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How to Monitor for Bacteria and Sewage. James Beckley Virginia DEQ VCWQ Summit October 27, 2012. Why Monitor for Fecal Bacteria and Sewage. Fecal bacteria is the largest impairment source of streams in Virginia; currently at 9,154 miles

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how to monitor for bacteria and sewage

How to Monitor for Bacteria and Sewage

James Beckley

Virginia DEQ

VCWQ Summit

October 27, 2012

why monitor for fecal bacteria and sewage
Why Monitor for Fecal Bacteria and Sewage
  • Fecal bacteria is the largest impairment source of streams in Virginia; currently at 9,154 miles
  • Waterbodies with fecal bacteria often have other issues such as increased sediment and nutrients
  • High levels of fecal bacteria and sewage in waterbodies increase the risk of illness
  • Sewage (leaking sewer lines, septic systems, straight pipes), the largest or second source of fecal bacteria in nearly any given waterbody
before we go further
Before We Go Further…
  • Culture tests have results reported in CFU or MPN
  • CFU or Colony Forming Units is the number of bacteria colonies that formed from the original bacteria in the sample
  • MPN or Most Probable Number is a statistical estimate of the number of bacteria that was present in the sample
  • Except for shellfish standards, Virginia Water Quality Standards only reference values by CFU
    • MPN data can still be used to gauge water quality
escherichia coli e coli
Escherichia Coli (E. coli)
  • Gram negative, rod shaped, facultative anaerobic bacteria
  • Normally found in the digestive tracks of warm blooded animals
  • Currently monitored in fresh waterbodies
    • Samples with >235 E. coil or an average >126 per 100 ml sample indicates excessive bacteria levels
fecal coliform
Fecal Coliform
  • Family of coliform bacteria species only found in the digestive tract of warm blooded animals
    • E. coli and other species are members
    • Since 2002, no longer used for freshwater recreation (e.g. swimming)
    • Still used by VDH to determine closure of shellfish beds. Average fecal coliform levels must be less than 14 and single maximum readings no more than 49 MPN or 31 CFU
  • Gram positive, spherical shaped, facultative anaerobic bacteria
  • Normally found in the digestive tracks of warm blooded animals
  • Currently monitored in saltwater (beaches)
    • Samples with >104 E. coil or an average >35 per 100 ml sample indicates excessive bacteria levels
methods to monitor for fecal bacteria
Methods to Monitor for Fecal Bacteria
  • Culturing of samples
    • Presence/Absence
    • Coliscan Eaygel
    • Petriflm
    • Colilert/Enterolert
    • Membrane Filtration
    • Multiple Tube Method
presence absence
  • Simplest culturing method
  • Sample placed in a bottle containing nutrient media
  • Color change/glow under UV or similar reaction indicates presence of the bacteria
  • Results in 24 hours
  • Normally used to test drinking water quality as no fecal bacteria should be present
coliscan easygel
Coliscan Easygel
  • An inexpensive and easy to use test for E. coli
  • Does not require a laboratory
  • Tests 1 to 5 ml of sample
  • Results in 24 to 48 hours
  • E. coli appear dark blue to purple
  • Results are in CFU

1 ml sample with 5 E. coli colonies

  • Non-laboratory based test to detect E. coli bacteria
  • Tests 1 ml of sample but can be coupled with membrane filtration to test 100 ml
  • E. coli appear dark blue with gas bubbles
  • Results are in CFU
colilert enterolert
  • Most popular lab based method due to relative low cost and ease of use
  • Results in 18 to 24 hours
  • E. coli glow under a UV light and have a yellow color
  • Enterococcus method (for salt water) glows under a UV light but no color change
  • Results in MPN
membrane filtration
Membrane Filtration
  • Filter sample through a fine pore (~0.6 um) filter
  • Tests up to 100 ml of sample
  • Results in 18 to 24 hours
  • Colony color depends on nutrient media
  • Results reported as CFU
multiple tube method
Multiple Tube Method
  • Not used as much due to introduction of Colilert/Enterolert
  • Samples inoculate multiple test tubes of media/auger
  • Results in 3 to 5 days
  • Number of test tubes with a positive reaction determines the MPN result
effective monitoring strategies
Effective Monitoring Strategies
  • “Shotgun” method
  • Targeted source identification/verification
  • Carpet sampling (AKA “B-52” method)
  • Storm event sampling
shotgun method
Shotgun Method
  • Set up sample stations scattered in the watershed
    • Sampling from public access points like bridges
  • Ideal for initial recon to find E. coli ‘hotspot’ segments
  • Moderate labor and cost intensive
targeted sampling
Targeted Sampling
  • Sample likely sources of fecal bacteria
    • Sewer line crossings or near septic systems
    • Areas of known dense wildlife or animal activity
  • Good to quickly rule out or confirm fecal sources
  • Requires planning to identify sources and may require landowner access
carpet sampling
Carpet Sampling
  • Sampling every possible source and waterbody segment
  • Extremely labor and cost intensive
  • Provides the most detailed picture of fecal sources

- No E. coli


- Several E. coli

violations (storm events)

- Constantly high (<50%)

