Alternatives Evalutation Concept_101019_ib cmmntsPNCWA 2019South Y Alternatives EvaluationA. Summary of Costs B. Three Evaluation Methods1. Primary Evaluation•Screening Criteria (from FS Workplan, Used for All Alternatives) 2. Additional Evaluation•EPA Remedial Action Objectives (RAO) Specific to South Y (From FS Workplan - see Handout 1) – Additional Evaluation•Other South Y Specific Objectives ( From FS Workplan - See Handout 1)3. Summaries for each Method are presented; Details for each alternative for each Method are available at end and intended for the FS Report10/10/2019DRAFT1
PNCWA 2019Alternatives Evaluation A. Summary of CostsEstimated Cost (2019 $)Alt 1: Base TreatmentAlt 2 Revised: PCE Extraction 3Alt 3: Conversion to Surface WTP 4Capital Cost$0 (no new infrastructure)-30% Total +50% -30% Total +50%$1.3M -$1.91M$1.8M -$2.8M$2.7M -$4.2M$40.5M $57.8M $86.7MO&M/year $726K $890K - $927K $629K - $1.6M (groundwater – surface water treatment plant)NPV1$726K/year $993K/year - $1.1M/year$4.9M/year$932/MGY$1,010/MGY$5,586/MGYEstimated Time to Implement0 year (current operations)3-5 years (well construction and equipping)10-15 years (pipelines, intake and WTP construction)Total PCE Removed over 50 years 2347 lbs –2,573 lbs(Baseline –Conservative)818 lbs – 4,136 lbs(Baseline – Conservative)232 lbs – 1,418 lbs(Baseline – Conservative)10/10/2019DRAFT2
PNCWA 2019Alternatives Evaluation A. Summary of CostsNotes1. Life-Cycle Cost Calculations:•Net Present Value (NPV) = Total of Capital Cost Recovery + Total Annual O&M Cost•Total Cost Over 30-Year Debt Service = Net Present Value x 30 Years•Interest Rate = 4%, Discount Rate = 5%2. Based on DRI Model results for Alternatives 1A(Baseline)/1B(Conservative), 2A(Baseline)/2B(Conservative) Option 2, and 3A(Baseline)/3B(Conservative)3. Alternative 2 costs range from GAC treatment (low) to new PTA treatment (high) and assumes GAC treatment is already installed at LBWC 5 (estimated capital cost = $1.8M per LBWC State-funded Construction Grant is not included). Alternative 2 O&M includes LBWC 5 GAC Treatment costs.4. Alternative 3 assumes 15 years of groundwater pumping and treatment until fully implemented (complete conversion to surface water treatment, with pre-implementation operations similar to Alternative 1 (existing infrastructure and O&M).10/10/2019DRAFT3
PNCWA 2019•Water Supply Reliability•Timeline for Implementation•Capital Cost•Relative O&M Cost•Ease of Construction•Ease of O&M•Disposal/Reuse•Permitting Requirements•Environmental Effects•Regional Clean-Up Benefit•Time to Achieve PCE ReductionAlternatives EvaluationB1. Screening Criteria10/10/2019DRAFT4
PNCWA 2019B1. Screening Criteria Summary and ScoringAlt 1: Base TreatmentAlt 2 Revised: PCE ExtractionAlt 3: Conversion to Surface WTPRelative Criteria Score(Worst to Best)10/10/2019DRAFT5
PNCWA 2019B1. Screening Criteria Summary and Scoring(without Disposal/Reuse)Alt 1: Base TreatmentAlt 2 Revised: PCE ExtractionAlt 3: Conversion to Surface WTPRelative Criteria Score(Worst to Best)10/10/2019DRAFT6
PNCWA 2019B1. Screening Criteria Relative Scoring Notes1. Reliable Water Supply: High - Provides secure water with non-detectable PCE in source water. Medium -Provides secure water with non-detectable PCE after treatment. Low - Potential PCE level increase in source water 2. Timeline for Implementation: High (0-2 years). Medium (3-5 years). Low (5+years). 3. Capital Cost: Low ($10,000,000 and above). Medium ($1,000,000 to $9,999,999. High (Under $1,000,000)4. O&M Cost: Low ($1,000,000 and above). High (Under $1,000,000).5. Ease of Construction: High (no foreseeable construction limits). Medium (some construction limits and coordination required). Low (construction limits or requires special construction methods). 6. Ease of O&M: High (no change in operation). Medium (increased operation complexity in groundwater facilities). Low (Difficult - increased operation complexity in both wells and surface water treatment plant). 7. Disposal/Reuse: High (no disposal requirements). Medium (disposal under NPDES permit with potential reuse). Low (disposal with no reuse). 