1. Advancing the research and academic mission of Florida International University. WorldsAhead Treatment/Constructed Wetlands Presented: June 30, 2014 to the FIU YALI Program by Dr. Yelena Katsenovich, Research Scientist

2. Advancing the research and academic mission of Florida International University. Presentation overview Introduction to treatment wetlands Introduction to treatment wetlands Types of treatment wetlands Types of treatment wetlands Performance expectations for CW Performance expectations for CW Constructed wetland design Constructed wetland design Case study Case study Conclusions Conclusions Benefits of constructed wetlands Benefits of constructed wetlands Future considerations Future considerations

3. Advancing the research and academic mission of Florida International University. Introduction The discharge of nutrient and organic-rich untreated wastewater into natural systems The discharge of nutrient and organic-rich untreated wastewater into natural systems – detrimental effects on the ecological balance of those systems – health of downstream end-users of the impaired water sources.

4. Advancing the research and academic mission of Florida International University. Introduction The primary health and environmental problems attributed to untreated water discharges are the following: Increased toxicity to fish and other aquatic organisms Increased toxicity to fish and other aquatic organisms Depletion of dissolved oxygen in receiving water bodies due to the presence of organic compounds and ammonia nitrogen Depletion of dissolved oxygen in receiving water bodies due to the presence of organic compounds and ammonia nitrogen Water eutrophication, resulting in an abnormal increase in algal growth Water eutrophication, resulting in an abnormal increase in algal growth

5. Advancing the research and academic mission of Florida International University. Introduction Conventional wastewater treatment systems are highly effective at removing contaminants; however, They rely on mechanical and electrical equipment that is both costly to acquire and to maintain. They rely on mechanical and electrical equipment that is both costly to acquire and to maintain. Successful operation requires highly experienced and trained operators. Successful operation requires highly experienced and trained operators. Scarce resources in many countries preclude the purchase, installation, operation and maintenance of such systems. Scarce resources in many countries preclude the purchase, installation, operation and maintenance of such systems. Without adequate maintanance systems almost invariably fail soon after installation. Without adequate maintanance systems almost invariably fail soon after installation.

6. Advancing the research and academic mission of Florida International University. Why wetlands? Increasingly stringent discharge standards coupled with the rising operation and maintenance costs of conventional treatment systems have brought attention to low-cost biological treatment technologies as environmentally sound and affordable alternatives Increasingly stringent discharge standards coupled with the rising operation and maintenance costs of conventional treatment systems have brought attention to low-cost biological treatment technologies as environmentally sound and affordable alternatives

7. Advancing the research and academic mission of Florida International University. Why wetlands? Constructed wetlands (CW) Relatively inexpensive to construct Relatively inexpensive to construct Require little regular maintenance Require little regular maintenance If properly designed, can be highly effective in treating wastewater. If properly designed, can be highly effective in treating wastewater. In recent years, such systems have seen a dramatic rise in popularity throughout Europe, Middle Asia, Africa, and the U.S. In recent years, such systems have seen a dramatic rise in popularity throughout Europe, Middle Asia, Africa, and the U.S.

8. Advancing the research and academic mission of Florida International University. Why wetlands? Constructed wetlands are beneficial for the sites that usually meet the following criteria: Little or no means to obtain electrical power Little or no means to obtain electrical power Temperate, arid, dry desert or hot tropical climates Temperate, arid, dry desert or hot tropical climates CW can be effective in cold climates if properly designed CW can be effective in cold climates if properly designed CW can be integrated into any available territory, flat terrain or pre-mountain terraces, which allows water flow by gravity CW can be integrated into any available territory, flat terrain or pre-mountain terraces, which allows water flow by gravity No access to a municipal sewage system. No access to a municipal sewage system.

9. Advancing the research and academic mission of Florida International University. Why wetlands? Despite numerous publications on the topic of CW Despite numerous publications on the topic of CW – Paucity of information regarding the ability of these systems to operate efficiently in hot tropical and dry desert climates. – Higher temperatures, combined with increased plant productivity and soil matrix activity contribute to substantial differences in biological and chemical parameters, making it difficult to apply wetland data obtained from cold or temperate climates to regions feature high temperatures.

10. Advancing the research and academic mission of Florida International University. Types of treatment wetlands There are several major types of CW systems: Horizontal subsurface flow (SSF) Horizontal subsurface flow (SSF) Surface flow (SF) Surface flow (SF) Hybrid designs, which incorporate both surface and subsurface flow systems Hybrid designs, which incorporate both surface and subsurface flow systems Vertical flow Vertical flow

11. Advancing the research and academic mission of Florida International University. Surface flow wetlands Free surface flow wetlands Densely vegetated basin or shallow channels Densely vegetated basin or shallow channels Lined conduits prevent wastewater percolation and contain sufficient soil to support rooted vegetation. Lined conduits prevent wastewater percolation and contain sufficient soil to support rooted vegetation. Water flows primarily horizontally and above ground Water flows primarily horizontally and above ground Typical hydraulic loading rates are between 0.3 and 2 in/day (0.7 and 5.0 cm/day), corresponding to 2 to 14 ha per 1000m³/day of flow. Typical hydraulic loading rates are between 0.3 and 2 in/day (0.7 and 5.0 cm/day), corresponding to 2 to 14 ha per 1000m³/day of flow.

