A third successive year of California's worst drought in a century has the Golden State's reservoirs at record lows. Agriculture has been affected, hitting the local economy, while some small communities risk running out of water.

But business is booming in California's Orange County Water District (OCWD), through a pioneering wastewater treatment facility that recycles used water -- or sewage -- and returns it to the drinking supply. The plant is expanding production from 70 to 100 million gallons per day, enough for 850,000 people, around one-third of the county population. As the OWCD output is mixed with the main groundwater supply it reaches over 70% of residents.

Discuss the following:

• The pros and cons of using treated waste water for drinking water and agriculture
• The process by which waste water is treated
• Alternative solutions for areas heavily hit by drought
• Where else waste water is treated and how the local population reacted