Corrosion Control Across Consecutive Systems

Transcription

1 Corrosion Control Across Consecutive Systems Richard Calbi Andrea McElroy

2 Overview System Overview Evaluation of Corrosion Control Treatment selected for SWNJ Hackensack System Analytical Evaluation Coupon Testing WaterPro! Desktop Software Implementation Strategy of CCT Corrosion Control Study to Evaluate Mixing of SUEZ Water- Richard Calbi, Ridgewood Water Evaluation of Results 2 I

3 NJ SWNJ Hackensack- System Overview 195,000 customers & 1 million residents Demand- (Haworth TP Flow) Winter: MGD Summer: MGD Range: MGD Different Sources of Water Main WTP: 95% of volume produced Wells & Interconnections: 5% 2,200 miles of main Disinfection Methods Primary WTP: Chloramines 3 I

4 Existing Corrosion Control Treatment Evaluation (PRE-2017) ph adjustment with sodium hydroxide (caustic) Monitoring the Langelier Saturation Index goal of 0.3 DIC of water is 20.6 mg/l C 2015 Lead and Copper Rule Sampling 51 homes sampled 90 th percentile = 14 ppb (just below the Lead Action Level of 15 ppb) th Percentile MG/L LEAD (mg/l) Action Level 4 I

5 Average ph in Haworth Distribution System Significant ph variations Avg ph at POE = 8.07 Most of system ph > 8.1 Other areas ph I

6 What are the options for CCT to Control Metals Release Lead? Goal is to transform soluble lead into less-soluble complexes through interaction with inorganic ions Two primary control mechanisms: ph/alkalinity/dic (carbonate) Orthophosphate (inhibitor) Must form Pb complexes to form effective scale 6 I

7 Evaluation of Options- Coupon Study Immerse metal coupons in water and test water To optimize corrosion control practices on lead, copper and cast iron/mild steel with corrosion inhibitor To compare zinc orthophosphate and phosphoric acid Various dosages Varying ph 3 different distribution system locations and POE Measured: ph Temperature Orthophosphate Lead Copper Water quality readings: 48 hours 16 days 42 days (6 weeks) 7 I

8 Lead Concentrations Based on PO 4 Dose 14,000 12,000 Lead Concentration (ug/l) 10,000 8,000 6,000 4,000 2, hour Phosphate Concentration (mg/l) Lead 48 Hours (ug/l) Lead 16 Days (ug/l) Lead 6 Weeks (ug/l) 8 I

9 Zinc Orthophosphate vs. Phosphoric Acid Lead (ug/l) Phosphate Initial Concentration (mg/l) 9 I H3PO4 (48 hrs) (Lead ug/l) H3PO4 (16 days) (Lead ug/l) H3PO4 (6 weeks) (Lead ug/l) ZOP (48 hrs) (Lead ug/l) ZOP (16 days) (Lead ug/l) ZOP (6 weeks) (Lead ug/l)

10 Lead Solubility Model Results Lead solubility models estimate the approximate reduction in theoretical lead solubility Generally translates to similar percent reduction in soluble lead concentrations at the tap Soluble lead only, Not effective for particulate lead (no model available) WaterPro! Software used for model 10 I

11 Lead Solubility Model Results at ph = Theoretical Pb(II) Solubility, mg/l PO4 = 0.5 mg/l Estimated 43% Reduction PO4 = 1.0 mg/l Estimated 62% Reduction I ph 8.1 Orthophosphate Dose, mg/l PO 4 3- Baseline

12 Lead Solubility Model Results at Lower phs Theoretical Pb(II) Solubility, mg/l ph = 7.5 PO4 = 0.5 mg/l Estimated 47% Reduction ph = 7.5 PO4 = 1.0 mg/l Estimated 65% Reduction I Orthophosphate Dose, mg/l PO 4 3- ph 8.1 ph 7.8 ph 7.5 Baseline

13 Implementation Strategy for CCT Design Zinc orthophosphate Initial dose of 0.5 mg/l (October 2017) Target dose of 1.0 mg/l (January 2018) Utilize existing tanks and containment area, new pumps, new piping Maintain ph in the interim and slowly drop Permitting Not required to do a loop study or coupon study if can show the chemistry will work and no anticipated adverse effects 13 I

