Simultaneous biodegradation of organic (chlorophenols) and inorganic compounds from secondary sludge of pulp and paper mill by Eisenia fetida

Background Present research communicates the role ofEisenia fetida in converting pulp and paper mill sludge intovaluable products by removing the high concentration ofdifferent chlorophenols and metals present in the sludge.Results Pulp and paper mill sludge was toxic to Eiseniafetida and therefore, it was mixed with composted materialin different ratio of experimental set up such as Set up: 1,(95:5), Set up: 2 (80:20) and Set up: 3 (50:50) on dryweight basis. We found very promising results by the applicationEisenia fetida in the sludge. Eisenia fetida removedall the twelve different chlorophenols more than95 % from the sludge which is declared as carcinogeniccompounds by United States Environmental ProtectionAgency (US-EPA) in 90 days of incubation. Heavy metalsconcentration was decreased significantly during the incubationperiod whereas some metal concentration was alsoincreased in the sludge due to mineralization. Carbon(C) and Nitrogen (N) were increased in the compostedmaterial, C:N ratio for Set 1 9:4 in Set 2 13:4 and Set 318:4 was observed which acts as soil conditioner. Whereassome other metals like (Ca, Mg, Na, K, Fe and Zn) wasincreased that are essential for the plant growth. There wasgreat reduction in adsorbable organic halogen (AOX) 95 %and extractable organic halogen (EOX) 90 % as compareto control. Eisenia fetida also removed pentachlorophenol(PCP) from the sludge with artificially increased concentrationabout 100 mg/kg.Conclusions By observing chlorophenols concentration,metals and carbon–nitrogen ratio, Eisenia fetida is actingas a potential candidate for the reclamation of industrialsludge. The result indicated that vermicomposting withEisenia fetida is better option to manage the sludge orconvert the sludge into nutrient-rich composted material ina short span of time.