Biotransformation of sludges from dairy and sugarcane industries through vermicomposting using the epigeic earthworm Eisenia fetida

Purpose In India, the global contribution of milk and sugarcane production are 21% and 12 to 15%. Dairy and sugarcane industries produce end products as sludge which is directly dumped in open land which pollute the land and groundwater of the nearby areas. The present study was aimed to utilize the vermicomposting technique to treat the sludge generated from these two industries. Method The dairy sludge, sugarcane press mud were homogenously mixed with cattle manure to form five different proportions of waste mixture M1, M2, M3, M4, and M5. The waste mixtures were kept in reactors for 15 days for pre-composting. Once the pre-composting temperature reached to 25 °C, fifty adults Eisenia fetida earthworms with an average weight of 0.4 to 0.5 gram each was introduced into each reactor. Results The highest production of earthworm cocoons was studied in the combinations of M4 and M5. The higher growth of earthworm was observed in M5 (39%) followed by M3 (34%). The germination index and carbon to nitrogen ratio were found to be 100 to 121% and 9 to 11, respectively, along with the negligible carbon dioxide evolution in every combination that revealed the maturity and stability of vermicomposting. Conclusion The vermicompost obtained from the combination of dairy (milk processing unit) and sugarcane industries press mud sludge was rich in nutrients and suitable to utilize as nutrients (fertilizer) for the crops. Vermicomposting can solve the issue of sludge management from these two industries with the utilization of end products as vermicompost.