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This study was conducted to evaluate the changes in microbiological, physical and chemical quality in wastewater during treatment operations of 17 wastewater treatment plants (WTPs) in cold and hot climate over a one-year period and to evaluate the quality of wastewater in drainages that discharges from these WTPs distributed in the province of Al-Sharqiya, in Egypt, in order to examine their potential environmental impacts and assess their disposal options. Total bacterial count (TBC), total yeasts count (TYC), totalCandidacount (TCC), total coliform count (TCFC), totalEscherichia coli(TEC) and totalSalmonellaandShigella(TSSC) counts were analysed in several samples subjected to various treatment processes sequentially, including untreated wastewater (UW), aeration treatment wastewater, oxidation treatment wastewater, anaerobic treatment wastewater and effluent (treated) wastewater (TW). Physicochemical parameters (temperature, pH, total suspended solids (TSS), total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrates (NO3−), sulphites (SO4−) and oil mg/l values of UW and TW in the WTPs) were examined in samples collected in different seasons. The results revealed that the influent wastewater was heavily contaminated with cultivable bacteria and inorganic and organic substances. Coliform bacteria were important indicators of pathogenic bacteria concentration reduction during the various wastewater processes; however, no correlation was found toCandidacontamination. The TBC, TYC, TCC, TCFC, TEC and TSSC were significantly decreased (p < 0.05) in treated water, and the maximum removal of TBC (60%), TYMC (59%), TCC (75%), TCFC (77%), TEC (75%) and TSSC (74%) took place during treatment resulting in an effluent of high quality. Moreover, TSS, TDS, BOD, COD, sulphite, nitrate and oil levels were significantly reduced (p < 0.05) in the effluent, resulting in maximum removal of pH (6%), BOD (90%), COD (89%), TSS (88%) and SO4(86%), obtained at the effluent. The results indicated that the treatment plants had a significant role in the control of pollution load from microbial, organic and inorganic pollution at the province of Al-Sharqiya, Egypt. Furthermore, microbiological parameters are essential for monitoring the appropriate WTPs operation, whileCandidamight be a significant indicator of effluent microbiological quality. [ABSTRACT FROM PUBLISHER]

The fate and seasonal variation of several microbial pathogens (MPs), includingSalmonellaspp. (SS),Escherichia coliO157:H7 (EC),Listeria monocytogenes(LM),Staphylococcus aureus(SA), biomarker bacteria, andCandidaspp. (CS) were investigated in a municipal sewage treatment plant (MSTP) located in Zagazig City, Egypt, employing an anaerobic/anoxic/oxic (A/A/O) process to monitor their incidences in both influent and effluent throughout the seasons of 2011. Enhancing the activity ofCandidapopulations and the bacterial biodegradation activities in the anaerobic–anoxic–oxic process is an axial pathway for the removal of phenol. In summer season, phenol degradation in MSTP was about 85% which was higher than that in winter season (60%). The chemical treatments routinely used in MSTP can effectively reduce 70% of MPs in wastewater in summer and more than 80% in winter. The concentrations of microbial populations in the effluent were much higher in summer and spring than in winter and autumn, which was closely related to degradation of phenol. Therefore, this study may raise a particular concern regarding the removal of MP and phenol from wastewater in summer seasons. [ABSTRACT FROM PUBLISHER]

The present study aims to evaluate the removal of phenol and zinc by Candida strains isolated from sludge and wastewater. It also aims to select candidates for biosorption and bioreduction to improve the traditional treatment process of wastewater and produce reclaimed water for irrigation. Forty-one Candida strains (12 Candida tropicalis, 13 Candida lipolytica, 6 Candida maltosa, 10 Candida parasopilis) from sludge and wastewater during treatment of sewage water were screened for their Zn biosorption and phenol removing potential. Four C. tropicalis, 3 C. lipolytica, 2 C. maltose and 6 C. parasopilis strains demonstrated the highest final population (>7 log CFU/ml) after 3 h of exposure to low pH and temperature. The majority of the tested strains were resistant and exhibited partial phenol degrading up to 700 μg/ml. Scanning electron microscopy of Candida indicated that there was neither damage in the cells nor signs of irregular wrinkled outer surface of cells when treated with phenol or Zn compared to the control. These strains are good candidates for further investigation within different sewage treatment plant systems to elucidate their potential biodegradation and bioabsorption of hazard benefits in the system used for treating wastewater. [ABSTRACT FROM AUTHOR]