14 Notification to Wholesale Customers 16 Wholesale Customers Franklin Lakes 85% Haworth WTP, 15% groundwater Corrosion control with low dose of polyphosphate/orthophosphate blend Passaic Valley Water Commission Corrosion control with 3 mg/l as PO 4 of straight orthophosphate Ridgewood Water SUEZ supplies approximately 10% of Ridgewood s water through 2 interconnections for approximately 10 months/year Corrosion control with polyphosphate/orthophosphate blend with a PO 4 residual target of mg/l 14 I

15 CORROSION CONTROL STUDY TO EVALUATE MIXING OF SUEZ WATER Village of Ridgewood, NJ

16 Outline 16 System Overview Background of Project Study Objectives Testing Equipment and Methodologies Results and Discussion Conclusions Supplemental Monitoring

17 System Overview 17 Existing Facilities and Distribution System Ridgewood buys between 0.55 MGD - 3 MGD finished water from SUEZ for 10 months/year. System Type Source Type SUEZ SYSTEM Secondary Disinfection Corrosion Control Haworth WTP Surface Water Chloramination Zinc Orthophosphate 1 Franklin Lakes Wells Groundwater Free chlorine RIDGEWOOD SYSTEM Ridgewood Wells Groundwater Free chlorine 1 Prior to October 2017, ph adjustment was used. Poly/orthophosphate blend Poly/orthophosphate blend

18 Background of Project 18 Ridgewood finished water received from SUEZ: Primarily Haworth WTP A mix of surface and groundwater from the Franklin Lakes wells can occur as well as groundwater only October 2017 SUEZ added zinc orthophosphate to Haworth WTP for corrosion control Lawlins Interconnection was deactivated due to potential impacts in Ridgewood s system.

19 19 Purpose Evaluate the impact of zinc orthophosphate in Ridgewood s system when blending Ridgewood/SUEZ water

20 Study Objectives 20 Determine if lead/copper was elevated in Ridgewood s system after introduction of SUEZ water. Determine the effects of zinc orthophosphate on drinking water quality in RW system after introduction of SUEZ water. Assess other factors that shape water quality, including lead and copper release, in each water system.

21 Comprehensive vs. Regulatory Approach 21 Regulatory vs. Comprehensive Perspective Regulatory each distribution system water quality problem is viewed separately. Works for ideal pipe with ideal water, but many aging water systems are complex Comprehensive drinking water flows through pipes with various qualities of chemical scales and biofilms that have built up on pipe walls over time Addresses all distribution system problems, including lead and copper release, by cleaning out the chemical scales and biofilms on pipe walls Reference: Water Research Foundation Project 4586, Optimization of Phosphorus-Based Corrosion Control Chemicals Using a Comprehensive Perspective of Water Quality

22 Comprehensive vs. Regulatory Approach 22 Comprehensive Regulatory Reference: Water Research Foundation Project 4586, Optimization of Phosphorus-Based Corrosion Control Chemicals Using a Comprehensive Perspective of Water Quality

23 SUEZ PRS Monitoring Station Ridgewood PRS Monitoring Station SUEZ PRS Monitoring Station Lenape Booster Station (SUEZ Only) Ridgewood PRS Monitoring Station Russel Well (Control & Blended) 23 Testing Equipment

24 3 Conditions were simulated/sampled Additional Sampling Locations: 4 Ridgewood well entry points SUEZ Haworth WTP entry point SUEZ Shadow Ridge entry point Condition 1 Condition 3 24 Methodology

25 Results and Discussion 25 4 Water Types were studied: Ridgewood Groundwater Only SUEZ groundwater mixed with SUEZ surface water SUEZ surface water only 50/50 blend of RW groundwater and SUEZ surface water Lead and Copper Release: SUEZ surface water had lower lead/copper release than groundwater scenarios SUEZ groundwater had similar release as Ridgewood groundwater 50/50 blend lead and copper release was not significantly different from Ridgewood groundwater

26 Results 26 Uniform Corrosion Parameter Averages for System Water Ridgewood Ridgewood/SUEZ SUEZ SUEZ surface Parameter Units groundwater surface water groundwater water Total Alkalinity mg/l as CaCO ph SU Temperature deg C Calcium mg/l as Ca Magnesium mg/l as Mg Conductivity us/cm ORP mv Orthophosphate mg/l as PO Chloride mg/l as Cl Sulfate mg/l as SO Note: 1 The orthophosphate dosage in the surface water was later raised to 1.0 mg/l as PO 4.

