Investigating the Potential of Swimming Pools Sullage Reuse for Landscape Irrigation, Case Study: Tehran city

In recent years, excessive usage of surface and underground water resources has exerted great stress on Iran's water resources. A survey of water use trends in the past years and forecasts of water needs in the coming years, makes undesirable  perspective for the imbalance between water demand and resources in the near future. Planning for the exploration and use of unconventional water resources, such as gray water and sullage reuse, will greatly help to balance water shortage. In this research, sewage of swimming pools has been investigated because it is a type of urban sewage that has high technical, economic and environmental potential for implementation of urban sullage recycling project. A case study was carried out on 10 public swimming pools in Tehran to determine the volume and 7 pools for qualitative investigation on sewage of different parts of swimming pools. The results indicate that pools have a high quality and high volume wastewater that cause conceivable potential for recycling. For example, the average COD of the tested samples was 153 ppm and the maximum was 246 ppm, which is equivalent to organic load of weak urban wastewater. This wastewater also meets the standards of landscape irrigation in most of parameters, and in the other parameters such as organic load of some samples has a small variance from these standards, which could be met with a simple treatment unit like a depth filtration and an activated carbon. In addition, an average of 120 cubic meters of sullage per day is generated in each aquatic center complex, which is more than the production of gray water in a 700 people capacity residential complex. Reuse of this sullage, in addition to reducing transportation costs and load of centralized treatment plants, will reduce the pressure on water resources of our country by supplying water for non-potable purposes such as irrigation of landscaping.