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Applied Polymer Systems, Inc.
Polymer Enhanced Soil Stabilization Applied Polymer Systems, Inc.
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Course Overview Note: Floc Logs and Pond Logs referred to in this course are also known as polymer blocks in the industry. Silt Stop Powder is also know as polyacrylamide powder or emulsion. Common definitions used in the erosion, sediment control, and water clarification industry Quick Review of the Fundamentals of Polymer Enhancement Silt Stop Powder Facts Polymer Enhanced Soil Stabilization Polymer Enhanced Sediment Control Toxicity Testing Sample Analysis Rules for Polymer Use
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Definitions Anionic Polymer: A negatively charged polymer.
Acute Hypoxia: Occurs when cationic polymers attach to the negatively charged gill plates of aquatic organisms causing them to suffocate. Best Management Practice (BMP): “A measure that is implemented to protect water quality and reduce the potential for pollution associated with storm water runoff.”1 Cationic Polymer: A positively charged polymer. LC50: “The toxicant concentration that is lethal to 50 percent of exposed organisms at a specific time of observation.” 2
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Definitions NTU (Nephelometric Turbidity Units): “The standard unit of measurement for turbidity in water analysis.”3 Turbidity: “A measure of the amount of material suspended in the water. Increasing the turbidity of the water decreases the amount of light that penetrates the water column. High levels of turbidity are harmful to aquatic life.”4 NTU measures all particulate, including particles less than 0.45 microns . Polyacrylamide (PAM):A water soluble polymer used in water clarification and erosion, sediment, and dust control. Polymer: “A macromolecule formed by the chemical union of five or more identical combining units called monomers.“5 TSS (Total Suspended Solids): is a measurement of sediment particles 0.45 microns and larger.
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Acronyms United States Department of Agriculture
United States Department of Agriculture Agricultural Research Service NWISRL Kimberly, ID Northwest Irrigation and Soils Research Laboratory
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Quick Review of the Fundamentals of Polymer Enhancement: Why We Need PAM How is Sediment Harmful How Polymer Enhancement Works
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Why We Need PAM How is Sediment Harmful?
0.3 NTU NTU To get some perspective, drinking water is less than 1 NTU. Without Federal guidelines, 1,000 NTU water could be discharged into lakes and streams, destroying aquatic ecosystems At 1,000 NTU, we see reduced growth, reduced feeding rates, delayed hatching rates, and, even, death. Image from City of Calgary Drainage & Dewatering FAQ’s
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How is Sediment Harmful?
This study shows why the EPA effluent guidelines and rules and regulations for discharge limits are so important. Even in low turbidity conditions (10 – 100 NTUs), aquatic organisms start to show signs of stress. Image from Lake Superior Duluth Streams.org Water Quality: TSS & Turbidity site
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How Polymer Enhancement Works
This is a schematic depiction of the interactions of anionic PAM with charged soil particles in the presence of calcium. 6 The negatively charged anionic polymer attaches to the negatively charged soil particle by bridging with something having a 2+ charge, such as Calcium, in the soil.
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Polymer Enhanced Soil Stabilization Soft Armoring
The polymer + jute + sediment all bind together. Soil specific polymer (must be tested before application) Soil Coconut or jute matting (provides a fibrous surface for attachment)
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Polymer Enhanced Soil Stabilization Soft Armoring
As the polymer reacts, it begins binding the sediment into larger, agglomerated particles that adhere to the matting, mulch, or straw.
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Sample Analysis A sample analysis needs to be done before any application of polymers in order to determine the best product for that site. Polymers are site specific and not “one size fits all”. A sample analysis from Applied Polymer Systems
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Silt Stop Powder Facts
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Silt Stop Powder: Just the Facts
can be applied, dry, over bare soil. reacts with the metals and clays within the soil to bind them together. can be applied by hand or with a seed/ fertilizer spreader. can be added into a hydroseeding mix and applied over exposed soil and slopes. can be applied at the same time as seed and fertilizer. reacts with the soil, binding the mulch, seed, fertilizer, and other additives to the soil, holding it together until vegetation is established.
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Polymer Enhanced Soil Stabilization:
Soft Armoring Hydroseeding Dust Control 15
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Polymer Enhanced Soil Stabilization Soft Armoring
This is the application of polymer powder to a soft pliable matting such as jute, coir, coconut, hemp or burlap which is placed onto the soil surface. Applications are for soil stabilization such as bare soil, steep slopes, and areas of high velocity flow.