27 Results 27 Chemical Scale Parameter Averages for System Water Parameter Units Ridgewood groundwater Ridgewood/SUEZ surface water SUEZ groundwater SUEZ surface water Total Lead mg/l Total Copper mg/l Total Iron mg/l Total Manganese mg/l Total Aluminum mg/l Total Zinc mg/l Turbidity NTU Conductivity us/cm Note: 1 The orthophosphate dosage in the surface water was later raised to 1.0 mg/l as PO 4 which raised the zinc concentration. Biostability Parameter Averages for System Water Parameter Units Ridgewood groundwater Ridgewood/SUEZ surface water SUEZ groundwater SUEZ surface water Free chlorine mg/l Total chlorine mg/l Dissolved organic mg/l carbon Ammonia mg/l as N Nitrite mg/l as N Nitrate mg/l as N Total Phosphorus mg/l as P Total Phosphorus mg/l as PO Orthophosphate mg/l as PO Non-orthophosphate mg/l as PO % Orthophosphate %

28 Conclusions 28 No significant lead/copper release from mixing of Ridgewood/SUEZ surface water. Lead/Copper appeared to stay the same or decrease Zinc did not appear to influence the release of lead and copper In blend, there was a transition from dissolved to particulate form which can cause formation of pipe wall scales. It is advantageous to routinely remove these scales. No influencing effect from orthophosphate on lead and copper release. Reasons could include orthophosphate dosage, or interference by existing chemical scales/biofilms. System has nutrients for microbiological growth in water and tendency to form biofilms where microorganisms can thrive. This increases the potential for microbiologically influenced corrosion.

29 Recommendations & Continued Efforts 29 Provide consistent supply of water to Lawlins Interconnection. Minimize source water changes (prefer Haworth supply). Improved chlorine residual monitoring and booster chlorination control. Addition of analyzer to measure orthophosphate. Review of current flushing program to proactively address turbidity and minimize chemical scales. Assess well water quality and routinely clean wells. Continued data sharing between Ridgewood and SUEZ. Including maintenance, flushing schedule, well cleaning schedule, chemical changes, flow changes, and main breaks which could affect the water quality delivered to Ridgewood. Additional Monitoring due to Lawlins Interconnection Reactivation.

30 Next Steps and Outcome 30 Determine the effects of Lawlins Interconnection reactivation through additional monitoring. NJ Directive Released July 2018 when a water system proposes changes to its source water or treatment, the Division is requiring an evaluation to be made to determine potential impacts to water quality that could adversely influence lead and/or copper levels in the distribution system.

31 Evaluation of Corrosion Control Treatment Andrea McElroy

32 90 th PERCENTILE COMPARISON MG/L SUEZ LEAD 90th Percentile (mg/l) Action Level Ridgewood Water 90th Percentile (mg/l) Number of Samples over the Action Level Month Monitoring 1/1/2017-6/30/ Month Monitoring 7/1/ /31/ Month Monitoring 1/1/2018-6/30/2018 SUEZ RIDGEWOOD WATER I

33 LEAD PROFILE DATA- RESIDENT IN LEAD POOL (Tier 1i) 80 9/27/ /1/2017 1/10/2018 2/27/2018 3/27/2018 4/25/2018 6/20/2018 7/30/ LEAD (PPB) ML OF SAMPLE 33 I

34 FIRST DRAW AT RESIDENT IN LEAD POOL LEAD (PPB) /27/ /1/2017 3/27/2018 FIRST DRAW I

35 NEXT STEPS Continue to optimize: Begin lowering ph, using the Langelier, currently at 7.7 Zinc Orthophosphate dosage of 1.0 ppm Materials Surveys at Lead Pool customers during meter changes to ensure accurate sample site selection by subcontractor. Materials Surveys going forward upon meter changes and other operations by SUEZ Employees. Continue to work with Ridgewood Water on additional monitoring and fulfilling the recommendations as described above. 35 I

36 QUESTIONS/COMMENTS? Acknowledgements Ridgewood Water Sandra Kutzing, CDM Smith Tony Delescinskis, SUEZ Thomas Neilan, SUEZ Michael Assante, SUEZ AGRA Environmental 36

37 Ridgewood Water Acknowledgements 37 SUEZ Water Mott MacDonald Process Research Solutions, LLC Rundle Spence