A low-cost, integrated composting technology, which includes microbe-aided ‘vermistabilisation’, can convert toxic sludge from the textile industry into plant probiotics in a short time. Textile waste, usually toxic, is produced at every stage of the manufacturing process, and affects the ecosystem.
S Senthil Kumar from Geobiotechnology Laboratory, National College (Autonomous), Tiruchi, in partnership with the Perundurai Common Effluent Treatment Plant (PCETP) in Erode, Tamil Nadu, has developed a technology that uses microbes as well as earthworms in sludge processing and management. This ‘vermistabilisation’ technology offers twin benefits — safe waste management; and turning an industrial pollutant into a biofertiliser for sustainable agriculture.
First, the textile mill sludge undergoes microbial pre-composting, using novel dye decolourising bacteria, for 30 days. Next, during vermistabilisation, the pre-composted sludge is mixed with equal parts cow dung to make it a growth medium for earthworm action, and then set aside for 60 days. This combined process brings the advantages of both microbial- and earthworm-mediated composting.
Currently, field trials are on at PCETP, with various compositions of chemical sludge and cow dung. Preliminary results show effective stabilisation and mineralisation of the nutrients; there is also a decrease in pH, total organic carbon (TOC), and the carbon-nitrogen ratio. There is an increase in the simultaneous stabilisation and mineralisation of the organic matter into inorganic nutrients, which could be utilised for plant growth. Furthermore, potentially large quantities of worm biomass will be available as ‘probiotic’ food for cattle, poultry and fish farming, leading to a self-sustainable integrated farming system.