Total Suspended Solids (TSS)

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Total Suspended Solids (TSS) Reduction
Presenter Keith Noble, Saginaw Bay District
Office
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A compliance assistance document is available on
the MS4 website
Reduce suspended solid discharges
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Total Suspended Solids Reduction

• Permits require reduction of TSS
• Jurisdictional Permit - Maximum Extent
  Practicable with a Goal of 25 reduction
• Watershed Permit Maximum Extent Practicable (?
  reduction)
• Total reduction from the whole system

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Reduction from paved surfaces to surface waters
as compared to annual loading from runoff with no
suspended controls.

• Includes
• Streets, roads and highways
• Parking lots
• Other impervious surfaces

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Permits also require

• Reduction in dust and suspended solids from
  unpaved surfaces
• Reduce the discharge of other pollutants from
  impervious surfaces
• Salt and Sand for improved traction
• Petroleum products

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TSS Reduction can be achieved by a combination of
the following
Pollution Prevention - Improved Material Handling
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• Pollution Prevention- Street Sweeping

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Cleaning Catch Basins
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• Catch Basin Inserts

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• Pollution Prevention - Treatment

Settling (Wet Detention Pond)
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TreatmentFiltration
Filter Berm at stream crossing
Filter Berm
Vegetated Buffer
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Treatment Infiltration
Bioswales
Retention Ponds
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Removal efficiencies of BMPs assumes that

• Installed according to product specifications
• Built according to design criteria
• Are adequately maintained

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TSS Reduction

• Reduction of sediment from activities already
  regulated shall not be counted toward the TSS
  reduction.
• Regulated activities include

• Construction sites regulated under the Part 91
  Soil Erosion and Sedimentation Control Program
• Facilities regulated by the industrial storm
  water program

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TSS reduction to be reported

• First Progress Report
• Describe current level of control
• Estimate load reduction from existing controls
  (Perform TSS calculations)

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TSS reduction to be reported

• Second Progress Report
• Evaluate effectiveness of current practices (TSS
  calculations)
• Identify methods for improving effectiveness or
  to achieve 25 goal
• To be implemented in 2013

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Mean TSS Runoff values for several land uses
Calculating TSS Reduction
TSS Concentration TSS Concentration TSS Concentration
Land Use Category (Paved surfaces) Mean mg/l Mean lbs/ft3 Land Use Category (Paved surfaces) Mean mg/l Mean lbs/ft3 Land Use Category (Paved surfaces) Mean mg/l Mean lbs/ft3
High Density Residential 97 0.0061
Commercial (Parking Lots, Sidewalks) 77 0.0048
Industrial (Fleet Maintenance, Storage Yards) 149 0.0093
Highway (Roads, Streets, etc.) 141 0.0088
Adapted from Rouge River Wet Weather
demonstration Project, Selection of Storm Water
Pollutant Loading Factors RPO-MOD-TM34.00,
October 1994, Table 3-13 (To convert mg/l to
lbs/ft3, multiply by 6.243 X 10-5)
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Calculating TSS Reduction

• Step 1- Determine the uncontrolled load for each
  facility. TSS lbs/ft3 is taken from the table on
  TSS runoff values for land uses.

TSS in lbs X Precipitation in feet X area of
pavement in ft2 TSS pounds ft3
year
year
TSS load for 20 miles of road Precipitation
32 inches 2.7 ft (0.0088 lbs/ft3)(2.7
ft/year)(20 miles)(25 ft)(5280 ft/mile)
62,726 lbs/year
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Calculating TSS Reduction

• Step 2 - Add up the uncontrolled load for each
  paved surface that discharges to the MS4.
• Load from
• 20 miles of residential roads 62,726
  lbs
• 1 acre municipal parking lots 565 lbs
• 10,000 ft2 paved surfaces at parks 165 lbs
• 20,000 ft2 paved surfaces at DPW 502 lbs
• Total for all paved surfaces 63,958
  lbs

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Calculating TSS Reduction

• Step 3 Select the BMPs for each site and
  calculate the TSS removed, after implementation,
  for each site based on the chosen BMPs
• Use BMPs already in place or under consideration
  
• Removal efficiencies can be found on data bases
• Use appropriate efficiency numbers that are
  defensible
• Uncontrolled TSS load X BMP efficiency for type
  of paved area TSS reduction for type of paved
  area

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Calculating TSS Reduction
 CA1Ralph to add BMPs.
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TSS Removal Efficiency of Select BMPs
Treatment Method Median Suspended Solids Removal Efficiency ()
Dry Detention 49
Wet Detention 80
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TSS Removal Efficiency

• Use Actual Amount Removed for
• Street Sweeping
• Catch Basin Cleanout
• Sediment Removed from catch basin inserts
• Efficiency Dependent upon
• Loadings
• Equipment
• Frequency

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BMP Removal Efficiency

• Example 1
• 10 miles of roads with open channels
• (vegetated ditches next to roads without curbs)
  
• 31,363 lbs (.68 for open channels BMP)
• 21,327 lbs removed
• Example 2
• Sediment picked up from 10 miles of street
  sweeping on curbed streets that were swept twice
  during the year (To determine the number of cubic
  yards of sediment from street sweeping, multiply
  the number of yd3 by lbs/yd3
• (actual sediment removed from streets))
• 10,000 lbs removed

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BMP Removal Efficiency

• Example 3
• Vegetative filters at parks (lawns)
• 165 lbs (.86 for Vegetative Buffers) 142 lbs
  removed
• Example 4
• Sediment removed from catch basin inserts at DPW
• (actual sediment taken from catch basin inserts)
  
• 450 lbs removed
• Example 5
• Dry detention basin at Municipal parking lot
• 565 lbs (.49 for Dry Detention Basin) 277 lbs
  removed

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• Step 4 - Add up the calculated load removal for
  each site that discharges in the MS4 area and the
  actual amounts removed from catch basin cleanout,
  street sweeping and catch basin inserts. This is
  the TSS removed from the system after BMP
  implementation.
• Roads with open channels BMP 21,327
  lbs removed
• Sediment from street sweeping 10,000 lbs
  removed
• Parks with vegetative buffers 142 lbs removed
• Sediment from catch basin inserts 450 lbs
  removed
• Parking lot with dry detention basin 277 lbs
  removed
• Total TSS removed 32,196 lbs

32,196 pounds of sediment are not discharged to
the receiving waters
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• Step 5 Divide the sum of the TSS removed from
  the system, after BMPs are applied, by the sum of
  the loading from the system, before BMPs are
  applied.
• Sum of TSS removed with BMPs 32,196 lbs
• Sum of TSS load without BMPs 63,958 lbs
• 63,958 lbs 32,196 lbs 31,762 lbs

TSS load w/out BMPs
TSS removed w/ BMPs
-

Treated TSS load
31,762 lbs of sediment is deposited into the
receiving waters
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• Step 6 The result, times 100, is the percentage
  reduction
• (Sum of TSS load with BMPs ) X 100 TSS
  Reduction Sum of TSS load without BMPs
• 32,196 lbs x 100 50.3 TSS reduced
• 63,958 lbs

• Percent TSS reduction is 50.3

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• Existing practices (BMPs) already in place within
  the MS4 may achieve the 25 reduction goal.
• Do existing practices meet the Maximum Extent
  Practicable standard?

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Questions?