Terre Kleen™ Design Manual

Terre Kleen Design Manual
Introduction to Inclined Plate Sedimentation Technology
Inclined plate sedimentation technology has been used in the drinking water
industry for over 70 years.
Terre Kleen has adapted this technology to the stormwater industry (US Patent
6,676,832 B2).
Terre Kleen is an inclined plate hydrodynamic separator. The Terre Kleen separator is
contained within a HS-25 precast concrete structure. Each stacked overlapping plate is inclined
55º, creating a settling cell containing 6.4 ft 2 of horizontally projected sedimentation surface
area in a precast structure area of only 1.08 ft 2 . This design results in the lowest cost of
sedimentation surface area in the industry.
The precast concrete structure has two (2) chambers. Stormwater
enters the inlet/primary chamber where oil, grease, trash and debris
are floated and permanently captured and coarse sediment
settles. The storm water exits through a screened orifice below the
floatable layer and above the settled layer. The flow enters near the
bottom of the inclined plates; parallel treatment of the divided water
flow occurs as it rises to the top of each plate, where the water
discharges over each cell weir and recombines for discharge
through the effluent pipe.
Gravity separates the sediment particles from the water flow
and the sediment slides on the inclined surfaces to a collection
hopper located below the plates. Baffles separate the captured
sediment in the hopper from the main flow to prevent re-suspension
or scour.
(Picture highlights flow arrow concept for one cell in a nine cell Terre Kleen TK09).
Terre Kleen NO BY-PASS Treatment Design: (See figure 1)
1) Design storm flow: 2Terre Kleen treats the entire flow and removes sediment as
required under the permit. All floatables such as oil, grease, trash and debris are
removed from the entire flow.
2) Exceeding design storm flow: 3Terre Kleen treats the entire flow; sediment in
design storm flow is removed as required under the permit; sediment in the excess flow
is removed at a rate below the permit rate. All floatables such as oil, grease, trash and
debris are removed from the entire flow.
3) Excessive storm flow: 45excessive flow, such as 50/100-year storms do not by-pass
the Terre Kleen Treatment for design and excess design flows are as stated above.
The volume of the storm flow unable to flow through the inclined plates enters the
internal flow through duct located between the inlet chamber and the grit chamber.
When the excessive flow exceeds the capacity of the internal flow through duct, this
excess water exits the inlet chamber through a screen located at the top of the baffle
wall and proceeds over the “excess flow weir”. All floatables such as, trash and debris
trapped oil inside the oil booms remain in front of the screen.
Page 1 of 12

4) Maintenance: Cleanout of captured pollutants is required to maintain the design
efficiency of the Terre Kleen. When the captured sediment and/or other pollutants
reach the recommended maintenance levels they must be removed to prevent
interference with continued operations. THSS recommends locating the Terre Kleen
where a commercial vacuum truck has direct access to the device under its own power.
Disposal cost of the Terre Kleen content is about 50% to 70% less than other systems
because the overlapping settling cells reduce the volume of water per effective settling
area
FIGURE 1: Terre Kleen Drawing
Plan drawings and details (AutoCAD), suggested specifications, Installation instructions
and Maintenance instructions are at www.terrestorm.com.
75 inches
Figure 1
Page 2 of 12

FIGURE 2:
Inclined Plate Technology Efficiency
Figure 2a is a conventional sedimentation basin. The Q/ (L x W) is the effective rate at
which the water rises towards the overflow weir.
Figure 2b is a horizontal basin where additional floors increase the settling area.
Figure 2c is the equivalent of basin 2b with overlapping inclined plates.
Figure 2d is the basin adapted to facilitate sediment collection in a hopper and multiple
settling cells to maximize settling efficiency and system economy.
Page 3 of 12

