System Assessment Reports Information Sessions January 2013 Todays - PowerPoint PPT Presentation

System Assessment Reports – Information Sessions January 2013

Today’s Presentation • Updates to Nova Scotia’s Municipal Drinking Water Treatment Standards • Updates to Terms of Reference for System Assessment Reports • Questions

Nova Scotia’s Municipal Drinking Water Treatment Standards • First introduced in 2002 • Updated in 2012 to include: – Cryptosporidium as a target micro- organism for surface water and GUDI supplies • Chlorine resistant – Minimum requirements for alternate primary and secondary disinfectants – Minimum requirements for membrane filtration – Management of waste streams

Nova Scotia’s Municipal Drinking Water Treatment Standards (cont’d) • Fundamentals: – Based on 3-log reduction for protozoa ( Giardia and Cryptosporidium ) and 4-log reduction for viruses – Filtration for all surface water and GUDI supplies – Disinfection for all supplies – Redundancy for critical processes – Continuous monitoring for critical processes – Management of waste streams

Log Reduction Components • Log removal by physical treatment – Filtration for surface water and GUDI supplies – Performance indicator • Turbidity – Continuous monitoring • Log inactivation by disinfection – Applies to all supplies – Performance indicators • CT concept – chemical disinfectants – Continuous monitoring of chlorine residual • IT concept – UV disinfection – Continuous monitoring of intensity

System Assessment Reports • Due April 1, 2013 • Last assessments were based on assumptions • These assessments must demonstrate performance – with turbidity criteria to be awarded log removal credits – with disinfection criteria to meet CT/IT – with continuous monitoring requirements – with discharge criteria for waste streams • Based on data from last calendar year – can be 2011 – no need to wait for 2012 data

System Assessment Reports (cont’d) • Based on the multiple barrier and source to tap concepts – Source characterization – Treatment and distribution system – Operations and management

Source Characterization – Section 2 • Section 2.1 – Source Description and Schematic – Describe primary source(s) – Describe any sources that are used as back-up supplies – Identify sources on a map – Document precautions for use of back-up supplies • Municipalities that purchase water from an adjoining system – Identify system connections on a map – Document the name of the municipal system that water is purchased from – Proceed to Section 2.3

Microbial Risks – Section 2.2 • Surface Water – Section 2.2.1 – Summarize microbial risks – Summarize water quality variability • Turbidity • Colour • TOC • pH • Alkalinity • Temperature – Provide raw water coliform and protozoa data if available

Microbial Risks – Section 2.2 (cont’d) • Groundwater – Section 2.2.2 – Verify classified in accordance with GUDI protocol – Summarize GUDI status by individual well – Discuss wells that are no longer in use if applicable – For GUDI wells • Table A.1 • MPA results • Protozoa data if available – Inspect the site to verify no changes to surrounding area – Provide raw water coliform data – Corrective action for wells • Qualified hydrogeologist per GUDI Protocol

Chemical Risks – Section 2.3 • Disinfection by-products – Section 2.3.1 – THMs – HAAs – Others – Table 1 in Terms of Reference • Summarize concentrations – Tables A.2 and A.3 – Calculate locational running annual average based on a minimum of four quarterly samples • Exceedances require corrective action

THMs and HAAs – Sampling Locations HAA formation • Identify sampling locations on a map Concentrations (ug/L) Free Chlorine (mg/L) • Verify sampling locations are appropriate THMs HAAs Chlorine Time (hours)

Lead and Corrosion Control – Section 2.3.2 • Lead – Verify sampling locations and frequency is appropriate • Flushed samples • Stagnant samples – Identify sampling locations on a map • Corrosion control – Review the corrosion control program • Langelier Index is not an adequate measure of corrosivity – Summarize water quality results • Exceedances require corrective action

Aluminum – Section 2.3.3 • For facilities using aluminum-based coagulants – Compare average of 12 monthly samples at treatment facility to stipulated limit • Exceedances require corrective action

Guidelines for Canadian Drinking Water Quality – Section 2.3.4 • Table A.4 • Required every five years for raw and treated water • Verify that sampling locations and frequencies are appropriate • Detections require discussion and enhanced monitoring recommendations • Include lab reports from last round of sampling; indicate date for next round of sampling • Exceedances require corrective action

