Characterization of Sewage Sludge of Wastewater Treatment Plants in Alexandria | ||||
| Journal of High Institute of Public Health | ||||
| Article 9, Volume 33, Issue 3, July 2003, Page 529-542 | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jhiph.2003.194803 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| Olfat D. El-Sebaie1; Ahmed H. Hussein1; Mohamed H. Ramadan1; Magda M. Abd El-Atty1; Helaly A. Helaly2 | ||||
| 1High Institute of Public Health, Alexandria University, Egypt | ||||
| 2Alexandria General Organization for Sanitary Drainage, Alexandria, Egypt | ||||
| Abstract | ||||
| Provision of two primary sewage treatment plants in Alexandria has resulted in production of substantial quantities of sludge [46,000 tds/y]. This will increase to 112,000 tds/y by 2010. Alexandria sewerage system is a combined system which receives both industrial and domestic wastewater. Industrial contributions to wastewater influent streams can significantly increase industrial contaminants. In evaluating sludge use/disposal alternatives, municipality should first determine the sludge amount and characteristics. Therefore, the present study aims at characterization of the sludge produced at both wastewater treatment plants and after at dewatering at the Mechanical Dewatering Facility [MDF]. The study extended over one year. The collected samples have been subjected to physical and chemical analyses, and microbiological examination. The pH values of East Treatment Plant [ETP] liquid sludge and the short sedimentation time indicated that there was no chance for the bioconversion processes. The slightly lower pH value of the West Treatment Plant [WTP] liquid sludge could be due to bioconversion during the storing in the equalization tanks for a long time. There were no observable differences for most of the measured parameters of ETP and WTP liquid sludges. The significant differences of VS, C%, and C/N between both sludges were due to sludge from co-settling of ETP with the suspended solids of WTP influent and to the effect of industrial wastewater discharges to WTP. The heavy metals contents of ETP, WTP, and MDF sludges were in agreement with the standards of Egyptian regulation for sludge re-use [Decree 222/2002], and USEPA and EC directives. However, the mean lead value was very close to the limit mentioned in the Egyptian decree. The Most Probable Number [MPN] of Total coliform [TC] and Faecal coliform [FC], and different eggs; larvae; and worms of parasitic species for sludge from both plants were unsafe for the sludge re-use. The MPN of TC and FC of the MDF sludge were almost similar to their corresponding values in the feed sludge. However, parasites showed big reduction. The study ended by some recommendations which can be made to improve the quality of the produced sludge. | ||||
| Keywords | ||||
| Characterization; Sewage Sludge; Wastewater Treatment; Plants; Alexandria | ||||
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