Despite the fact that wastewater is a major source of pollution it is considered a sustainable and valuable resource that should be collected, treated to acceptable standards and reused not only to preserve the environment and groundwater aquifers, but also to conserve and augment the water resources. The reuse of treated wastewater, mainly for agricultural irrigation, would promote water conservation through replacement of fresh water reallocated for domestic use from the Palestinian agricultural sector. This would also result in guaranteed regular supplies of fresh water to the citizens. The dispersed pattern of houses in the rural Palestinian localities and remote areas makes it economically unfeasible to construct wastewater collection networks and centralized wastewater treatment plants. On-Site small scale wastewater treatment plants, respond to the needs and conditions of rural localities. They can solve the wastewater collection and disposal problems in such communities, along with the benefit of generating a water resource that can be utilized for irrigation purposes. Despite the several advantages that the utilization of small scale On-Site wastewater treatment units can provide, introducing of such technology in the Palestinian rural areas has been a hard task; due to several reasons among those reasons is the high cost of such imported plants, with no locally made real alternatives. This encouraged the Applied Research Institute – Jerusalem (ARIJ) to work in finding alternative solutions to the faced challenges. In August 2005, engineers of the Water and Environment Research Unit (WERU) at (ARIJ) managed to transform the theoretical knowledge to a real application. In this application, a small scale wastewater treatment plant was constructed based on the activated sludge Technology1, which includes a cylindrical bioreactor having as its main body a plastic tank with a total volume of 2500 liter, partitioned into four hydraulically independent zones. These are the mechanical debris collection basket, the de-nitrification zone, the activation / nitrification zone and the separation zone. The idea was to accommodate all the treatment process in a local available plastic tank.