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Polymer Enhanced Water Clarification

Polymer Enhanced Water Clarification

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Polymer Enhanced Water Clarification

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  1. Polymer EnhancedWater Clarification Applied Polymer Systems, Inc. www.siltstop.com

  2. 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 • Floc Logs: Facts and Application Rates • Polymer Enhanced Storm Water Treatment • Polymer Enhanced Water Clarification • Polymer Enhanced Particle Collection • Polymer Enhanced Treatment of Geothermal Well Discharge • Toxicity Testing • Sample Analysis • Rules for Polymer Use

  3. 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

  4. 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.

  5. Definitions Blinding Off: This occurs when sediment coats the outside of a polymer log, preventing it from continuing to react with the turbid water. This usually happens in hard water or in the presence of more than 4% solids.

  6. Acronyms United States Department of Agriculture United States Department of Agriculture Agricultural Research Service NWISRL Kimberly, ID Northwest Irrigation and Soils Research Laboratory

  7. Quick Review of the Fundamentals of Polymer Enhancement:Why We Need PAMHow is Sediment HarmfulHow Polymer Enhancement WorksMetal and Nutrient Reduction

  8. Why We Need PAMHow is Sediment Harmful? 0.3 NTU 991 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

  9. 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

  10. 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.

  11. How Polymer Enhancement Works Flocculation occurs when the polymer binds to the suspended soil in the water column, forming larger, heavier particulate that settles out of the water column, leaving the water clarified.

  12. How Polymer Enhancement Works • Flocculated particulate being captured by jute matting. • Clean water discharging from a site.

  13. Metal & Nutrient Removal with Floc Logs • Like sediment, metals by themselves can be very light and stay suspended in the water column. • When they become bound through flocculation, they form heavier flocs that can settle out of the water column. • This slide shows the reduction of metals from a wash plant in Canada.

  14. 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

  15. Floc Logs: Facts and Application Rates

  16. Floc Logs: Just the Facts Floc Logs: are designed for use in flowing conditions for treating turbid water to remove suspended sediment. must demonstrate 95% or better NTU reduction based on initial test reports. should be placed as close to the source of the turbid flowing water as possible. are designed to work with turbid water that contains 4% or less solids. If the sediment load of the water is larger than this limit, a grit pit or settling tank may needed to encourage primary settling before treatment. are toxicity tested by an independent third party EPA certified lab and are shown to be non-toxic to fish or other aquatic organisms.

  17. Floc Logs: Application Rates One Floc Log will treat about 430,000 gallons. For maintenance, use one log per one million gallons of water. The number of logs is determined by the flow rate of the water and the volume of water being treated. The length of the mixing portion of the treatment system is determined by the flow rate and reaction time required for the polymer.

  18. Floc Logs: Application RatesRough Approximations For Determining the Number of Floc Logs Needed Based on the Floc Log Reaction Time to the GPM of the System. Use the chart to determine the GPM for the Reaction. Take the pumping GPM and divide it by the GPM obtained from the chart. Example: Expected Flow Rate: 1300 GPM Reaction Time: 50 seconds From Chart: Reaction GPM: 40 Number of Floc Logs needed will be: 1300 / 40 = 33

  19. Polymer Enhanced Storm Water Treatment: Storm Drains Down Drains Closed Pipe Systems

  20. Polymer Enhanced Storm Water TreatmentStorm Drains • Inserting site-specific Floc Log at drop inlets within the storm-drain system will create a passive treatment system. • Securing Floc Logs within the pipe, as close to the source of turbidity as possible, allows the water to mix with the site-specific polymer blend and begin reacting with the suspended sediment. • Turbidity of the water should not exceed 4% solids.

