Cary/Apex Water Treatment Facility- Ozone Biofiltration Pilot Study March 26, 2018 Judith Labrada Bill Dowbiggin, PE
Agenda Project Background Project Drivers Why CAWTF considered a change? What is Ozone Biofiltration? Pilot Test Objectives and Setup Results Conclusions What s Next 2
Project Background
Cary Apex Water Treatment Facility - CAWTF Municipal WTP jointly owned by the towns Cary and Apex Originally built as 16 MGD CDM Smith designed and oversaw expansion to its 40 MGD Expansion included addition of ozone generation Current project is expanding the plant to 56 MGD Jordan Lake raw water source Distributes water to Cary, Morrisville, RDU airport, portions of Research Triangle Park, and Western Wake county 4
Purpose of Pilot Study Potential environmental and social benefits reported from use of Ozone biofiltration (OBF) Improved disinfection Oxidation of some inorganics (iron/manganese) Taste, odor, and color removal Removal of contaminants of Emerging Concern (CEC) OBF removes Biodegradable Ozone Byproducts such as Carboxylic Acids and Aldehydes- Cleaner Distribution System Plants current configuration allows for easy transfer to OBF 5
What is Ozone Biofiltration?
Biofiltration is Biologically Active Filtration Conventional Treatment Process Biological Treatment Process Cl 2 Cl 2 7
Biofiltration Can Occur with Anthracite, Sand, or GAC 10X Re-Agglomerated Coal Particulates 100 X 1 millimetre Voids in the Packed Bed 10 millimeters Macroscopic Crack/Crevice Bacteria (0.001-0.015 mm) grow on the surfaces and in the voids between particles 8
GAC (Agglomerated PAC) Allows and Protects More Bacteria in Internal Pores 1,000X Binder Residue 100 microns Localized Structure Graphitic Crystallite 1,000,000X Macroscopic Pores due to Re-agglomeration Graphite plate 1000 angstroms Source - Calgon Carbon Corporation 9
Biomass Accumulation on Biofiltration Media after 95 Days Media Mean Biomass (nmol lipid-p/g) Anthracite pre-cl 2 2 Anthracite (Cl 2 BW) 6 Anthracite 55 Sand 90.6 GAC (bituminous coal) 305 GAC (lignite coal) 465 GAC (wood) 382 Source: Wang et al. 1995 10
Pilot Test Objectives and Setup
Pilot Test Objectives Remove Mn to well below 0.05 mg/l Demonstrate if old anthracite without chlorine can work Demonstrate if new anthracite without chlorine can work Find a biofiltration approach that works at ph values that are effective with alum to avoid switching to ferric Convert to biofiltration if data supports anticipated benefits T&O, DBP, Emerging contaminants Biological stability/ozone byproducts 12
Pilot Plant Filter Configuration Column Media Conditions 1 Old (existing) anthracite Chlorine Dose: 2.89 ppm 2 New anthracite Caustic addition to reach ph 7.0, and assist with manganese removal Dose: 6-7 ppm 3 New GAC Chlorine Dose: 2.42 ppm 4 New GAC Caustic addition to reach ph 7.0, and assist with manganese removal Dose: 6-7 ppm 5 Spent GAC * No chlorine *All Filters FAP - Dose : 0.12 ppm Orthophosphate - Dose : ~ 0.05 as P mg/l Both chemicals are added to the day tank after ozone has been applied. 13
