الفهرس يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
There are several techniques of domestic sewage treatment, one of the highly developed and simplest processes is anaerobic treatment technique, which has been presently given attention in Egyptian research programs in order to enhance the environmental conditions for a serious contamination to the groundwater and to nearby drains, especially for the rural areas of the Egyptian villages.
By using on-site treatment technique, an improvement was introduced into conventional septic tank which is considered as the most widely used in rural Egypt. These modifications were done previously and tested for 6 months at Iowa State University by T.Sabry and S.Sung. That modified septic tank (USBR) is divided into two compartments: an upflow septic tank followed by Anaerobic Baffled Reactor (ABR) filled with crashed stones.
The aim of this research is to optimize the (USBR) system and determine the best hydraulic design of the system using domestic sewage of Egyptian village. To achieve this aim a laboratory scale installation was established at Oseem wastewater lift station, Giza, Egypt. The Oseem wastewater lift station receives raw sewage from Oseem village and the surrounding villages.
During 18 months of continuous operation and monitoring, this system has shown very satisfactory removal results. The average results using HRT of 42 hr, 36 hr, 30 hr, 24 hr, 18 hr, and 12 hr were 71.7%, 76.9%, 95.3%, 79.4%, 93.5% and 87.8% respectively, for the total chemical oxygen demand (Total-COD) removal, 31.2%, 56.3%, 64.3%, 29.6 %, 77.9% and 25.2% respectively, for the soluble chemical oxygen demand (Soluble-COD) removal, 89.2%, 69.9%, 82.6%, 79.0%, 90.6% and 65.9% respectively, for the total biochemical oxygen demand (BOD5) removal, 94.6%, 86.8%, 92.5%, 87.4%, 94.6% and 75.8% respectively for the total volatile suspended solids (VSS) removal and 95.1%, 91.7%, 96.3%, 89.9%, 95.1% and 85.1% respectively, for the total suspended solids (TSS) removal. The HRT of 36 hr and 18 hr gave the best removal efficiency compared to the other HRTs.
During this study, some proportional volume modifications were done into the USBR system (first compartment V1/ second compartment V2). The proportional volumes used were 1:1, 1.5:1 and 3:1, respectively at HRT of 24 hr. The average results were 79.4%, 81.3% and 82.1% for the total chemical oxygen demand (total COD) removal respectively, 29.6%, 68.0% and 69.6% for the soluble chemical oxygen demand (soluble COD) removal respectively, 79.0%, 91.7% and 85.6% for the total biochemical oxygen demand (BOD5) removal respectively, 87.4%, 92.0% and 93.4% for the total volatile suspended solids (VSS) removal respectively, and 89.9%, 93.8% and 94.0% for the total suspended solids (TSS) removal respectively. The V1:V2 of 1.5:1 and 3:1 gave the best removal efficiency compared to the other V1:V2 of 1:1.
Furthermore, the system was imposed to hydraulic load which is two and three times more than normal rate without significant drop in its performance.