Parker Water & Sanitation District Frank Jaeger, District Manager James Roche, Superintendent

PARKER WATER AND SANITATION DISTRICT THE VIRUS STUDY

Study Objectives  Determine the performance of the AWT system for removal of the major classes of microbiological contaminants  Compare the AWT discharge with the microbiological quality in Cherry Creek

Study Design  One Year Study – Oct 1999 – Oct 2000  Four Indicator organisms – Total Coliform Fecal Coliform - F. Strep – E. Coli  Giardia and Cryptosporidium  Enteric Viruses

 Two sample points on Cherry Creek Scott Rd – 6.7 miles upstream Cottonwood Rd – 3.8 miles downstream  Three plant sample points After Secondary but before filters After filters but before UV disinfection After UV disinfection

 ICR methodology used for Giardia, Cryptosporidum, and Enteric Virus sampling and analysis  Laboratory used (BioVir) was certified to perform all three analyses for the ICR reporting.  Sampling performed by Mountain Water Indicator microbiology by Adams labs

The levels of all four microbial indicator organisms were significantly lower in the AWT effluent than at either Cherry Creek site. Parameter Scott Rd Cottonwood Rd AWT Stream Standard Geo Mean cfu/100ml cfu/100ml cfu/100mlcfu/100ml Total Coliform F. Coliform E. Coli F. Strep

The AWT process removed significant numbers of the four microbial indicators. OrganismPre-filter(Secondary) Post filter (Pre-UV) Post UV (AWT) cfu/100mlcfu/100mlcfu/100ml T. Coliform 263, F. Coliform 14, E. coli 5, Fecal Strep 1, *Values are geometric means.

 AWT Total Coliform Geometric mean for the study - 57 cfu/100ml (12 samples)  AWT Total Coliform Geometric mean for normal operation – 0.96 cfu/100ml (194 samples)  AWT Total Coliforms were less than 100 CFU/100 ml over 91% of the time

CONCLUSIONS  The AWT effluent is higher quality and more consistent than the natural water in Cherry Creek for all classes of microbiological organisms tested.  Giardia and Virus were consistently reduced from levels as high as 500 to 1000 IFA positive organisnms/100 Liters to levels of less than 1 IFA positive organism/100 Liters.

CONCLUSIONS  Microbial indicator organisms were consistently removed to levels significantly below the stream standard.  Frequent monitoring of bacterial indicators is the best technique to control the disinfection process. Total coliform is the most sensitive disinfection indicator.

CONCLUSIONS  A dual barrier disinfection system, with prefilter chlorination, followed by post filter UV disinfection was more effective on Total Coliform than post filtration UV disinfection alone.

CONCLUSION  The combination of AWT effluent and Cherry Creek raw water, stored in Rueter Hess Reservoir, and treated in a water treatment plant (probably membrane), with chlorine disinfection will provide a reliable, quality, substitute supply for the customers of the Parker Water and Sanitation District.