Ecological Engineering: Nutrient Uptake

1. It has been said that streams are the gutters down which flow the ruins of continents. L.B. Leopold et al. 1964. Ecological Engineering: Nutrient Uptake Patrick Corbitt Kerr University of Notre Dame

2. Stormwater Management: The Industry Direction • Quantity • (-) Water Supply (Irrigation, Drinking Water,…) • (+) Flooding (Rate or Volume?) • Quality • Importance • Safe for humans (Acute vs Chronic) • Ecosystem Conscious • Aesthetics • Components • Groundwater vs Surface Water • Type of Pollutants • Pollutant Source: Urban or Rural • Sediment & Watercourse Stability Image from http://www.the-macc.org/wp-content/uploads/2009/04/storm2.jpg

3. Stormwater Pollutants • Sediment • Nutrients (Nitrogen, Phosphorus, Organic Matter) • Microorganisms (e.g. Coliform Bacteria) • Toxic Substances • Pesticides • Salt (Chloride) • Oil and Grease (e.g. Polycyclic aromatic hydrocarbons (PAHs)) • Heavy Metals (e.g. Lead, Zinc, Copper) • Heat • Litter

4. Nutrients • Nutrients: Chemicals that an organism needs to live and grow. • Macronutrients: • Carbon (C) • Nitrogen (N) • Phosphorus (P) • If the aquatic ecosystem requires nutrients, why then are nutrients considered a pollutant? • An oversupply of nutrients to a certain species can result in excessive growth; thereby choking out other species. • The Solution is …. Balance.

5. Algae (Phytoplankton) Blooms • Upper left: Cyanobacterial (blue-green algal) bloom in the Gulf of Finland region of the Baltic Sea. • Upper right: Dinoflagellate red tide bloom near the Japanese Coastline (Sea of Japan). • Lower left: Cyanobacterial bloom in the St Johns River Estuary, near Jacksonville, Florida. • Lower right: Mixed cyanobacterial-chlorophyte bloom in North Island, New Zealand Image from http://lepo.it.da.ut.ee/~olli/eutr/html/htmlBook_78.html

6. Hypoxia • Means “Low Oxygen” • Algae blooms consume oxygen • (0 mg/L) is “anoxia” • Called “Dead Zones” because animals can’t survive • Kills mobile animals like fish • Kills shellfish and other less mobile animals • Nursery habitat is destroyed • Releases stored pollutants • Chemical reaction between hypoxic water and bottom sediments • Overall ecosystem is stressed (Birds, mammals, too!) Image from: srwqis.tamu.edu/hot-topics/hypoxia.aspx

7. Gulf of Mexico Hypoxia Image from: http://water.usgs.gov/nawqa/sparrow/gulf_findings/hypoxia.html

8. The Mississippi River Basin: N & P Yield Image from: http://water.usgs.gov/nawqa/sparrow/gulf_findings/delivery.html

9. Percent N & P Contribution by State Image from: http://water.usgs.gov/nawqa/sparrow/gulf_findings/by_state.html

10. Sources: Nitrogen & Phosphorus Image from: http://water.usgs.gov/nawqa/sparrow/gulf_findings/primary_sources.html

11. The Nutrient (Biogeochemical) Cycle • Macro-Scale vs Micro-Scale: • Hydrosphere, Lithosphere, Atmosphere, Biosphere • Water Cycle • Conservation of Mass & Energy • Ecosytem Components: • Solar Energy ( Light / Temperature ) • Producers • Consumers • Decomposers • Water • Soil / Water / Air Chemistry Image from: ga.water.usgs.gov/edu/watercyclehi.html

12. Nutrient Cycling: Carbon • Organic (O) • Has C • Inorganic(I) • Dissolved (D) • Particulate (P) Image from: http://www.epa.qld.gov.au/wetlandinfo/site/ScienceAndResearch/ConceptualModels/Conceptintromore/Palustrine/MainFloodplainHeath/FloodplainHeathNutrientCycling.html