  21. Work Area Down Drain Soft Armor around mouth of down drain will prevent erosion and undercutting Polymer Enhanced Storm Water TreatmentDown Drains – Side View Silt Fence or Sediment Retention Barrier (SRB) for final clarification Polymer enhanced jute matting allows polymer reacted sediment to attach to the matting, creating a highly erosion-resistant surface and clarifying runoff water Site-specific Floc Log placed in pipe, lower than the mouth of down drain

  22. FLOW Floc Log rope tied off to secure in pipe Hole cut into pipe allows easy access to Floc Log Floc Log Partial obstruction in pipe to increase mixing potential Floc Log Polymer Enhanced Storm Water TreatmentClosed Pipe System

  23. Polymer Enhanced Water Clarification: Dewatering Bag Mixing and Dewatering Ditches Mixing and Dewatering Split-Pipes In-Stream Baskets Tank Systems

  24. Polymer Enhanced Water ClarificationDewatering Bag • Dewatering bags reduce sediment being discharged during dewatering. The fine particulate that escapes can be flocculated and captured in the treatment train that follows the dewatering bag. • DO NOT use Polymer BEFORE a Dewatering Bag…The bag will blind off!

  25. Polymer Enhanced Water ClarificationDewatering Bag • The end of the system is wider to create a dispersion zone for particle collection. • On bare soil, the treatment train is covered with geo-textile fabric to prevent erosion and collection of new soil. • The treatment train is covered with jute material and staked in place.

  26. Polymer Enhanced Water ClarificationMixing and Dewatering Ditches bales Step 1: Create ditch The ditch can be dug into the ground, or created by building up the walls with straw or hay bales. Step 2: Line with commercial grade (4 mils or greater) plastic The plastic sheeting is used to prevent the water being treated from picking up sediment and causing erosion. Step 3: Lay Jute Matting The jute matting provides a surface to collect the flocculated particulate.

  27. Polymer Enhanced Water ClarificationMixing and Dewatering Ditches Step 4: Place Floc Logs The Floc Logs are positioned in a line at the top of the ditch, allowing the water to flow over and around them. Step 5: Apply Silt Stop Powder Sprinkling the correct site-specific Silt Stop powder over the jute matting in the bottom portion of the ditch will assist in final water clarification.

  28. Polymer Enhanced Water ClarificationMixing and Dewatering Ditches • Logs should be applied close to the source of turbidity and in a ditch narrow enough for water to have contact with the Floc Logs. • MIXING IS KEY! If the ditch is made larger to accommodate higher flows then there needs to be enough logs in the system to accommodate the flows. Polymer + Soil matrix forms an agglomeration

  29. Polymer Enhanced Water ClarificationMixing and Dewatering DitchesCase Study: Temporary Dewatering Ditch Temporary dewatering systems, such as this one, made from hay bales and commercial grade plastic (4 mils or greater) provide an economical and easy solution.

  30. Polymer Enhanced Water ClarificationMixing and Dewatering DitchesCase Study: Temporary Dewatering Ditch • The top end of the ditch is made narrow so water is forced to flow over and around the logs, facilitating mixing and reaction. Mixing is key! • Commercial grade plastic covers the hay bales and ditch to prevent additional sediment from entering the dewatering treatment ditch and to prevent the water from seeping out between the hay bales. • Logs are placed in the upper 1/3 to 1/2 of the ditch.

  31. Polymer Enhanced Water ClarificationMixing and Dewatering DitchesCase Study: Temporary Dewatering Ditch • The treatment ditch is wider at the bottom to slow down the velocity of the water. • Jute particle collection fabric is placed at the end of the treatment system to capture the polymer charged particles.

  32. Polymer Enhanced Water ClarificationMixing and Dewatering DitchesCase Study: Temporary Dewatering Ditch Turbid water is pumped into the treatment system.

  33. Polymer Enhanced Water ClarificationMixing and Dewatering DitchesCase Study: Temporary Dewatering Ditch • Mixing occurs in the narrow portion of the system where the water is forced to be in contact with the Floc Logs. • As the turbid water flows over and around the polymer logs, the log slowly dissolves and the polymer enters the turbid water where it mixes and reacts, charging the particles and creating flocculent.

  34. Polymer Enhanced Water ClarificationMixing and Dewatering DitchesCase Study: Temporary Dewatering Ditch • Once the polymer-charged particles, or flocs, have been formed, the jute fabric provides a fibrous surface to capture the flocs. • Jute or some other fibrous surface works best to capture flocculated particulate.

  35. Polymer Enhanced Water ClarificationMixing and Dewatering DitchesCase Study: Temporary Dewatering Ditch • The untreated water was greater than 800 NTU. • After treatment, the discharge water was 2.1 NTU. • When they were finished, cleanup was quick and easy.