8. Permitting Requirements: High (no new permits will be required). Medium (no challenges during permitting process). Low (some challenges during permitting process). 9. Environmental Effects: High (no effects). Medium (temporary effects). Low (permanent effects). 10.Regional Clean-up Benefit: High (remove significant amount of PCE from groundwater). Medium (Provide some PCE groundwater removal benefits). Low (provide little PCE groundwater removal benefits) 11.Time to achieve PCE Reduction: High (Short - PCE becomes lower than MCL in 30 years after implementation). Medium (PCE becomes lower than MCL in 50-60 years after implementation). Low (Long - PCE becomes lower than MCL more than 60 years). Scores for each criteria are normalized against the Alternative that meets the criteria the best, e.g., if the Alternative with the highest Regional Clean-up Benefit is Alternative 2 with 818 lbs of PCE removed in 50 years, then the score for Alternative 2 is 100 (%), the score for Alternative 1 is 42 (347 lbs of PCE removed in 50 years), and the score for Alternative 3 is 28 (232 lbs of PCE removed in 50 years).10/10/2019DRAFT7
PNCWA 2019Alternatives EvaluationB2. General EPA Remedial Action Objectives1. Allow additional groundwater production without treatment2. Remedies that do not increase volume of groundwater impacted by HVOCs3. Reduce PCE concentration to <50 ppb at drinking water wells 5a. Supply water without detectable HVOCs to customers5b. Comply with regulatory requirements and directives regarding HVOCs5c. Estimate mass on contaminant removed over project life6. Address groundwater in mid-plume area7. Remove the majority of PCE mass in groundwater in the mid-plume area within 30 yearsNote: RAO 4. is not applicable10/10/2019DRAFT8
PNCWA 2019B2. Remedial Action Objectives Summary – RAO MetGeneral EPA RAOsAlt 1 Alt 2 Alt 31. Allow additional groundwater production without treatment2. Remedies that do not increase volume of groundwater impacted by HVOCs3. Reduce PCE concentration to <50 ppb at drinking water wells 5a. Supply water without detectable HVOCs to customers5b. Comply with regulatory requirements1and directives regarding HVOCs5c. Estimate mass on contaminant removed over project life6. Address groundwater in mid-plume area7. Remove the majority of PCE mass in groundwater in the mid-plume area within 30 years21. i.e. Drinking Water Standards for water supply, 2. Based on DRI Model Results10/10/2019DRAFT9
PNCWA 2019B2. Remedial Action Objectives Alternatives Scoring SummaryCriteriaAlternative 1:Base TreatmentAlternative 2 Revised:PCE ExtractionAlternative 3:Conversion to Surface WTP1. Groundwater production w/o treatmentMedium Low Not applicable2. Remedies that do not increase volume of groundwater impacted by HVOCsMedium High Low3. Reduce PCE to < 50 ppb Medium Medium Low5a.Water supply w/o detectable HVOCsMedium Medium High 5b. Meeting regulatory requirements/directives re HVOCsHigh High High5c. Mass of PCE removed1MediumHighLow6. Area of attainmentMediumHighLow7. Restoration w/in 30 years MediumHighLow10/10/2019DRAFT10
PNCWA 2019B2. RAO Scoring Notes•1. Groundwater production w/o treatment: Low = GW With Significant PCE treatment needed, Medium = GW with some PCE treatment, High= GW Without PCE treatment•2. Remedies that do not increase volume of groundwater impacted by HVOCs: Low = Potentially draws plume to uncontaminated wells or does not intercept plume, medium = intercepts some PCE, High = Protects wells downgradient from PCE•3. Reduce PCE to < 50 ppb•5a. Water supply w/o detectable HVOCs: Low = contaminated supply w/no treatment, Medium = contaminated supply w/treatment, High = uncontaminated supply•5b. Meeting regulatory requirements/directives = (i.e. meet drinking water standards) •5c. Mass of PCE removed1: Low = no PCE removed, Medium = baseline PCE removed, High = additional PCE removal•6. Area of attainment: Low = no additional PCE removal, medium = baseline PCE removal, High = additional PCE removal•7. Restoration w/in 30 years: Low = Wells never <MCL, Medium = Some Wells <MCL in 30 years, High = All Wells <MCL before 30 years10/10/2019DRAFT11