Table 1 Inclined Plate Design Creates Sedimentation Surface Area
Terre
Kleen
Model
Footprint
(Structure Ft 2 )
Settling
Surface
Area
(SSA)
SSA per
structure
Ft 2
85% Removal of
OK110-d 50 =110
PSD=53-212 μM
TK09 31.5 ft 2 (4.5’ x 7’) 57 ft 2 180 % 7.9 cfs
TK18 45.5 ft 2 (6.5’ x 7’) 115 ft 2 253 % 16.0 cfs
TK27 59.5 ft 2 (8.5’ x 7’) 173 ft 2 290 % 23.9 cfs
TK36 73.5 ft 2 (10.5’ x 7’) 230 ft 2 313 % 31.9 cfs
TK45 87.5 ft 2 (12.5’ x 7’) 288 ft 2 329 % 40.0 cfs
TK54 101.5 ft 2 (14.5’ x 7’) 346 ft 2 340 % 48.0 cfs
TK63 115.5 ft 2 (16.5’ x 7’) 403 ft 2 349 % 55.9 cfs
Sizing the Terre Kleen
The Terre Kleen performance has been independently verified :
1. EPA ETV NSF Joint Verification Statement and Report
i. 100% removal rate of 200µm or greater particles in field test
2. Penn State University (PSU) laboratory test
i. 78% net weighted annual TSS removal per NJCAT protocol
3. Alden Laboratory NJCAT Protocol Test
i. 54% net weighted annual TSS removal
Empirical data suggests that the actual Particle Size Distribution (PSD) for “street surface
contaminants” is coarse.
Sansalone, John J. ,Koran, Joseph M., Smithson, Joseph A., Buchberger, Steven G., (1997),
Characteristics of Solids Transported from an Urban Roadway Surface WEFTEC 1997
Sartor, James D. and Gail B. Boyd, (1972), Water Pollution Aspects of Street Surface
Contaminants, EPA-R2-72-081
Shaheen, Donald G. (1975) Contributions of Urban Roadway Usage to Water Pollution, EPA
600/2-75-004
Using the Terre Kleen independent 3 rd party tests and adapting them to the above referenced
empirical data; applying the relationships set forth in Stokes’ Law, Chart 1 provides suggested
treatment design flow and peak flows for Terre Kleen:
Stokes Law: V particle settling = 2 x R 2 x g x (γ particle – γ water )
9 x ν kinematic
Stokes’ Law calculates the settling velocity of particles in water under certain conditions. The
law sets forth the proportional relationship between the water, the particles, and Gravity. This is
useful in understanding the performance of a hydrodynamic separator when density and particle
size are changed.
Clearly, if g was zero, the V particle settling would be zero. Gravitational force is vertically
downward, therefore, the correct settling area of a cell is the cell’s horizontally projected area.
(see calculation for the stacked inclined plates of a Terre Kleen
The particle size R affects the settling speed exponentially. A comparison of different Particle
Size Distributions illustrates this relationship and its effects: when a d 50 =70 Micron is compared
to a d 50 = 100 Micron the settling speed of the 100 Micron particle is 100 2 / 70 2 = 2.04 faster. In
Page 4 of 12

this case, a particle size increase of 42% gives a settling speed increase of 204%. This means
design capacity increases exponentially as the particle size increases.
Plan drawings and details (AutoCAD), suggested specifications, Installation instructions
and Maintenance instructions are at www.terrestorm.com.
NOTE :
The specific size Terre Kleen chosen for each specific site will depend upon
the site conditions. The Engineer of Record must make a determination regarding:
1. size of drainage area
2. site characteristics regarding type of soil, particle size distribution and sediment
concentration
3. design of collection and transportation system, which will include pipes sizes and
rates of flow
4. specification of treatment flow
5. specification of peak flow
6. sediment removal rate required by the permit/regulations
7. Additional removal and storage requirements for trash, oil.
8. Space limitations and access conditions
9. Maintenance monitoring methods (i.e. manual or automatic)
Frequently Asked Questions
1. What size particles does a Terre Kleen remove?
Answer Terre Kleen removes 83% of the net annual weighted SSC with a
PSD of 1 micron to 1000 micron. (Penn State University NJCAT
test)
Answer EPA ETV NSF has verified that the Terre Kleen removes 98% of
particles = or > 200 micron
Answer 100% of particles > 50 micron at a surface loading rate of 22.5
gpm/ft² (Alden Laboratory NJCAT test)
2. What amount of trash and debris is removed by the Terre Kleen?
Terre Kleen removes 100% of trash and debris. The fully baffled
primary chamber and the internal by-pass design results in the
continuous capture of all trash and debris regardless of the flow
intensity. There is no loss of captured trash or debris at any flow.
3. What amount of oil and grease is removed by the Terre Kleen?
Answer The Terre Kleen uses flotation in the primary (receiving) chamber.
Oil and grease are floated and absorbent booms absorb 1 quart of
oil each. This removes virtually 100% of the oil and grease in
normal stormwater runoff.
4. Does the Terre Kleen remove any other pollutants, i.e. phosphorus, glycols
salts, nutrients, etc.?
Nutrients such as phosphorous, nitrogen and other pollutants
such as glycols and salts will be removed if they are attached
to the settled particles.
Colloidal and dissolved particulates adhere or agglutinate to the
coarser particulate. Thus, by settling the coarser pollutants, the
finer particulates are removed by the carrier particle that sinks.
5. Will the water inside of the Terre Kleen freeze ?
Page 5 of 12