  36. Polymer Enhanced Water ClarificationDewatering Ditch Video

  37. Polymer Enhanced Water ClarificationMixing and Dewatering Split-Pipes • This application can be used for dewatering or recirculation treatment systems. • Overlap the split pipe segments so that the up-stream piece overlaps the down-stream piece. Seal the joints if needed • Checks can be placed along the split pipe to increase turbulence and mixing with the logs. • Lining with jute or similar matting will provide a place to capture flocculated sediment.

  38. Polymer Enhanced Water ClarificationMixing and Dewatering Split-pipes • In low flow situations, sand bags, rock checks, cinder blocks etc. can be used to facilitate mixing. • When jute matting is added to the system, the flocculated particulate has a surface on which to attach, allowing clean water to discharge.

  39. Polymer Enhanced Water ClarificationIn-Stream Baskets • This is a wire basket system designed to hold a number of Floc Logs and allow water to flow over and around them. • In-stream baskets are used on sites with high flow rates or sites where diversion of the water is not feasible, such as storm water ditch and drain cleanout projects. • Additional Floc Logs can be attached to the working equipment to provide additional dosing directly at the point of turbidity.

  40. Polymer Enhanced Water ClarificationIn-Stream BasketsCase Study: Leitner Creek Bypass Canal • A 4400 foot long canal that discharges into Estero Bay, an OFW (Outstanding Florida Waterbody). • Water levels vary from several inches to over four feet in depth. • Typical problems include: • High turbidity levels from cleanout efforts • Unsightly and lengthy turbidity plumes • Odor complaints as a result of organic sediment Beginning of project

  41. Polymer Enhanced Water ClarificationIn-Stream BasketsCase Study: Leitner Creek Bypass Canal A box was designed and constructed to provide a movable mixing zone for the Floc Logs.

  42. Polymer Enhanced Water ClarificationIn-Stream BasketsCase Study: Leitner Creek Bypass Canal • Several logs were attached to the box so agitation and current flow would dissolve the polymer, releasing a low dosage of the polymer mix to react with the turbidity in the water. • This caused the mucky sediment to form floc material and chelating bridges between individual particles which formed larger, heavier clumps of sediment that settled out with gravity.

  43. Polymer Enhanced Water ClarificationIn-Stream BasketsCase Study: Leitner Creek Bypass Canal Turbidity values in the work area ranged between 423 - 1,000 NTUs.

  44. Polymer Enhanced Water Clarification In-Stream Baskets Case Study: Leitner Creek Bypass Canal • To prevent the reacted particles from escaping the canal, particle curtains were installed. • Reacted particles attach to the surface of the particle curtains while allowing the water to flow through them.

  45. Polymer Enhanced Water ClarificationIn-Stream BasketsCase Study: Leitner Creek Bypass Canal • Two hundred (200) feet downstream of the work area, turbidity was down to 7.5 NTUs. • These levels continued to remain low and resisted re-suspension, so that even more than 1,000 feet downstream of the work area, turbidity levels remained in the range of 10 - 13.5 NTUs.

  46. Polymer Enhanced Water ClarificationIn-Stream BasketsCase Study: Leitner Creek Bypass Canal The polymer enhanced BMPs for this project maintained clear water discharges with NTU values within OFW requirementsandsignificantly reduced odor and increased water clarity resulting in reduced complaints from area residents.

  47. Polymer Enhanced Water ClarificationTank Systems • Tanks Systems: • are designed to be portable and to perform in a variety of flow conditions. • are more efficient when enhanced by the use Floc Logs.

  48. Polymer Enhanced Water ClarificationTank Systems • Launder (pipe) needs to be long enough to meet the required reaction time as seen on the site-specific lab report. • Launder must be installed with a gradient drop that allows the turbid water to flow through it; higher sediment load will require a greater angle to allow the Floc Logs to mix effectively.

  49. Polymer Enhanced Water ClarificationTank Systems Treated water enters the tank where heavier, flocculated particles settle out or are captured by polymer charged particle curtains before the water leaves the tank.

  50. Polymer Enhanced Water ClarificationTank Systems Particle curtains are a simple, effective way to capture fine flocculated particulate. As the treated water flows through the curtains, the water gets progressively cleaner.