E. coli Counts

storm event sampling
Storm Event Sampling
  • Sampling at the first stages of a major rainstorm
    • Shows the worst case scenario of site bacteria levels
    • Helpful in identifying sources of bacteria not readily seen during dry sample events
  • Most effective if samples are collected within the first hour of a storm
  • >¼” rainfall is often enough to elevate bacteria levels
  • Storm event sampling can be a part of any plan
before heading out
Before Heading Out
  • Let someone know you are heading out to sample and when you expect to be back
    • If possible, it is good to have a co-sampler join you
  • Check the weather prior to going out
    • Dress appropriately for expected field conditions
  • Inspect equipment
    • Needed sample equipment is in good condition (coolers, sample bottles, marker, sample bucket, etc.)
    • Have backup sample bottles if needed
    • Have safety equipment (first aid kit, flares, etc.)
if sampling along a road
If Sampling Along a Road
  • If a safe parking area away from the road is not available, pull completely off the road and onto the shoulder
    • Park away from sharp curves
    • Leave sufficient room to exit/enter the vehicle
    • Turn on the vehicle hazard signal
    • If possible, wear a reflective or orange safety vest
    • Try to exit away from the path of motor vehicles
bridge safety
Bridge Safety
  • Be aware of traffic conditions
  • If there is a no loitering or fishing sign, best not to sample on the bridge
  • Sample on the upstream or the safest side of the bridge
contaminated water
Contaminated Water
  • Use extra protection if water has an unusual odor or color
  • Wear gloves or have hand sanitizer available during sampling
  • Wash or disinfect hands after sampling and prior to eating
  • Always assume sample water contains pathogens!
optical brightener monitoring to find intermittent discharges

Optical Brightener Monitoring to Find Intermittent Discharges

Katie Register, Executive Director

Clean Virginia Waterways

monitoring for intermittent discharges
Monitoring for Intermittent Discharges


  • camp out
  • odd hour monitoring
  • caulk dams
  • pool sampling
  • optical brightener monitoring
about optical brighteners
About Optical Brighteners
  • Laundry detergents are highly fluorescent due to optical brighteners that are added
  • Makes white “whiter”
  • OB do not occur in nature

Gain insight into the history of an outfall without being physically present

  • Simple presence or absence test
the obm process
The OBM Process

Fabric swatch is key

  • Must never have been exposed to detergents
  • Purchasing information at end of this presentation
the obm process1
The OBM Process

Various traps & anchoring techniques.

Can be made with PVC, hose clamps, brick & wire.

the obm process2
The OBM Process

If you use cotton pads (as opposed to fabric), you can make a trap using wire mesh.

the obm process3
The OBM Process

Place in streams or in outfall for several days.

7 days is good.

Best in low flow situations.

  • Prevent contamination, wear gloves.
  • Secure it with monofilament for retrieval.
the obm process4
The OBM Process

Retrieve samples.

Rinse off sediment. Label the fabric swatches (dates, location)

Dry the fabric swatches (not in direct sunlight)

the obm process5
The OBM Process
  • Place under a long-wavelength UV light.

Compare to non-exposed fabric

  • Fluorescence = positive signature for household waste water in the stream.
  • Specks or spots of fluorescence on fabric can be ignored.
fabric treated with various levels of tide laundry soap
 Fabric treated with various levels of Tide laundry soap.

From: Illicit Discharge Detection and Elimination: A Guidance Manual for Program Development and Technical Assessments

when to use obm
When to use OBM

To isolate intermittent discharges

  • Dry weather flows
  • When you suspect faulty septic systems
  • Storm drain cross-connections
  • Want animal/human waste differentiation
  • Not suitable for enforcement action but when done in combination with a larger sampling program is a valuable indicator in helping to identify problem
  • Bacteria, field observations, etc.
pros of using obm
Pros of using OBM
  • Simple, cost effective
  • Sensitive to intermittent discharges of undiluted laundry water
  • Minimal safety & waste disposal concerns
  • Suitable for volunteer monitors
  • 100 cotton pads (Free of OB) for $13
  • Wire cages or PVC pipe + hose clamp
  • Monofilament line
  • Rubber gloves
  • long-wavelength UV light $250 to $350
case studies
Case Studies
  • Massachusetts – routine OBM tested positive, yet low bacterial counts. Testing upstream found direct discharge of washing machine (done to reduce flow to a stressed septic system)
case studies1
Case Studies
  • Massachusetts – High bacterial counts in a sewered city indicated animals as source.
  • So they did OBM which came back positive. Answer was leaking sanitary sewer pipe.
  • OBM also helped find an older section of town that was never tied into the central sewer system
case studies2
Case Studies
  • Licensed septic pumper was washing down his equipment into a storm drain that discharges to a shellfish area. His license was revoked by the Board of Health.
learn more
Learn more…
  • An Optical Brightener Handbook by Dave Sargent & Waye Castonguay. 1998.
  • EPA ‘s National Pollutant Discharge Detection & Elimination & Stormwater web sites
  • A lesson plan by Clean VA Waterways:
cotton fabric
Cotton fabric
  • Cotton fabric suitable for PVC pipe: Ozark Underground Lab sells fabric for $1.25 per piece. 417-785-4289 or
  • VWR International sells cotton pads suitable for use in wire trap. 100 for $13. Item 21902-985. 1-800-932-5000
thank you
Thank you