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Issue No:10, Vol.3 |
Oct - 2010 |
ISSN: 0974-5645 |
| RESEARCH ARTICLES |
Viewers & PDF |
| 5. Sustainable biomethane, biofertilizer and biodiesel system from poultry waste. Gene Drekeke Iyovo, Guocheng Du and Jian Chen. Indian J.Sci.Technol. Vol. 3, Issue 10, pp: 1062-1069. Domain site: http://www.indjst.org. |
 
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- Abstract
In this study we developed and tested a sustainable system that produces high-yield outputs of biomethane,
biofertilizer and biodiesel. These were achieved by blending of poultry manure (PM), paper pulp and algae waste
sludge in co-digestion producing biomethane, digestate filtrated semi-solid and aqueous, the former as biofertilizer and
latter used in algal cultivation to enhance algal biomass for biodiesel production. The varied blending of the substrates
resulted in carbon/nitrogen ratios (C/N) of 26, 30, 31, 34 and 37 which were assessed for biomethane. C/N 26 resulted
in 1045 mL/L/d (74% biomethane content) which was highest yield comparing to other C/N, C/N 30 achieved in similar
(1010 mL/L/d) making the C/N range for optimum biomethane for these substrates ranging between C/N 26 to 30.
Pretreatments of the digestate improve the yields of biomethane in C/N 26 and 30 significantly. We assessed all the
digestates from each of the C/N 26, 30, 31, 34 and 37 based on nitrogen mineralization and found C/N 26 to 31 as
being nutrients-rich. Digestate in algal supplemental indicated glucose depletion linearly depleting, lowest with the
nutrients-rich that is C/N 26 to 30. As expected, digestates from C/N 34 and 37 in single-addition failed to yield
comparable algal yields then yields from C/N 26, 30 and 31 digestates at 120 h that achieved dry cell weight (DCW) of
7.72, 7.8 and 7.12 g/L respectively. To improve alga biomass yield and enhance cellular lipid content and its final yield,
we investigated two-stage supplemental feeding strategy using digestates from C/N 26 and 30. Based on cultivation
‘without’ digestate that showed growth phases, we added digestate at lag-exponential (0-120 h) and stationary (120-
180 h) phases. The supplemental feeding resulted in rapid glucose depletion achieving 9 g/L at 120 and reaching lipid
yield 3.77 g/L after 180 h. Conclusively, a circular system using the biowastes discussed or similar in nature can
develop and constitute a self-supporting sustainable system opportunities.
- Keywords: Poultry manure, biomethane, biogas, biofertilizer, Chlorella vulgaris, biodiesel.
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