Effects of Organic Load, pH, and EC Variations of Raw Wastewater and Weather Condition on the Efficiency of Yazd Stabilization Ponds

Document Type : Research Paper

Authors

1 Faculty Member of Civil Engineering Dept., Islamic Azad University, Yazd branch, Yazd

2 Water and Wastewater Laboratory Expert, Yazd Water and Wastewater Company, Yazd

3 Faculty Member of Yazd University of Medical Sciences, Dept. of Environmental Health, Yazd

4 Member of Statistics and Information Office in Yazd Provincial Government, Yazd

Abstract

This study investigates the effects of organic load, pH, and EC variations of raw wastewater as well as the effect of weather condition on organic removal in Yazd wastewater Stabilization Ponds (2007). During the course of this study, composite samples were collected from the inlet and outlet of the anaerobic pond and the final effluent to measure such quality parameters as BOD5, COD, TSS, EC, and pH.  BOD5, COD, TSS, and Fecal coliform removal efficiencies in the final effluent were found to be 64.9%, 44.9 %, 62.6 %, and 99.96%, respectively. No intestinal nematode egg was observed. Comparison of BOD5 and COD concentrations in the filtered and non-filtered samples showed that 52% of the BOD5 and 57% of the COD in the final effluent, respectively, were due to the presence of algal mass and organic suspended solids in the non-filtered samples. The results showed that variations in organic load, pH, EC as well as seasonal weather variations had no effects on organic removal and that the removal of BOD5 was almost constant. Effluent EC was higher than influent EC. This phenomenon can be related to the evaporation rate in wastewater stabilization ponds. The survey of algae in the final effluent showed that the major species of algae were Phytoconis, Chlorella, and Anabaena.

Keywords

References

1- Nelson, K., Cisneros, B., Tchobanoglous, G., and Darby, D. (2004). “Sludge accumulation, characteristics, and pathogen inactivation in four primary waste stabilization ponds in central Mexico.” Wat. Res., 38,  111-127.
2- سازمان بهداشت جهانی (1375). برکه‌های تثبیت فاضلاب ( اصول طراحی و اجرا )، مترجم : ندافی، ک., نبی زاده، ر., چاپ اول، انتشارات مؤسسه علمی فرهنگی نص، تهران.
3- مارا , د .(1377). راهنمای طراحی برکه‌های تثبیت فاضلاب در ایران، مترجم : شقاقی , ش. , انتشارات شرکت مهندسی آب و فاضلاب کشور.
4- موحدیان عطار، ح.، بینا، ب.، اربابی، م. (1374). ”بررسی راندمان برکه های تثبیت در حذف تخم انگلها و کلیفرم‌های مدفوعی. “م. آب و فاضلاب، 15، 2-11.
5- Ensink, J., Mukhtar, M., Hoek, W., and Konradsen, F. (2007). “Simple intervention to reduce mosquito breeding in waste stabilization ponds.” Transactions of the Royal Society of Tropical Medicine and Hygiene,  101, 1143-1146.
6- Peng, J. F., Wang, B. Z., Song, Y., Yuan, P., and Liu, Z. (2007). “Adsorption and release of phosphorus in the surface sediment of a wastewater stabilization pond.” Eco. Eng., 31, 3192-3197.
7- Kouraa, A., Fethi, F., Fahde, A., Lahlou, A., and Ouazzani, N. (2002). “Reuse of urban wastewater treated by a combined stabilization pond system in Benslimane (Morocco).” Urban Water, 4, 373-378.
8- واحد آمار شرکت آب و فاضلاب استان یزد، 1386.
9- مهندسین مشاور طرح و تحقیقات آب و فاضلاب. (1382). گزارش بازنگری مطالعات مرحله اول تصفیه خانه فاضلاب شهر یزد،
مهندسین مشاور طرح و تحقیقات آب و فاضلاب، اصفهان.
10- واحد آمار اداره کل هواشناسی استان یزد ایستگاه سینوپتیک یزد، 1386.
11- APHA., AWWA., WPCF. (2005). Standard methods for examination of water and wastewater, 21th Ed., Washington. D.C.
12- Torres, J. J.,  Soler, A., Saâez, J., and Llorens, M. (2000). “Hydraulic performance of a deep stabilisation pond fed at 3.5 m depth.” Wat. Res., 34 (3), 1042-1049.
13- Abbas, H., Nasr, R., and Seif, H. (2006). “Study of waste stabilization pond geometry for the wastewater treatment efficiency.” Eco. Eng., 28, 25-34.
14- Agunwamba, J. C. (2001). “Effect of tapering on the performance of waste stabilization ponds.” Wat. Res., 35 (5), 1191-1200.
15-Fernandez, A., Tejedor, C., and Chordi, A. (1992). “Effect of different factors on the die-off of fecal bacteria in a stabilization pond purification plant.” Wat. Res., 26 (8), 1093-1098.
16- کیوانی، ن. (1382). ضوابط و استانداردهای زیست‌محیطی، معاونت محیط زیست انسانی سازمان حفاظت محیط زیست، چاپ اول، انتشارات دایره سبز، تهران.
17- Muñoz, R., and Guieysse, B. (2006). “Algal–bacterial processes for the treatment of hazardous contaminants: A review.” Wat. Res., 40, 2799-2815.
18- یار قلی، ب.، و هانی، ه. (1380). ”آبیاری قطره ای با پساب برکه‌های تثبیت فاضلاب و حل مشکل گرفتگی قطره چکان. “م. آب و فاضلاب، 37، 50-57.
19- Dalu, J. M., and Ndamba, J. (2003). “Duckweed based wastewater stabilization ponds for wastewater treatment (a low cost technology for small urban areas in Zimbabwe.” Physic. Chem., 28, 1147-1160.
Journal of Water and Wastewater; Ab va Fazilab ( in persian )
Volume 20, Issue 2 - Serial Number 2
Serial number:70
May and June 2009
Pages 55-61

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