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Polymer Enhanced Soil Stabilization Soft Armoring
Silt Stop polymer powder reacts with the metals and clays within the soil to bind them together. This complex attaches to the matting, creating a highly erosion-resistant surface that will support vegetation along with aiding in the attachment of fine particulate to the matting surface. The same slope about four weeks later.
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Polymer Enhanced Soil Stabilization Soft Armoring
A matrix is formed when the polymer binds with the soil.
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Polymer Enhanced Soil Stabilization Soft Armoring
Once the polymer-soil matrix is formed, the soil is more resistant to erosion. Close up view of polymer treated soil
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Polymer Enhanced Soil Stabilization Soft Armoring
Mattings such as jute or coconut work very well because they are pliable (great for soft armoring) and have fibrous hairs where the polymer charged particles get trapped, like flypaper. With an open weave matting, it doesn’t matter if the polymer is applied under or over the matting. The important thing is that the polymer touches both the soil and the matting to bind it together. Matting such as jute or coconut is not the only matting that can be used but it works very well because it is pliable (soft armoring) and has fibrous hairs where the polymer charged particles get trapped, like flypaper. Jute, which has an open weave, can be applied before or after polymer application. I need to stress that, here, that the polymer must have contact with both the matting and the soil for binding to take place. If you have a closed weave matting, you must apply the polymer before the matting or there will be little to no binding. Open weave soft matting works best.
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Polymer Enhanced Soil Stabilization Soft Armoring
This microscopic view shows why something like jute, with its high surface area of fibers, provides excellent performance when applied with polymer. Matting or fabric with a high surface area of fibers will result in best performance. Something like plastic would be ineffective because there is nowhere for the polymer charged particles to attach.
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Polymer Enhanced Soil Stabilization Soft Armoring
Notice how the polymer + matting + sediment binds together on the jute. The polymer must have contact with both the matting and the soil for binding to take place. Jute fabric in the field showing how polymer + matting + sediment binds together. 22
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Polymer Enhanced Soil Stabilization Soft Armoring and Grassing
Polymer applied by itself may last severe rain events, but when applied with matting, everything gets bound together, forming an inexpensive version of a bonded fiber matrix that can last months. Adding vegetation can turn a temporary application into a permanent application. 1. The unprepared site 2. Rills and gullies are filled 3. Slope is soft armored and seeded 4. Vegetation is successfully established
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Polymer Enhanced Soil Stabilization Case Study: Soft Armoring and Grassing
First, the ground is raked or graded to even it out.
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Polymer Enhanced Soil Stabilization Case Study: Soft Armoring and Grassing
Then, jute is laid and the soil-specific polymer is applied to the jute to provide a surface area on which the polymer charged particles can attach. This stabilizes the soil to prevent erosion and facilitates root establishment.
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Polymer Enhanced Soil Stabilization Soft Armoring and Grassing
This site was soft armored with jute matting and vegetation was established. Both the polymer and jute are biodegradable so there is no need to remove the jute from the site.
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Rain Simulator
Plain Matting (no polymer) The University of Central Florida conducted a demonstration simulating a one inch per hour rain event to compare polymer enhanced soft armoring to plain matting. The results are clear. Polymer Enhanced Soft Armoring The Management Academy Rainfall Simulator during the Florida Department of Transportation Training class in October, 2009.
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Rain Simulator
Later, the rainfall was increased to 10 inches. Since it was not producing good storm water quality at one inch per hour, the matting on the right side was removed. The polymer enhanced soft armoring, on the left, still produced very good water clarity.
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Soft Armoring Information Using Geotextile Matting
Prepare Site Fill any rills or gullies caused by previous erosion. Ensure the matting can be applied flush to the soil surface to prevent tenting. Apply Silt Stop Powder This can be applied by hand or with a seed/ fertilizer spreader. Grass seed and fertilizer may be applied at the same time. Apply Matting If the matting is tight, apply matting last, over the polymer powder, seed, and fertilizer. With an open weave matting, the polymer can be applied under or over. Secure the matting to the soil surface with stakes or soil staples, taking care to ensure the matting is flush to the ground.
