Liner Construction & Testing Guidance Overview

Transcription

1 Liner Construction & Testing Guidance Overview Ruben Meza, Jr., P.E. Waste Permits Division Municipal Solid Waste Permits Section 2017: TCEQ Environmental Trade Fair

2 Agenda Summary of Revised Guidance Document Liner Design Basic Requirements Compacted Clay Liner Geomembrane Geosynthetic Clay Liner (GCL) Geocomposite Material 2

3 Description of Revised Guidance New Title: Guidance for Liner Construction & Testing for a MSW Landfill Procedures for installation & testing of liner system Complies with regulations in 30 TAC Chapter 330, Subchapter H: Liner System Design & Operation Status: finalize by late summer

4 Document History September 1, 1993: QA-QC for Waste Containment Facilities July 1, 1994: Liner & Construction Handbook July 7, 2000: Final Cover Systems Cons & Testing (Draft) November 1, 2001: Liner Construction & Testing (Draft) 4

5 Noted Revisions Flexibility for soil compaction New section for protective cover Low-ground-pressure equipment may travel on geomembrane Revised geomembrane procedures: manufacturing testing: GRI GM-13 seaming procedures: GRI GM-9 seam testing: GRI GM-19 5

6 Noted Revisions Revised testing methods: clay liner, geomembrane, and GCL Test Methods: geocomposite drainage layer Flexibility for testing methods Updated Glossary 6

7 Liner Quality Control Plan Regulations 30 TAC : Design Criteria 30 TAC : Leachate Collection System 30 TAC : Alternative Liner Design 30 TAC : Special Liner Design Constraints 30 TAC : Liner Quality Control Plan 30 TAC : SLER & GLER 7

8 Landfill Liner Design Basic Requirements 8

9 Liner System Design 9

10 Type I Liner 2-ft Protective Cover Single / Double Sided Geocomposite 60-mil Smooth/Textured HDPE Geomembrane 2-ft Clay Liner 10

11 Type I Liner with GCL 2-ft Protective Cover Single / Double Sided Geocomposite 60-mil Smooth / Textured HDPE Geomembrane Unreinforced / Reinforced GCL 11

12 Class 1 Cell 2-ft Protective Cover Single / Double Sided Geocomposite 60-mil Smooth / Textured HDPE Geomembrane 3-ft Clay Liner 12

13 Type IV Liner Compacted Clay Liner 1-ft Protective Cover 3-ft Clay Liner In-Situ Liner 4-ft In-Situ Liner Top one foot for protective cover 13

14 Compacted Clay Liner Installation & Testing 14

15 Compacted Clay Liner Requirements Design Values Plasticity Index 15 Liquid Limit 30 Percent Passing No. 200 Sieve 30% Percent Passing one-inch sieve = 100% Permeability 1 x 10-7 cm/sec 15

16 Soil Testing Source Borrow Materials Source Borrow Materials Soil Classification Moisture/Density Relationship Sieve Analysis Atterberg Limits Coefficient of Permeability 16

17 Moisture / Density Relationship Test: standard / modified proctor test Results: max dry unit weight & optimum moisture content Use parameters to compact liner Source: EPA/600/R-93/182, September

18 Soil Compaction Sheepsfoot Roller Tamping Foot Roller 18

19 Constructed Liner Conformance Testing Field Density Atterberg Limits Permeability Thickness Verification 19

20 Geomembrane Installation & Testing 20

21 HDPE Geomembrane HDPE: High Density Polyethylene Composition: 97% polyethylene resin 2 3% carbon black and additives Typically 60-mil Source: 21

22 Hot Wedge Seaming Hot Wedge Welding Machine Hot Wedge Seaming 22

23 Extrusion Welding Extrusion Welding Machine Machine Cross Section 23

24 Geomembrane - Seams Source: EPA/600/R-93/182, September

25 Geomembrane Manufacturer Testing Manufacturer Testing: GRI GM-13 Thickness Density Tensile Properties Tear Resistance Puncture Resistance Stress Crack Resistance Carbon Black Content Carbon Black Dispersion Oxidation Induction Time Oven Aging UV Resistance 25

26 Geomembrane Conformance Testing Conformance Testing: Thickness Density Carbon Black Content & Dispersion Tensile Properties Destructive Testing Shear Peal Non-destructive Testing Air Pressure Vacuum Box 26

27 Hot Wedge Seaming Seam Strength Seam Strength from GRI GM- 19 for 60 mil HDPE Geomembrane: Shear Strength: 120 lb/in Shear Elongation: 50% Peel Strength: 91 lb/in Peel Elongation: 25% Source: 27

