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Treated Wastewater Reuse For Landscape Irrigation and Amenity Lake Evaporation Make-Up Presented to: Houston Land/Water Sustainability Forum May 13, 2008 Presented by: D. Ray Young, P.E. Slide 2 Use of Wastewater Treatment Plant Effluent Governed by TCEQ Chapter 210 Rules for Use of Reclaimed Water Slide 3 Reclaimed Water - Domestic or municipal wastewater which has been treated to a quality suitable for beneficial use, pursuant to the provisions of this chapter and other applicable rules and permits. Slide 4 Type I Reclaimed Water Use: Human contact with reclaimed water is likely: Residential home irrigation Park or golf course landscape irrigation (unrestricted access) School yards and athletic fields Fire protection (internal sprinklers or fire hydrants) Toilet or urinal flushing Irrigation of food crops Irrigation of pastures for milking cows Maintenance of lakes where wading or fishing may occur Slide 5 Type II Reclaimed Water Use: Human contact with reclaimed water is not likely: Irrigation of sod farms Irrigation of limited access highway right of ways Irrigation of food crops where direct contact with edible parts unlikely or where food crops undergoes pasteurization Irrigation or non-potables uses at a wastewater treatment facility Maintenance of lakes where direct human a contact unlikely Soil compaction/dust control in construction areas - no aerosol drift Cooling tower make-up water where significant aerosols are not released adjacent to public access areas Slide 6 Type I/II Quality Requirements Type I Type II BOD5, mg/l 5 20 CBOD 5 15 Turbidity, NTU 3 n/a Fecal Coliform (geo. mean), CFU/100 ml 20 200 Fecal Coliform (single grab), CFU/100 ml 75 800 Slide 7 Frequency of Sampling and Analysis of Reclaimed Water Type I Reclaimed Water Uses Twice/ Week Type II Reclaimed Water Uses Once/Week Slide 8 Costs for Sampling & Analysis of Reclaimed Water (*) Type I - $89.00/Week Type II - $16.50/Week (*) In addition to WWTP Effluent Analysis cost of $75.00/Week Slide 9 Typical WWTP Effluent TPDES Permit Limits in Harris County Monthly Avg. 7-day Avg. Daily Max Single Grab CBOD 10 15 25 35 TSS 15 25 40 60 NH3-N 2 5 10 15 Fecal Coliform n/a n/a n/a n/a Slide 10 Variability of Wastewater Treatment Plant Effluent Quality Process Upset from Toxicity Process Upset from Peak Flows (I/I) Clarifier Weir Cleaning Digester Decanting Operator Error Slide 11 Slide 12 Special Requirements for Using Reclaimed Water Reclaimed water managed in ponds for storage may not discharge to receiving streams, except from rainfall events Storage ponds must be lined Signs must be posted at all storage areas and hose bibs reading, Reclaimed Water, Do Not Drink, in both English and Spanish. Hose bibs painted purple and not standard hose size unless locked Exposed piping and piping within buildings to be painted purple Slide 13 Slide 14 Slide 15 Slide 16 Slide 17 Slide 18 Slide 19 Slide 20 Slide 21 Questions? D. Ray Young, P.E. W ATER E NGINEERS, I NC. 17230 Huffmeister Road Cypress, Texas 77429 281-373-0500 dry@waterengineers.com