%Click Show more to see transcript% Has anybody heard about how much alcohol people drank back in the middle ages and renaissance? It is true! Anywhere near population centers, the water was so contaminated that it tasted terrible and often caused illness. Strangely, the average person did not know that disease could come from the water, they only hated the taste. Water was "for the poor to drink, and for the rich to dress their meat”. The main drinks were ales, meads, and wines which involved boiling to brew or had enough alcohol to disinfect. This changed in the 18th and 19th century, as doctors realized how important water and water quality is, and the world of water supply changed forever. Slide 1: Today Water supply is in another transition period. As you can see from these before and after photos, the surface waters of california are severely strained, costing billions of dollars in damage to our agricultural and entertainment sectors. click Slide 2: This presentation focuses on 3 topics. First, how recycling impacts our water supply. Then how the advanced treatment processes are used to make recycled water safe. Finally I will highlight one of the flagship programs for recycled water in California, Orange County’s GroundWater Replenishment System. click Slide 3: Here is a simplified water cycle diagram. You can see that we take in water from the source, meaning lakes, rivers, or groundwater if we have to. The water is treated then it is used by people. it goes to the wastewater treatment plant where it is cleaned, not always well, and pumped out again. They say if you drink a cup of tap water in New Orleans, you are drinking water that has passed through 7 other kidneys before reaching you, as each major city takes in water from the Mississippi and then discharges into it. Here in Los Angeles, most of our water is eventually pumped out into the ocean down by LAX click The thing to notice is how recycling and/or reusing water allows us to take in less water. We still need to take in some water, to account for losses throughout the cycle, but the required input is decreased dramatically. As populations grow, the local sources of water may not be adequate, and the most simple solution is to keep water we take in. click Slide 4: after the water leaves the wastewater treatment plant. Where it would normally be pumped back into the environment. It enters an advanced treatment plant click First, the water is filtered using microfiltration or ultrafiltration. You can see the diminishing sieve size, eliminating nearly everything that is suspended in the water. click The size of the openings are 1 100 millionth of a meter for UF The remaining contaminants are dissolved. NS Then there is reverse osmosis. This graphic illustrates a common type of RO membrane, where the water comes into the middle and is subjected to such high pressures that it flows lateral