Innovative Groundwater Treatment. Sarah Wilson, Anna Comerton and Elia Edwards OWWA/OMWA Joint Annual Conference London, ON; May 4-7, 2014

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1 Innovative Groundwater Treatment Sarah Wilson, Anna Comerton and Elia Edwards OWWA/OMWA Joint Annual Conference London, ON; May 4-7, 2014

2 Typical Groundwater Quality Chemical composition of GW influenced by hydrogeochemical cycle Typically provide consistent water quality Low particulate and organics concentrations Lower potential presence of pathogens when compared to surface water Presentation will not discuss particulate removal or disinfection

3 Treatment Challenges GW aquifers have long residence times Renewed less frequently If aquifer contaminated, contaminants can occur at high concentrations Presence of contaminants in aquifer can present unique water system management and treatment challenges

4 Common GW Contaminants Common groundwater contaminants include the following: Iron and manganese Hardness and alkalinity Total dissolved solids (TDS) Dissolved organic carbon (DOC) and colour Arsenic and sulfur Nitrate Fluoride

5 Management Approaches Depending on specific contaminant and its concentration, and well arrangement, non-treatment approaches can include: Raw water blending in multi-well system Source protection/improvement to reduce contaminant levels Finding a new raw water source

6 Advanced Treatment Processes If alternative source or management approach not feasible or desirable, treatment must be considered Advanced treatment to address a specific contaminant or water quality issue include following main processes: Advanced oxidation Biological processes Membrane filtration Ion exchange

7 Contaminant: 1,4-Dioxane

8 1,4-Dioxane Removal Greenbrook WTP, Waterloo, ON In July 2004, low concentration of 1,4-dioxane detected in supply wells WTP shut down as precautionary measure WTP capacity of 150 L/s AE assisted with treatability study for removal of 1,4- dioxane and overall process retrofit/upgrade design at WTP New UV/hydrogen peroxide advanced oxidation process for 1,4-dioxane removal Also included new iron and manganese filters

9 1,4-Dioxane Removal Greenbrook WTP - AOP Pilot-Test Results Bench-scale and pilot testing was completed for 3 AOP treatments: 3 K4B ETL Mid-run UV/H 2 O 2 Run 1 Run 2 Run 6 Run 7 O 3 /H 2 O 2 2 TiO 2 /H 2 O 2 1,4-Dioxane Log Removal 1 0 TROJAN APT PURIFICS

10 1,4-Dioxane Removal Greenbrook WTP, Waterloo, ON

11 1,4-Dioxane Removal Greenbrook WTP, Waterloo, ON Three medium-pressure UV reactors decompose hydrogen peroxide (H 2 O 2 ) into hydroxyl radicals Hydroxyl radicals ( OH) have short half-life (10-9 s) and attack organic molecules Radicals break up 1,4-dioxane structure Reduce to bonded molecules or carbon dioxide

12 Contaminant: Ammonia

13 Ammonia Removal Yellow Quill First Nation WTP, Yellow Quill, Saskatchewan Local ground water supply of extremely poor quality but sufficient quantity Alternative raw water source not feasible Required treatment to remove iron, manganese, arsenic, DOC, ammonium, hardness and TDS Biological membrane system selected

14 Ammonia Removal Biological System - Background Consists of biological pre-treatment filtration process combined with high-efficiency RO system Biological filtration step oxidizes contaminants such as iron, arsenic, ammonium and DOC RO membrane removes contaminants not removed during pre-treatment RO permeate run through calcium and magnesium mineral bed

15 Ammonia Removal Yellow Quill First Nation WTP - Pilot Study Pilot Configuration Aerated raw water / Iron removed water Filter Media GAC Anthracite Coarse Sand Oxygen Content in the water supplied to each biological column is >10 mg/l

16 Ammonia Removal Piloting Results - GAC Media 2 Total Ammonia (mg/l) Nov 26 Cold-start filter 9 w eek start-up Iron-free aerated Raw aerated 0.2 Red arrow s indicate backw ash maintenance dates 0 26-Nov 17-Dec 7-Jan 28-Jan 18-Feb 11-Mar 1-Apr

17 Ammonia Removal Yellow Quill First Nation WTP - Treatment Process Initial process based on pilot work O 2 Contactor 3 Stage Bio Filters RO Membranes ph Correction Disinfection

18 Ammonia Removal Yellow Quill First Nation WTP - Bio-Membrane Process Treatment Step 1 Iron and Arsenic Reduction Biofilter 1 Treatment Step 2 Ammonium to Nitrates Oxygen Biofilter 2 Treatment Step 3 Dissolved Solids Removal Chlorine ph/lsi Correction Potable Water Raw Water Air Biofilter 3 Membrane

19 Ammonia Removal Yellow Quill First Nation WTP - Biological System

20 Contaminant: Nitrate

21 Nitrate Removal Bethel WTP, County of Brant, Ontario Greenfield WTP (50 L/s capacity) to meet increasing water demand in Paris, Ontario

22 Nitrate Removal Bethel WTP, County of Brant, Ontario Bethel Road wells source for WTP Low turbidity, moderate alkalinity and hardness, and moderate to high TDS Nitrate only health-related parameter exceeding ODWSOG (10 mg/l) Main treatment processes to address nitrate removal and 1 and 2 disinfection Reduction of hardness and TDS not objectives

23 Nitrate Removal Investigated Treatment Alternatives Membrane Filtration Low-energy RO identified as preferred membrane approach Ion Exchange (IX) Selective anionic resins for nitrate removal chosen Pilot testing of RO and IX in parallel performed in Nov/Dec. 2010

24 Nitrate Removal Bethel Road - RO & IX Pilot Test

25 Nitrate Removal Reverse Osmosis - Background Non-selective process removes 99% of all dissolved minerals and organic compounds as well as biological and colloidal suspended matter >90% removal of nitrate Continuous generation of waste (concentrate/reject stream) Larger volume, low concentration waste compared to IX

26 Nitrate Removal Bethel WTP - RO Pilot Testing Results Full-Scale Design Considerations Anti-scalant addition (1-2 mg/l) only pre-treatment required RO permeate nitrate of <1 mg/l expected RO recovery of 80% expected 2-stage system Post-treatment to stabilize RO permeate required via raw water blending or chemical adjustment

27 Nitrate Removal Ion Exchange - Background Selective process involving removal of unwanted ions by exchanging them with desirable ions stored in resins Nitrate (NO 3- ) exchanged with chlorite (Cl - ) Cyclical waste generation Small volume, high salt concentration waste compared to RO

28 Nitrate Removal Bethel WTP - IX Pilot Testing Results Full-Scale Design Considerations Effluent nitrate levels ~2 mg/l IX recovery of >98% expected Equalized waste chloride ~10,000 mg/l IX selected for nitrate removal at Bethel WTP IX system pre-selected/pre-purchased Contract awarded to Orica Watercare in April 2011 First WTP in Ontario to provide nitrate removal via IX (to be commissioned in November 2012)

29 Nitrate Removal Bethel WTP - Ion Exchange Vessels

30 Summary Non-treatment approaches should be considered first i.e., new water source, blending, etc. Many innovative treatment options available when contaminants present in groundwater source Evaluate based on overall treatment objectives and cost/benefits

31 Acknowledgements Shengtao Weng, Linda Wojcicka Region of Waterloo County of Brant Orica Watercare Inc. Veolia Water Solutions

32 Questions? Thank You! Sarah Wilson, M.A.Sc., E.I.T. Process Designer Water Group Associated Engineering The East Mall Toronto, ON, M9B 6E2 Tel: Web: