CONSTRUCTED WETLANDS Green Technology with Multiple Benefits

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1 CONSTRUCTED WETLANDS Green Technology with Multiple Benefits Constructed Wetlands Workshop Caesar Kleberg Wildlife Center March 7, 2018 because water is precious. Loretta Mokry, PWS Alan Plummer Associates, Inc. ENVIRONMENTAL ENGINEERS * DESIGNERS * SCIENTISTS

2 Presentation Outline 2 Overview of Constructed Wetlands Types Applications Benefits

3 Terminology 3 Constructed wetlands Treatment wetlands Wetlands established for the purpose of providing water quality improvement Artificial wetlands Created wetlands Restored wetlands Mitigation wetlands

4 Overview of Constructed Wetlands 4 Complex, dynamic systems designed (engineered) to take advantage of the contaminant removal processes that occur in nature when water, soils, plants, microorganisms and the atmosphere interact. Includes processes used in conventional treatment, but also others that are unique to natural systems (photosynthesis, photo-oxidation, and plant uptake)

5 Constructed Wetlands 5 Wetlands have a very high productivity and therefore also a high capacity to transform and store organic matter and nutrients An engineered wetland system designed to harness natural processes for the purpose of improving water quality Technically and operationally simple, but involving complex interactions between: Water Soil Plants Micro-organisms, and The atmosphere

6 Advantages vs. Disadvantages (General) 6 Advantages Lower construction costs Lower operational costs Low energy use Moderation of surge flows Fewer mechanical problems No (or minimal) chemical use Easier operation 24/7 operator not required No continuous sludge handling Longer retention time for treatment processes to occur Disadvantages Large land requirements Climatic conditions affect treatment Possible suspended solids (e.g. algae, detritus) problems Possible animal problems (rodents/birds/turtles) Sludge removal more complicated Longer response time to operational adjustments

7 Types of constructed wetlands 7 Free water surface (FWS) Subsurface flow (SSF)

8 Variations of Free-water Surface Wetlands 8 Floating islands/ floating treatment wetlands Hemi-marsh

9 Advanced Designs for Subsurface Flow Wetlands 9 Horizontal Subsurface Flow (HSSF) Vertical Flow (VF) both downflow and upflow Hybrid Systems Sludge Dewatering Reed Beds Intensified Wetlands Forced-Bed Aeration Fill and Drain (Reciprocating) Tidal-flow Reactive Media (ammonia, phosphorus, etc.)

10 Why Intensify Treatment Wetlands? 10 Intensive wetland systems require more energy and O&M than passive systems, but can address site constraints or high strength treatment needs: Limited land area; provides more treatment per area than passive wetland systems Existing system is overloaded; need to increase treatment capacity Change in regulatory standards (nitrification) High seasonal loadings Minimize bed clogging Minimize water loss through evapotranspiration (ET) Less energy demand than required for conventional treatment systems

11 Forced Bed Aeration 11

12 Reciprocating (Fill-and-Drain) Wetlands 12

13 Tidal-flow Wetland 13

14 Hybrid Systems Combinations of Passive and/or Advanced Designs 14

15 Hybrid Systems Combinations of Passive and/or Advanced Designs 15

16 Hybrid Systems Combinations of Passive and/or Advanced Designs 16

17 Constructed Wetland Designs 17 Design flexibility facilitates effectiveness in meeting treatment objectives Wetland systems can be customized Treat various polluted water sources Address site constraints Minimize supplemental energy Provide multiple benefits

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19 Applications 19 Municipal wastewater treatment Industrial wastewater treatment Stormwater (from both urban and agricultural areas) Agricultural wastewater treatment (CAFOs, irrigation return flows) Landfill leachate treatment Acid mine drainage On-site wastewater systems Water reuse for potable raw water supply

20 20 Example Applications CONSTRUCTED WETLANDS

21 Bayside, TX WWTF 21 Facultative Lagoon followed by 3 wetland cells totaling about 1.5 acres Design Flow MGD Google Earth Image 8/29/2017

22 City of Beaumont s Cattail Marsh City of Beaumont s Cattail Marsh 600 acres Average annual permitted flow: 31.9 MGD;

23 Union Carbide (Dow Chemical) Seadrift Operations Manufacturing Site Constructed Wetland Cells (110 acres) Secondary and Tertiary Lagoons

24 Invista Wetland 53 acres Treatment capacity: 3 MGD

25 Stormwater - Urban 25

26 Stormwater - Agricultural 26

27 Water Reuse Polishing Treatment for Return Flows to Supplement Yield of Water Supplies 27

28 Water Reuse Polishing Treatment for Return Flows to Supplement Yield of Water Supplies 28 NTMWD s East Fork Water Reuse Project East Fork Wetland Panoramic Aerial June 6, 2017

29 John Bunker Sands Wetland Center 29

30 MULTIPLE BENEFITS 30

31 Multiple Benefits of Constructed Wetlands 31 Water Quality Improvement Development of Wetland Habitat Areas Educational Opportunities Preservation of Green Space/ Recreational Opportunities Community Outreach Research Opportunities

32 Build it and they will come 32

33 Build it and they will come 33

34 Build it and they will come 34 Since 2011, 9 eaglets successfully raised; 8 th generation in the making now

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37 From Butterflies to Reptiles to Mammals 37 Monarch Butterflies on Baccharis along East Fork Wetland cells Mink River Otter Diamondback Water Snake American Alligator Texas Bobcat

38 Students

39 Special Events 39 Annual Fund Raising Event at John Bunker Sands Wetland Center

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42 SUMMARY Multiple benefits achieved with constructed wetland systems enable society to protect receiving waters, preserve green space, restore habitat and increase habitat diversity, reduce demand on fossil fuel energy consumption, sequester carbon, and provide opportunities for ecotourism and public education

43 QUESTIONS? Alan Plummer Associates, Inc. Loretta Mokry, PWS