1. LAND APPLICATION SYSTEMS

2. OUTLINE OF PRESENTATION
Types of Land Applications: Brief Overview.
Definitions: Basic Terminology
3. Subsurface, Shallow Systems: In Depth
a. Leachfields
b. Mound Systems
c. Seepage Pits
4. Land Disposal Systems: In Depth Coverage
a. Slow Rate (SR) Infiltration Systems
b. Rapid Infiltration (RI) Systems
c. Overland Flow Systems
d. Planning and design
d. Comparison

3. DEFINITIONS Effluent: Flow going out of or leaving a process.
Influent: Flowing into
BOD: Biological oxidation demand
TSS: Total suspended solids
TN: Total nitrogen
TP: Total phosphorous
FC: Fecal Coliform
AWT: Advanced water treatment
SAR: Soil absorption rate
SR: Slow rate
RI: Rapid infiltration
OF: Overland flow

4. Types of Land Application Systems: Three Basic Types
SUBSURFACE, SHALLOW AND DEEP SYSTEMS
Used in single dwellings and small clusters of dwellings
LAND DISPOSAL SYSTEMS
Used for pretreated municipal effluents
IRRIGATION AND LANDSCAPE USES
Used for final treatment and discharge of wastewater on vegetated plots

5. Types of Land Application Systems
The greater the waste strength, the larger the system must be.
This is true for all system types, and although each type of system introduces water into the soil differently, sizing for the system you choose is critical.
At some point the soil will not accept any more wastewater, causing failure.

6. SUBSURFACE, SHALLOW SYSTEMS

7. SUBSURFACE, SHALLOW SYSTEMS
Used for single dwelling or small clusters of dwellings
In California there’s about 1 million households currently being served by these systems

8. SUBSURFACE, SHALLOW SYSTEMS
Three most common shallow subsurface systems:
Leachfields (a.k.a. Leaching Chambers)
Mound Systems
Seepage Pits

9. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS

10. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS
Used to dispose of previously treated effluents (usually originally treated by means of septic tank)

11. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS
Usually set of leaching chambers in trenches
Connected to primary treatment system by a pipe
Effluent is distributed into the soil

12. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS

13. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS
ADVANTAGES:
Easy and economic to construct
Soil in trenches not likely to be compacted
Extended useful life: low intrusion on soil and silt
Small footprint

14. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS
DISADVANTAGES:
Not well suited for soils with high percolation rates (e.g. sandy soils)
Not well suited for soils with high groundwater levels

15. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS
Setback distances:

16. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS
Soil Acceptance Rate:

17. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS
Preliminary Cost Estimate:

18. SUBSURFACE, SHALLOW SYSTEMS: LEACHFIELDS
The seat under the old oak tree in a leachfield at Brookmans Park

19. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM

20. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM
Used to further treat pre-treated effluents
Comprised of pressure-dose sand filters that lie above the ground
Discharge directly to the soil

21. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM

22. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM
Suited for sites with restriction such as:
Slow or fast permeability
Shallow soil cover over creviced or porous bedrock
Elevated water table

23. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM

24. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM

25. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM
ADVANTAGES:
Accommodate sites that otherwise are not suitable for in-ground or at-gate onsite disposal
Do not discharge directly to surface water bodies
Can be used in most climates
Little excavation required
Mound System
Advantages to the Mound Systems

26. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM
DISADVANTAGES:
Relatively high construction costs
Mound location can affect surface drainage pattern
Require pumping/siphon systems
Aesthetically obtrusive
Seepages/Leakages can affect mount integrity

27. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM
Criteria for Design:

28. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM
Cost Estimate for Mound Systems:

29. SUBSURFACE, SHALLOW SYSTEMS: MOUND SYSTEM
Picture of a typical on-site mound system 

30. SUBSURFACE, SHALLOW SYSTEMS: SEEPAGE PITS

31. SUBSURFACE, SHALLOW SYSTEMS: SEEPAGE PITS
Used for disposal of treated wastewater effluents
Brick, block, or precast chambers placed in deep excavations surrounded by gravel of crushed rocks
Effluents enter the chamber where it’s contained until it seeps through the walls and goes into the excavation wall