Guidelines for Monitoring Public Drinking Water Supplies – Section 2.3.5 • Table A.5 • Verify that sampling locations and frequencies are appropriate for raw and treated water – Every year for surface water and GUDI – Every two years for groundwater • Discuss water quality trends • Include lab reports from last round of sampling • Exceedances require corrective action

Source Water Protection Plan Monitoring – Section 2.3.6 • Step 5 of the source water protection program • Summarize parameters being monitored, sampling frequency, concentrations • Discuss water quality trends

Filter Backwash Water – Section 2.4 • If backwash water is discharged upstream of raw water intake, document the impact on the source • If source is impacted, provide recommendations

Source Quantity – Section 2.5 • Compile water withdrawal approvals – Include copy in Appendix • Complete Table A.6 to compare actual withdrawals to approved limits – Monthly withdrawal is m 3 (not m 3 /d) • Provide recommendations – If actual withdrawals exceed approved limits – If growth is forecast to increase withdrawals beyond approved limits

Source Water Protection Plan – Section 2.6 • Identify protection zones on a map • Submit zones in GIS format • Summarize the status of the SWP plan and implementation schedule • Document the dates of the last two SWP meetings • Note the status of meeting actions and SWP plan deliverables • Make recommendations to address concerns

Conclusions and Recommendations – Section 2 • Refer to Terms of Reference – pages 14 and 15 – Microbial risks – Chemical risks – Filter backwash water risks – Source quantity – Source water protection plan • Carry forward to Section 5

Treatment Processes – Section 3 • Compile existing Approval(s) to Operate – Include copy in Appendix • Provide a schematic of treatment process – Source to treated water entering the distribution system

Turbidity and Associated Criteria – Section 3.1.2 • Verify filtration meets turbidity limits – Mandatory to be awarded log removal credits • Surface Water – individual filter effluent turbidity values – Evaluating engineered filtration – 95 th /99 th percentile – If not achieved, recommend corrective action • GUDI – individual well turbidity values – Evaluating natural filtration – 1 NTU, 95 th percentile – If not achieved, contact NSE • Submission options – Calculated or graphed values

Filter 2 Turbidity Measurements and Exceedances # of # of %age of %age of Readings Readings time time Readings exceeding exceeding below . below . /day .15NTU .20NTU 15 NTU 2NTU 708 0 0 1-Aug 100.00% 100.00% 1403 0 0 2-Aug 100.00% 100.00% 725 1 0 3-Aug 99.86% 100.00% 847 0 0 4-Aug 100.00% 100.00% 1241 0 0 5-Aug 100.00% 100.00% 702 2 0 6-Aug 99.72% 100.00% 1131 0 0 7-Aug 100.00% 100.00% 808 1 0 8-Aug 99.88% 100.00%

Filtration Process – Other Requirements • Standard operating practices • Continuous monitoring, alarms, alerting • Inspect turbidimeter – Range, accuracy, maintenance, QA/QC • Redundancy – Surface water – Minimum of two filters • Membrane filtration – Section 3.1.3 – Table B.1 – Integrity testing – Organics rejection rate (if applicable)

Non-GUDI Wells • Evaluating turbidity spikes – Daily grab or continuous measurement – 1 NTU, 95 th percentile – If not achieved, contact NSE • Submit turbidity values for individual wells or combined flow – Option 1: Calculated values – Option 2: Graphed values • Inspect measurement method – Continuous or grab

Primary Disinfection – Section 3.1.4 • Document log inactivation required • Discuss how disinfection is achieved – Chemical disinfectant or UV • Provide a process schematic • Inspect the process and instrumentation – Redundancy (minimum of two units) – Continuous measurements, alarms, alerting – Range and accuracy – Maintenance, QA/calibration program • Standard operating procedures

Primary Disinfection – Section 3.1.4 • Chlorine – Calculate CT – Verify never out of design range otherwise provide daily calculations • Ultraviolet light – Verify IT – Verify never outside of design range otherwise provide daily calculations • See Appendix D of Treatment Standards for CT/IT sample calculations