Moisture Trap Tank Fig 11. Gas Meter Fig: 12 Cooking Sheds with Gas stoves using Biogas 3. RESULTS AND DISCUSSION The biogas plant (fig 14.) is established to handle 500 kg of food waste /day. The generated biogas gas is supplied to the kitchens (fig 13.) for 2 hrs in the morning and 2 hrs in evening daily. The digesting effluents are good in plant nutrients and are used as liquid manure for growing plants (fig 15.) Fig 13. Biogas pipeline to Kitchen sheds Fig 14. Biogas Plant Economics of Food Waste Biogas Plant Plant design is to handle 500 kg of food waste/day. Monthly Revenue of Biogas Plant 10 Kg s of kitchen waste = 1 m 3 Biogas (with 60% methane)

6 500kg of kitchen waste=50 cum of biogas 1m 3 Biogas = 0.54 Kg s worth of LPG. Fig 15. Groundnut grown with Biogas plant manure 50 biogas= 27 kg LPG 1m 3 Biogas = 5500 K.Cal worth of heat energy 50 cu.m. of biogas is equal to 27 kg LPG/day Value of 27 kg of LPG = Rs.2700/day Daily 1000 lit of digested effluent are obtained. It is good organic manure with plant nutrients like micro and macro nutrients and NPK. This can be used for growing plants as well as in agriculture. Value of Rs.0.25 /lit. The value of manure per day = Rs.250/- Total expected revenues from biogas plant per day= ~ Rs.2,950/- Monthly revenue: Rs.88500/- Per year= Rs lakhs Total monthly expenditure on biogas plant = 15,000/- Electricity = Rs. 1000/- Operator salary= Rs.10,000/- Water= Rs.1500/- Miscellaneous expenditure: Rs.2,500/- Net benefit Net benefit per month: 88, = Rs.73500/- Per year: 10, 62,000 1, 80, 000 =8.82 lakhs Payback period = project cost / net benefit Rs lakh/ 8.82 lakh = 2.1 years. 3.1 Discussion Biogas production from food waste is an environment friendly technology [19]. We can ban the use of fire wood at workmen camp. Bio gas is the best option to retain the workmen at workmen campus. Plant design is to handle 500 kg of food waste /day. 27 kg LPG is obtained from 500kg of kitchen waste. The Value of 27 kg of LPG is Rs.2700/day. Daily 1000 litres of digested effluent was obtained. It is good organic manure with plant micro and macro nutrients. This can be used in agriculture. The value of manure per day is Rs.250/-. The annual revenue is Rs lakhs and the annual expenditure is 1.8 lakhs. The net benefit is 8.82 lakhs. Payback period is 2.1 years. It can be shifted from one project to other project because it is skid mounted, specially designed for construction sites. It is the production of renewable energy and will reduce the release of greenhouse gases and independent of fossil fuel [20]. Micro-economical benefits by energy and fertilizer substitutes and macro-economic benefits through decentralizing energy generation and environmental protection is the main advantage of biogas plant using food waste at the workmen camp [21].

7 4. CONCLUSION A waste-to-energy plant can reduce the volume of waste by as much as 90%. This Bio gas plant will serve the workmen for cooking by avoiding the fossil fuel and it is an initiative for green revolution in workmen camp at the construction area. This establishment is the first time in the construction industry at workmen camp in India. It controls the environmental pollution and fulfilled the concept of Reduce, Reuse, Recycle and Renewable. REFERENCES 1. FAO (2013b). Key Findings, Save food: Global Iiitiative on food losses and waste reduction, Retrieved August 28, 2013 from 2 E. A. Tsavkelova, M. A. Egorova, E. V. Petrova, and A. I. Netrusov, Biogas Production by Microbial Communities via Decomposition of Cellulose and Food Waste, Applied Biochemistry and Microbiology. 48 (4) (2012) D. C. Wyld, Taking out the trash (and the recyclables): RFID and the handling of municipal solid waste, International Journal of Software Engineering & Applications. 1 (1) (2010) A. Demirbas A, Waste management, waste resource facilities and waste conversion processes, Energy Conversion and Management, 52 (2011) Apte, V. Cheernam, M. Kamat, S. Kamat, P. Kashikar, and H. Jeswani, Potential of Using Kitchen Waste in a Biogas Plant, International Journal of Environmental Science and Development. 4 (4) (2013) P. Laxmi, P. B. Nagarnaik, Conversion of Biodegradable Waste to Fertilizer and Energy, international journal of advanced engineering sciences and technologies. 5 (2) (2011) Y. Lili, H. Yue, Z. Mingxing, H. Zhenxing, M. Hengfeng, X. Zhiyang, R. Wenquan. Enhancing biogas generation performance from food wastes by high solids thermophilic anaerobic digestion: Effect of ph adjustment, International Biodeterioration & Biodegradation. 105 (2015) H.N. Huu, H. Sonia, B. Charles, Energy potential from the anaerobic digestion of food waste in municipal solid waste stream of urban areas in Vietnam, International Journal of Energy and Environmental Engineering. 5 (4) (2014) Z. Ruihong, E. Hamed, H. Karl, W. Fengyu Wang, L. Guangqing, C. Chris, G. Paul, Characterization of food waste as feedstock for anaerobic digestion, Bioresource Technology. 10. J.B. Holm-Nielsen, T. Al Seadi, P. Oleskowicz-Popiel, The future of anaerobic digestion and biogas utilization, Bioresource Technology. 100 (2009) T. Ramachar, K. Mohammed Rafi, M. Umamahesh, N.V.S. Guptha, Municipal Solid Waste Management (Msw) Scenario in Kurnool City, Andhra Pradesh, India, Global Journal of Researches in Engineering. 12 (2) (2012) T.V. Ramachandra, B. Shruthi, Environmental audit of Municipal Solid Waste Management, International journal of Environmental Technology and Management, 7 (2007) K. Daniel Meyer, S. Tonia, K. Eckhard, Organic Waste for Compost and Biochar in the EU: Mobilizing the Potential, Resources. 4 (2015) R.S Pawar, D.B, Panaskar, Solid Waste Pollution and Collection in Scrap Houses of Nanded, Maharashtra (India), Universal Journal of Environmental Research and Technology. 1 (2011) O. Mustafa, O. Semra, O. Yuksel, Potential evaluation of biomass-based energy sources for Turkey, Engineering Science and Technology, an International Journal. 18 (2015) C.J. Koroneos, E.A. Nanaki, Integrated solid waste management and energy production - a life cycle assessment approach: the case study of the city of Thessaloniki, Journal of Cleaner Production. 27 (2012) B. David, H. Tobias, M. Russell, M. Dominik, F. Wolf, An Evaluation of Optimal Biogas Plant Configurations in Germany, Waste and Biomass Valorization. 5(5) (2014) P. Deborah, V. Francesca, G. Giuseppe, Evaluation of Environmental Compatibility for a Biomass Plant, Waste and Biomass Valorization. 5(5) (2014) S. Consonni, F. Viganò, Material and energy recovery in integrated waste management systems: The potential for energy recovery, Waste Management. 31 (2011) K.H. Chua1, M. S. Endang Jati, Y. P. Leong, Sustainable Municipal Solid Waste Management and GHG Abatement in Malaysia, Green & Energy Management. 04 (2011) P. Laxmi, P. B. Nagarnaik, Conversion of Biodegradable Waste to Fertilizer and Energy, international journal of advanced engineering sciences and technologies. 5 (2) (2011)