13. Nutrient Cycling: Nitrogen • State Changes • Nitrification(Gain O) • De-Nitrification (Lose O) • Fixation ( N2 Uptake) • Assimilation( NH4, NO3 Uptake) • Mineralization • Assimilatory Uptake • Structural Synthesis • Dissimilatory Uptake • Bacteria obtain Energy Image from: http://www.epa.qld.gov.au/wetlandinfo/site/ScienceAndResearch/ConceptualModels/Conceptintromore/Palustrine/MainFloodplainHeath/FloodplainHeathNutrientCycling.html

14. Nutrient Cycling: Phosphorus • Uptake • Autotrophic • Heterotrophic • Mineralization • Bacterial Activity • Adsorption • Balance • Water Column • Sediment Imagefrom: http://www.epa.qld.gov.au/wetlandinfo/site/ScienceAndResearch/ConceptualModels/Conceptintromore/Palustrine/MainFloodplainHeath/FloodplainHeathNutrientCycling.html

15. Nutrient Transport: Spiraling Concepts and Methods for Assessing Solute Dynamics in Stream Ecosystems Stream Solute Workshop Journal of the North American Benthological Society, Vol. 9, No. 2. (Jun., 1990), pp. 95-119.

16. Ecosystems change spatially Seeks a dynamic balance between form & function The watercourse changes Width, Depth, Velocity, Sediment Load, Canopy Cover, Temperature, Flow Characteristics The stream community & biogeochemical processes conform to the new structure. River Continuum Concept (RCC) www.tcnj.edu/~bshelley/EcolTCNJ.htm

17. Definition: The total flux of nutrient from the water column to the stream bottom, expressed on the basis of stream bottom area (e.g., mg/m²/hr) Biotic & Abiotic Element Cycling Rate Pathways Residence Time Nutrient Uptake (U) Image from: http://www.biol.vt.edu/faculty/benfield/freshwater/freshwaterlocked/fredfigs.html

18. Biotic Uptake • Stoichiometry of Organic Matter • Redfield Ratio: C:N:P = 106:16:1 • Not Phytoplankton • Silica • Diatoms Image from: labs.psc.riken.jp/pnbmrt/Research_English.html

19. Abiotic Uptake • Some nutrients adsorb to sediment particles. • Adsorption capacity varies • By nutrient and chemical state: • Phosphorus (H2PO-4 ) is most adsorptive • By Media: • Capacity dependent on makeup and chemical properties • pH, total and reactive calcium, total and reactive Fe, Al oxide • Capacity also increases as: • Size & Density decreases • Porosity and Surface Area increases • Not Permanent -> Desorption Image from: http://www.phosphoreduc.com/fr/our-technology/technical-info/25-phosphorus-adsorption-capacity.html

20. How does this relate to us as Professional Civil Engineers?

21. The Design Process: • What conditions are we considering? • Existing or Pre-Existing • Proposed or Ultimate • What is our design criteria? • Quantity: • Typically: Peak Discharge (Match α-yr Post to ß-yr Pre) • But sometimes ….Volume • Recharge (ReV), Channel Protection (CPV), Overbank Flood Protection (Qp), Extreme Flood (Qf) • Quality: • Water Quality Standards: What Format? • Waterbody Type or Waterbody Specific? • Concentration, Load, or Indicator (Clarity or Chl-a)?

22. The Water Quality Challenge • Who’s leading the charge? • Environmental Groups • EPA • Coastal States: Maryland, Florida, etc. • Who/What is being targeted? • Point versus Non-Point Sources • Urban Areas (Agricultural/Rural has largely been avoided) • Construction Practices: Erosion & Sediment Control • Stormwater BMPs: New Construction & Retrofits • Stream Restoration • How do we design stormwater BMPs? • Uniform Sizing Criteria: (Performance Based?) • Water Quality Volume (WQV)

23. WQv ( A Standard Solution?) • Methods: • Post-Conditions vs Pre-Conditions Difference • Post-Conditions Total • Regression Equation: function of P, I, and A • WQV = [(P)(RV)(A)]/12 Where: • WQV = Water Quality volume (acre-feet) • P = Precipitation (inches) • Rainfall necessary to facilitate full movement of pollutants (“First Flush”) • A = Drainage Area (acres) • RV = Volumetric Runoff Coefficient = 0.05 + 0.009(I) • I = Percent Impervious Area (%) • Function of Load and BMP Performance (Pollutant Specific)

24. The Water Quality Volume • Issues: • Regression equation doesn’t account for non-impervious area • Are nutrient-laden areas being considered? • For storms greater than P, can WQV be targeted? • Consider a 100% Impervious Site, designed for P = 1”: • P is a function of Duration, Time of Concentration, and Land Cover • Peak Water Quality Flowrate (QWV) P = 1” P > 1” WQV” 100% Treated Duration Dependent Any Duration

25. What to do with the Water Quality Volume? • Suppose we account for the “First Flush” and can isolate all the pollutants by that WQV, what are our goals? • Ideally we wish to TREAT the water? • In Water/Wastewater: • We have effluent criteria defined by concentration and load • We measure (sample) both influent and effluent • We alter it chemically and mechanically • But, most importantly, though, we can remove mass (SLUDGE) • Why is sludge removal so important? • Some pollutants can be broken down but unless N, P, Heavy Metals, etc. are removed from the system and assuming steady flow the load in will equal the load out. • If removal is the ultimate goal, then how?

26. Removing N & P N & P come in many different forms. Which do we target? Perhaps, we should first identify ways to remove nutrients, and maybe that will decide for us… Image from: http://www.biol.vt.edu/faculty/benfield/freshwater/freshwaterlocked/fredfigs.html

27. General Ways to Remove Pollutants • Separation is the first step to pollutant removal. • Methods of separation we know from water/wastewater treament: • 1) Screening • 2) Skimming • 3) Settling • 4) Filtering • Can’t use active treatment systems or mechanical means • Typically referred to as a Pre-Treatment. • Pollutants are separated WITHIN the system. Full Removal requires maintenance (Typically considerable). • These methods will often FAIL under HIGH flows.

28. Screening • Typically refer to as trash racks • We focus on the Inlet Image from: http://www.mitchamcouncil.sa.gov.au/site/page.cfm?u=1496 Image from: http://www.waterwatchadelaide.net.au/index.php?page=how-does-a-wetland-work

29. Skimming • Solution: • Submerged Outlets • High flow overflow? • Use Bypass Control Structures • Reduces both size of structure and effectiveness Image from: http://www.baysaver.com/products/BaySeparators/index.html Image from: http://www.ene.gov.on.ca/envision/gp/4329eimages/figure4.41.gif

30. Settling • Theoretical Solutions: • Force it with a vortex • Inhibit (re-)suspension • Slow Flow (Long Release Time) • Not Turbulent (Wide/Deep) • Long Paths (Baffles, Islands, L:W) • Design Options: • SW Manual Criteria • Length to Width Ratio • 1.5:1 to 3:1 • Forebay • (Typically at least 10% WQv) • Use Stoke’s Law • Need to know influent load

31. Stoke’s Law Equation: • VS = settling velocity (cm/s) • g = gravity (m/s²) • ρS and ρW = densities of the particle and water (g/cm³) • µ = dynamic viscosity • d = effective particle diameter

32. Applying Stoke’s Law • Solids Budgeting • Simple Solution • Complex Solution

33. Resuspension • Bed Scour is a function of shear stress • Shear Stress is a function of velocity gradient, therefore consider the : • Velocity of the flow path • Orbital Velocity (from wind forced waves) • Wind Velocity • Depth • Fetch • Affects both aeration and suspension Image from: http://www.ozcoasts.org.au/glossary/images/resuspension.jpg