32. SUBSURFACE, SHALLOW SYSTEMS: SEEPAGE PITS

33. SUBSURFACE, SHALLOW SYSTEMS: SEEPAGE PITS
ADVANTAGES:
Easy to construct
Requires little maintenance
Able to treat on sites with inadequate land resources for a standard absorption field

34. SUBSURFACE, SHALLOW SYSTEMS: SEEPAGE PITS
DISADVANTAGES:
Danger of groundwater contamination
Effluent is concentrated at one point, rather than large area
Small flow able to be treated

35. SUBSURFACE, SHALLOW SYSTEMS: SEEPAGE PITS

36. LAND DISPOSAL SYSTEMS

37. LAND DISPOSAL SYSTEMS
Used to dispose of pretreated municipal effluents
Not widely used due to large land requirements, exacerbated by code-required setbacks (often including buffer areas and fencing)
Also used less frequently due to requirement of significant pretreatment before application

38. LAND DISPOSAL SYSTEMS
Three main land disposal systems used for pretreated municipal effluents:
Slow-Rate Systems (SR)
Rapid Infiltration Systems (RI)
Overland Flow (OF)

39. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS

40. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
The oldest and most widely used form of land treatment, requires largest land area compared to the other land disposal systems
Used to further treat wastewater effluent via contact with the soil-vegetation system
Used when stringent requirements are placed on nutrients, pathogens, metals, and organics
Used in agricultural, turf (e.g., golf courses, parks), and forest systems

41. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
SR type 1- chosen to maximize amount of water to the minimum area of land
SR type 2- chosen to optimize hydraulic loading for irrigation purposes

42. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS: Type 1
Intended for wastewater treatment and hydraulic loading
Limited by the hydraulic capacity of soil (nitrogen removal ability, etc.)
Vegetation covers usually include perennial grasses due to the high nitrogen uptake ability, long WW application season, and low maintenance

43. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS: Type 2
Primarily intended for providing water and nutrients to agricultural, turf, and forest system
Can not be applied to products consumed by humans

44. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS: Type 2
Treatment Plant and Golf Coarse:

45. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS:
Slow Rate Spray Irrigation:

46. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS:
Harvesting Forage:

47. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS:
Spray Irrigation in Forest:

48. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS:
Drip Irrigation:

49. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS:
b.) Recovery Pathways
Underdrains
Wells
a.) Application Pathway
Applied Wastewater
Evapotranspiration

50. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
Organics are removed mainly within the first 1 to 2 cm by biological oxidation, filtration, and adsorption
OXIDATION e.g.:
Organic matter + O2 + bacteria -----> new cells + CO2 + NO3- + H2O

51. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS

52. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
Particulate material is filtered through the soil matrix

53. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
Nitrogen is removed by:
Vegetation uptake
Biological denitrification
Ammonia volatilization
Retention within soil matrix

54. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS

55. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
Phosphorus removal via crop uptake and fixation processes in the soil matrix.

56. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
SR Systems are very effective at removing harmful wastewater constituents

57. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
ADVANTAGES:
• Significantly reduced operational, labor, chemical, and energy requirements compared to conventional wastewater treatment systems.
• Economic return from the use and re-use of water and nutrients to provide marketable crops.
• Little or no disposal of effluent production.
• Recycling and reuse of water reduces water distribution and treatment costs for crop irrigation.

58. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
DISADVANTAGES:
•Large land requirements
Specific problems associated with poor site selection include:
• Soil structure dispersion resulting from high dissolved salts concentration.
• Runoff and erosion for sites with steep slopes or lack of adequate erosion protection.
• Inadequate soil or groundwater characterization resulting in operational hydraulic problems.

59. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
General design parameters for SR system:

60. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
Flowchart For The Design Of A Slow Rate System

61. LAND DISPOSAL SYSTEMS: SLOW-RATE SYSTEMS
A preliminary estimate of costs for planning purposes:

62. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION

63. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
NEED TO COVER THESE WORDS!
more
Usually used for:
Ground water recharge
Surface water recharge
Recovery of renovated water (by wells or underdrains) for reuse
Temporary storage of treated waters

64. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
Wastewater percolates through the soil and is treated through downward flow
Vegetation is NOT a part of the treatment

65. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
a.) Hydraulic Pathway
Percolation
Evaporation
Applied Wastewater
Flooding Basins
Recovered Water
b.) Recovery Pathways
Underdrains
c.) Natural Drainage Into Surface Waters
Flooding Basin
Hydraulic pathways for RI systems:

66. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
Most RI failures are due to improper soil elevations.
Soil depth, soil permeability, and depth to groundwater are the most important factors in site evaluation.

67. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
Removal rates are dependent on:
Wastewater characteristics
Soil characteristics
Travel distance
Climatic and seasonal variables

68. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
BOD, Suspended Solids, and Fecal Coliforms are almost completely removed
Nitrogen removal is about 50-99%
Phosphorus removal is about 70-99%

69. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
Advantages:
Gravity distribution methods consume no energy.
• No chemicals are required.
• RI is a simple and economical treatment.
The process is not constrained by seasonal changes.
• Effluent is of excellent quality.

70. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
Advantages:
And then there were three
• The process is very reliable with sufficient resting periods.
• The process is suitable for small plants where operator expertise is limited.
• RI provides a means for groundwater recharge, controlling
groundwater levels, recovering renovated water for reuse or discharge to a particular surface water body, and temporary storage of renovated water in the aquifer.

71. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
Disadvantages:
Usually won’t meet nitrogen levels required for drinking water aquifer discharge.
Requires long term commitment of significant land area
Requires annual removal of accumulated deposits of organic matter
May require occasional removal and disposal of the top few inches of soil
Clogging can occur when influent is received at high application rates from algal laden lagoons and ponds

72. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
Flowchart For The Design Of A Rapid Infiltration System:

73. LAND DISPOSAL SYSTEMS: RAPID INFILTRATION
Estimating Costs for Rapid Infiltration Systems
(O&M includes the annual tillage of infiltration surfaces, and the repair of dikes, fences, and roads every 10 years.)

74. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS

75. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Used to achieve secondary treatment effluent quality when applying effluents comming from primary treatment facilities.
High removal of Nitrogen, BOD, and Suspended Solids

76. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Applying of previously treated wastewater effluents to a vegetation-covered, graded land
Applied via grated pipes or nozzles at top of slope or by sprinkler systems within the site

77. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS

78. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Best suited for sites with relatively impermeable soils

79. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Land Requirements:
Low permeability soils
Grading within 2-8%

80. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Perennial grasses used for:
Erosion control
Slope stability
Effluent treatment

81. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Removal mechanisms for BOD and Suspended Solids:
Biological Oxidation
Sedimentation
Filtration

82. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Removal mechanisms for Nitrogen (typically removes 75-90%):
Plant uptake
Denitrification
Ammonia Volatilization

83. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Removal mechanisms for Phosphorus (typically removes 50-70%- can increase by addition of alum of ferric chloride prior to land application):
Fixation processes in the soil matrix
Crop uptake

84. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Effluent is collected in ditches and can be reused or discharged to a surface water body
If discharged to surface body: NPDES permit required

85. LAND DISPOSAL SYSTEMS: OVERLAND FLOW SYSTEMS
Flowchart For the Design Of Overland Flow Systems

86. LAND DISPOSAL SYSTEMS: COMPARISON

87. LAND DISPOSAL SYSTEMS: COMPARISON
Desirable characteristics, not rigorous standards:

88. LAND DISPOSAL SYSTEMS: COMPARISON
Terrestrial treatment units, design features, and performance (Reed et al, 1995):

89. LAND DISPOSAL SYSTEMS: COMPARISON
Expected water quality: function of hydraulic loading, available soils for treatments, vegetation.

90. LAND APPLICATION SYSTEMS

91. LAND APPLICATION SYSTEMS