RESUMO
This study aims at evaluating the quality of currently produced sewage sludge in Doha, State of Qatar. Doha urban areas are currently served by two tertiary wastewater treatment plants at Al-Neaaga [Doha south plant] and Al-Sailiyah [Doha west plant]. Industrial areas around Doha are getting wastewater treatment facilities where extra amounts of sludge will be generated. Sludge is composed of primary and secondary sludge and sedimented sand filters backwash. It undergoes further treatment by drying beds for Doha south plant and centrifugation for Doha west plant. Doha south plant produced 190 m[3]/d sludge, Doha west plant produced 110 m[3]/d sludge, and industrial region plant produced 16 m[3]/d sludge. Samples were collected weekly for two months before and after drying beds from Doha south plant, after centrifuge and after storage from Doha west plant, and from industrial region plant. Samples were analyzed chemically and microbiologically. The results revealed that sludge produced by the three plants had heavy metals concentration way below the EBA ceiling limits for land application. On the other hand, the microbiological characterization of the product classified it as class B sludge according to EBA classification which requires significantly reduction of pathogen. Ascaris lombricoides and Toxocara cati were the most dominant ova detected. The sludge produced needs monitoring and further treatment before its application on land