BIOGAS PRODUCTION FROM AGRICULTURAL WASTES AND FEASIBILITY STUDY TO ENRICH BIOGAS MANURES
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Date
2014
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ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
Abstract
The experiment was conducted during 2013-14 at Department of Agricultural
Microbiology and Bioenergy, and Department of Soil Science & Agricultural
Chemistry, College of Agriculture, Rajendranagar, ANGRAU, Hyderabad.
Cow dung along with other agricultural wastes (press mud, poultry litter,
kitchen wastes, maize stalks and fruit wastes) were used for the biogas production in lab
scale. Along with the estimation of biogas production different parameters like Total
Solids (TS) per cent, Total Volatile Solids (TVS) per cent, Volatile Fatty Acids (VFA),
pH, Nitrogen (N), Phosphorous (P), Potassium (K), Organic carbon per cent, Biological
Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Electrical Conductivity
(EC) and methane percentage was estimated.
For each treatment 750 g of substrate and 1500 ml of water was used as
inoculum mixture in 3 liters glass bottles. In T1 250 g cow dung + 500 g press mud +
1500 ml water, T2 250 g cow dung + 500g poultry litter + 1500 ml water, T3 250 g cow
dung + 500 g kitchen wastes + 1500 ml water, T4 250 g cow dung + 500 g maize stalks
+ 1500 ml water, T5 250 g cow dung + 500 g fruit wastes + 1500 ml water and T6 750 g
cow dung + 1500 ml water were used. The experiment was run for ten weeks and all the
parameters were observed in the initial, 7th, 14th, 21st, 28th, 42nd, 56th day of gas
production.
At the end of tenth week the gas production was significantly more in T1 (Cow
dung + Press mud) 9903.31 ml, compared toT6 (Cow dung alone) 8103.31ml, T2 (Cow
dung + Poultry litter) 6079.98 ml, T3 (Cow dung + Kitchen waste) 4066.63 ml, T5 (Cow
dung + Fruit waste) 3373.32 ml and less in T4 (Cow dung + Maize stalks) 3099.97 ml.
By the end of the process the degradation of total solids (TS) per cent was
significantly more in T6 (Cow dung alone) 57.16 per cent and less in T5 (Cow dung +
Fruit waste) 32.55 per cent. The degradation of total volatile solids (TVS) per cent was
significantly more in T6 (Cow dung alone) 37.41 per cent and less in T5 (Cow dung +
Fruit waste) 14.32 per cent.
pH in the substrate was estimated and it was significantly more in T1 (Cow
dung + Press mud) 7.66 and less in T3 (Cow dung + Kitchen waste) 5.77. By the end of
the process pH was more in T6 (Cow dung alone) 6.82 and less in T5 (Cow dung + Fruit
waste) 3.67. The N per cent and P per cent in the process of anaerobic digestion was
reduced while K per cent was increased. At the end of the process the reduction in BOD
was observed and significantly more reduction was observed in T5 (Cow dung + Fruit
waste) 58.74 per cent and less reduction in T4 (Cow dung + Maize stalks) 27.68 per
cent. At the end of the process, decrease in COD was observed and was more in T6
(Cow dung alone) 52.15 per cent and less reduction in T4 (Cow dung + Maize stalks)
18.77 per cent.
The second experiment on feasibility to enrich the biogas manures with
beneficial microorganisms was carried at Department of Agricultural Microbiology and
Bioenergy, College of Agriculture, Rajendranagar, ANGRAU, Hyderabad.
The slurry samples from all the six treatments and three replications were
collected dried in trays under the sun until the moisture was 50 per cent. The dried
manure samples were divided into two and one part was sterilized and the other was
used as the same i.e. unsterilized. The population of beneficial microorganisms in the
dried manures was estimated and the population of Pseudomonas (46.0×103CFU g-1)
and Azospirillum (24.0×103CFU g-1) was more in T6 (Cow dung alone), the population
of Rhizobium was more in T1 (Cow dung+ press mud) 46.0×103CFU g-1 and the
population of Azotobacter was more in T2 (Cow dung + Poultry litter) and T6 (Cow dung
alone) 42.0×103CFU g-1.
The beneficial microorganisms used in the study for enrichment were
Rhizobium, Pseudomonas, Azotobacter and Azospirillum. The organisms were
inoculated individually and also as consortia in to the manure samples of all the six
treatments and the viability was monitored.
In the unsterilized manure samples enriched individually with beneficial
microorganisms the viability of Rhizobium was significantly more in T5 (Cow dung +
Fruit waste), for Pseudomonas viability was significantly more in T3 (Cow dung +
Kitchen waste), for Azotobacter viability was significantly more in T6 (Cow dung alone)
and for Azospirillum viability was significantly more in T5 (Cow dung + Fruit waste). In
the sterilized manure samples the viability of Rhizobium was significantly more in T3
(Cow dung + Kitchen waste), for Pseudomonas viability was significantly more in T3
(Cow dung + Kitchen waste), for Azotobacter viability was significantly more in T2
(Cow dung + Poultry litter) and for Azospirillum viability was significantly more in T1
(Cow dung + Press mud).
The viability appears to be good upto the end of fourth week irrespective of
treatments and also in unsterilized and sterilized biogas manure samples for Rhizobium,
Pseudomonas and Azospirillum whereas for Azotobacter the viability appears to be
good only upto the end of third week irrespective of treatments and also in unsterilized
and sterilized biogas manures.
In the unsterilized manure samples enriched with consortia of beneficial
microorganisms the viability of Rhizobium was significantly more in T5 (Cow dung +
Fruit waste), for Pseudomonas the viability was significantly more in T5 (Cow dung +
Fruit waste), for Azotobacter viability was significantly more in T6 (Cow dung alone)
and for Azospirillum viability was significantly more in T6 (Cow dung alone). In the
sterilized manure samples the viability of Rhizobium was significantly more in T1 (Cow
dung + Press mud) for Pseudomonas viability was significantly more in T5 (Cow dung
+ Fruit waste), for Azotobacter viability was significantly more in T1 (Cow dung + Press
mud) and for Azospirillum viability was significantly more in T2 (Cow dung + Poultry
litter).
The viability appears to be good upto the end of third week irrespective of
treatments and also in unsterilized and sterilized biogas manure samples for Rhizobium
and Azospirillum whereas for Pseudomonas, the viability was good upto the end of
fourth week irrespective of treatments in unsterilized biogas manures and upto the end
of third week in sterilized manure samples. For Azotobacter, the viability appears to be
good only upto the end of third week irrespective of treatments in unsterilized biogas
manures and upto the end of fourth week in sterilized biogas manures.
Description
Keywords
BIOGAS, PRODUCTION, AGRICULTURAL, WASTES, FEASIBILITY, ENRICH, BIOGAS, MANURES