New Options for Coating Water and Wastewater Treatment Plants

1. New Options for Coating Water and Wastewater Treatment Plants Presented by Bruce Snyder Business Development Manager Water and Wastewater

2. Protective Coatings Technologies • Coatings technology for years remained the same. • Raw material supplier began to seek a competitive advantage. • Coatings manufacturers began to take advantage of new technologies. • Today, coatings technologies are improving like electronics (very frequently).

3. Why? Prior to the Clean Water Act of 1972, H2S concentrations were below 10 ppm in most municipal systems. The result was very gradual acid attack to concrete and metals. As a result, thin film systems (<25m) such as coal tar epoxy provided effective protection for 10-15 years.

4. 1980 Following the amendment of the Clean Water Act of 1980, industrial pretreatment of wastewater affluent to eliminate or reduce the presence of heavy metals (lead, mercury, cadmium) was mandated. Prior to 1980, these metals killed or retarded the growth of bacteria.

5. Add Covers and Longer Detention Times Consequently, H2S has risen to levels as high as several hundred ppm, averaging over 30 ppm in collection piping, manholes and tanks. H2SO4 concentrations have risen from solutions of 1.5% to as high as 7%, resulting in pH ranges found to be as low as 1.5-2.5, and often less than 1.0! add decreased inflow/infiltration

7. The Result Coating systems that served well prior to 1980, like coal tar epoxy, now often fail in months, not years! Microbial H2SO4 generation attacks steel, concrete, and ductile iron.

11. Controlling Corrosion 1. Change design parameters. (Minimize slow flow or stagnant conditions in treatment stream) 2. Different materials of construction. (Use of vitrified clay, ductile iron, plastics, anti-microbial concrete) 3. Modification of sewage environment. (Raise pH above 9 temporarily to kill SRB; sulfate reducing bacteria) 4. Installation of barrier coatings!

12. Selection Criteria • Remember! – ALL ORGANIC MATERIALS ARE PERMEABLE • “Select materials or systems that provide optimum balance of performance, risk, and cost factors” (Quote – Concrete Repair Manual Vol. 1)

13. Why Flake Filled Topcoat? • Flake Filled with inert material • MIO, Graphite, Glass, Mica • Lower Co-Efficient of Expansion • Reduce permeability (immersion service) • Increase abrasion resistance • Reinforces coating tensile & flexural strength

14. Micaceous Iron Oxide Fe2O3 Flakes then align in parallel fashion. Crystals of MIO are fractured into thin flakes.

15. Types Of Flake Reinforcement Glass Micaceous Iron Oxide (MIO) Graphite (resistance to halogenated acids)

16. Glass Flake Reinforced Amine Epoxy • Upgrade to coal tar epoxy • Lower permeability • Corrosion, impact, and abrasion resistant • Higher dry film thickness than unreinforced epoxies

17. Fast Cure Reinforced Immersion Grade Urethane • Typically aromatic polyurethanes • MIO reinforced • Resistant to H2S and MIC corrosion • Low temperature application • Fast dry and cure times • Monolithic application

18. 100% Solids Epoxy Lining / Mortar/FRE • Amine cured • Chemical Resistant • Resistant to hydrogen sulfide gas, carbon dioxide gas, and microbiologically induced corrosion, and sulfuric acid attack. • High build capabilities

19. 100% Solids Epoxy Lining

20. 100% Solids Epoxy Lining

21. 100% Solids Polyurethane Elastomer • Aromatic polyurethane • High film build capabilities • Flexibility • Quick setting – short downtime • Chemical resistance • Excellent abrasion and impact resistant • Vertical & overhead application • Monolithic application

22. Manhole Rehabilitation

23. 100% Solids Polyurethane Elastomer

24. Fast Cure Polyurea • Fast set and cure, short downtime • Seamless, flexible and waterproof • Chemical resistant • Impact, tear, and abrasion resistant • Bridges moving cracks to 1/8" • Retains physical properties at -20°F to 250°F

25. Fast Cure Polyurea

26. AR425 Polyurea

27. Manhole Rehabilitation

28. Why? Stop I/I (Infiltration and Inflow) and Rebuild

29. Chemical Grouts • Chemical Grouts are broken down into 4 basic Categories. 1.Acrylamide 2.Acrylate 3.Acrylic 4.Polyurethane

30. Polyurethane’s Polyurethane Chemical Grouts are broken in to three categories. 1.Hydrophobic 2.Hydrophilic 3.Multi Component

31. Hydrophilic Flexible Resin only Great Bond Absorbs Water Medium to High Shrinkage Medium Expansion Foam or Gel Hydrophobic Rigid and Flexible Resin + Catalyst Good Bond Repeals Water Low Shrinkage High Expansion Adjustable Set Times Foam Hydrophilic & Hydrophobic

32. Injection Procedures INJECTION STEPS • Determine the location of the leaks. • Slow Down Water Flow. • Drill Injection Port Holes • Insert injection Port or Wall Spear. • Mix Material • Inject Material

33. Insertion of Ports/Wall Spear

34. Injecting the back side

35. Complete encapsulation

36. Here are four products designed to solve problems in Manholes: Polyurethane foam A flexible Polyurethane for cracks and pipe penetration. Hydrophobic: A Polyurethane capable of shutting off gushing leaks and filling voids. Gel : A Polyurethane gel that will seal leaks and stop infiltration through the walls. OAKUM: A dry jute rope when soaked in Polyurethane is capable of filling large cracks. Grouting Leaks in main line pipes can easily be accomplished using Acrylates or Acrylamide grouts. Hydrophilic & HydrophobicPolyurethane Grouts

37. Cementitious Repair Coatings • Portland cement by-products or calcium aluminates • Sprayed or trowel applied • New product mixes allow radial spray with no entry into manhole • Will degrade as the original surface did

38. Advantages Tighter matrix – lower permeability Chemical resistant Drive water off faster than pure portland Disadvantages Susceptible to MIC Longer overcoat time than Calcium Aluminate Mortar Micro Silica/Fumed Silica Mortars

39. Microsilcate Application

40. Microsilcate Application

41. Microsilcate Application

42. Advantages With stands MIC longer than portland based materials Faster set times (Typically 4-24 hours) Can be used as a stand alone liner Disadvantages Susceptible to MIC, but at a reduced rate. Cost Calcium Aluminate Mortar Two types available in the market. Pure Calcium Aluminate Mortar Binder or paste are calcium aluminate as well as the aggregate. Calcium Aluminate Mortar Binder or paste are calcium aluminate and the aggregate is typically silicon dioxide (Silica Sand)

43. Questions?