Mother Nature s Treatment Methods: Using Passive Treatment for a Variety of Wastewater Streams Brian Tornes, PE
History of Wastewater Treatment Background
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 Fever Hepatitis Malaria
First Attempt at Sanitation Bury the Problem 1800 1900s Pits
Advent of Modern Wastewater Treatment Primary Treatment Insert WWTP photo Secondary Treatment Activated Sludge Tertiary Treatment Filtration
Needs of a Treatment Plant Infrastructure (Tanks, pumps, piping, aerators) POWER (and lots of it) Sludge Disposal Mechanism Maintenance
Passive Treatment An 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 Wetlands An 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 Oxygen Getting Plants Established Algae Growth Natural Decomposition of Plant Material Stormwater Entry Wildlife (Muskrat)
Phyto-Treatment An 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 Access Road Landfill Cap Degraded Cap Municipal Solid Waste Western Unnamed Tributary Interim / Daily Cover Leachate/Groundwater
Precipitation Cap Erodes Leachate Seeps Form Secondary Leachate Accumulates Leachate/Groundwater Increases
Formation of Wetland-Type Vegetation Landfill Cap Saturates Upgradient Leachate Seeps Provide Further Saturation Erosion Channels Form Wetland-Type Vegetation Grows
Wetland Development Landfill Wetland-Type Cap Becomes Vegetation Saturated Grows
Erosion of Toe of Landfill Slope Surface Water Has Eroded Toe of Slope Waste 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 System Onsite Leachate Storage Tank(s) Onsite Wetland Treatment Cell(s)/Mitigation Wastewater Line Formal Leachate Collection System - Additional Regulatory Requirements
Alternative Remediation (Recovery Wells)
Alternative Remediation (Recovery Wells) Recovery Wells Leachate Storage Tanks Onsite Wetland Remediation Cell 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 Filtration Microbial 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
Alternative Treatment Streams Landfill Leachate Stormwater Runoff Groundwater Remediation (Including PCBs) Acid Mine Drainage (metals treatment) Small Capacity Sanitary Wastewater
Questions? Thank you!