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Soft Armoring Application Rates
Gentle to Moderate slopes (0 to 4H:1V) High Clay Content: # powder High Sand Content: # powder Steep slopes (3H:1V to 1H:1V) High Clay Content: # powder High Sand Content: # powder
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Highway 98 DOT Project
Highway 98 Beach and Sand Stabilization
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Highway 98 DOT Project
In July, 2005, 14 miles of Highway 98, between Carabelle and Eastpoint, was damaged by Hurricane Dennis.
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Highway 98 DOT Project
After initial repair, erosion required an industrial BMP (Best Management Practice) that would work on beach sands.
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Highway 98 DOT Project
A Polymer Enhanced Soft Armoring System was chosen for this remediation. The site was graded, then covered with an organic layer of compost. All this was covered with jute matting.
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Highway 98 DOT Project
Polymer was applied at a rate of 50 pounds polymer per acre. The polymer enhanced jute acts as a binding media for the polymer, compost, and sand. Jute + Polymer Compost Sand
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Highway 98 DOT Project
Sod was placed over the polymer enhanced jute.
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Highway 98 DOT Project
This area withstood a tropical depression and category one hurricane after initial installation. One year after placement, there was no erosion or need for further repair.
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Highway 98 DOT Project
Where the sod failed, the polymer enhanced soft armoring application kept everything bound together so roots could take hold and vegetation could be established.
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Polymer Enhanced Soil Stabilization Soft Armoring Case Study: Highway 98 DOT Project
Note that without polymer enhancement to bind the materials together, erosion can occur beneath the sod, resulting in failure.
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Polymer Enhanced Soil Stabilization Hydroseeding
Ways PAM can be applied: For smaller scale applications it can be applied through a hand/fertilizer spreader, modified leaf blower, etc. For large scale applications it can be applied through a hydroseeder as seen above. Anything that you would typically put in your hydroseed mix can be applied in conjunction with PAM. It is suggested, however, that the PAM be added as the last additive so that it does not end up sitting in the tank for long periods of time. Site-specific polymer reacts with the soil, binding the mulch, seed, fertilizer, and other additives to the soil, holding it together until vegetation is established. 40
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Polymer Enhanced Soil Stabilization Hydroseeding
Anything that you would typically put in your hydroseed mix can be applied in conjunction with PAM. Add Silt Stop emulsions as the final additive so it does not sit in the tank for long periods of time. Polymer emulsion with hydroseed mix being applied to slopes.
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Polymer Enhanced Soil Stabilization Hydroseeding
Open weave matting can be applied before hydroseeding areas, especially in areas with steep slopes or sandy conditions. This will provide additional structural support that will create a highly erosion-resistant surface to support the establishment of vegetation. Slope vegetation about four weeks after polymer enhanced hydroseeding application.
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Polymer Enhanced Soil Stabilization Case Study: Hydroseeding
This steep slope had runoff with each rain event. Open weave matting was put in place for stabilization, followed by a hydroseeder applied powder, seed, and fertilizer.
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Polymer Enhanced Soil Stabilization Case Study: Hydroseeding
The same slope a few weeks later. Erosion, seed, and fertilizer loss is reduced. Tackification, growth, and runoff water quality is increased.
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Hydroseeding Application Information
Prepare Site Fill any rills or gullies caused by previous erosion. Ensure the matting can be applied flush to the soil surface to prevent tenting. Apply Matting Secure the matting to the soil surface with stakes or soil staples, taking care to ensure the matting is flush to the ground. Preferably, use matting with ½ - 1 inch open spaces. Hydroseeding Mix Fill the hydro-seeder tank with water and add the normal mix of seed, fertilizer, fiber mulch, etc. Add Silt Stop Powder Slowly add the Silt Stop polymer as the final additive to the hydroseed mix while the agitator is running to ensure mixing. Be sure the machine has an agitator or mechanical mixing device. If there is no mixing potential, you must use emulsion, not powder. Allow 5 minutes of mixing before application. Apply Hydroseed Spray the hydroseed mixture over the top of the open-weave matting. Proper application should result in complete coverage with no visible bare soil.