Inspection of installed Terre Kleens has not shown any freezing
of the water inside of a Terre Kleen.
6. Will the water in a Terre Kleen become a breeding area for mosquitoes?
No. The water in the grit chamber is always enclosed underground.
The water in the primary chamber, even when exposed to the
surface, will not provide a breeding area as it contains an oil and
grease sheen, which discourages mosquito growth.
7. Does installation of a Terre Kleen require any special knowledge or
experience?
No. Each Terre Kleen is delivered fully assembled within the
precast concrete structure. Installation is no different from the
installation of any precast concrete structure. Terre Hill Stormwater
Systems provides an on site person to observe the installation to
assure its proper installation.
8. Does Terre Hill Stormwater Systems provide any Warranty ?
Yes. Terre Hill provides a four (4) year warranty against defective
products. The warranty includes both labor and material.
9. What is the typical weight for each size Terre Kleen ?
TK09 20,300 lbs
TK18 24,600 lbs
TK27 41,300 lbs
TK36 51,200 lbs (no section shall exceed 48,000lbs)
TK45 81,500 lbs (no section shall exceed 48,000lbs)
TK54 90,000 lbs (no section shall exceed 48,000lbs)
TK63 103,000 lbs (no section shall exceed 48,000lbs)
10. What are the Operation & Maintenance (O&M) Costs?
Inspection to document pollutant capture should occur quarterly
during the first year after installation to establish a cleanout cycle.
Generally, cleanout using a vacuum truck will be required 1x every
18 months.
The accumulated sediment, oil, grease, trash and debris must be
disposed of at a licensed, permitted facility.
The water can be decanted back into the Terre Kleen, free of the
pollutants.
The O&M annual costs are estimated to be less than 5% of the
total construction costs.
The estimated useful life of a Terre Kleen is 100 years; there are no
other maintenance costs expected other than the 18 month routine
clean out cycle.
11. How do the Maintenance costs and procedures compare to other Stormwater
BMPs?
The vacuum clean out process is not time consuming nor complex.
The maintenance procedures for other BMPs such as wet ponds,
wetlands, rain gardens, bio retention facilities and porous
pavements can be time consuming, complex and costly.
Wet ponds and wetlands require dredging to remove sediment
build up. Sediment must be removed to maintain hydraulic loading;
storage capacity; hydraulic residence time and to avoid washout &
scour of sediment and the chemical release of attached
phosphorous caused by anaerobic conditions.
Page 6 of 12

