الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
During the last decades, international attention became focused upon the issues of water supply and sanitation and the severe health and environmental problems that were arising as a result of inadequate supply of these basic human needs, especially in developing countries, where all the world predict that the next war will be about water resources. Egypt is one of the developing countries that currently facing serious water quality and quantity problems. As the population growth and expanding urban centers have amounts of wastewater which for the most is discharged without treatment into water bodies. This lead to the ongoing study of the problems of domestic wastewater especially in remote urban and less densely populated rural areas in Egypt. And to select the most appropriate technology for wastewater treatment in these areas. In general, the method selected in this study for domestic and industrial wastewater treatment was waste stabilization ponds. In developing regions, WSPs often represent the most appropriate and self-sustaining technology, available at low cost, especially in warm climates and where land availability is not restricted. However waste stabilization ponds are the only treatment alternative capable of producing effluents that can be reused for agricultural purposes and aquaculture without the need for disinfection. In most situations, pond effluents will fail to meet the recommended standards and would require upgrading before reuse by suitable methods. Most of the suitable methods are not appropriate for use in developing countries and are too costly. However there are, some forms of natural post-treatment which are feasible by using aquatic plants (water hyacinth). Water hyacinth has been used successfully to upgrade treatment waste stabilization effluents (WSPs), particularly for the removal of algae. In addition it is able to uptake large amounts of nutrients and heavy metals. At the same time its roots provide support for a gelatinous biomass which further stabilizes organic matter, producing CO2, inorganic substances and other materials, most of which are concentrated by the plants. Bacteria and other organisms adhere to the gelatin-covered parts. All these substances are removed from the water, when water hyacinth is harvested, especially when it is found in high density through growth phase during hot seasons. As a result, very low concentrations of ammonia and BOD are present in water hyacinth ponds, which is important for fish rearing. The reuse of wastewater in aquaculture is one way for diminishing the extent of pollution accompanied with resources conservation. The primary objective of this study is to investigate the feasibility of the proposed system and the optimum needed stages of treatment, in order to achieve variable design criteria for the effluent suitable for fish aquaculture following the water hyacinth aquaculture treatment. This objective was achieved through the study of physico-chemical, and biological changes in the tested wastewater effluents after each change in the design criteria basically, detention time and surface area of the ponds. The second objective was to test both water hyacinth and fish productivity and study the fish suitability for human consumption. Sample sites were chosen to represent the influents to the waste stabilization pond system (raw sewage) and the effluent of each pond during the period of investigation. Pilot plant scale oxidation ponds was designed to study and treat the influent of Maamoura pumping station. These ponds were connected in series where the effluent passes from a unit to another by gravity starting in an anaerobic pond followed by a facultative pond, then maturation pond which was implanted with water hyacinth to upgrade the effluent characteristics according to WHO guideline, then ending with post maturation pond which used to polish the final effluent. Both maturation and post maturation ponds were used for fish aquaculture (Tilapia). Characterization of effluent generated at variable detention times and the factors affecting on treatment steps were studied throughout the year. The following is a summary of the operational conditions of the influent and WSPs effluents: From the results the average values of the influent (raw sewage) were characterized by zero dissolved oxygen, high concentration of ammonia (25 - 47 mg/l) and phosphates (4.9 - 7.4 mg/l), moderate values of pH were (7.1-7.4), recorded. In addition, the influent possesses a considerable amount of helminthes as well as total and faecal coliform up to 19.7×1013 & 88×1012 respectively. 1-Anaerobic pond: It was designed as the deepest circular basin with a diameter of 0.3 m and 2.14 m deep. Detention times (3,2 and 1 days) was applied in this pond. The pond effluent is characterized by increase in sedimentation rate of suspended solids as settleable solids accompanied with very low percentage reduction of BOD.