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Hydroseeding Application Rates
Gentle to Moderate Slopes (0 to 4H:1V) High Clay Content: 10-20 # powder or gallons emulsion High Sand Content: 15-20 # powder or gallons emulsion Steep Slopes (3H:1V to 1H:1V) 20-35 # powder or gallons emulsion 25-50 # powder or gallons emulsion Silt Stop emulsion or powder shall be added to all hydroseeding mixes at the above application rates per 3000 gallons of water and then applied at the rate of 3000 gallons of hydroseed mix/ acre.
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Polymer Enhanced Dust Control
The same polymer can be used to reduce airborne dust. If there is no rain, the polymer breaks down under UV light in about six months.
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Polymer Enhanced Dust Control Dust Control Video
This site was treated with APS 712 Silt Stop powder via a water truck two weeks before this was filmed. The wind speed was 50 MPH.
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Dust Control Application Information
Add Emulsion/Powder to Water Add Silt Stop to the water slowly to prevent clumping and poor performance. It is suggested that the polymer material be added while the tank is filling and/or the agitator is running. Allow 2-3 minutes of mixing time before application. Spray Target Area Spray the target area just like a normal water application. Spray needs to contact at least 85% of the target surface area to be effective. 100% coverage is preferred.
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Dust Control Application Rates
¼ - ½ gallons of emulsion or 7-10 pounds of powder / 1000 gallons water per 1/3 acre coverage. Polymeric additions to water are limited by high viscosity. Do not exceed 1 gallon emulsion / 1000 gallons water.
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Sediment Retention Barrier (SRB)
Polymer Enhanced Sediment Control: Inlet Protection Sediment Retention Barrier (SRB) Rock Checks Demucking 51
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Polymer Enhanced Sediment Control Soft Armoring: Inlet Protection
As with other Soft Armor applications, the polymer powder binds the soil to the matting to prevent storm water from undercutting the inlet protection device. Also, turbid water passing across the polymer enhanced jute matting reacts with the polymer, clarifying the water and dropping out the suspended particles before they enter the storm drain system. Since the silt fence is not loaded up with sediment, it is better able to prevent fine particles from moving through it.
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Polymer Enhanced Sediment Control Soft Armoring: Outlet Protection
The outlet is enhanced by laying jute matting over the dissipater rocks then applying the soil-specific Silt Stop powder over it. The particulate formed during reaction with the Floc Log in the storm-drain system exits the outlet structure. The jute matting applied around the structure provides surface area for the particulate to adhere, resulting in increased water clarity. The jute matting around the outlet also creates a highly erosion-resistant surface which protects the surrounding soil structure from high velocities.
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Polymer Enhanced Sediment Control Sediment Retention Barriers (SRB)
This typical silt fence captures the larger particulate but not the fines which are still able to move through to the other side.
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Polymer Enhanced Sediment Control Sediment Retention Barriers (SRB)
This BMP is used to prevent sediment from leaving the site. It is constructed from two parallel rows of silt fence with alternate layers of loose straw (or other organic matter) and polymer powder between the rows. Notice the difference in water quality between the left side and the right side of the SRB.
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Polymer Enhanced Sediment Control Sediment Retention Barriers (SRB)
Cross section of a Sediment Retention Barrier (SRB) 6” straw, wood chips, or organic fill Soil-specific Silt Stop powder (50# total per 75 LF of SRB) 25 # / Acre Silt Stop powder covered with straw or jute FLOW 3 ft
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Polymer Enhanced Sediment Control Sediment Retention Barriers (SRB)
Notice that the SRB is at the outer edges of the site right next to the tree save. It is being used as the final clarification mechanism. This SRB at the outer edge of the site is comprised of alternating layers of straw and polymer powder, and acts as the final clarification mechanism. 57
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SRB Information Grade Site
Fill low spots to ensure the installation of the silt fence is as level as possible. Install Silt Fence Place a double row of silt fence perpendicular to the direction of flow. The two lines of silt fence should be 4 to 6 feet apart. Fill with layers of woodchips/ straw and Silt Stop powder Loosely fill the area between the silt fences with alternating layers of woodchips or straw and the site-specific Silt Stop powder.
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SRB Application Rates 50# powder / 75 linear feet of SRB.
Place loose straw or mulch 3 feet deep between the silt fences (do not compact). The silt fence shall allow water to pass at a rate of 70 GPM/ft2 or greater.