Terre Kleen Sizing Chart
Chart 1 illustrates the design flows and peak flow capacities of the various Terre Kleen models. This Chart reflects to achieve a 80% net annual
weighted TSS removal efficiency.
Using Chart 1 as a reference, with the site conditions identified, the site specific Terre Kleen can be determined.
1
Terre
Kleen
Model
CHART 1
A B C D E F G H I J K L M N O P Q
Settling
Design 1
area in
Design
Design 1
Design
Design 1
Design
Design 1
Design
Capacity
sedimentation
50 =50
flow head
Capacity
flow head
Capacity
flow head
Capacity
flow head
Peak 2a Peak 2,4
Standard 5 Standard 5 Minimum
max pipe
grade to
d
loss 6 d 50 =110
loss 6 d 50 =150
loss 6 d 50 =200
loss 6 Flow head loss 6
Sediment Trash and
Diam.
pipe
Storage Oil volume
chamber
Micron
Micron
Micron
Micron
invert 3
Standard
pipe invert
to device
bottom
PSD 38-68 μ M PSD 38-300 μ M PSD 38-640 μ M PSD 38-1000 μ M
2 TK02 12.8 sf 0.6 cfs 0.05 In. 1.6 cfs 0.36 In. 2.1 cfs 0.62 In. 2.6 cfs 0.95 In. 4.0 cfs 2.25 In. 18 In. 88 CF 133 Gallon 3.27 Ft 6.25 Ft
3 TK03 19.2 sf 0.9 cfs 0.11 In. 2.3 cfs 0.74 In. 3.2 cfs 1.44 In. 3.8 cfs 2.03 In. 5.4 cfs 4.11 In. 18 In. 88 CF 133 Gallon 3.27 Ft 6.25 Ft
4 TK04 25.6 sf 1.2 cfs 0.20 In. 3.1 cfs 1.35 In. 4.2 cfs 2.48 In. 5.1 cfs 3.66 In. 7.2 cfs 7.30 In. 18 In. 88 CF 133 Gallon 3.27 Ft 6.25 Ft
5 TK05 32.0 sf 1.5 cfs 0.32 In. 3.9 cfs 2.14 In. 5.3 cfs 3.95 In. 6.4 cfs 5.77 In. 9.0 cfs 11.40 In. 18 In. 88 CF 133 Gallon 3.27 Ft 6.25 Ft
6 TK06 38.4 sf 1.8 cfs 0.46 In. 4.7 cfs 3.11 In. 6.3 cfs 5.59 In. 7.7 cfs 8.35 In. 10.8 cfs 16.42 In. 18 In. 88 CF 133 Gallon 3.27 Ft 6.25 Ft
7 TK09 57.0 sf 2.7 cfs 1.03 In. 6.9 cfs 6.70 In. 9.4 cfs 12.44 In. 11.4 cfs 18.30 In. 15.0 cfs 31.70 In. 24 In. 80 CF 175 Gallon 3.27 Ft 6.25 Ft
8 TK18 115.0 sf 5.5 cfs 1.31 In. 14.0 cfs 8.49 In. 18.9 cfs 15.48 In. 22.9 cfs 22.73 In. 28.0 cfs 34.00 In. 36 In. 116 CF 253 Gallon 3.27 Ft 6.25 Ft
9 TK27 172.0 sf 8.2 cfs 1.45 In. 20.9 cfs 9.45 In. 28.3 cfs 17.33 In. 34.3 cfs 25.45 In. 42.0 cfs 38.20 In. 42 In. 151 CF 331 Gallon 3.27 Ft 6.25 Ft
10 TK36 230.0 sf 11.0 cfs 1.58 In. 27.9 cfs 10.18 In. 37.9 cfs 18.79 In. 45.9 cfs 27.56 In. 56.0 cfs 41.00 In. 52 In. 187 CF 409 Gallon 3.27 Ft 6.25 Ft
11 TK45 288.0 sf 13.7 cfs 1.65 In. 35.0 cfs 10.78 In. 47.4 cfs 19.76 In. 57.4 cfs 28.98 In. 70.0 cfs 43.00 In. 60 In. 223 CF 487 Gallon 3.27 Ft 6.25 Ft
12 TK54 346.0 sf 16.5 cfs 1.93 In. 42.0 cfs 12.47 In. 57.0 cfs 22.97 In. 69.0 cfs 33.66 In. 77.0 cfs 42.00 In. 72 In. 259 CF 565 Gallon 3.27 Ft 6.25 Ft
13 TK63 403.0 sf 19.2 cfs 1.96 In. 48.9 cfs 12.72 In. 66.4 cfs 23.46 In. 80.4 cfs 34.40 In. 89.0 cfs 42.00 In. 72 In. 295 CF 643 Gallon 3.27 Ft 6.25 Ft
1. Design flow is based on 80% Weighted Removal of sediment per NJDEP Lab. protocol and adjusted for d 50 as indicated and Particle Size Distribution as indicated.
2. Peak headloss is defined by minimum grade to pipe invert distance in standard Terre Kleen models. Larger head-losses cause over topping or require increased grade elevations.
2a. Greater peak flow designs create larger head losses. They are optional and avoid external by-pass structures.
3. Add 9" for grade adjust and frame and cover, otherwise cast frame into the lid.
4. Excess design overflow through a screen is possible above insert.
5. Special designs are available to address special design issues.
6. Headloss value is due to the clean insert only. Add water depth in the influent pipe(s) entry and exit losses to this value to find the hydraulic grade line up stream.
Temperature of the water may change average particle size may change particle density may change. All affect the performance directly or
exponentially in case of particle size. Therefore we offer a small range of variables and the relative performance of Terre Kleen in CFS.
Page 7 of 12

