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Evolution of chemical and biological characterization during thermophilic composting of vegetable waste using rotary drum composter
Sudharsan Varma, V. & Kalamdhad, A. S.
Abstract
Vegetable waste usually contains high levels of
organic matter, moisture and nutrients that make the waste
unsuitable for disposal in municipal landfills. Composting
of vegetable waste is in practice by many urban local
bodies, and therefore, it was composted along with cow
dung and sawdust in a 550-L batch scale rotary drum
composter. Four different trials of varying waste combinations
of vegetable waste, cow dung and sawdust, i.e.,
trial 1 (5:4:1), trial 2 (6:2:1), trial 3 (7:2:1) and trial 4
(8:1:1) were composted by adding 10 kg of dry leaves as
bulking agent with a total mass of 100 kg. With proper
combinations of organic waste mix, a maximum temperature
of 66.5 ° C was observed in trial 1 and 61.4 ° C in trial
2, when compared to other two trials with prolonged
thermophilic period. Due to such elevated temperature,
higher degradation was observed in trials 1 and 2 with
inactivation of pathogens to considerable amounts. Furthermore,
final compost had total nitrogen of 2.31 and
3.01 %, total phosphorous of 4.30 and 3.27 % and final
carbon-to-nitrogen ratio of 15 and 12, in trials 1 and 2,
respectively. Carbon dioxide evolution and oxygen uptake
rate of compost samples was analyzed for its stability and
was observed to reduce completely at the end of 20 days
with lower emission rates.
Keywords
Vegetable waste; Composting; Rotary drum composter; Temperature; Carbon-to-nitrogen ratio; Stability
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