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Polymer Enhanced Sediment Control Rock Checks
Standard rock check systems usually only capture the heavier sediments. Using polymer enhancement technology allows the rock check system to become effective as a water clarifying system while retaining the ability to be an effective sediment control device.
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Polymer Enhanced Sediment Control Rock Checks
Apply one or two layers of open weave jute matting to the entire surface of each rock. Apply the site-specific powder evenly to the matting.
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Polymer Enhanced Sediment Control Rock Checks
Apply jute matting to the rock check. Apply the correct soil specific polymer to the matting. The fibrous matting provides surface area for the attachment of the soil-polymer matrix.
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Polymer Enhanced Sediment Control Rock Checks
Notice how the fine sediments become attached to the matting, reducing the impact on ponds and streams.
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Polymer Enhanced Sediment Control Rock Checks
Polymer enhanced soft armored rock checks are placed in the diversionary ditch. The more rock checks in a series, the better the water quality. On the left hand side, polymer enhanced soft armoring was applied and vegetation is already beginning to establish. Notice the SRB at the outer edges of this site. This site is a prime example of using a treatment train. Construction is still being done on this site as you can see at the right hand side of this picture. Polymer enhanced soft armored rock checks are placed in the diversionary ditch. Notice on the left hand side that polymer enhanced soft armoring was applied and vegetation is already beginning to establish. 64
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Rock Check Information and Application Rate
Prepare site Fill any rills or gullies caused by previous erosion. Ensure the stormwater will sheet flow over the dispersion field. Install Checks or Wattles These can be made from sandbags, rock, wood, rip-rap, or other materials. Their purpose is to slow the velocity of the stormwater and encourage ponding. Line with Jute Matting The jute matting provides a surface on which the particulate, formed during treatment, can adhere. A layer of plastic beneath the jute matting may be necessary, especially in highly erosive soils. Application Rate Evenly apply the site-specific Silt Stop powder over the jute covered dispersion field. Use approximately 5 pounds / 30 ft3 rock. Apply like salt, not sugar. The Silt Stop powder reacts with the sediment, binding it together and adhering it to the jute matting.
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Polymer Enhanced Sediment Control Demucking
Site specific powder is applied to the mucky surface. Once applied, heavy equipment can be used to mix the powder into the muck. Allow the mixed muck to sit for approximately 20 minutes.
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Polymer Enhanced Sediment Control Demucking
After 20 minutes, the polymer will have bound the soil together, making it more manageable.
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Polymer Enhanced Sediment Control Demucking
The manageable muck can be put into dump trucks and hauled off site.
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Polymer Enhanced Sediment Control Demucking
If the soil is not contaminated, the treated muck can be used as a soil amendment or applied anywhere there is disturbed soil, turning problem soil into a resource. High organic polymer treated mud is very erosion resistant and will hold fertilizer and seed in place.
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Polymer Enhanced Sediment Control Demucking
In this case, polymer was applied over the surface of the mucky and unmanageable sediment basin using a modified leaf blower.
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Demucking Application Information
Remove Standing Water Pump the standing water off or dig a sump and allow the water to drain off the working area. The polymer will not react properly if there is standing water covering the sediment. Apply Silt Stop powder Apply the site-specific Silt Stop powder evenly to the surface of the wet sediment. The powder can be applied using a hand, mechanical, or pneumatic spreader. Mix the Silt Stop powder into the soil Using the excavation equipment (or hand shovel), stir the powder into the mud to a depth of three feet. While mixing, the sediment should bind together and thicken. If the sediment is deeper than three feet, the mixing and removal will have to be done in layers.
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Demucking Application Rates
50 pounds of Silt Stop powder/ cubic yards. This application rate will vary with soil type and content. There can be no standing water.
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Toxicity Testing
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Toxicity Testing The highlighted text indicates that toxicity testing of any polymer blend product should be “based on reasonable worst-case analysis”. The idea is to test the whole product before it is applied to ensure that it is not toxic. If the whole product is not toxic then any residual of the product would not be toxic. Note: Floc Log testing was conducted using worst-case analysis. All toxicity tests were conducted using ASTM procedures at full chemical exposure. Chitosan tests were conducted using effluent after reaction filtration. This is not worst-case analysis and does not follow ASTM procedures.