Additional Considerations:
Terre Kleen is fully assembled inside a rectangular precast concrete structure
designed and engineered by Terre Hill Stormwater Systems to meet the site-specific
service conditions:
1. Terre Hill Storm water Systems is the Engineer of Record for structural integrity
of Terre Kleen based on the peripheral site data provided by the Engineer of
Record for the site.
2. Buoyancy conditions may require a bottom flange to be part of the structure.
3. Traffic loading affects the design of the lid.
4. Pipe inverts may require the casting of access manholes into the lid to gain
elevation.
5. Inlet grates may be placed above the primary chamber to allow the Terre
Kleen to be the last inlet in a design.
6. Pipes may enter the primary chamber between 9 and 3 o’clock at various angles.
The discharge is typically at 6 o’clock.
7. The exterior of the structure may be coated to resist acid surroundings.
8. The Terre Kleen insert is a welded plate assembly manufactured from marine
grade aluminum (#5052). Hardware is stainless steel and seals are neoprene
rubber.
9. Lids contain the Terre Kleen logo and the words “Stormwater Treatment
Device”.
10. Oil absorption booms that absorb and permanently remove ¼ gallon of oil are
placed in the inlet/primary chamber
11. An additional screening/floatables chamber may be placed prior to Terre Kleen
at locations where site conditions/use may warrant, such (i.e. malls, stadiums,
race tracks and other areas where throw away containers are used)
12. A treatment train design is recommended. Use of the Terre Kleen as a
pretreatment device will remove oil, grease, litter, trash, debris and sediment
prior to discharge into a filter, a wet pond, a wetlands, a detention or infiltration
basin, rain garden, bio-retention area or other treatment structures.
13. Pretreatment with a Terre Kleen will preserve the functionality of the
subsequent treatment BMPs; protect its useful life; and reduce maintenance
costs by: 1) preventing pollutants from entering those devices and 2)
concentrating pollutant removal in the easily accessible Terre Kleen.
Maintenance Procedures
Maintenance Record
When a Terre Kleen unit is newly installed, frequent inspection is highly
recommended. The design of the Terre Kleen unit permits easy inspection. It is
recommended that during the first two years after installation, inspections be performed
at least quarterly for the purpose of noting the rate of sediment and floatable
accumulation.
Attached is a form that may be used for recording information resulting from the
inspections. Maintaining accurate records provides a history of the pollutant
Page 8 of 12

