SUITABILITY OF WASTE WATER GROWN MICROALGAE FOR BIODIESEL PRODUCTION
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Date
2017
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DIVISION OF MICROBIOLOGY ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI
Abstract
Increased demand for fuel have challenged many researchers to ponder over
environment friendly alternative fuel by using different feedstocks and waste water
resources as a growing medium. The objective of the present study was to assess the
efficiency of selected microalgal genera to remove nutrients and grow efficiently in
secondary treated sewage waste waters. The biomass thus, obtained can have potential
in the area of biodiesel production. The three microalgal genera namely
Chlamydomonas sp., Chlorococcum sp. and Chlorella sp. were able to grow in waste
waters collected from two sites namely Nirankari Coronation Pillar Plant and Okhala
Sewage Treatment Plant, Delhi, India during rainy, winter and summer seasons.
These microalgal exhibited high lipid production in waste waters, and were able to
remove nutrients from such waters. They also showed removal efficiency of more
than 70% for NH4-N and 60% for PO4-P. The removal efficiency for NO3-N was also
significant. The lipid rich Chlorella sp. was subsequently cultivated in waste water
collected from Okhla Sewage Treatment Plant. The biomass harvested was used for
the extraction of lipids and subsequent transesterification to form biodiesel. The
biodiesel obtained was analysed in terms of FAME profile. After transesterification,
the yield of FAME was 80.8% with major fatty acids as palmitic, linoleic, oleic and
linolenic. The physical parameters predicted from empirical equations on the basis of
fatty acid methyl esters showed cetane number as 56.5, iodine value of 75.5 g I2100 g-
1, high heating value 40.1 MJ/kg, flash point 135°C, kinematic viscosity 4.05 mm2/s
with density of 860 g/cc and cold filter plugging point as 0.7°C. FTIR and 1H, 13C
NMR spectrum confirmed the chemical nature of biodiesel. The results indicated that
the quality of biodiesel was almost as per the criteria of ASTM standards, hence,
waste water grown Chlorella sp. can be used as a promising strain for biodiesel
production. Cost of one kg biodiesel production was calculated as Rs. 180/kg which
included cultivation, harvesting, oil extraction and transesterification cost of Chlorella
sp. grown in waste water. Algae are therefore, considered as an economical choice for
biodiesel production, because of the availability and environmental friendly
properties. The present study indicated feasibility of waste water grown Chlorella sp.
in the area of quality biodiesel production.
Description
t9673
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