Moonlight Beach Urban Runoff Ultraviolet Treatment Facility Effectiveness Assessment

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Moonlight Beach Urban Runoff Ultraviolet
Treatment Facility Effectiveness Assessment

• Moonlight Beach
• City of Encinitas, California
• Katherine Weldon, REHS
• Paul Hartman

Stormwater Copermittee Meeting Nov. 16th, 2006
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Presentation Outline

• Background Kathy Weldon
• Facility Summary Kathy Weldon
• Results Paul Hartman
• Water Quality
• Operations Maintenance
• Recommendations Conclusions Kathy Weldon
• Q A

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Presentation Outline

• Background Kathy Weldon
• Facility Summary Kathy Weldon
• Results Paul Hartman
• Water Quality
• Operations Maintenance
• Recommendations Conclusions Kathy Weldon
• Q A

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Moonlight State Beach

• 47 million economic value to the City
• Over 1,200,000 visitors a year
• Surfing, swimming

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Watershed Overview
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Cottonwood Creek

• Discharges onto Moonlight Beach
• Flows year round at 150 gpm during dry weather
• 303(d) impaired at Beach for bacteria

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Chronic Postings

• F from environmental groups
• Consistently ranked one of the worst beaches for
  water quality
• Posted 93 days in 2000
• TMDL site

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AB411 Standard

• AB411 introduced enterococcus standard in 2000
• One hit standard - Exceedance of total, fecal or
  enterococcus means beach postings
• Water quality exceedances represent potential
  health risks and cause negative public perceptions

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Clean Water Program

• Source Control
• Source identification (water quality testing)
• Educate businesses along creek
• Implemented structural BMPs

• Maintenance
• Purchased Vac-con Truck
• Began routine inlet cleaning in 1999
• Installed inlet filters
• Increased street sweeping efforts

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State Water Resources Control Board Clean
Beaches Initiative Grant Funding

• States Goal to reduce beach postings by 80
• 40 million set aside for grants
• Compatible goals
• State awarded City 1,000,000 in grants for a UV
  light bulb!!
• First CBI project completed!

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Project Goals

• Protect Public Health by eliminating or reducing
  the risk of illness from urban runoff
• Reduce Beach Postings at Moonlight Beach

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Presentation Outline

• Background Kathy Weldon
• Facility Summary Kathy Weldon
• Results Paul Hartman
• Water Quality
• Operations Maintenance
• Recommendations Conclusions Kathy Weldon
• QA

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Initial Options

• Chemical treatment
• Introduction of chemicals not acceptable
• Divert to sanitary sewer
• Creek flow has historical, aesthetic and
  biological value
• Impact of sanitary system unacceptable

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Alternative Analysis

• Ultraviolet treatment (selected alternative)
• Low impact to creek
• Highly effective for this water quality
• No chemicals
• Compact system
• Ozone/ultraviolet treatment
• More expensive O M
• Ozone generation and residual
• Larger space requirements

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UV Facility Process Overview

• Intake line from creek inside of existing box
  culvert
• Wet well with alternating pumps
• Basket filters
• Multimedia filters
• UV light bulbs
• Discharge from facility re-introduced to creek
  inside existing box culvert

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Intake and Filtration

• Intake and discharge are located within existing
  box culvert for permit streamlining
• 15 bypass for biological connectivity
• Removable weir for storm events

• Low turbidity crucial for performance of UV
  lamps, monitored continuously
• Basket filter for larger particles
• Multimedia filter for removal of turbidity

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Ultraviolet Light Chambers

• Two 4-foot chambers
• Eight bulbs total
• Plumbed in series

• 254 NM wavelength

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Presentation Outline

• Background Kathy Weldon
• Facility Summary Kathy Weldon
• Results Paul Hartman
• Water Quality
• Operations Maintenance
• Recommendations Conclusions Kathy Weldon
• Q A

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Monitoring Program

• Bacteria
• Four locations
• Influent
• Effluent
• Creek Mouth
• Mixing Zone
• Weekly

• Continuous Monitoring
• Turbidity
• Flow
• Biological Monitoring
• Habitat assessment
• Aquatic assessment

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3 Year Monitoring Results

• gt99 Bacteria Kill in Treated Water from the Plant

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Reductions in Beach Postings
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Reduced Bacteria Concentrations

