Transporting Urban Wastewater to Irrigate Green Fields Located in City Periphery, Sebha as a model

Abstract

The direct discharge of untreated urban wastewater into open areas, rivers or sea shores is an indication of neglect and mismanagement of the use of water resources and leads to harm to human health as well as the safety of the environment in general. Avoiding these damages requires integrated and wise management which is able to find the right solutions to benefit from this water for the appropriate purposes such as agriculture. The city of Sebha, which is one of the cities of the southern Libyan desert, has a population of 133,206 people, according to the 2006 census. The treatment plant was establish in the  city of Sebha in 1988 AD, where it receives urban wastewater and pushes it through a pipe to a collection tank and from it to  open areas north of the city, 5,000 meters away from it. Because of the continuous flow of urban wastewater, this space turned into a pond with an area of 79 hectares by the year 2011 AD, which caused the accumulation of waste, the growth of weeds and the emission of unpleasant odors annoying the population, so some previous studies recommended making use of urban wastewater in the construction of green spaces to improve climatic conditions, or in planting trees that are resistant to sand crawling on roads, or in the production of timber, therefore; in this research, a polyethylene pipe with a diameter of 800 mm, a pressure of 10 bar, and a length of 16000 m, was designed using the EPANET 2.0 Software program to transfer the current and expected urban wastewater after 50 years from the collection tank to the Zallaf area. The possibility of the natural flow of water depending on the slope of the earth's surface was also investigated. The researcher concluded that the natural flow of water is not possible and that the transfer of water from the collection tank to the Zallaf area requires a 554.3 liter/sec discharge pump and 12-meter head