accumulation for this unit and can be used as a comparison to other Terre Kleen units
that are in use in your region.
To determine sediment accumulation, a stadia rod or similar measuring device may be
used. Cleaning is recommended when the sediment is found to be at the level shown in
the Terre Kleen flow diagram. To avoid underestimating the volume of sediment in the
chamber, care must be exercised in lowering the measuring device to the top of the
sediment pile. The clean-out procedure may occur anytime after a rain event. It is not
necessary to wait for particles to settle due to the high sedimentation efficiency of the
device.
Maintenance Cleaning
The Terre Kleen is designed with clear access to the primary and grit chambers. A
vacuum truck, or similar trailer mounted equipment, can be used to clean both
chambers by lowering the suction hose through the openings. The oil and litter in the
primary chamber should be removed first. Depending on the equipment used, it may be
necessary to remove floating trash and debris with a net or rake. To further prevent
discharge of hydrocarbons, “oil absorption booms” were added to the primary chamber
during installation. They will float among the litter and begin to sink as they absorb oil.
The boom size 2¼” Ø x 12” will absorb about a quart of oil and solidify it within the
boom. These booms should be replaced when they become saturated with oil and no
longer appear above the water surface. Depending on the site conditions, the number
of booms can be adjusted up or down. Additional booms can be purchased from Terre
Hill Concrete Products. ( The sorbent booms are placed in the primary chamber for the
absorption of gasoline; diesel fuel, lube oil, jet fuel, transformer oils, chlorinated
solvents, aromatic solvents, hydraulic oils, and light crude. The sorbent boom is
Rubberizer® boom manufactured by Haz-Mat Response Technologies Inc. A standard
TerreKleen TK09 has 4 booms, TK18 has 8 booms, TK27 has 12 booms, TK36 has
16 booms, TK45 has 20 booms, and TK54 has 25 booms.)
After the oil and litter is removed, the grit chamber can be cleaned out. Finally, switch
back to the primary chamber to remove remaining debris. Water can be sprayed into the
chambers as necessary to loosen debris.
Sludge dispersion manifold
Each Terre Kleen water quality device contains a “Sludge Dispersion Manifold”. The
manifold pipes are mounted to the floor underneath the inclined plate settler and
connect to a hose that leads to the clean out opening at grade level. This hose is
pressurized by the vacuum truck’s spray nozzle. While the suction nozzle removes the
captured pollutants, the pressurized manifold sprays water through the small horizontal
holes in the manifold pipes. This water lifts and disperses the sludge blanket causing it
to drain to the suction nozzle.
Page 9 of 12

Disposal
Disposal of removed material will depend on the nature of the drainage area. For
example, sediment collected from a system of stormwater inlets may possibly be
disposed at a landfill after the liquid fraction is decanted at a sewage treatment facility.
Material removed from the Terre Kleen must be handled according to local, state, and
federal regulations. Some materials, such as sediment and detritus from lawn areas
may be reused on site, which is often recommended by the local authorities. After the
clean-out procedure is complete, replace the manhole covers securely to the frames for
safety purposes.
Cold Weather Concerns
There is limited data concerning cold weather effects on a properly maintained Terre
Kleen device. The depth of the structure in the soil insulates it from freezing which is
similar to exposure conditions of septic tanks. When inlets are integrated into the Terre
Kleen, exposure to freezing may become an issue and may result in more runoff
bypassing the treatment system due to a build-up of snow and ice. Saltwater
stratification in the water may also reduce detention time. Colder temperatures reduce
Page 10 of 12

the settling velocity of particles, which can result in fewer particles being “trapped“. The
amount of grit and sand in the runoff from paved areas may be significantly increased in
the winter, which may warrant more frequent maintenance. Access to the device for
maintenance may be more difficult.
Confined Space Entry
Regular maintenance and clean out does not require confined space entry into the
Terre Kleen unit. If confined entry is required, it will need to be performed by qualified
personnel who are properly trained for confined space activity using proper equipment
as per the latest OSHA regulations.
The Terre Kleen will trap floatable litter and oils that are not emulsified in the
stormwater runoff. Keep sparks and open flames away when working around a
Terre Kleen unit that may contain flammable material.
Terre Hill Stormwater Systems manufactures a complete line of stormwater
treatment and management structures designed for NPDES permit compliance:
Terre Kleen
Terre Arch (patent pending 11/569,437)
Terre Box
Terre Hill Watertight Joint Seal System (patent pending 12/150,722)
Terre Filter (patent pending 61/191,484)
Please contact Terre Hill Stormwater Systems :
Dale Groff 717 445 3114 dgroff@terrehill.com
Hans de Bruijn 717 445 3116 hdebruijn@terrehill.com
Gene LaManna 717 445 3111 glamanna@terrehill.com
Page 11 of 12

Terre Hill Stormwater Systems
PO Box 10
485 Weaverland Valley Rd
Terre Hill, PA 17581
800 242 1509
717 445 3100
717 445 0242 (fax)
www.terrestorm.com
http://terrehillstormwater.blogspot.com/
Page 12 of 12