title: Comparison of vermicompost characteristics produced from sewage sludge of wood and paper industry and household solid wastes.
abstract: BACKGROUND
  The aim of this study was to determine the potential of produced compost from the sludge of wastewater treatment plant using earthworms and compare it with the vermicompost produced from household solid waste.
  
  
  METHODS
  In the current study, three treatments with the same conditions in terms of organic wastes type were prepared to produce vermicompost from household solid waste and sewage sludges using earthworms. The standard methods were used to determine the physical and chemical parameters in the different produced vermicomposts.
  
  
  RESULTS
  The mean of C/N in the household solid waste, raw biological and chemical sludges was 32, 22.5, and 26.5, respectively. These levels were 16.5, 14.5, and 15 in the vermicomposts. The mean of nitrogen and phosphorus percentages in the vermicompost of solid waste, biological and chemical sludges was 2.2%, 2.6%, 2.3% and 0.72%, 0.54%, and 0.56%, respectively. The mean percentages of organic matters in the initial substrates and vermicomposts of solid waste, biological and chemical sludges were 97.2%, 90%, 80.5% and 65.8%, 67.8% and 63% respectively. The concentrations of heavy metals decreased in all vermicomposts. The EC levels in solid waste, biological and chemical sludges were 1459, 1041, and 1487 μs/cm, respectively. These levels were 544, 385 and 635 μs/cm in the produced compost.
  
  
  CONCLUSIONS
  Eisenia fetida can convert household solid waste, and biological and chemical sludges produced from wastewater treatment plant into a high-quality and acceptable compost.
authors.affiliation: Department of Environmental Health Engineering, Babol University of Medical Sciences, Babol, Iran.|Environmental Health Research Center (EHRC), Babol University of Medical Sciences, Babol, Iran.
authors.forename: A I
authors.initials: AI
authors.lastname: Amouei
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Z
authors.identifier: 0000-0001-9251-2668
authors.initials: Z
authors.lastname: Yousefi
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: T
authors.initials: T
authors.lastname: Khosravi
keywords: Biological and chemical sludges; Earthworm; Eisenia fetida; Household solid waste; Vermicompost