28 Extrusion Welding Seam Strength Seam Strength from GRI GM- 19 for 60 mil HDPE Geomembrane: Shear Strength: 120 lb/in Shear Elongation: 50% Peel Strength: 78 lb/in Peel Elongation: 25% Source: 28

29 Shear Test GRI Testing Photos 29

30 Shear Test Photo 1 Source: 30

31 Shear Test Photo 2 Source: 31

32 Shear Test Photo 3 Source: 32

33 Shear Test Photo 4 Source: 33

34 Shear Test Photo 5 Source: 34

35 Peel Test GRI Testing Photos 35

36 Peel Test Photo 1 Source: 36

37 Peel Test Photo 2 Source: 37

38 Peel Test Photo 3 Source: 38

39 Peel Test Photo 4 Source: 39

40 Peel Test Photo 5 Source: 40

41 Peel Test GRI Testing Photos Source: Photo 1 41

42 Peel Test GRI Testing Photos Source: Photo 2 42

43 Geosynthetic Clay Liner (GCL) Installation & Testing 43

44 GCL Summary Bentonite layer supported by geotextiles and/or geomembranes Held together by needling, stitching, or chemical adhesives 44

45 GCL: Non-reinforced Source: Designing with Geosynthetics 6th ed. 45

46 GCL: Internally Reinforced Source: Designing with Geosynthetics 6th ed. 46

47 GCL - Sodium Bentonite sodium montmorillonite variety naturally occurring mineral found in Wyoming and North Dakota Properties: k 1 x cm/sec w 100% self healing Source: 47

48 Geotextiles - Overview Made from polymeric fibers Fibers are made from polypropylene, carbon black, and additives Once fibers are manufactured they are joined together to make a fabric or geotextile Geotextiles are classified as woven and nonwoven 48

49 Woven Geotextile Woven Geotextile at 24X Magnification Source: EPA/600/R-93/182, September

50 Nonwoven Needle Punched Geotextile Nonwoven Needle Punched Geotextile at 24X Magnification Source: EPA/600/R-93/182, September

51 Nonwoven Heat Bonded Geotextile Nonwoven Heat Bonded Geotextile at 24X Magnification Source: EPA/600/R-93/182, September

52 GCL Installation Subgrade preparation similar to procedures in geomembrane section Joining GCLs is done by overlapping without sewing or other mechanical connections Overlap distances should be marked on GCL by manufacturer (typically 6 12 in.) 52

53 GCL - Installation GCL with needle punched nonwoven geotextiles require bentonite in the overlap regions Minimum Bentonite Required: 0.25-lb dry bentonite per linear foot of lap joint Bentonite in lap-joint must be the same type used in the manufacture of the GCL 53

54 GCL Manufacturer Testing Bentonite Free Swell Fluid Loss Geotextile Mass / unit area Grab Tensile Strength Geomembrane Mass / Unit Area Thickness Tensile Properties GCL Product Bentonite mass / unit area Bentonite moisture content Tensile strength Grab tensile strength Permeability Lap Joint Permeability 54

55 GCL Conformance Testing GCL Product Bentonite mass / unit area Permeability Direct shear 55

56 Direct Shear Device - GCL Source: Shear Strength of GCL s,

57 Direct Shear - GCL Source: Shear Strength of GCL s,

58 Interface Shear Testing GCL / Geomembrane Source: Shear Strength of GCL s,

59 Failure Envelope τ " = c % + σ tan δ Source: Shear Strength of GCL s,

60 Geocomposite Material Installation & Testing 60

61 Geocomposite Material Composition: geonet with a geotextile or geomembrane heat bonded on 1 or both sides Geocomposite drainage layer has replaced granular drainage layer Fluid flows within the geonet Source: 61

62 Geonets - Summary Manufactured similar to geomembrane Composition: 97% polyethylene; 2 3% carbon black and additives Typically covered with a geomembrane or geotextile Source: 62

63 Geocomposite - Installation Material is positioned and unrolled over substrate material (typically geomembrane) The material is either overlapped or sewn together In any case, follow manufacturers directions for installation and connections 63

64 Geocomposite Manufacturer Testing (Resin) Geonet Density Melt Flow Index Geonet Density Mass / Area Thickness Compression Transmissivity Geotextile Mass / Area Grab Tensile Strength Trapezoidal Tear Strength Burst Strength Puncture Strength Thickness Apparent Opening Size Permitivity 64

65 Geocomposite Conformance Testing GCL Product Transmissivity Interface Shear or Ply Adhesion 65

66 Conclusion Draft guidance has been posted online: ts/msw_permits/msw_liners_covers.html We are accepting stakeholder comments until May 31, We plan to have this document finalized by late summer

67 Questions? How to contact us: Texas Commission on Environmental Quality Municipal Solid Waste Permits Section P. O. Box MC-124 Austin, TX Phone: Fax: