Wastewater Facilities Upgrade Project Novato Sanitary District Wastewater Facilities Upgrade Project Water and Environment

Background 2005 Novato Sanitary District had two treatment plants Novato Plant: 3.6 million gallons/day Ignacio Plant: 1.6 million gallons/day Peak wet weather flows = 7 times average flow All treatment components over 20 years old Majority of components are 30 to 50 years old Some facilities have been reused three times Plant had reliability issues Additional flow and load was forecasted More stringent regulations were coming

Novato treatment plant

Novato Treatment Plant 3.6 million gallons/day

Ignacio treatment plant

Ignacio Treatment Plant 1.6 million gallons/day

Existing Plants Had Difficulty Meeting Previous NPDES Limits and … No. of Violations

…Regulatory Requirements Were Getting Stricter New “zero spill” tolerance requirement Zero exceedance of effluent limitations Mandatory fines for each exceedance (SB709) District under mandatory time schedule for upgrades (March 2008-2010) Reduction in discharge limits for mercury, cyanide and others Ignacio must meet full secondary treatment EPA and RWQCB were ambiguous but worrisome regarding ‘blending’

Permit Conditions Vary Based on Discharge Location Season Permit Condition Operational Mode Reclamation - Summer June thru August BOD5 40 mg/L Carbonaceous Bay Discharge – Spring and Fall May, Sept, Oct BOD5 15 mg/L TSS 10 mg/L NH3 6 mg-N/L Nitrification Bay Discharge - Winter November thru April BOD5 30mg/L TSS 30 mg/L Note that these are average monthly values.

Condition Assessment Conducted on All Plant Components

Many Plant Areas Were Not Reusable

Several Alternatives Were Considered Replace both treatment plants Consolidate treatment at one plant Novato site Ignacio site Type of treatment process Oxidation ditch Activated Sludge (MLE) MBR Consolidation at Novato with Activated Sludge recommended Lowest cost Highest reliability Lowest environmental impact

New Consolidated Treatment Plant Ignacio Transfer PS and Equalization Basins

Construction Cost Summary of Total Project Item Construction Estimate $ million* Construction Bid $million Novato Treatment Plant 75 67 Ignacio PS + FM 12 11 Total 87 78 *Escalated to mid pt of construction

Flow Path, New Treatment Plant From Collection System Ignacio PS To Reclamation or Outfall

New Consolidated Plant Aeration 4 X 115,000 cu ft basins Anoxic zones Primary Clarifiers 2 X 100 ft diameter, covered tanks Headworks 2 X Aquaguard Screens, 15 mm opening 2 X Vortex grit chambers Influent PS 6 X 9.4 MGD Submersible Pumps Secondary Clarifiers 2 X 125 ft diameter UV Disinfection 3 Channels

Innovative Aeration Design Avoids Flow Equalization and Blending Summer conditions require only carbonaceous removal Designed to avoid nitrification to save energy Winter conditions: Permit requires nitrification for Bay discharge Peak wet weather flows up to 7 times average Design of dual mode aeration avoids need to equalize peak flows Conventional MLE operation up to 18 MGD Transition to contact stabilization 18 to 47 MGD

Nitrification Mode Winter Flow < 18 MGD Primary Effluent ZONE F AERATED ZONE E AERATED Aeration Basin 3 ZONE A ZONE B ZONE C ZONE D AERATED RAS Aeration Basin 4

Contact Stabilization Mode: Winter Flow at > 18 MGD ZONE F AERATED ZONE E AERATED Primary Effluent ZONE A ZONE B ZONE C ZONE D AERATED RAS

Cost Saving Measures Totaled $17 million Item Savings, $ millions Innovative method to treat peak wet weather flows 3.0 Postponement of third secondary clarifier 4.1 Reuse of existing emergency generators 1.5 Reuse of existing diesel pumps at effluent pump station 1.0 Deletion of parallel force main 2.4 State Revolving Fund low interest loan 5.5* *Present worth of interest savings

Annual Energy Savings Came From Many Sources Design Element Net Annual Savings, kWh Net Annual Power Savings, $ Utility Water Discharge Pressure 30,400 $3,950 Plant Elevation 30,800 $4,000 Submerged Weirs at Peak Flows 38,450 $5,000 Premium Efficiency Motors 83,000 $10,800 Aeration Basin Depth 85,750 $11,150 Energy Efficient Blowers 310,000 $40,250 NSD Annual Total Savings 528,000 $76,000 Present Worth of Savings, 30 yrs, 5% $1,200,000 Typical Annual Energy for AS Plant** 3,394,500 $441,285 at 1,200 kwh/MG and $0.13 electrical cost

Plant is in Start-up, and Performing Well Parameter Units Average Monthly Nov - Apr May, Sept, Oct Typical Performance of New Plant BOD5 mg/l 30 15 5 to 10 TSS 10 3 to 6 Ammonia 6 <1 Oil and Grease Mg/l 5 < 5 Enterococcus Per 100 ml 35 < 10 to 15 Fecal Coliform MPN 140 4 to 8

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