12. Advancing the research and academic mission of Florida International University. Surface flow wetlands Flow depths are normally less than 1.3 ft (0.4 m), they can range from 0.3 to 2.0ft (0.09 to 0.06m) (Kadlec and Knight 1996). Flow depths are normally less than 1.3 ft (0.4 m), they can range from 0.3 to 2.0ft (0.09 to 0.06m) (Kadlec and Knight 1996).

13. Advancing the research and academic mission of Florida International University. Subsurface flow wetlands Consist of shallow, gravel-filled basins that usually feature aquatic, rooted vegetation. Consist of shallow, gravel-filled basins that usually feature aquatic, rooted vegetation. The water level remains below the surface of the rock or gravel media to avoid public exposure and/or the creation of mosquito breeding grounds. The water level remains below the surface of the rock or gravel media to avoid public exposure and/or the creation of mosquito breeding grounds.

14. Advancing the research and academic mission of Florida International University. Subsurface flow wetlands Typical flow depths vary from 1.6 to 2.6ft (0.49 to 0.79 m). Typical flow depths vary from 1.6 to 2.6ft (0.49 to 0.79 m). Recommended hydraulic loading rates 0.8 - 8in/day (2 - 20cm/day), corresponding to a wetland of 4.7 to 47 acres per mgd of flow (0.5 - 5 ha per 1000m³/day of flow) (Kadlec and Knight 1996, Halverson 2004). Recommended hydraulic loading rates 0.8 - 8in/day (2 - 20cm/day), corresponding to a wetland of 4.7 to 47 acres per mgd of flow (0.5 - 5 ha per 1000m³/day of flow) (Kadlec and Knight 1996, Halverson 2004). SSF CWs are more effective at suspended solids reduction and lowering biological oxygen demand (BOD) per unit land area. SSF CWs are more effective at suspended solids reduction and lowering biological oxygen demand (BOD) per unit land area.

15. Advancing the research and academic mission of Florida International University. Performance expectations for CW CW are conducive to many different applications: Sludge mineralization, Sludge mineralization, Drinking water pretreatment, Drinking water pretreatment, Purification of contaminated groundwater Purification of contaminated groundwater Treatment of wastewater originating from a variety of sources. Treatment of wastewater originating from a variety of sources.

16. Advancing the research and academic mission of Florida International University. Performance expectations for CW CW can function as a secondary step after conventional primary treatment CW can function as a secondary step after conventional primary treatment Valuable component of combined systems of lagoons, facultative and biological ponds. Valuable component of combined systems of lagoons, facultative and biological ponds. The combination of these relatively inexpensive systems serves as an ecological buffer and ensures the attainment of required treatment objectives and goals. The combination of these relatively inexpensive systems serves as an ecological buffer and ensures the attainment of required treatment objectives and goals.

17. Advancing the research and academic mission of Florida International University. Performance expectations for CW SourceContaminants Removed/Degraded Domestic Wastewater BOD*, COD*, TSS*, TN*, NO 3 -, NH 4, TP, PO 4 +3, Fecal coliform, Animal Wastewater BOD, COD, TSS, TN, NO 3 -, NH 4, TP, PO 4 +3, Fecal coliform. Industrial & Stormwater Runoff TSS, metals, TSS, TDS*, TN, NO 3 -, NH 4, TP, PO 4 +3, oil& grease, pH, sulfate, phenols Mine Wastewaters**Metals, acidity, iron, sulfate Groundwater Chlorinated organics, explosives, PAHs*, petroleum hydrocarbons Urban StormwaterTSS, Metals, TN, NO 3 -, TP, PO 4 +3, oil, grease and gasoline Agricultural RunoffTN, NO 3 -, NH 4, TP, PO 4 +3, Pesticides, Herbicides, fertilizers Kadlec, R.H. and Knight, R.L., Treatment Wetlands, CRC Press, Lewis Publishers *biochemical oxygen demand (BOD), total suspended solids (TSS), total nitrogen (TN), total phosphor (TP), total dissolved solids (TDS), Polycyclic aromatic hydrocarbons (PAHs) **CW also function to control pH in mine wastewaters

18. Advancing the research and academic mission of Florida International University. Total Suspended Solids (TSS) TSS loadings of less than 30 kg/d-ha produce an effluent with under 20 mg/L TSS TSS loadings of less than 30 kg/d-ha produce an effluent with under 20 mg/L TSS Loadings of up to 50 kg/d-ha result in effluent concentrations not exceeding 30 mg/L (US EPA 2000) Loadings of up to 50 kg/d-ha result in effluent concentrations not exceeding 30 mg/L (US EPA 2000) Systems with open water zones showed greater TSS reduction than those that were fully vegetated Systems with open water zones showed greater TSS reduction than those that were fully vegetated Estimated total removal efficiency for TSS in wetland systems ranges from 70% to 90% (US Army Corps of Engineers 2003) Estimated total removal efficiency for TSS in wetland systems ranges from 70% to 90% (US Army Corps of Engineers 2003)

