4. CarolloTemplateWaterWave.pptx
5
Key Project Goals
• Richland Chambers and Cedar Creek
– Improve chloramine feed efficiency
– Protect intake conduit/towers
– Improvements to existing chemical systems
• Benbrook
– Design new chloramine feed system
• Sampling program to monitor chloramine decay
• Quantify impacts of biofilm on pipeline friction
factor and power use
5. CarolloTemplateWaterWave.pptx
6
Key Project Goals
• Richland Chambers and Cedar Creek
– Improve chloramine feed efficiency
– Protect intake conduit/towers
– Improvements to existing chemical systems
• Benbrook
– Design new chloramine feed system
• Sampling program to monitor chloramine decay
• Quantify impacts of biofilm on pipeline friction
factor and power use
13. CarolloTemplateWaterWave.pptx
14
pH variability in source waters
5.0
6.0
7.0
8.0
9.0
10.0
11.0
8/11/1987 5/7/1990 1/31/1993 10/28/1995 7/24/1998 4/19/2001 1/14/2004 10/10/2006
pH
Date
RC (0.5m) CC (0.5m)
*Note: Data from Jan 1990 to Mar 2008
14. CarolloTemplateWaterWave.pptx
15
pH variability in source waters
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0
PercentnotExceeding(%)
pH
RC (0.5m) CC (0.5m)
*Note: Data from Jan 1990 to Mar 2008
15. CarolloTemplateWaterWave.pptx
16
Higher pH decreases chloramine decay:
Cedar Creek
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 5 10 15 20 25 30 35 40 45
TotalChlorine,MonochloramineResidual(mg/L)
Time (hours)
pH 7.0 Total Chlorine
pH 7.0 Monochloramine
pH 8.3 Total Chlorine
pH 8.3 Monochloramine
Notes:
1) Water Source:CedarCreek
2) Date:8/26/2014
3) Cl2:N ratio: 4.5:1
4) Chloramine Dose:5.0 mg/L
5) Simultaneousadditionof chlorine and ammonia
39. CarolloTemplateWaterWave.pptx
40
Conclusions
• Optimum chloramine formation conditions lead to
– Reduced decay
– Reduced DBP formation
• Significant nitrification occurring in the pipeline
– Increased chloramine loss
• Demonstrated simple test for the presence of
nitrifying bacteria
44. CarolloTemplateWaterWave.pptx
45
Historical LSI – Raw Water
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
PercentnotExceeding(%)
LSI
Cedar Creek Reservoir Richland Chambers Reservoir Benbrook Reservoir
Notes:
1) Data from Jan 1990 to Mar 2008 (depth
ranges from 3-6m)
2) Data obtained from Appendix A of Water
Quality Analysis Technical Memorandum (RPS Espey)
45. CarolloTemplateWaterWave.pptx
46
Caustic currently fed to Cedar Creek for
Corrosion control
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
-1.500 -1.000 -0.500 0.000 0.500 1.000 1.500
PercentnotExceeding(%)
LSI
Cedar Creek Intake Cedar Creek Treated
46. CarolloTemplateWaterWave.pptx
47
DBP formation testing
0
2
4
6
8
10
12
14
16
18
20
Waxahachie
(10 hours)
LakePump
Station Hold
(22 hours)
Bench (22
hours)
Waxahachie
(13 hours)
LakePump
Station Hold
(22 hours)
Bench (22
hours)
TTHM(µg/L);HAA5(µg/L);NDMA(ng/L)
TTHM
HAA5
NDMA
Total Chlorine Demand
Notes:
1) Samplescollected9/4/2014
2) Benchtesting - Chlorine and ammoniaadded
simultaneously ata 4.5:1 Cl2:N ratio
3) NDMA detectionlimit = 2 ng/L
Richland Chambers Cedar Creek
47. CarolloTemplateWaterWave.pptx
48
High Cl2/N ratio increases DBP formation
0
2
4
6
8
10
12
14
Cedar Creek Richland Chambers Benbrook
NDMAFormation(ng/L)
4.5:1
5.5:1
Notes:
1) 48 hour incubation
2) pH ambient
3) TOC: CedarCreek= 5.8 mg/L; Richland
Chambers= 4.5 mg/L;Benbrook= 4.7 mg/L