Mother Nature s Treatment Methods:

Transcription

1 Mother Nature s Treatment Methods: Using Passive Treatment for a Variety of Wastewater Streams Brian Tornes, PE

2 History of Wastewater Treatment Background

3 The Start of Sanitation Evidence of Sewers as Far Back as 8000 BC Cesspits 4000 BC Lothal, Western India 2500 B.C.

4 Rome s Advances Combined Sewers at their best

5 Regression of the Middle Ages

6 Treatment During This Time Dilution was the solution Downstream users problem Natural breakdown of wastes

7 Population Explosion Rapid Growth Concentrated Populations Home Conveniences Health Issues

8 Understanding the Need for Treatment Plague of Justinian Black Death Bubonic Plague Yellow Fever Cholera Typhoid Fever Hepatitis Malaria

9 First Attempt at Sanitation Bury the Problem s Pits

10 Advent of Modern Wastewater Treatment Primary Treatment Insert WWTP photo Secondary Treatment Activated Sludge Tertiary Treatment Filtration

11 Needs of a Treatment Plant Infrastructure (Tanks, pumps, piping, aerators) POWER (and lots of it) Sludge Disposal Mechanism Maintenance

12 Passive Treatment An alternative to conventional treatment systems

13 Types of Passive Treatment Constructed Wetlands Surface and subsurface Phyto-Treatment Use of trees

14 Potential Benefits Low Electrical Energy Requirement Function Under Both High and Low Loading Rates Low Operating Cost

15 Constructed Wetlands An alternative to conventional treatment systems

16 Constructed Wetlands How do they work?

17 Wetland Case Study: Camp Otterbein Owned by United Methodist Church in Logan, Ohio Summer Camp/Weekend Retreats Capacity for 180 guests

18 Wastewater Treatment at Camp Otterbein 1950 s Package Plant for 10,000 gpd Secondary Level Treatment Poorly Maintained Operation

19 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

20 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

21 Remote Treatment Problems (Packaged Treatment Plant) Poor Maintenance Equipment failures No operation adjustments Power Failures Load Fluctuations(Upsets) Ineffective treatment

22 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

23 Septic vs. Activated Sludge Septic Pretreatment Concerns Odor Higher solids loading to wetland Nitrogen Loading Much larger wetland is required (10-12 times)

24 System Flow Diagram

25 Activated Sludge Process

26 Wetland Design Features (Configuration) Rectangular Avoid short-circuiting Low velocity

27 Inlet/Outlet Features Even Flow Distribution Level Adjustment Capabilities Liner Protection

28 Wetland Design Features (Liner) Cross Section Liner: Clay vs. GCL 12 Topsoil

29 Wetland Construction 1 year to maturity

30 Concerns with Constructed Wetlands Low Dissolved Oxygen Getting Plants Established Algae Growth Natural Decomposition of Plant Material Stormwater Entry Wildlife (Muskrat)

31 Phyto-Treatment An alternative to conventional treatment systems

32 Phyto-Treatment (Phytotechnology Mechanisms) Phytosequestration Rhizodegradation Phytohydraulics Phytoextraction Phytodegradation Phytovolatilization *Phytotechnology Technical and Regulatory Guidance and Decision Trees, Revised (ITRC, February 2009)

33 Watson Road Landfill

34 Existing Conditions NPDES Permit Exceedances Landfill Cap Erosion Leachate/Groundwater Interim/Daily Cover/Leachate

35 Newark Watson Road Landfill Access Road Landfill Cap Degraded Cap Municipal Solid Waste Western Unnamed Tributary Interim / Daily Cover Leachate/Groundwater

36 Precipitation Cap Erodes Leachate Seeps Form Secondary Leachate Accumulates Leachate/Groundwater Increases

37 Formation of Wetland-Type Vegetation Landfill Cap Saturates Upgradient Leachate Seeps Provide Further Saturation Erosion Channels Form Wetland-Type Vegetation Grows

38 Wetland Development Landfill Wetland-Type Cap Becomes Vegetation Saturated Grows

39 Erosion of Toe of Landfill Slope Surface Water Has Eroded Toe of Slope Waste Exposed Leachate Discharge Points Formed

40 Landfill Toe Erosion

41 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

42 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

43 Alternative Remediation (Recovery Wells)

44 Alternative Remediation (Recovery Wells) Recovery Wells Leachate Storage Tanks Onsite Wetland Remediation Cell Offsite Wastewater Line

45 The Solution - Phyto-Cap Planting Over 3,000 Willows and Poplars Inter-Planting of Another 300 Native Hardwoods

46 And E-Buffer Evapotranspiration Subsurface Filtration Microbial Activity at the Root Zone

47 Phytoremediation

48 Operational Concerns Up to 5 Years for Maturity Compliance Sampling Access Deer Insects Voles

49 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

50 Passive Treatment Not for all waste streams, but where opportunities exist

51 Alternative Treatment Streams Landfill Leachate Stormwater Runoff Groundwater Remediation (Including PCBs) Acid Mine Drainage (metals treatment) Small Capacity Sanitary Wastewater

52 Questions? Thank you!