LAND APPLICATION SYSTEMS

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LAND APPLICATION SYSTEMS
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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

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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

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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

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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.

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SUBSURFACE, SHALLOW SYSTEMS
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SUBSURFACE, SHALLOW SYSTEMS

• Used for single dwelling or small clusters of
  dwellings
• In California theres about 1 million households
  currently being served by these systems

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SUBSURFACE, SHALLOW SYSTEMS

• Three most common shallow subsurface systems
• Leachfields (a.k.a. Leaching Chambers)
• Mound Systems
• Seepage Pits

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SUBSURFACE, SHALLOW SYSTEMS LEACHFIELDS
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SUBSURFACE, SHALLOW SYSTEMS LEACHFIELDS

• Used to dispose of previously treated effluents
  (usually originally treated by means of septic
  tank)

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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

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SUBSURFACE, SHALLOW SYSTEMS LEACHFIELDS
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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

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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

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SUBSURFACE, SHALLOW SYSTEMS LEACHFIELDS
Setback distances
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SUBSURFACE, SHALLOW SYSTEMS LEACHFIELDS
Soil Acceptance Rate
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SUBSURFACE, SHALLOW SYSTEMS LEACHFIELDS
Preliminary Cost Estimate
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SUBSURFACE, SHALLOW SYSTEMS LEACHFIELDS
The seat under the old oak tree in a leachfield
at Brookmans Park
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SUBSURFACE, SHALLOW SYSTEMS MOUND SYSTEM
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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

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SUBSURFACE, SHALLOW SYSTEMS MOUND SYSTEM
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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

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SUBSURFACE, SHALLOW SYSTEMS MOUND SYSTEM
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SUBSURFACE, SHALLOW SYSTEMS MOUND SYSTEM
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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

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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

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SUBSURFACE, SHALLOW SYSTEMS MOUND SYSTEM
Criteria for Design
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SUBSURFACE, SHALLOW SYSTEMS MOUND SYSTEM
Cost Estimate for Mound Systems
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SUBSURFACE, SHALLOW SYSTEMS MOUND SYSTEM
Picture of a typical on-site mound system 
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SUBSURFACE, SHALLOW SYSTEMS SEEPAGE PITS
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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 its contained
  until it seeps through the walls and goes into
  the excavation wall

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SUBSURFACE, SHALLOW SYSTEMS SEEPAGE PITS
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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

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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

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SUBSURFACE, SHALLOW SYSTEMS SEEPAGE PITS
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LAND DISPOSAL SYSTEMS
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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

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LAND DISPOSAL SYSTEMS

• Three main land disposal systems used for
  pretreated municipal effluents
• Slow-Rate Systems (SR)
• Rapid Infiltration Systems (RI)
• Overland Flow (OF)

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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
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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

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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

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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

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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

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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS Type 2
Treatment Plant and Golf Coarse
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
Slow Rate Spray Irrigation
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
Harvesting Forage
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
Spray Irrigation in Forest
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
Drip Irrigation
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
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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 -----gt new cells
  CO2 NO3- H2O

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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS

• Particulate material is filtered through the soil
  matrix

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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS

• Nitrogen is removed by
• Vegetation uptake
• Biological denitrification
• Ammonia volatilization
• Retention within soil matrix

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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS

• Phosphorus removal via crop uptake and fixation
  processes in the soil matrix.

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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS

• SR Systems are very effective at removing harmful
  wastewater constituents

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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.
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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.
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
General design parameters for SR system
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
Flowchart For The Design Of A Slow Rate System
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LAND DISPOSAL SYSTEMS SLOW-RATE SYSTEMS
A preliminary estimate of costs for planning
purposes
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LAND DISPOSAL SYSTEMS RAPID INFILTRATION
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LAND DISPOSAL SYSTEMS RAPID INFILTRATION

• Usually used for
• Ground water recharge
• Surface water recharge
• Recovery of renovated water (by wells or
  underdrains) for reuse
• Temporary storage of treated waters

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LAND DISPOSAL SYSTEMS RAPID INFILTRATION

• Wastewater percolates through the soil and is
  treated through downward flow
• Vegetation is NOT a part of the treatment

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LAND DISPOSAL SYSTEMS RAPID INFILTRATION
Hydraulic pathways for RI systems
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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.

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LAND DISPOSAL SYSTEMS RAPID INFILTRATION

• Removal rates are dependent on
• Wastewater characteristics
• Soil characteristics
• Travel distance
• Climatic and seasonal variables

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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

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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.

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LAND DISPOSAL SYSTEMS RAPID INFILTRATION

• Advantages

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.
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LAND DISPOSAL SYSTEMS RAPID INFILTRATION

• Disadvantages
• Usually wont 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

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LAND DISPOSAL SYSTEMS RAPID INFILTRATION

• Flowchart For The Design Of A Rapid Infiltration
  System

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LAND DISPOSAL SYSTEMS RAPID INFILTRATION
Estimating Costs for Rapid Infiltration
Systems (OM includes the annual tillage of
infiltration surfaces, and the repair of dikes,
fences, and roads every 10 years.)
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LAND DISPOSAL SYSTEMS OVERLAND FLOW SYSTEMS
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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

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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

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LAND DISPOSAL SYSTEMS OVERLAND FLOW SYSTEMS
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LAND DISPOSAL SYSTEMS OVERLAND FLOW SYSTEMS

• Best suited for sites with relatively impermeable
  soils

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LAND DISPOSAL SYSTEMS OVERLAND FLOW SYSTEMS

• Land Requirements
• Low permeability soils
• Grading within 2-8

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LAND DISPOSAL SYSTEMS OVERLAND FLOW SYSTEMS

• Perennial grasses used for
• Erosion control
• Slope stability
• Effluent treatment

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LAND DISPOSAL SYSTEMS OVERLAND FLOW SYSTEMS

• Removal mechanisms for BOD and Suspended Solids
• Biological Oxidation
• Sedimentation
• Filtration

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LAND DISPOSAL SYSTEMS OVERLAND FLOW SYSTEMS

• Removal mechanisms for Nitrogen (typically
  removes 75-90)
• Plant uptake
• Denitrification
• Ammonia Volatilization

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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

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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

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LAND DISPOSAL SYSTEMS OVERLAND FLOW SYSTEMS

• Flowchart For the Design Of Overland Flow Systems

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LAND DISPOSAL SYSTEMS COMPARISON
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LAND DISPOSAL SYSTEMS COMPARISON

• Desirable characteristics, not rigorous standards

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LAND DISPOSAL SYSTEMS COMPARISON

• Terrestrial treatment units, design features, and
  performance (Reed et al, 1995)

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LAND DISPOSAL SYSTEMS COMPARISON

• Expected water quality function of hydraulic
  loading, available soils for treatments,
  vegetation.

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LAND APPLICATION SYSTEMS
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LAND APPLICATION SYSTEMS