A new report published in the International Journal of Environment and Pollution finds that waste from the textiles industry could be transformed into rich, agricultural compost, with the use of earthworms and animal manure.
Indian researchers Vinod Gard, Renuka Gupta and Priya Kaushik of the Guru Jambheshwar University of Science and Technology have found a particular species of earthworm to be productive in converting the huge volumes of solid sludge produced by the textiles industry into compost.
The earthworm, known as Eisenia foetida, tends to thrive in rotting vegetation, animal waste and compost, making it a commercially grown species for composting.
Solid textile mill sludge is difficult to dispose of, as landfilling and incineration are not viable options given the expense and environmental concerns. Indian textiles industries are under pressure to find sustainable and cost-effective alternatives to the disposal of this industrial waste.
Textile manufacturing produces large amounts of wastewater which, when treated, creates a sludge as the water is removed and the pollutants are concentrated.
Earthworms are added to the sludge mixture, along with urine-free cow and horse dung, beginning a process that changes the physical and chemical properties of the mixture significantly.
The researchers found the vermicompost process created a compost-like, homogeneous mixture after 180 days.
The earthworms thrive in the manure-enhanced textile sludge, lowering the pH of the alkaline sludge, decreasing the ratio of carbon to nitrogen in the material and increasing the amount of nitrogen and phosphorous available for aided plant growth.
The successful tests with vermicompost in textile sludge can prove extremely useful in countries like India which manufacture large amounts of textiles for export. Research has shown other means of treating post-industrial textile waste, including anaerobic digestion, to be successful as well, often producing gases that can be used as fuel.