1. Centre for Rural Development and Technology IITD
Industry Day Theme # 4: Sustainable Habitat
Anaerobic valorization of kitchen , vegetable and fruit waste
Adya Isha, PMV Subbarao, Virendra Kumar Vijay, Ram Chandra
CRDT, Indian Institute of Technology Delhi, Hauz Khas, New Delhi – , India
Abstract
The present paper is based on studies conducted on pilot scale digester fed with kitchen waste. To minimize the acidification effects in the digester it was operated at 3–4% total solids. The results obtained were at par with data presented by other researches. Cumulative biogas, methane and carbon dioxide yield at standard temperature and pressure condition over 90 days were 1045, 515 and 462 m3, respectively with total 1690 kg of input volatile solids with the average total volatile solid removal efficiency of 68.0% with hydraulic retention time of 35 days. Moreover, the average methane and carbon dioxide content was found as 50.35% and 43.68%, respectively. The average specific methane yield (at standard temperature and pressure) with kitchen waste substrate over the 90 day of time period was recorded as 0.27 m3/kg total solids and 0.30 m3/kg volatile solids
Result
Table 4. Carbon, hydrogen, nitrogen contents and carbon- nitrogen ratio of the feed materials.
Table1. Physiochemical properties of feed materials.
Feed material
Moisture content (%)
Total solids (%)
Volatile solids (%)
Non- volatile solids (%)
Cattle dung
81.64
18.40
78.86
21.20
Kitchen waste
84.05
15.95
89.55
10.45
Feed material
C(%)
H(%)
N(%)
C/N ratio
Cattle dung
35.20
4.60
1.55
22.7
Kitchen waste
40.81
6.01
2.12
19.21
Introduction
With growing population, urbanization and industrialization waste generation and disposal has become a national as well as global issue. In, India approximately 141,000 tonnes/day (on wet basis) of municipal solid waste is generated with a collection efficiency of 90% [1]. Of the total municipal solid waste generated nearly 50% waste is composed of biodegradable components
A major portion of this biodegradable component which largely contain kitchen waste, food & vegetable market waste and food waste is open dumped and left for degradation and feeding to stray cattle which attract flies, diseases bearing vectors and unpleasant odor [2].
A small portion of kitchen waste is also being processed to compost using either vermi–composting or other composting techniques [3,4]. Management of kitchen waste by compositing releases nearly 300g CO2 per kg dry matter with 27% volatile matter conversion, this suggests underutilization of the potential of kitchen waste [5].
The novelty of the research focused on utilization of kitchen waste as a sole substrate in anaerobic digestion process.
Materials and Methods
Fig 1. Variation of methane and carbon dioxide content in biogas produced from kitchen waste.
Fig 3. Daily biogas production rate from kitchen waste
Centre for Rural Development and Technology IITD
Fig 4. Cumulative biogas, methane and carbon dioxide yields from kitchen waste substrate.
Conclusions
The proximate and ultimate analysis of kitchen waste revealed that waste is rich in volatile solid content and easily hydrolysable.
For minimizing acidification effects the feed was diluted with twice the amount of water and 3–4%TS was maintained in the digester. The pH was regularly monitored and it seems to be stable in between 7.0–7.5.
Anaerobic digestion of kitchen resulted into 0.53 m3 biogas/kg TS and 0.59 m3 biogas/kg VS. The results were at par with similar kind of studies conducted previously.
References
[1] CPCB, Consolidated annual review report on implementation of municipal solid wastes (management and handling) rules, 2000.
[2] Das, D., Srinivasu, M.A., Bandyopadhyay, M., Solid state acidification of vegetable waste. Indian Journal of Environmental Health. 40(4), 333–342.
[3] Garg, P., Gupta, A., Satya, S., Vermicomposting of different types of waste using Eisenia foetida: A comparative study. Bioresource Technology. 97(3), 391–395.
[4] Chang, J.I., Hsu, T.E., Effects of compositions on food waste composting. Bioresource Technology. 99(17), 8068–8074
Acknowledgement
First author gratefully acknowledge the support of Indian Institute of Technology Delhi for conducting this research work.
Industrial Significance
The biogas generated from kitchen, vegetable and fruit waste can be utilized in power generation and Bio-CNG.
Technology Readiness Level: Small scale biogas enrichment & bottling unit has already being developed at IITD which can be given to Industries to generate Bio-CNG.