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.

Use of Wastewater Treatment Plant Effluent Governed by TCEQ Chapter 210 Rules for Use of Reclaimed Water

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.

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

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

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 Fecal Coliform (single grab), CFU/100 ml

Frequency of Sampling and Analysis of Reclaimed Water Type I Reclaimed Water Uses – Twice/ Week Type II Reclaimed Water Uses – Once/Week

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

Typical WWTP Effluent TPDES Permit Limits in Harris County Monthly Avg. 7-day Avg. Daily Max Single Grab CBOD TSS NH3-N Fecal Coliform n/a n/a n/a n/a

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

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

Questions? D. Ray Young, P.E. W ATER E NGINEERS, I NC Huffmeister Road Cypress, Texas