title: Characterization of Industrial Wastewater Sludge in Oman from Three Different Regions and Recommendations for Alternate Reuse Applications.
abstract: BACKGROUND
  Domestic and industrial wastewaters are mostly treated by biological process such as activated sludge, aerobic pond, and anaerobic treatment. This study focuses on characterizing the quality of sewage sludge in the Sultanate of Oman chosen from three industrial sewage treatment plants (STPs): Rusayl Industrial Estate (RSL.IE); Sohar Industrial Estate (SIE); and Raysut Industrial Estate (RIE).
  
  
  METHODS
  Samples of recycled activated sludge (RAS) and wasted activated sludge (WAS) were collected over a period of 12 months across above mentioned STPs. Parameters analyzed are electrical conductivity (EC), potential of hydrogen (pH), cations, anions and volatile content (VC).
  
  
  RESULTS
  The obtained values for pH and EC were low for both RAS and WAS samples, except EC values of RIE that was more than 1000 μS/cm. The range of VC percentages in RAS and WAS samples were 44 to 86% and 41 to 77%, respectively. The measured values for chloride, sulfate, nitrate and phosphate were higher than the other anions.
  
  
  CONCLUSIONS
  The average values of the cations in RAS and WAS samples were within the Omani Standards, suitable for the re-use of sludge in agriculture except for Cd in RSL.IE. The study recommends that a regular maintenance should be performed at the studied STPs to prevent any accumulation of some harmful substances, which may affect the sludge quality, and the sludge drying beds should be large enough to handle the produced sludge for better management.
authors.affiliation: Center for Environmental Studies and Research (CESAR), Sultan Qaboos University, Muscat, Sultanate of Oman.
authors.forename: Mahad S
authors.initials: MS
authors.lastname: Baawain
authors.affiliation: Sohar Industrial Port Company, Sohar, Sultanate of Oman.
authors.forename: Mohsin
authors.initials: M
authors.lastname: Al-Jabri
authors.affiliation: Center for Environmental Studies and Research (CESAR), Sultan Qaboos University, Muscat, Sultanate of Oman.
authors.forename: B S
authors.initials: BS
authors.lastname: Choudri
keywords: Analysis; Characterization; Heavy metals; Industrial Wastewater sludge; Sultanate of Oman; physicochemical