The Hindu 17.04.2013
New technology for management of solid waste
KAU develops microbial cultures for composting.
Scientists at Kerala Agricultural University have
developed two microbial cultures that can replace cow dung in aerobic
composting for large-scale management of solid waste.
The
university’s Department of Agricultural Microbiology developed the
microbial isolates including bacteria, fungi and actinomycetes from
various sources like soil, degrading plant materials and cow dung.
Demonstration
units set up at several apartments in the Thrissur Corporation and the
ladies hostel on the main campus of the university have proved the
efficacy of the technology.
“This is a response to the growing challenge of solid waste management in Kerala,” says P. Rajendran, Vice Chancellor.
“Urbanisation,
changes in lifestyle and food habits and the decrease in availability
of land have led to waste accumulation and a change in the composition
of garbage. The repercussions of this are serious and unpredictable,” P.
Rajendran said.
Dr. Rajenran said the composting
method developed by the university would enable efficient conversion of
solid waste into organic manure, making it the best option for
large-scale composting plants.
Conventional
composting employs cow dung as a source of microbial inoculum for
degradation of waste. But cow dung has become a rare commodity,
especially in urban areas, triggering the search for efficient microbial
cultures as an alternative.
The research team
carried out studies to evaluate the efficacy of microbes utilising
cellulose, lignin, protein and starch degradation. Seven efficient
isolates selected from the preliminary studies were further screened
using vegetable waste.
Two of the isolates,
Bacillus subtilis
and
Bacillus niabensis
were found to be effective and completed the degradation of solid biodegradable waste within 17 days.
The
technology was validated at the Communication Centre, Mannuthy, with
vegetable waste collected from the market. The resultant compost was
found to have a fine texture. When analysed for nutritional quality, it
was found to have a pH of 7.4, moisture 25%, Carbon to Nitrogen ratio
of 22 and nitrogen 1% – indicating its suitability as organic manure.
Dr.
Rajendran advocates an integrated approach to bio-solid waste
management, incorporating different methods to suit local conditions.
“For independent households, biogas plants are the best, which generate
energy for fuel, apart from giving slurry that can be used as good
quality manure. For housing colonies and apartments, aerobic composting
will be optimum. The compost from the unit may be used for organic
terrace cultivation of vegetables,” he says.