DESIGN AND FABRICATION OF A PORTABLE BIO-DIGESTER TO PRODUCE METHANE GAS FROM FOOD WASTE

Author(s): 

Yeoh Shir Lee1*, Md. Mizanur Rahman

Affiliation(s): 

1Mechanical Engineering Program, Faculty of Engineering, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah

*Corresponding Author Email: yeohshirlee2018@gmail.com

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Malaysia has been facing difficulties to acquire a suitable land to dump household solid wastes, mainly from foods. Methane gas releases from these household wastes when those wastes started to degrade. Methane gas is listed as one of the harmful greenhouse gases which takes part in global warming. In the contrast, this gas can be used as source energy and also can be a suitable alternative option of natural gas. Therefore, if methane, produced from food wastes, is stored properly for future use then it can contribute in national development. The device is used for methane gas production is known as bio-digester. The commercial bio-digester is very big in size and it required large space therefore, under this project, it aims to design and fabricate a portable bio-digester for household use. It consists of four main part; inlet for feeding waste, digester tank, outlet for slurry and gas collector. The size and weight of the bio-digester is re-design to ensure it movability. SolidWorks software is used to design and analysis to optimize its size. Prototype is fabricated for experiments to carry out. 1 litre of food waste mixed with water (volumetric ratio 1:1) is fed into digester tank for seven days to ensure sufficient methane gas is produced from household waste. The pH and temperature values are maintained 7.0 and 30˚C to 50˚C respectively. As the result, the degradation process is happened, and the rotten egg smell is detected. Besides, the fruit waste is proved able to speed up the whole process. However, the gas accumulated is not sufficient to be burnt. In short, the larger volume of bio-digester or duplicating the prototype model but centralize the gas storage is suggested to be built in the future. In addition, the appearance of fruit waste is essential for a faster rate of decomposition.