Overview
This lecture discusses Orange County's innovative approach to water scarcity: recycling wastewater into drinking water using advanced purification technology.
Southern California's Water Crisis
- Southern California faces a severe water shortage despite proximity to the Pacific Ocean.
- Desalinating ocean water is too expensive to be a practical solution.
- Over 1.3 billion gallons of wastewater are sent to sea daily in the region.
Orange County's Groundwater Replenishment System
- Orange County built a major plant to recycle wastewater into drinking water.
- The facility serves 2.4 million people, creating 70 million gallons of clean water per day.
- The plant was necessary due to rapid population growth and limited water resources.
Water Purification Process
- The process starts with microfiltration to remove large particles; filter holes are about two microns in size.
- Reverse osmosis forces water through a plastic membrane, blocking bacteria, viruses, and chemicals, allowing only water molecules through.
- Ultraviolet (UV) light treatment is the final step to destroy any remaining organic molecules.
Quality Assurance and Public Perception
- The facility has an on-site lab for continuous water quality monitoring.
- The process aims to reassure the public that recycled water is safe and tastes like regular water.
- Historical note: all water on Earth is continually recycled; no truly "new" water exists.
Broader Implications
- The project provides optimism due to its scientific effectiveness.
- Frustration exists due to lack of political will in other regions to adopt similar water recycling.
- Orange County’s project is expensive but cheaper than alternatives or inaction.
Key Terms & Definitions
- Microfiltration — A filtration process removing particles larger than two microns from water.
- Reverse Osmosis — A process that removes contaminants by forcing water through a plastic membrane at the molecular level.
- Ultraviolet (UV) Treatment — Use of UV light to neutralize any remaining organic contaminants in water.
Action Items / Next Steps
- Review details about each stage of water purification for upcoming quiz.
- Read about water scarcity issues in Southern California for context.