Table VI.

Categories of Waste water Reuse and Potential Constraints ^a, ^b

Waste water reuse categories	Potential constraints
1. Agricultural irrigation Crop irrigation Commercial nurseries	•Surface and groundwater pollution if not properly managed •Marketability of crops and public acceptance •Public health concerns related to pathogens (bacteria, viruses, parasites) •Effect of water quality, particularly on soils & crops
2. Landscape irrigation Parks Schoolyards Freeway medians Golf courses Cemeteries Greenbelts Residential	•Public health concerns related to pathogens •Use area control including buffer zone; may result in high user cost
3. Industrial recycling and reuse Cooling Boiler feed Process water Heavy construction	•Constituents in waste water related to scaling, corrosion biological growth, and fouling •Cross connection potable and reclaimed water lines •Public health concerns, particularly aerosol transmission of pathogens in cooling water
4. Groundwater recharge Groundwater replenishment Salt water intrusion control Subsidence control	•Organic chemicals in reclaimed waste water and their toxicological effects •Possible contamination of groundwater aquifer used as a source of potable water •Total dissolved solids, nitrates, and pathogens in reclaimed wastewater
5. Recreational/environmental uses Lakes and ponds Marsh enhancement Streamflow augmentation Fisheries Snowmaking	•Health concerns related to presence of bacteria,viruses and other pathogens (e.g., enteric infections and ear, eye and nose infections) •Eutrophication due to P and N in receiving water •Toxicity to aquatic life
6. Nonpotable urban uses Fire protection Air conditioning Toilet flushing	•Public health concerns on pathogen transmitted by aerosols •Effects of water quality on scaling, corrosion, biological growth, and fouling •Cross connections of potable and reclaimed water lines
7. Potable reuse	•Constituents in reclaimed water, especially trace organic chemicals and their toxicological effects •Health concern regarding pathogen transmission

^aTaken from Waste water Engineering, Metcalf and Eddy, McGraw-Hill, 2003.

^bArranged in descending order of projected volume of use.