Cayucos Sustainable Water Project Treatment Process Technology - - PowerPoint PPT Presentation

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Cayucos Sustainable Water Project Treatment Process Technology - - PowerPoint PPT Presentation

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Cayucos Sustainable Water Project Treatment Process Technology Selection June 2, 2016 2 Presentation Overview Treatment Objectives Treatment Process Alternatives Recap Evaluation Criteria Cost Evaluation Assumptions

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Cayucos Sustainable Water Project

Treatment Process Technology Selection

June 2, 2016

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  • Treatment Objectives
  • Treatment Process Alternatives Recap
  • Evaluation Criteria
  • Cost Evaluation Assumptions
  • Treatment Technology Screening Evaluation

Presentation Overview

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Wastewater Treatment Process Overview

Unrestricted Irrigation Potable Reuse

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Select a process technology that is…

  • Proven and dependable
  • Robust and minimizes compliance risk
  • Capable of providing potable reuse opportunities
  • Cost effective and maximizes value for ratepayers’ investment
  • Sustainable for future regulations and population growth
  • Energy efficient

Treatment Process Objectives

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Alternative 1

Conventional Activated Sludge (CAS)

Alternative 2

Oxidation Ditch

Alternative 3

Membrane Bioreactor (MBR)

City of Soledad, CA City of Fillmore, CA Los Osos, CA

Nutrient Removal Treatment Process Alternatives

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Nutrient Removal Alternative 1 - CAS

City of Soledad, CA

+ Advantages

  • Several non-proprietary configurations
  • Many operational variants
  • Technology is well understood
  • Disadvantages
  • Large process footprint
  • Susceptible to process upsets due to

load and flow variations

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Nutrient Removal Alternative 2 – Ox Ditch

BBARWA, Big Bear, CA

+ Advantages

  • Established technology
  • Resilient under flow and load variations
  • Low biosolids production
  • Disadvantages
  • Large process footprint
  • Plant capacity expansion can be difficult
  • Some modifications are proprietary
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Nutrient Removal Alternative 3 - MBR

+ Advantages

  • Compact footprint suitable for expansion
  • Combines biological treatment and membrane

filtration to enable effective disinfection

  • Effluent quality provides great potable reuse

potential

  • Disadvantages
  • Membrane replacement relatively expensive
  • Requires equalization or additional units to

handle peak flow events

  • Membranes need regular cleaning
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Economic Criteria

  • Life cycle cost

Non-Economic Criteria

  • Adaptability for Potable Reuse
  • Peak Loading Resiliency
  • Peak Flow Resiliency
  • Maintenance Requirements
  • Chemical Needs
  • Odor Potential
  • Process Footprint
  • GHG Emissions/Energy Efficiency
  • Water Quality Reliability
  • Adaptability to Phase Tertiary Treatment

Evaluation Criteria

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Cost Evaluation Assumptions

Process Alternative 1 CAS Alternative 2 Ox-Ditch Alternative 3 MBR Headworks PC Fine Screening Equalization BNR BNR SC BNR SC BNR MF/UF Filtration MF/UF MF/UF Solids Treatment Thickening / Stabilization Thickening / Stabilization

PC = Primary Clarification BNR = Biological Nutrient Removal SC = Secondary Clarification MF/UF = Microfiltration/Ultrafiltration

Include processes that differentiate treatment alternatives

  • Apples to apples treatment technology cost

comparison:

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Cost Evaluation Assumptions

Influent pumping Course screening Grit Removal Disinfection Advanced Treatment Solids Dewatering

Exclude Common Elements

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Cost Evaluation Assumptions

  • Capital costs

– 20% Contingency – 30% Indirect costs

  • O&M costs included for primary, secondary,

filtration, and solids handling

  • Annualize costs over 30 years at 2% interest
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Treatment Technology Screening Evaluation

Sum weighted scores and rank highest to lowest score Establish importance/weighting factors for qualitative and economic scores (Based on District’s priorities and Project Charter) Score qualitative criteria (3= highest score, 2= mid-score, 1= lowest score) Normalize Annualized Life Cycle Cost

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Non-Economic Criteria Scoring

CRITERIA Alternatives Alternative 1 – CAS Alternative 2 – Ox Ditch Alternative 3 - MBR Adaptability for Potable Reuse 3 3 3 Peak Loading Resiliency 2 3 3 Peak Flow Resiliency 2 2 1 Maintenance Requirements 2 3 1 Chemical Needs 2 2 2 Odor Mitigation 1 2 3 Process Footprint 1 1 3 Energy Requirements 2 2 2 Water Quality Reliability 2 2 3 Ability to Phase Tertiary Treatment 3 3 1

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CRITERIA Importance/ Weighting Ranking Total Annualized Cost 1 Adaptability for Potable Reuse 2 Peak Loading Resiliency 2 Peak Flow Resiliency 2 Water Quality Reliability 2 Maintenance Requirements 6 Odor Mitigation 6 Energy Requirements 8 Process Footprint 9 Chemical Needs 10 Ability to Phase Tertiary Treatment 11

Treatment Technology Screening Evaluation

Criteria Ranking

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16 CRITERIA

ALTERNATIVES (SCORING)

Alternative 1 CAS Alternative 2 Ox- Ditch Alternative 3 MBR Total Annualized Cost 0.14 0.15 0.14 Adaptability for Potable Reuse 0.14 0.14 0.14 Peak Loading Resiliency 0.09 0.14 0.14 Peak Flow Resiliency 0.09 0.09 0.05 Water Quality Reliability 0.09 0.09 0.14 Maintenance Requirements 0.05 0.08 0.03 Odor Mitigation 0.03 0.05 0.08 Energy Requirements 0.04 0.04 0.04 Process Footprint 0.01 0.01 0.04 Chemical Needs 0.02 0.02 0.02 Ability to Phase Tertiary Treatment 0.01 0.01 0.00 Total Score 0.72 0.82 0.81

Treatment Technology Screening Evaluation

Alternatives Scoring

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17 CRITERIA

ALTERNATIVES (SCORING)

Alternative 1 CAS Alternative 2 Ox- Ditch Alternative 3 MBR Total Annualized Cost 0.14 0.15 0.14 Adaptability for Potable Reuse 0.14 0.14 0.14 Peak Loading Resiliency 0.09 0.14 0.14 Peak Flow Resiliency 0.09 0.09 0.05 Water Quality Reliability 0.09 0.09 0.14 Maintenance Requirements 0.05 0.08 0.05 Odor Mitigation 0.03 0.05 0.08 Energy Requirements 0.04 0.04 0.04 Process Footprint 0.01 0.01 0.04 Chemical Needs 0.02 0.02 0.02 Ability to Phase Tertiary Treatment 0.01 0.01 0.00 Total Score 0.72 0.82 0.83

Treatment Technology Screening Evaluation

Alternatives Scoring

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Key Findings

  • Oxidation Ditch

– Slightly lower cost – Peak flow and loading resiliency – Option to by-pass filtration process during peak flows – Ability to phase tertiary treatment

  • MBR

– High water quality reliability – Small footprint – Better odor mitigation options

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Recommendation

  • Receive feedback from the BOD on priorities and

preferences

  • Select a preferred treatment process alternative
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Next Steps

  • Refine preferred treatment alternative

– Process sizing – Footprint requirements – Solids handling study – Supporting facilities needs assessment

  • Conceptual Site Plan
  • Facilities Plan