Ferric Sulfate Success Story - OWASA s Switch to Ferric Sulfate Leads to a Reduction in Disinfection Byproducts NC AWWA-WEA CONFERENCE NOVEMBER 13-16, 2016 Orange Water and Sewer Authority A public, non-profit agency providing water, sewer and reclaimed water services to the Carrboro-Chapel Hill community.
Orange Water and Sewer Authority Public, non-profit agency Provide water, wastewater and reclaimed serves to the Carrboro-Chapel Hill Community Serve over 83,300 customers Partnership for Safe Water Phase IV Excellence in Water Treatment (5 Years Consecutive) Area-Wide Optimization Program (AWOP) (5 Years Consecutive)
Water Treatment Plant Process 20 MGD Capacity average 7.2 MGD Surface Water Treatment Coagulation Flocculation Sedimentation Conventional Super Pulsators Filtration Disinfection Optional Permanganate Feed Primary Coagulant Coagulant Aid Potassium Permanganate Powder Activated Carbon Sodium Hydroxide Pulsators
Our Journey Managing Change Research & Evaluation Consulting with State Regulators Community Engagement Making Plant Process Changes Communicating Results OWASA Jones Ferry Water Treatment Plant Staff
Reasons for Resisting Change No reasons to change Fear of the unknown Fear of failure Fear of the loss of security Lack of resources
Successfully Implementing Change Clearly communicate the need for the change Clearly communicate the path forward Have backup plan Get people involved Find ways to build confidence in the team Be supportive Regularly communicate those positive results through the process
Research & Evaluation Jar Tests Research Articles Visit other Utilities Chemical Distributors
Consult with State Regulators! Approved for a 2-Year Trial Developed a Water Quality Sampling Plan Turbidity Total Organic Carbon/Dissolved Organic Carbon Disinfection By-Products Water Quality Parameters (Corrosion Control) Temperature ph Alkalinity Conductivity Calcium Hardness Ortho-Phosphorous Chloride to Sulfate Ratio Lead and Copper Robert Herring (OWASA Laboratory Analyst) performing water quality testing.
Community Engagement News Releases Water Quality Report Card Newsletters Bill Inserts
Process Changes Caustic Feed Additions Raw Water Individual Filters Created Target phs Flash Mix 5.4-5.7 Individual Filters > 6.5 Raw Water Caustic Addition Individual Caustic Addition
Trending Pulsator Turbidity vs. ph 1.000 5.80 0.900 Pulsator Turbidity ph 5.70 0.800 5.60 Turbidity (NTU) 0.700 0.600 0.500 5.50 5.40 5.30 ph 0.400 5.20 0.300 5.10 0.200 5.00 2/1/2015 2/4/2015 2/7/2015 2/10/2015 2/13/2015 2/16/2015 2/19/2015 2/22/2015 2/25/2015 2/28/2015
Ferric Sulfate Advantages Ferric Sulfate is a low cost iron salt. Ferric Sulfate more versatile works at a wider range of raw water conditions. Ferric produces a heavier floc that settles better during the colder months. Ferric Sulfate is better at removing more total organic carbon. Disadvantages x Requires a larger dose. x Requires additional ph adjustments within the treatment process. x Produces more solids, due to the increased amount of solids removal. x Harsher on equipment and structures. x Staining
Total Organic Carbon (TOC) Removal 100.0 Percent Removal 80.0 60.0 40.0 Increased Total Organic Carbon Removal by 10%. 20.0 0.0
Finished Water Total Organic Carbon 3.00 2.50 2.00 Average Finished Water TOC decreased from 2.14 to 1.33 mg/l Concentration (mg/l) 1.50 1.00 0.50 0.00
Trihalomethanes (THMs) Reductions 80.0 70.0 60.0 Overall Reduction of 42% Average Concentration (mg/l) 50.0 40.0 30.0 Alum Ferric - Year 1 Ferric - Year 2 20.0 10.0 0.0 25% 54% 40% 49% May August November February
Haloacetic Acids (HAAs) Reductions 60.0 50.0 40.0 Overall Reduction of 51% Average Concentration (mg/l) 30.0 20.0 Alum Ferric - Year 1 Ferric - Year 2 10.0 23% 67% 47% 67% 0.0 May August November February
1.2 Solids Disposal 13 14% Increase in Solids 1.0 Wet Tons per Million Gallons Treated 0.8 0.6 0.4 0.2 0.0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
125 Alum and Ferric 100 75 Coagulant Dose mg/l 50 25 0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Alum Ferric Note: Switched from Alum to Ferric in March 2014.
40 Caustic 35 30 25 Caustic Dose mg/l 20 15 10 5 0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Post Caustic Pre Caustic
30 Carbon 20 Carbon Dose mg/l 10 0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
5 Potassium Permanganate 4 Potassium Permanganate Dose mg/l 3 2 1 0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Chemical Cost Comparison Chemical Alum Ferric Cost Difference Primary Coagulant $125,000 $272,200 +147,000 Caustic $64,300 $204,900 +140,600 Carbon $319,100 $221,300-97,800 Potassium Permanganate $183,300 $41,000-142,300 Total Cost $691,700 $739,200 +47,500
In Closing Thank you to our Team of dedicated people and their commitment to continuous improvement! Interact with other Utilities Seek guidance and leadership from State Regulators Inform and Engage your Community Regularly Communicate Results ORANGE WATER AND SEWER AUTHORITY A public, non-profit agency providing water, sewer and reclaimed water services to the Carrboro-Chapel Hill community.
0.06 Compliance Lead Results 90th Percentile 1992-2014 0.05 Concentration (parts per million) 0.04 0.03 0.02 0.01 0 0.004 EPA Action Level 0.015 ppm <0.003 0.002 0.004 <0.003 0.004 <0.003 <0.003 <0.003 <0.003 1992 1993 1994 1995 1999 2002 2005 2008 2011 2014 Year
0.06 Compliance Lead Results Individual Sites 1992 2014 0.05 Concentration (parts per million) 0.04 0.03 0.02 0.01 EPA Action Level 0.015 ppm Not Detectable 0 1992 1992 1993 1994 1995 1999 2002 2005 2008 2011 2014 1993 1994 1995 1999 Year 2002 2005 2008 2011 2014
0.06 Customer Requested Lead Results Individual Sites 1992-2015 Concentration (parts per million) 0.05 0.04 0.03 0.02 0.01 EPA Action Level 0.015 ppm Not Detectable 0 Year