PNCWA 2019Alternatives EvaluationB3. South Y Specific Objectives•Preserve ability to recover HVOC response costs from responsible parties and/or state grant funding in the future•Beneficial use of extracted groundwater•Reduce costs for groundwater remedial wellhead treatment to customers•Perform community outreach and information activities regarding HVOCs in groundwater10/10/2019DRAFT12
PNCWA 2019B3. South Y-Specific ObjectivesSummarySouth Y Specific ObjectiveAlt 1 Alt 2 Alt 3Preserve ability to recover HVOC response costs from responsible parties and/or state grant funding in the futureBeneficial use of extracted groundwaterReduce costs for groundwater remedial wellhead treatment to customers**Perform community outreach and information activities regarding HVOCs in groundwater* Short-term grants may be available for O&M10/10/2019DRAFT13
PNCWA 2019TAC Considerations•The costs and alternative evaluation are intended to provide a comparison of the alternatives to each other•The costs are an order of magnitude comparison of costs between the alternatives•The timeframe of implementation of the alternatives are not all the same •Each alternative has a different outcome with respect to contaminant clean up•Each TAC member has a slightly different perspective and goal; the evaluation criteria attempt to capture the various perspectives•Given these perspectives, what recommendations would each TAC member arrive at?10/10/2019DRAFT14
PNCWA 2019DETAILED EVALUATION FOR FS REPORT FOLLOWS10/10/2019DRAFT15
PNCWA 2019B1. Screening CriteriaAlternative 1: Base TreatmentCriteriaScore ExplanationWater Supply Reliability Low/MediumPotential for PCE levels to increase, Provides PCE treatmentTimeline for Implementation Short Current operations/infrastructure already implementedCapital CostLow Requires no new infrastructureRelative O&M CostLow Requires no additional costs above planned O&MEase of ConstructionHigh Requires no new infrastructureEase of O&MHigh Requires no additional O&MDisposal/ReuseLow No foreseeable additional disposal/reuse requiredPermitting Requirements Low No new permittingEnvironmental Effects Low No foreseeable additional environmental effectsRegional Clean-Up Benefit1Medium 347 (Baseline) – 2,573 (Conservative) lbs PCE removed 2019-2068Time to Achieve PCE Reduction1Medium PCE concentrations to drop below MCL for all TKWC/LBWC wells by 2045 (baseline) or >2068 (conservative)1. Based on DRI Model Results for Model Alternative 1A/1B10/10/2019DRAFT16
PNCWA 2019B1. Screening CriteriaAlternative 2 (Revised): PCE ExtractionCriteriaScore ExplanationWater Supply Reliability Medium Provides PCE treatmentTimeline for Implementation Medium New well drilling (LBWC 4R) and air stripper equipping. Assumes LBWC 5 treatment already implemented.Capital CostMedium New well drilling (LBWC 4R) and air stripper equipping. Assumes LBWC 5 treatment already implemented.Relative O&M CostLow Additional pumping (LBWC 4R) and treatment O&MEase of Construction Medium New well drilling (LBWC 4R) and air stripper equipping on existing LBWC 4 siteEase of O&MMedium Additional pumping (LBWC 4R) and treatment O&M, with treated water discharge10/10/2019DRAFT17
PNCWA 2019B1. Screening Criteria Alternative 2 (Revised): PCE Extraction (continued)CriteriaScore ExplanationEase of O&MMedium Additional pumping (LBWC 4R) and treatment O&M, with treated water dischargeDisposal/ReuseHigh All LBWC 4R treated water produced to be discharged to sewer or storm drain systemPermitting Requirements Medium Air Board Permitting for air stripper, NPDES permit if LBWC 4R to discharge to storm drain systemEnvironmental Effects Medium/HighTemporary environmental effects during construction, new tall structure for air stripper treatment system at LBWC 4 siteRegional Clean-Up Benefit1High 818 (Baseline)– 4,136 (Conservative) lbs PCE removed 2019-2068Time to Achieve PCE Reduction1Short PCE concentrations to drop below MCL for all TKWC/LBWC wells by 2036 (Baseline) or >2068 (Conservative)1. Based on DRI Model Results for Model Alternative 2A/2B Option 210/10/2019DRAFT18
