1. 1 CTC 450 Review Advanced WW Treatment Advanced WW Treatment Removal of Nitrogen Removal of Nitrogen Removal of phosphorus Removal of phosphorus Complete removal of pathogens Complete removal of pathogens Removal of other toxics Removal of other toxics

2. 2 Objectives Understand the basics with respect to reusing wastewater Understand the basics with respect to reusing wastewater

3. 3 Water Reuse Reuse is defined as direct application of treated WW for agricultural and urban irrigation, industrial reuse, groundwater recharge, and others Reuse is defined as direct application of treated WW for agricultural and urban irrigation, industrial reuse, groundwater recharge, and others Discharging WW to a receiving water that is ultimately used downstream for a water source is not considered reuse (dilution/separation in time and space) Discharging WW to a receiving water that is ultimately used downstream for a water source is not considered reuse (dilution/separation in time and space)

4. 4 Water Reuse - Functions Treated effluent is used as a water resource for beneficial purposes Treated effluent is used as a water resource for beneficial purposes Effluent is kept out of streams, lakes and beaches Effluent is kept out of streams, lakes and beaches

5. 5 Water Reuse – Main Concerns Reliable treatment of WW Reliable treatment of WW Protection of public health Protection of public health Gaining public acceptance Gaining public acceptance

6. 6 Matter of Economics Water reuse may be less costly Water reuse may be less costly Use N/P for irrigation instead of providing tertiary processes to prevent eutrophication Use N/P for irrigation instead of providing tertiary processes to prevent eutrophication Water shortages – a future possibility (CA/AZ/FL) Water shortages – a future possibility (CA/AZ/FL)

7. 7 Potential Drawbacks Pathogens via physical contact or aerosols Pathogens via physical contact or aerosols Public perception Public perception

8. 8 Water Statistics Recycled WW Recycled WW 983 MGD (1995) 983 MGD (1995) 2% of total wastewater release (41,000 mgd) 2% of total wastewater release (41,000 mgd) CA/AZ/FL account for majority CA/AZ/FL account for majority

9. 9 Water Quality Effluent Stds Dependent upon reuse application Dependent upon reuse application Agricultural irrigation (restricted -with respect to human activity ) Agricultural irrigation (restricted -with respect to human activity ) fodder,fiber,seed crops fodder,fiber,seed crops Agricultural irrigation (unrestricted) Agricultural irrigation (unrestricted) processed food, food eaten raw processed food, food eaten raw Urban irrigation (restricted) Urban irrigation (restricted) Golf courses, cemeteries, highway medians Golf courses, cemeteries, highway medians Urban irrigation (unrestricted) Urban irrigation (unrestricted) Parks, playgrounds, residences, comml landscaping Parks, playgrounds, residences, comml landscaping

10. 10 Advantages/Disadvantages of Agricultural Irrigation Already contains nutrients and soil amendments Already contains nutrients and soil amendments Agricultural areas may be nearby Agricultural areas may be nearby Money for cash crops Money for cash crops In arid regions, ww may be the only source of water In arid regions, ww may be the only source of water Nitrate - groundwater Nitrate - groundwater Heavy metals - soils Heavy metals - soils Pathogens - farm workers Pathogens - farm workers

11. 11 Agricultural Irrigation Storage required to balance supply/demand Storage required to balance supply/demand

12. 12 Design of Irrigation Systems Balance water to determine storage requirements Balance water to determine storage requirements Balance nitrogen to prevent migration Balance nitrogen to prevent migration

13. 13 Urban Irrigation Piping systems color-coded Piping systems color-coded Cross-connections prohibited Cross-connections prohibited Warning signs Warning signs Reuse water pipes placed 3’ below potable water pipes Reuse water pipes placed 3’ below potable water pipes

14. 14 Groundwater Recharge Surface infiltration (surface spreading) Surface infiltration (surface spreading) Direct injection Direct injection Issues Issues Fate of particulates Fate of particulates Fate of bacteria/viruses Fate of bacteria/viruses Fate of dissolved organic/inorganic constituents (particularly toxics) Fate of dissolved organic/inorganic constituents (particularly toxics)

15. 15 Groundwater Recharge US federal requirements/standards have not been established US federal requirements/standards have not been established Currently regulated by state agencies Currently regulated by state agencies

16. 16 Storage Issues Need for storage Need for storage Type (open or closed) Type (open or closed) Discharge requirements Discharge requirements Problems: Problems: Odors, loss of chlorine residual, low DO Odors, loss of chlorine residual, low DO Temperature stratification, bird/rodents Temperature stratification, bird/rodents Algal blooms, regrowth of microorganisma Algal blooms, regrowth of microorganisma

17. 17 Agricultural Irrigation-Example Tallahassee, FL 2000 acres; 2000 acres; 16 pivot irrigators 16 pivot irrigators irrigators controlled by computer irrigators controlled by computer low-drift nozzles low-drift nozzles Vegetation-canola, corn, sorghum, grass Vegetation-canola, corn, sorghum, grass Monitoring wells Monitoring wells Capacity-23 mgd Capacity-23 mgd Four parallel treatment plants (fig 14-4) Four parallel treatment plants (fig 14-4)

18. 18 Residential Lawn Watering El Dorado Hills, CA Dual plumbed distribution system Dual plumbed distribution system 66 mg reservoir 66 mg reservoir Drip irrigators-no restriction times Drip irrigators-no restriction times Spray irrigators-restricted to 9pm-6am Spray irrigators-restricted to 9pm-6am Back-up: potable lake water Back-up: potable lake water Plant doesn’t meet required water quality Plant doesn’t meet required water quality System can’t meet peak irrigation demands System can’t meet peak irrigation demands

19. 19 Urban Reuse St. Petersburg, FL Irrigation of parks, school, golf courses, comm’l and residential irrigation Irrigation of parks, school, golf courses, comm’l and residential irrigation Some water injected into deep-well system Some water injected into deep-well system Effluent requirements: Effluent requirements: SS-5 mg/l (in practice 1-3 mgl/l) SS-5 mg/l (in practice 1-3 mgl/l) Chlorine residual-1 mg/l after 15 min (in practice 4 mg/l) Chlorine residual-1 mg/l after 15 min (in practice 4 mg/l)

20. 20 Industrial Reuse Los Medanos Energy Center, CA WW treatment plant provided recycled water to the energy center WW treatment plant provided recycled water to the energy center Water is used for the heat recovery steam generator make-up and water for the evaporative cooling system Water is used for the heat recovery steam generator make-up and water for the evaporative cooling system Treatment processes: Treatment processes: Dual-media, ultra- and activated carbon filtration for TOC removal Dual-media, ultra- and activated carbon filtration for TOC removal Antiscalant chemical added for evaporative system Antiscalant chemical added for evaporative system Reverse osmosis for evaporative cooling Reverse osmosis for evaporative cooling

21. Final Exam Review Water Processing-Clarifier following Coagulation (25 pts) Water Processing-Clarifier following Coagulation (25 pts) Wastewater Processing-Trickling Filter (25 pts) Wastewater Processing-Trickling Filter (25 pts) Wastewater Processing-Clarifier (25 pts) Wastewater Processing-Clarifier (25 pts) 25 pts – will cover material presented after the midterm 25 pts – will cover material presented after the midterm 21

22. Final Exam Review Open book/open notes/ Open book/open notes/ Can use computer (but monitored) Can use computer (but monitored) No cell phones; no old tests No cell phones; no old tests Show all work Show all work Know the standards Know the standards Don’t forget units Don’t forget units Conversions-concentration to mass Conversions-concentration to mass 22