Non-potable water for use in irrigation systems
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The document discusses various alternative non-potable water sources that can be used for irrigation systems instead of potable water due to increasing water scarcity and regulation. It describes different sources like recycled water, rainwater, graywater, stormwater, cooling tower blowdown, and desalination. For each source, it covers technical considerations like water quality, collection methods, storage, regulations, costs, and which design professionals would be involved. The conclusion is that there are many viable alternatives to potable water for irrigation, but each source's benefits vary and costs, return on investment, health, and maintenance needs to be evaluated for the specific project.
Non-potable water for use in irrigation systems
- 1. The Future of Water Tom Kundrat CIC, CLIA Product Manager
- 2. The world’s water crisis
- 4. Increasing regulation New Green Codes requiring use of non-potable and/or reclaimed water Stronger regulation in particular markets US: California, Florida, Texas, Arizona Worldwide: Australia, Israel, Spain Anticipate similar levels of regulation across the US
- 5. Residential Water Bill Increases (Past 12 Years) • Atlanta, GA 233% • San Francisco, CA 211% • Wilmington, DE 200% • Philadelphia, PA 164% • Portland, OR 161% Increasing Water Costs
- 6. Emerging irrigation technologies Continued purple identification Manufacturer investments in reclaimed- resistant materials Valves Spray heads Expansion of irrigation systems to include water harvesting equipment Innovation in intelligent control systems
- 8. Non-Potable Water for use in Irrigation Systems Sources, Definitions and Technical Considerations Lance Sweeney, ASIC President Sweeney + Associates, Inc.
- 9. Summary Potable Water, that which is suitable to drink, is becoming an increasingly precious commodity. In some areas, it is illegal to use potable water to irrigate the landscape. Many project owners, Landscape Architects, and Irrigation Designers are looking at non-potable water sources to replace, or reduce, the dependency on potable water. The use of non-potable water is not without its challenges. These include availability, reliability, agency requirements, water quality, plant suitability, and specialty equipment. There may also be competition for these non-potable water sources from other water users on the project. Many projects use non- potable water for such uses as flushing toilets and filling cooling towers. Non-potable water may be the right choice for your landscape irrigation system, this webinar will help you make that decision.
- 10. Non-Potable Water Sources Agency Provided Non-Potable Water Recycled / Reclaimed Water Project Provided Non-Potable Water Rainwater Storm Water Gray Water Air Conditioner Condensate Cooling Tower Blow-down On Site Sewerage Treatment Raw Water Desalination
- 11. Recycled / Reclaimed Water Treated and delivered to site by local agency. May be required for use by the local agency. Water rates might be lower than potable water or even subsidized. Generally of high quality, but can have high salt and chlorine levels. Not necessarily well suited for all plant materials. Local agency and health department rules vary by state, county and city. Some agencies require yearly inspections of systems. Purple color coded pipe, equipment, and valve boxes required. Backflow prevention devices may be required. Signage required. No sprinkler overspray allowed. May be delivered in a lower water pressure than potable supply.
- 12. Rainwater Rainwater is collected off of roofs and other hard surfaces. Rainwater stored in cisterns below or above grade and in buildings. Generally clean, but can pick up contaminants off the roof. Make-up water may require an air gap between potable source and storage. First flush diverters and filtration required. Some agencies require use within 48 hours. Stored rainwater can become septic quickly unless treated. Can have a long Return On Investment (ROI), depending on region. Best suited in regions where rain occurs during summer growing season. In ground systems can be designed by Landscape Architects. Little agency involvement, but they are catching up!
- 13. Rainwater Rainwater is collected off of roofs and other hard surfaces. Rainwater stored in cisterns below grade, above grade and in buildings. Generally clean, but picks up contaminants on roof. First Flush diverters and filtration required. Make-up water may require an air gap between potable source and storage. Some agencies require use within 48 hours. Stored rainwater can become septic quickly unless treated. Can have a long Return On Investment (ROI). Best suited in regions where rain occurs during summer growing season. In ground systems can be designed by Landscape Architects, systems within buildings require design by MEP Engineers. Little agency involvement, but they are catching up!
