Water Resources Management and Sewage Recycling, Solutions for Domestic Water Supply in Arid Areas, Case Study: Mashhad City

As a result of the climate change and water abstraction in neighbouring countries, domestic water supply to boarder line cities has faced serious challenges due to reduction in available water. Mashhad city is one of the most strategic cities of Iran that would face with water scarcity challenge. Though the Oman Sea water desalinization and transfer to Mashhad is being studied at the moment, this paper defines water demand and conventional and non-conventional regional water supplies and shows that the available regional water resources can meet domestic demand. Despite the low volume of water supply in some individual projects; local water management is superior to sea water transfer scenario in terms of economic and environmental aspects. Agricultural water consumption management based on groundwater entitlement and sewage water recycling are more suitable scenarios for domestic water supply. There are two alternatives for recycling sewage water including 1) substituting agricultural water with sewage in adjacent aquifers and convey clean water for domestic use and 2) secondary treatment of effluent and injecting it into domestic aquifer. Future domestic demand of Mashhad city is 1.5 times of existing demand and regional water supply schemes not only can meet the demand but also provide 122 MCM excess water (31% of demand) as confidence limit.