34. Sediment Transport • Sediment Balance • Bed Load • Suspended Load • Costly to Model Image from: cals.arizona.edu/.../riparian/chapt4/p7.html Image from: medinaswcd.org/streams.htm

35. Fluvial Geomorphology Image from: http://www.thecottagekey.com/waterlevels_andflows_diagram2.gif www.fgmorph.com/fg_8_5.php

36. Transient Storage • A) Surface Transient Storage (STS) • B) Hyporheic Transient Storage (HTS) • Nutrient Uptake Increases as: • Transient Storage Increases • Geomorphic Features • Hydralic Gradient • Velocity/Flow Decreases • Turbulence Increases • Depth Decreases • Residence Time Increases

37. Surface Transient Storage • Non-Advective: • Stagnant • Turbulent • Boundary Layer • Receives Light • Aerobic

38. Hyporheic Zone • Underground • No Light • Driven by Hydraulic Gradient • Moves Oxygen into Bed/Bank • Leaves Bed/Bank as anaerobic Image from: http://www.pc.ctc.edu/coe/images/Hyporheic.jpg

39. Filtration versus Infiltration • Filters • Not Vegetated • Replaceable Media • Infiltration • Groundwater Recharge • Reduces Nutrient Load • Leaches Pollutants into GW

40. Outlet Filters • Vertical Perforated Riser • Slow release (Essentially orifice equation times # of holes) • Concentric (Not Focused) Image from: http://www.ene.gov.on.ca/envision/gp/4329eimages/figure4.24.gif

41. Example of an Underground Sand Filter • Montrose Parkway – Phase I • Urban Setting: No room for pond or above ground BMPs • Solution: Underground Sand Filter… Quality Solution: Quantity SSF: Separator Sand Filter

42. Choosing the best method

43. How do we measure performance? Load or Concentration How do we rate performance? Reduction % or Final Effluent Result BMP Performance

44. Comparing Pollutant Removal Efficiencies among Different BMPs

45. Dry versus Wet methods Dry > Wet Filtration/Infiltration Groundwater Recharge In-basin vegetation in addition to perimeter BioRetention Dry < Wet Less effective for oils, greases, & hydrocarbons Disturbance of Bottom Sediments Leaching

46. Combination Facilities • 2+ facilities • Target different pollutants • Pre-Treat for Next BMP • Start at Source • Grass Channels instead of Curb, Gutter, & Sewers Image from: http://h2o.enr.state.nc.us/wswp/images/wet_pond.gif Image from: www.fhwa.dot.gov/environment/ultraurb/3fs5.htm

47. Pond Depth (Shallow or Deep) • Shallow: • Pros: • More Vegetation • Higher oxygen content • Greater Wetted Contact Area • Cons: • More bottom disturbance -> Greater Turbidity • Thermal Increase • Wider Pond: Less Canopy Cover • Deep • Pros: • Cooler Water • Less Disturbance • Cons: • Stratification and Anoxia • Less Wetted Contact Area • Less Vegetation

48. State Requirements (Min , Max) (GA) Max Depth: (GA: 8 ft ) Min Depth: (GA: 3ft to 4ft) Design for maximum depth to avoid Anoxia (FL) If TP is known, calculate chyl-a: TP = total P concentration (µg/l) Chyl-a = chlorophyll-a (mg/m³) Calculate Mean Secchi Disk Depth SD = Secchi disk depth (m) Calculate Depth of DO For Deeper Depths Aeration or Mixing is Required Pond Depth Design

49. Maximizing Nutrient Uptake Summary • Pre-Treat • Screen, Skim, Settle, Filter (abiotic Uptake) • Treat (Biotic Uptake) • Healthy Ecosystem • Biodiversity • Vegetation (Diversify) • Plan Form Features (Abnormal Geometry) • Habitat (In-Pond Features) • Pore Diffusivity • Bed/Bank Material • Construction Methods • Can’t rely on maintenance!

50. Case Studies: Austin, TX