mother nature’s treatment methods -...
TRANSCRIPT
Mother Nature’s Treatment Methods: Using Passive Treatment for a Variety of
Wastewater StreamsBrian Tornes, PE
History of Wastewater TreatmentBackground
The Start of Sanitation
Evidence of Sewers as Far Back as 8000 BC
Cesspits 4000 BC
Lothal, Western India 2500 B.C.
Rome’s Advances
Combined Sewers at their best
Regression of the Middle Ages
Treatment During This Time
Dilution was the solution
Downstream users’ problem
Natural breakdown of wastes
Population Explosion
Rapid Growth
Concentrated Populations
Home Conveniences
Health Issues
Understanding the Need for Treatment
Plague of Justinian Black Death Bubonic Plague Yellow Fever Cholera Typhoid FeverHepatitisMalaria
First Attempt at Sanitation – Bury the Problem
1800 – 1900s Pits
Advent of Modern Wastewater Treatment
Primary Treatment
Secondary Treatment Activated Sludge
Tertiary Treatment Filtration
Insert WWTP photo
Needs of a Treatment Plant
Infrastructure (Tanks, pumps, piping, aerators)
POWER (and lots of it)
Sludge Disposal Mechanism
Maintenance
Passive TreatmentAn alternative to conventional treatment systems
Types of Passive Treatment
Constructed Wetlands Surface and subsurface
Phyto-Treatment Use of trees
Potential Benefits
Low Electrical Energy Requirement
Function Under Both High and Low Loading Rates
Low Operating Cost
Constructed WetlandsAn alternative to conventional treatment systems
Constructed Wetlands – How do they work?
Wetland Case Study: Camp Otterbein
Owned by United Methodist Church in Logan, Ohio
Summer Camp/Weekend Retreats
Capacity for 180 guests
Wastewater Treatment at Camp Otterbein
1950’s Package Plant for 10,000 gpd
Secondary Level Treatment
Poorly Maintained Operation
Design Loading
Hydraulic Loading : 10,000 gpd Water meter: 0 – 5,400 gpd (7,600 gpd peak) High storm water inflow and infiltration
BOD : 220 mg/l TSS : 220 mg/l
Wastewater Handling Alternatives
Pump to Logan (2 miles)
Activated Sludge Process with Sand Filtration/Disinfection
Activated Sludge with (0.3 Acre) Constructed Wetland
Septic Tank(s) with Constructed Wetland
Remote Treatment Problems(Packaged Treatment Plant)
Poor Maintenance Equipment failures No operation adjustments
Power Failures
Load Fluctuations(Upsets) Ineffective treatment
Why Pay More for Wetlands
Replaces Dosing Chamber, Sand Filters, Disinfection
Wetland Advantages Excess solids removal Excess nutrient/BOD uptake Handles fluctuating loads Low maintenance Natural setting
Septic vs. Activated Sludge
Septic Pretreatment Concerns
Odor
Higher solids loading to wetland
Nitrogen Loading Much larger wetland is required (10-12 times)
System Flow Diagram
Activated Sludge Process
Wetland Design Features (Configuration)
Rectangular Avoid short-circuiting Low velocity
Inlet/Outlet Features
Even Flow Distribution Level Adjustment Capabilities Liner Protection
Wetland Design Features (Liner)
Cross Section Liner: Clay vs. GCL 12” Topsoil
Wetland Construction – 1 year to maturity
Concerns with Constructed Wetlands
Low Dissolved OxygenGetting Plants Established Algae GrowthNatural Decomposition of
Plant Material Stormwater EntryWildlife (Muskrat)
Phyto-TreatmentAn alternative to conventional treatment systems
Phyto-Treatment (Phytotechnology Mechanisms)
Phytosequestration Rhizodegradation Phytohydraulics Phytoextraction Phytodegradation Phytovolatilization
*Phytotechnology Technical and Regulatory Guidance and Decision Trees, Revised (ITRC, February 2009)
Watson Road Landfill
Existing Conditions
NPDES Permit Exceedances Landfill Cap Erosion Leachate/Groundwater Interim/Daily Cover/Leachate
Newark Watson Road Landfill
WesternUnnamedTributary
DegradedCap
AccessRoad
MunicipalSolid Waste
Leachate/Groundwater
Interim / Daily Cover
Landfill Cap
Precipitation
Leachate/Groundwater Increases
Precipitation
Secondary LeachateAccumulates
Cap ErodesLeachate Seeps Form
Formation of Wetland-Type Vegetation
Landfill Cap SaturatesUpgradient Leachate Seeps Provide Further
Saturation Erosion Channels FormWetland-Type Vegetation Grows
Wetland Development
Landfill Cap Becomes Saturated
Wetland-Type Vegetation Grows
Erosion of Toe of Landfill Slope
Surface Water Has Eroded Toe of SlopeWaste Exposed Leachate Discharge Points Formed
Landfill Toe Erosion
Leachate Management Alternatives
Pump and Treat Cap repairs Cut-off wall Pump over 1 mile to
City WWTP Variable leachate
volume Expensive
Phyto-Treatment Cap repairs Tree planting to reduce
leachate volume Treatment buffer to
meet limits Continued NPDES
discharge Lower costs
Recovery Wells/Horizontal Trench
Install Water Recovery Wells or Horizontal Trench SystemOnsite Leachate Storage Tank(s)Onsite Wetland Treatment Cell(s)/MitigationWastewater Line Formal Leachate Collection System - Additional
Regulatory Requirements
Alternative Remediation (Recovery Wells)
Alternative Remediation (Recovery Wells)
Onsite WetlandRemediation Cell
LeachateStorage Tanks
Recovery Wells
Offsite Wastewater Line
The Solution - Phyto-Cap
Planting Over 3,000 Willows and Poplars Inter-Planting of Another 300 Native Hardwoods
And E-Buffer
Evapotranspiration Subsurface FiltrationMicrobial Activity at the
Root Zone
Phytoremediation
Operational Concerns
Up to 5 Years for Maturity Compliance Sampling Access Deer Insects Voles
Results
Deer – Required replanting of 80% of trees with deer guards
241 NPDES exceedances between 2003 and 2009 (72 for ammonia)
Since installation in 2012, only 3 minor exceedances, none of which were for ammonia
Estimated capital cost savings of $3.5 Million over traditional collect and pump
Operational savings still growing
Passive Treatment
Not for all waste streams, but where opportunities exist…
Landfill Leachate Stormwater RunoffGroundwater Remediation
(Including PCBs) Acid Mine Drainage
(metals treatment) Small Capacity Sanitary
Wastewater
Alternative Treatment Streams
Questions?Thank you!