PNCWA 2019B1. Screening CriteriaAlternative 3: Conversion to Surface Water Treatment Plant (WTP)CriteriaScore ExplanationWater Supply Reliability High Switch to surface water supply not contaminated by PCETimeline for Implementation Long Anticipated Design/Implementation phases complete in 10-15 yearsCapital CostHigh New infrastructure: Lake Tahoe intake pipeline/pump station, raw water pipelines, water treatment facility, storage, treated water pipelines, and distribution system improvementsRelative O&M CostHigh Pumping for Lake Tahoe intake, WTP operator, new WTP chemicals, new pipelines Ease of ConstructionLow New infrastructure: Lake Tahoe intake pipeline/pump station, raw water pipelines, water treatment facility, storage, treated water pipelines, and distribution system improvements. Horizontal directional drilling (HDD) for new pipelines in Lake Tahoe and developed areasEase of O&MLow Pumping for Lake Tahoe intake, WTP operator, new WTP chemicals, new pipelines 10/10/2019DRAFT19
PNCWA 2019B1. Screening Criteria Alternative 3: Conversion to Surface WTP (continued)CriteriaScore ExplanationDisposal/ReuseMedium Recycle backwash water to head of WTP at 10% of WTP flowPermitting Requirements High Water Rights Permit modification, NPDES permit, environmental permittingEnvironmental Effects Medium Temporary environmental effects during constructionRegional Clean-Up Benefit1Low 232 (Baseline) – 1,418 (Conservative) lbs PCE removed 2019-2033. Assume 2034 – 2068 Total PCE removal = 0 lbsTime to Achieve PCE Reduction1Long PCE concentrations not anticipated to drop below MCL for all TKWC/LBWC wells by 20681. Based on DRI Model Results for Model Alternative 3A/3B10/10/2019DRAFT20
PNCWA 2019B2. Remedial Action Objectives Alternative 1: Base TreatmentGeneral EPA RAOsObjective Met?1. Allow additional groundwater production without treatmentNo2. Remedies that do not increase volume of groundwater impacted by HVOCsNo3. Reduce PCE concentration to <50 ppb at drinking water wells Yes5a. Supply water without detectable HVOCs to customersYes5b. Comply with regulatory requirements and directives regarding HVOCsYes5c. Estimate mass on contaminant removed over project lifeYes6. Address groundwater in mid-plume areaYes7. Remove the majority of PCE mass in groundwater in the mid-plume area within 30 years1Yes1. Based on DRI Model Results for Model Alternative 1A/1B10/10/2019DRAFT21
PNCWA 2019B2. RAO -ScoringAlternative 1: Base TreatmentGeneral EPA RAOsScore Explanation1. Groundwater production w/o treatmentMedium Some wells already contaminated by PCE/equipped with GAC treatment2. Remedies that do not increase volume of groundwater impacted by HVOCsMedium Limited additional protection for wells downgradient of PCE plume3. Reduce PCE to < 50 ppb Medium Wells with PCE above MCL already equipped with GAC treatment5a.Water supply w/o detectable HVOCsMedium For supply delivered with GAC treatment5b. Meeting regulatory requirements/directives re HVOCsHigh5c. Mass of PCE removed1Medium 347 (Baseline) – 2,573 (Conservative) lbs PCE removed 2019 (Baseline)-2068 (conservative)6. Area of attainment Medium TKWC 2 and LBWC 57. Restoration w/in 30 years Medium PCE concentrations to drop below MCL for all TKWC/LBWC wells by 2045 (baseline) or >2068 (conservative)1. Based on DRI Model Results for Model Alternative 1A/1B10/10/2019DRAFT22
PNCWA 2019B2. Remedial Action Objectives Alternative 2: PCE ExtractionGeneral EPA RAOsObjective Met?1. Allow additional groundwater production without treatmentNo2. Remedies that do not increase volume of groundwater impacted by HVOCsYes3. Reduce PCE concentration to <50 ppb at drinking water wells Yes5a. Supply water without detectable HVOCs to customersYes5b. Comply with regulatory requirements and directives regarding HVOCsYes5c. Estimate mass on contaminant removed over project lifeYes6.Address groundwater in mid-plume areaYes7. Remove the majority of PCE mass in groundwater in the mid-plume area within 30 years1Yes1. Based on DRI Model Results for Model Alternative 2A/2B Option 210/10/2019DRAFT23