14 Pilot Plant Filter Configuration
Pilot Sampling Plan Settled Water Ozonated Settled Water Filter 1 Filter 2 Filter 3 Filter 4 Filter 5 I E I E I E I E I E TOC W W W W W W W UV 254 W W W W W W W Turbidity OL/D W OL/D OL/D OL/D OL/D OL/D Differential Pressure Manganese 2/W* 2/W* OL/D OL/D OL/D OL/D OL/D OL/D OL/D OL/D OL/D OL/D 2/W* 2/W* 2/W* 2/W* 2/W* Nitrosamines FP 6M 6M 6M 6M 6M 6M 6M Trace Organics 1 (optional) 6M 6M 6M 6M 6M 6M 6M THM FP/HAA9 FP Q Q Q Q Q Q Q 1,4-Dioxane (optional) 6M 6M 6M 6M* 6M* 6M* 6M* Algal Toxins M 2 M 2 M 2 M 2 M 2 M 2 M 2 MIB 2/W* 2/W* 2/W* 2/W* 2/W* 2/W* Geosmin 2/W* 2/W* 2/W* 2/W* 2/W* 2/W* Aluminum M* M* M* M* M* Orthophosphate W W W W W Total Phosphorus M M M M M Ammonia M M M M M Chlorine Residual D W D W W DO W W W W W W W W W W 15 ph D W D W W
Pilot Results
Pilot Results 0.5 Manganese 0.45 0.4 Mg / L 0.35 0.3 0.25 0.2 0.15 0.1 SW OW Filter 1 Filter 2 Filter 3 Filter 4 Filter 5 0.05 0 8/1/2017 9/1/2017 10/1/2017 11/1/2017 12/1/2017 17
Pilot Results 0.12 Mn Removal w/ ph Adjustment Filter #2 & 4 8 0.1 7.5 Manganese - mg/l 0.08 0.06 0.04 7 6.5 6 ph 0.02 5.5 0 8/2/2017 9/2/2017 10/2/2017 11/2/2017 12/2/2017 5 FE2 - Mn FE4 - Mn FE2 - ph FE4 - ph 18
Pilot Results 0.35 Mn Removal During Spiking 0.3 0.25 0.2 0.15 0.1 0.05 0 10/20/2017 10/22/2017 10/24/2017 10/26/2017 10/28/2017 10/30/2017 11/1/2017 11/3/2017 11/5/2017 11/7/2017 11/9/2017 11/11/2017 11/13/2017 11/15/2017 11/17/2017 11/19/2017 11/21/2017 11/23/2017 11/25/2017 Mn - mg/l 11/27/2017 11/29/2017 12/1/2017 12/3/2017 12/5/2017 12/7/2017 Ozonated Filter 1 Filter 2 Filter 3 Filter 4 Filter 5 19
Pilot Results 4 Total Organic Carbon 3.5 3 TOC - mg/l 2.5 2 1.5 1 0.5 SW OW Filter 1 Filter 2 Filter 3 Filter 4 Filter 5 0 20
Pilot Results 0.4 Filter Effluent Turbidity 0.35 0.3 NTU 0.25 0.2 0.15 0.1 FE1 Turbidity FE2 Turbidity FE3 Turbidity FE4 Turbidity FE5 Turbidity 0.05 0 8/4/2017 9/4/2017 10/4/2017 11/4/2017 12/4/2017 1/4/2018 21
Pilot Results 4 Chlorine Dose & Residual 3.5 3 2.5 2 1.5 1 0.5 0 8/1/2017 8/3/2017 8/5/2017 8/7/2017 8/9/2017 8/11/2017 8/13/2017 8/15/2017 8/17/2017 8/19/2017 8/21/2017 8/23/2017 8/25/2017 8/27/2017 8/29/2017 8/31/2017 9/2/2017 9/4/2017 9/6/2017 9/8/2017 9/10/2017 9/12/2017 9/14/2017 9/16/2017 9/18/2017 9/20/2017 Mg / L WTP FE Cl2 Pilot FE1 WTP Cl2 Dose Pilot #1 Dose 22
Pilot Results 35 DBP Formation Potential 30 25 ug/l 20 15 THMs HAAs 10 5 0 Filter 1 Filter 2 Filter 3 Filter 4 Filter 5 23
Pilot Results Geosmin (ng/l) Settled Pre O3 Ozonated Filter 1 Filter 2 Filter 3 Sample Set 1 Sample Set 2 Sample Set 3 Sample Set 4 Sample Set 5 Filter 4 Filter 5 0 5 10 15 20 25 24
Judith Labrada labradaj@cdmsmith.com (919) 325-3565 Bill Dowbiggin, PE dowbigginwb@cdmsmith.com (919) 325-3519