English

 

Name of the Student : Subhi Samhan
Name of the supervisor/s :

Dr. Rashed Al-Sa'ed

Title of the thesis :

Pathogens Removal in UASB-Septic Tanks and Al-Bireh Oxidation Ditch Wastewater Treatment Plant

Abstract :  

The reuse of treated effluent represents a national interest and considered as an important component of the overall maximization of water resources in Palestine. However, all attempts on wastewater reuse not successful due to many reasons and illegal irrigation practices with partially treated effluent in certain areas still impose serious health hazards and environmental problems. Inadequate wastewater treatment facilities and lack of data on hygienic aspects of treated wastewater hampered the successful implementation of wastewater reuse schemes at the national level. The rational behind the newly launched Palestinian guidelines was not scientifically based; however entail rules and guidelines on treated wastewater reuse for agricultural irrigation and other purposes.

The main objective of this research was to compare pathogens removal in Upflow Anaerobic Sludge Blanket (UASB)-septic tanks and Al-Bireh wastewater treatment plant (AWWTP). The UASB-septic tanks, located at AWWTP, fed continuously with raw municipal wastewater from the aerated grit chamber of AWWTP. The two pilot scale UASB-septic tanks (R1 and R2) were operated at two different hydraulic retention times (HRT) of 2 and 4 days for R1 and R2 respectively. AWWTP, as an extended aeration system with aerobic sludge stabilization, the HRT was about one day. Both raw wastewater and treated effluent analyzed for microbial pathogens including indicator bacteria, protozoa and trophozoite using microscopic and specific culture media. Data obtained from this research study on Fecal coliform, Fecal streptococcus, Salmonellae Shigilla, Balantedium coli, Ascaris lumbrecoudes, Amoeba cysts, Giardia cysts, Trichuris trichiura, pathogens in the trophozoite form as Trichomonas, Strongyloides sterorlasis, Enterobius vermicularis are presented and discussed.

The results obtained revealed that the treated effluent of both treatment technologies needs further reclamation to comply with prescribed hygienic national guidelines for restricted agricultural irrigation. As, the removal efficacy for R1, R2, were 15.5%, and 15%, respectively for Fecal coliform and 6.9%, and 11% for Fecal streptococcus. On the other hand, the removal efficacy for oxidation ditch was 38% for Fecal coliform (p < 0.05) and 16% for Fecal streptococcus (p > 0.05). Though Salmonellae was detected in 30% of analyzed influent samples, it was not detected in any sample of the treated effluent of both treatment systems. Finally, parasites in term of cysts or trophoziote were completely removed from R1, R2 and oxidation ditch. The average values for surfactant in the influent was 8.15 mg/l and the average removal efficacy for R1, R2 and oxidation ditch were 0.95%, -0.55% (p > 0.05) and 86% (p < 0.05), respectively. Finally this study recommends the installment of post treatment stages (e.g. slow sand filters and disinfecting units) in both technologies under study to comply with national or regional quality guidelines for agricultural reuse or effluent discharge into receiving water bodies.