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Toxicity Testing Example of a Toxicity Report Done by a Third Party EPA Certified Lab
The chart above shows the fathead minnow survival percentage as the Floc Log concentration is increased. As shown, there is an 77.5% survival rate of the minnows at 1,680 ppm Floc Log concentration.
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Polymer LC50 Values (mg/L)
Toxicity Testing Example of a Toxicity Report Done by a Third Party EPA Certified Lab Polymer LC50 Values (mg/L) Polymer D. magna 48 hr O. mykiss 96 hr P. promealas 96 hr Al2Cl(OH)5 > 5000 390 517 DADMAC 17.5 0.49 1.65 Mimosa bark 258 No data 1.3 Chitosan 13.7 1.1 6.4 APS 706b Floc Log > 420 637 > 1680 APS 703d Floc Log 383 1900 APS 712 Silt Stop 1617 > 6720 The above chart compares the LC50 values of polymers commonly used in stormwater applications. The LC50 value is the lethal concentration where 50% of the population dies. As can be seen, Chitosan has extremely low LC50 values making it highly toxic.
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Toxicity Testing Very little Chitosan was required to kill this fish.
A 0.001% solution is like putting 645 grains of salt, or 1/128th of a teaspoon, into one gallon of water.
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Toxicity Testing Anionic Erosion and Water Clarification PAM based polymers are FAR less toxic than Fungicides, Insecticides, Rodenticides, Cationic Polymers, most Herbicides and even Concentrated Fertilizers. NWISRL Kimberly, ID
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Sample Analysis
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Sample Analysis A sample analysis needs to be done before any application of polymers in order to determine the best product for that site. Polymers are site specific and not “one size fits all”. A sample analysis from Applied Polymer Systems
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Rules for Polymer Use Polymers must be anionic and non-toxic to aquatic organisms with an EPA certified toxicity report (whole product WET tests using ASTM guidelines). Each site application must demonstrate 95% or better NTU reduction based on initial test reports. Polymers are unique for each application. There is no “one type fits all”. Testing must be done!
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References 1International Erosion Control Association. Resources: Terms & Acronyms. 2BioTox Laboratory. (2004, January). Report for chronic toxicity testing for Applied Polymer Systems Silt Stop 702 product. Retrieved from 3McGowan, W. (2000). All about Water. Des Plaines, Illinois: Scranton Gillette Communications, Inc. 4International Erosion Control Association. Resources: Terms & Acronyms. 5Lewis, R. J., Sr. (2007). Hawley's condensed chemical dictionary (15th ed.). Hoboken, New Jersey: John Wiley & Sons Inc.
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References Applied Polymer Systems. (2010, October). Applied Polymer Systems [Polymer Enhanced Best Management Practices Application Guide]. Retrieved from Lewis, R. J., Sr. (2007). Hawley's condensed chemical dictionary (15th ed.). Hoboken, New Jersey: John Wiley & Sons Inc. Minnesota Rural Water Association (Ed.). (2009). Minnesota water works operations manual. (Original work published 1994) Click Here Moss, N., & Dymond, B. (n.d.). Flocculation: Theory & application. Click Here Romøren, K., Thu, B. J., & Evensen, Ø. (2002, December). Immersion delivery of plasmid DNA II. A study of the potentials of a chitosan based delivery system in rainbow trout (Oncorhynchus mykiss) fry. Journal of controlled release, 85(1-3), doi: /S (02)00278-X Sojka, R. E., and Lentz, R. D. (1997). A PAM Primer: A brief history of PAM and PAM-related issues. pp Full Text
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References Stechemesser, H., & Dobias, B. (Eds.). (2005). Surfactant science series: Vol Coagulation and flocculation (2nd ed.). Boca Raton, Florida: Taylor & Francis. Click Here USDA Agricultural Research Service. (2009, August 19). PAM research. Retrieved from United States Department of Agriculture website: University of Central Florida. (2010, October 19). Stormwater Management Academy. Retrieved from USEPA (U.S. Environmental Protection Agency). (2003). Chitosan: Poly-D-glucosamine (128930) Fact Sheet. Full Text US EPA. (2008, November 21). Development Document for Proposed Effluent Guidelines and Standards for the Construction and Development Category. Full Text Wikipedia. (n.d.). Wikipedia: Polymer. Retrieved from
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