- 14. Storm Water Storm water is collected off of all surfaces of the project. Storm water stored in cisterns below grade and in buildings. Not as clean as rainwater as the collection surface is varied. Make-up water may require an air gap between potable source and storage. Some agencies require use within 48 hours. Stored storm water can become septic quickly unless treated. ROI may be shorter as it offsets other storm water requirements. Best suited in regions where rain occurs during summer growing season. Generally designed by Civil Engineers. Much more agency involvement.
- 15. Gray Water Gray water is diverted from sinks, showers and/or washing machines. Gray water stored in cisterns below grade and in buildings. Not a clean source of water and it can be hazardous. Gray water contains whatever is sent down the sink or drain. Soaps and chemicals can harm plants or soils. E-coli bacteria can occur from human contact. Gray water may be treated or untreated. Simple leach field type systems are very common on residences. Some agencies do not allow above ground application. Large commercial systems may require a permit, but residential units may not. Make-up water must have an air gap between potable source and storage. Generally required to be used within 24 hours of collection. Depending on complexity, may have a long ROI. Little agency involvement for small residential systems, more involved for large systems.
- 16. Air Conditioner Condensate AC condensate is the water collected off of cooling coils of an air conditioner. Usually a waste water product, so its use may offer multiple benefits. Can be coupled with other non-potable water collection strategies. AC condensate stored in cisterns below grade, above grade and in buildings. Very clean water source, basically distilled water. Make-up water may require an air gap between potable source and storage. Some agencies require use within 48 hours. Stored condensate can become septic quickly unless treated. Long ROI, but the ROI can be reduced if coupled with other alternative water sources. Best suited in warm, humid regions. Requires involvement of the MEP Engineer. Some agency involvement.
- 17. Cooling Tower Blow-down Blow-down water is the used water and wash down water from cooling towers. Usually a waste water product, so its use may offer multiple benefits. Can be coupled with other non-potable water collection strategies. Blow-down water stored in cisterns below grade, above grade and in buildings. Not a clean or suitable water source unless processed. Several treatment processes available. Substantial installation and maintenance costs. Make-up water may require an air gap between potable source and storage. Some agencies require use within 48 hours. Stored blow-down water can become septic quickly unless treated. Long ROI, but the ROI can be reduced if coupled with other alternative water sources. Requires involvement of the MEP Engineer. Some agency involvement.
- 18. On Site Sewerage Treatment Small sewer treatment plant suitable for a single project. Often used in remote sites or areas without suitable infrastructure. Water provided can be similar to recycled / reclaimed water. Requirements are the same as recycled / reclaimed water. Until project is populated, product water may be limited. Make-up water may require an air gap between potable source and storage. Complicated ROI as few projects use these systems for just irrigation need. Requires involvement of the Civil and MEP Engineers. Substantial agency involvement.
- 19. Raw Water Water from wells, lakes, ponds, rivers or canals. Water sources may be self replenishing. Water may be free of cost, other than pumping costs. Quality varies by source. Pumps, filters and injection systems required. Depending on water cost, equipment required, electricity costs, and maintenance the use of raw water could have a short or long ROI. Most systems can be designed by a Landscape Architect. Some agency involvement.
- 20. Desalination The conversion of salt water into fresh water. Sources include the ocean, raw water sources or wells. Several methods available. Reverse osmosis it the most popular for project specific systems. Resulting water quality can be very high. Process creates a salt brine that must be disposed appropriately. R.O. equipment is expensive and the energy costs are high. Most often used in areas where no potable supply is available. Often the desalination plant is set up to provide potable water to the project and the irrigation water is a blend of the potable water and the reject water. Lots of controversy in this process due to salt disposal challenges.
- 21. Conclusions There are many viable alternatives to the use of potable water for the irrigation of landscapes. Most projects have access to alternative water sources that can offset the use or completely eliminate the use of potable water. The benefits of each alternative sources vary with each project. The cost, return on investment, health concerns, and maintenance issues should be considered prior to the use of these alternative sources. The water quality of the alternative source should be considered when selecting the landscape plants for the project. The irrigation design should incorporate all required design methods and equipment to effectively use the alternative water sources.
- 22. Questions