• Creek Mouth
• Mixing Zone

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Removal Efficiency

• All bacteria is removed from treated water as
  evidenced by bacteria data from Influent to
  Effluent
• Bacteria concentrations are reduced overall by
  greater than 50 from upstream of the facility
  (influent) to the creek mouth at Moonlight Beach
• Regeneration of bacteria is occurring

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Special Study to Examine Bacteria Regeneration
Reach 2
Reach 1
Reach 3
UV Facility
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Special Study Results

• Rise (180) in Fecal Coliform concentrations
  immediately after treatment
• Open natural channel, likely animals
• Nearly 200 rise in all three indicators in 72
  pipes downstream of open channel
• Ideal conditions for bacterial growth in pipes,
  dark, wet, with organic matter
• Continued rise in enterococcus concentrations
  only, 57, in Reach 3 (on beach)
• Add in a few birds and typical wrackline on
  beach

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Seasonal Bacteria TrendsExamining data over
three years, grouping into seasons, and
calculating mean values

• Creek
• Peaking in late summer
• Lowest in winter
• Mixing Zone
• Lowest in spring
• Peaking in winter

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Ongoing Studies Management Actions

• Re-growth evaluation of open creek
• Birds along shoreline
• Wrack line removal program
• Sanitary system improvements

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Grades are Up!!
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Operations and Maintenance

• Facility in operation approximately 70 of the
  year, only during dry weather periods
• Daily operations checks and logs
• Periodic pump and valve maintenance
• Annual bulb replacement
• Relatively low maintenance!!

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Operations and Maintenance

• Intake structures cleaning screens, pump
  maintenance (2 new pumps in 4 years), valve
  maintenance
• Filtration system cleaning basket filters,
  occasional turbidimeter maintenance, multimedia
  filters require proper backwashing adjustments
  and occasional chlorine shock treatments (twice
  per year)
• UV Units annual bulb replacement

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OM Costs

• Staff time 1 hour daily
• Laboratory Costs 50 per sample
• (4 per week)
• New bulbs 500 each (x8, approx. 1 year life)
• Labor, water, power 15,000/year
• Total estimated 30,000 annual costs

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Presentation Outline

• Background Kathy Weldon
• Facility Summary Kathy Weldon
• Results Paul Hartman
• Water Quality
• Operations Maintenance
• Recommendations Conclusions Kathy Weldon
• Q A

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Conclusions

• 99 removal of all pathogenic organisms and
  bacteria prior to discharge at Moonlight Beach,
  Public Health is better protected!!
• Bacterial Re-growth is substantiated in the
  natural channel and in the storm drain pipes
• Continuous monitoring features have multiple
  benefits
• Cost effective method to reduce bacteria and
  protect public health

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Recommendations

• Regular cleaning of system piping to reduce media
  for bacterial growth
• Location of system should be as close to
  receiving water as possible to limit opportunity
  for re-growth after treatment
• Additional BMPs such as the removal of the wrack
  line may help reduce beach postings
• DNA and Epidemiology studies at the creek mouth
• Backwash multimedia filters with influent water
  when turbidity is low enough

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Project Awards

• APWA Technical Innovation Award and Project of
  the Year Award
• ASCE Award of Excellence
• NRDC Beach Buddy Award
• Consulting Engineers and Land Surveyors of
  California Engineering Excellence Award
• American Council of Engineering Companies
  National Recognition Award

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Teamwork/Cooperation/Partnerships were the key to
project success

• Local stakeholders support
• City officials
• Cottonwood Creek Conservancy
• San Diego Baykeepers
• Dedicated Project Team
• State Water Resources Control Board
• Laura Peters and Kathy Bare

• Project Designer
• PBSJ
• Contractor
• Falcon General Engineering
• UV Supplier
• Clear Creek Systems
• Construction Manager
• Brady Associates

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Presentation Outline

• Background Kathy Weldon
• Facility Summary Kathy Weldon
• Results Paul Hartman
• Water Quality
• Operations Maintenance
• Recommendations Conclusions Kathy Weldon
• Q A

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Contact Information

• Katherine Weldon, REHSkweldon_at_ci.encinitas.ca.us
  [phone]
• Paul Hartmanahartman_at_ci.encinitas.ca.us(760)
  633-2609
• City of Encinitas Website
• http//www.ci.encinitas.ca.us/Resident/Environmen
  t/CleanWP/

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QA
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Key Parameters
Characteristics Affecting UV Performance
Reference EPA Wastewater Technology Fact Sheet
Ultraviolet Disinfection (1999)
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Treatment Options Ozone Process
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Treatment Options UV Process