PNCWA 2019B2 RAO - ScoringAlternative 2: PCE ExtractionRemedial Action Objectives Score Explanation1. Groundwater production w/o treatmentLow Increase pumping at LBWC 5 and PCE extraction only at LBWC 4R2. Remedies that do not increase volume of groundwater impacted by HVOCsHigh Intercepts PCE plume at LBWC 5 and LBWC 4R3. Reduce PCE to < 50 ppb Medium Wells with PCE above MCL already equipped with GAC treatment, protects well downgradient of LBWC 5 and LBWC 4R5a.Water supply w/o detectable HVOCsHigh5b. Meeting regulatory requirements/directives re HVOCsHigh818 – 4,136 lbs PCE removed 2019-20685c. Mass of PCE removed1High TKWC 2 and LBWC 56. Area of attainment HighPCE concentrations to drop below MCL for all TKWC/LBWC wells by 2036 (baseline) or >2068 (conservative)1. Based on DRI Model Results for Model Alternative 2A/2B Option 210/10/2019DRAFT24
PNCWA 2019B2. Remedial Action Objectives Alternative 3: Conversion to Surface WTPGeneral EPA RAOsObjective Met?1. Allow additional groundwater production without treatmentNo2. Remedies that do not increase volume of groundwater impacted by HVOCsNo3. Reduce PCE concentration to <50 ppb at drinking water wells No5a. Supply water without detectable HVOCs to customersYes5b. Comply with regulatory requirements and directives regarding HVOCsNA5c. Estimate mass on contaminant removed over project lifeNA6.Address groundwater in mid-plume areaNo7. Remove the majority of PCE mass in groundwater in the mid-plume area within 30 years1No1. Based on DRI Model Results for Model Alternative 3A/3B10/10/2019DRAFT25
PNCWA 2019B2. RAO- ScoringAlternative 3: Conversion to Surface WTPRemedial Action Objectives Score Explanation1. Groundwater production w/o treatmentNot applicableAll water supply from Lake Tahoe2. Remedies that do not increase volume of groundwater impacted by HVOCsLow Does not remove PCE after complete conversion to WTP3. Reduce PCE to < 50 ppb High All water supply from Lake Tahoe or uncontaminated groundwater wells5a.Water supply w/o detectable HVOCsHigh5b. Meeting regulatory requirements/directives re HVOCsLow232 – 1,418 lbs PCE removed 2019-2033. Assume 2034 – 2068 Total PCE removal = 0 lbs5c. Mass of PCE removed1Low TKWC 2 and LBWC 5 to be destroyed6. Area of attainment LowPCE concentrations not anticipated to drop below MCL for all TKWC/LBWC wells by 20681. Based on DRI Model Results for Model Alternative 3A/3B10/10/2019DRAFT26
PNCWA 2019B3. South Y-Specific Objectives Alternative 1: Base TreatmentSouth Y Specific ObjectivesObjective Met?Preserve ability to recover HVOC response costs from responsible parties and/or state grant funding in the futureYesBeneficial use of extracted groundwaterYesReduce costs for groundwater remedial wellhead treatment to customersNo*Perform community outreach and information activities regarding HVOCs in groundwaterYes* Short-term grants may be available for O&M10/10/2019DRAFT27
PNCWA 2019B3. South Y-Specific Objectives Alternative 2: PCE ExtractionSouth Y. Specific ObjectiveObjective Met?Preserve ability to recover HVOC response costs from responsible parties and/or state grant funding in the futureYesBeneficial use of extracted groundwaterYesReduce costs for groundwater remedial wellhead treatment to customersNo*Perform community outreach and information activities regarding HVOCs in groundwaterYes* Short-term grants may be available for O&M10/10/2019DRAFT28
PNCWA 2019B3. South Y-Specific ObjectivesAlternative 3: Conversion to Surface WTPSouth Y Specific ObjectiveObjective Met?Preserve ability to recover HVOC response costs from responsible parties and/or state grant funding in the futureNABeneficial use of extracted groundwaterNAReduce costs for groundwater remedial wellhead treatment to customersNAPerform community outreach and information activities regarding HVOCs in groundwaterYes10/10/2019DRAFT29