الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The aim of the current study is to test bell siphon system as an innovative passive aeration system for anaerobic treatment effluent prior entering the aerobic treatment process, and To evaluate the performance of a low-cost compact sewage treatment plant that uses a combined anaerobic-aerobic system that is simple to install and run with zero energy requirements while producing high-quality effluent similar to that generated by traditional wastewater treatment plants.
Aeration is a process of diffusing oxygen into water in order to stimulate the aerobic bacteria for starting wastewater aerobic treatment process. A preliminary laboratory experimental program investigated the bell siphon system using deoxygenated water with almost zero dissolved oxygen concentration (DO) like anaerobic treatment effluent was carried out. System was used to build water pressure through a distribution system used for scattering water in air in order to diffuse oxygen into it. Holed arm pipe with different holes diameter and number, showerhead, fire sprinkler and modified fire sprinkler were tested as distributers to reach the optimum type which verify good oxygen diffusion in water and ensure least possibility for distributers clogging. DO concentration was measured for each distributer water effluent. The experiments showed that the modified fire sprinkler achieved the higher oxygen diffusion in water and best distribution, in addition to its geometry that prevent it from clogging.
A full scale pilot compact treatment system was set up at Madinaty WWTP. The treatment units consist of an up-flow anaerobic septic reactor; down-flow anaerobic packed-bed baffled reactor; passive aeration using bell siphon with modified fire sprinkler distributer; packed biological filter with settling tank and roughing filter.
The system worked at the plant for 170 days where system went through three main phases, startup stage which lasted for 37 days, partially stable phase lasted for 65 days where 11 samples were taken in it and steady state phase which lasted for 68 days where 19 samples were taken in it. The System was monitored by analyzing wastewater samples for pH, Temperature, total suspended solids (TSS), chemical oxygen demand (COD), total biochemical oxygen demand (BOD5), mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) parameters. Samples were collected from the raw wastewater influent the treatment system and from each stage effluent throughout the pilot setup, while sludge samples were drawn of 4 ports distributed along the height of the up-flow reactor.
from the test results, anaerobic treatment (represented in up-flow anaerobic reactor and down-flow anaerobic packed-bed baffled reactor) increased treatment removal efficiency to about 84.38%, 45.41% and 52.02% for TSS, BOD5 and COD concentration, respectively.
Aerobic treatment (represented in biological packed filter and settling tank) increased treatment removal efficiency to about 86.7%, 75.0% and 73.44% for TSS, BOD5 and COD concentration, respectively.
The whole system treatment removal efficiency were 92.9%, 78.4% and 80.0% for TSS, BOD5 and COD concentration, respectively. Also pH value was not affected during the whole treatment process.
The pH value, DO, TSS and BOD5 concentrations for the whole unit effluent met the limits of law 48/1982. While COD concentration did not met the law limits. The main causes of that since the start-up of the anaerobic treatment unit was slow and inefficient because of not using digested sludge seed, which is adapted to the wastewater composition, also the experiment duration was too short to show good results.