19. Advancing the research and academic mission of Florida International University. Organic Pollutants SF CW can yield effluent with less than 20 mg/L of BOD at mass loadings below 45 kg/d-ha (US EPA, 2000). SF CW can yield effluent with less than 20 mg/L of BOD at mass loadings below 45 kg/d-ha (US EPA, 2000). Fully vegetated systems typically produce 50% more effluent BOD and TSS than wetlands with open-water areas at comparable loading rates. Fully vegetated systems typically produce 50% more effluent BOD and TSS than wetlands with open-water areas at comparable loading rates. Treatment efficiencies and hydraulic and organic loading rates are significantly higher under hot and tropical conditions than in colder regions. Treatment efficiencies and hydraulic and organic loading rates are significantly higher under hot and tropical conditions than in colder regions. A South African research team observed COD removal in excess of 70% while evaluating the potential for SSF organic loading rates of 1200 kg/d-ha (Batchelor and Loots 1997). A South African research team observed COD removal in excess of 70% while evaluating the potential for SSF organic loading rates of 1200 kg/d-ha (Batchelor and Loots 1997).

20. Advancing the research and academic mission of Florida International University. Nutrients- Nitrogen (N) N removal dependent on the nitrogen species (ammonia, organic nitrogen, nitrate and nitrite or total Kjeldahl nitrogen (TKN)) and environmental conditions within the CW. N removal dependent on the nitrogen species (ammonia, organic nitrogen, nitrate and nitrite or total Kjeldahl nitrogen (TKN)) and environmental conditions within the CW. Removal of the reduced form of N requires a two-step nitrification-denitrification process. Removal of the reduced form of N requires a two-step nitrification-denitrification process. – Ammonia is first oxidized to nitrate (nitrification) in an aerobic conditions of SF wetlands. This nitrate then undergoes reduction to nitrogen gas (denitrification) under anaerobic conditions. An adequate amount of organic carbon is necessary to create the reducing conditions required for denitrification. An adequate amount of organic carbon is necessary to create the reducing conditions required for denitrification.

21. Advancing the research and academic mission of Florida International University. Nutrients- Nitrogen (N) In order to reduce N concentrations to 10 mg/L or less in SF, the influent TKN load must not exceed 5 kg/d-ha. In order to reduce N concentrations to 10 mg/L or less in SF, the influent TKN load must not exceed 5 kg/d-ha. Open-water segments can enhance the ammonia- removing capability of SF wetlands Open-water segments can enhance the ammonia- removing capability of SF wetlands – Due to the symbiotic relationships amongst aerobic and anaerobic microorganisms and algae – The process depends on parameters such as temperature, solar radiation, organic loading and hydraulic retention time (Arceivala 1981). Nitrogen removal in SSF wetlands is negligible as systems are usually anoxic, thereby inhibiting oxidation. Nitrogen removal in SSF wetlands is negligible as systems are usually anoxic, thereby inhibiting oxidation.

22. Advancing the research and academic mission of Florida International University. Nutrients- Phosphorus (P) P removal from wastewater is limited to adsorption onto sediment, uptake by biota and vegetation P removal from wastewater is limited to adsorption onto sediment, uptake by biota and vegetation Significant P removal requires large wetlands with extended hydraulic retention times. Significant P removal requires large wetlands with extended hydraulic retention times. Recent study determined that a P load of ≤ 45g m −2 year −1 would be required to achieve a total effluent concentration of 1.5 mg/L from the subtropical CW of the Florida Everglades (Kadlec 2006). Recent study determined that a P load of ≤ 45g m −2 year −1 would be required to achieve a total effluent concentration of 1.5 mg/L from the subtropical CW of the Florida Everglades (Kadlec 2006). P loading of <1.5 kg/d-ha and retention time of at least 15 days is needed to achieve only a 1.5 mg/L reduction in total phosphorous (U.S. EPA, 1999). P loading of <1.5 kg/d-ha and retention time of at least 15 days is needed to achieve only a 1.5 mg/L reduction in total phosphorous (U.S. EPA, 1999). P removal averages in 0.12 g P/m 2 -day, considered a low removal rate (Vymazal, 2004, 2005). P removal averages in 0.12 g P/m 2 -day, considered a low removal rate (Vymazal, 2004, 2005).

23. Advancing the research and academic mission of Florida International University. Pathogens Most pathogens attach to suspended particles or behave as free- swimming, planktonic organisms. Most pathogens attach to suspended particles or behave as free- swimming, planktonic organisms. Removal mechanisms mimic those applied to suspended solids: Removal mechanisms mimic those applied to suspended solids: – sedimentation, attachment to underwater surfaces, adsorption to biofilms, incorporation into soil or sediment (Kivaisi, 2001). Enteric helminthes are persistent and dangerous parasites eliminated via the sedimentation of their eggs and then inhibiting eggs in the anoxic soil conditions. Enteric helminthes are persistent and dangerous parasites eliminated via the sedimentation of their eggs and then inhibiting eggs in the anoxic soil conditions. Data indicate a 100-fold reduction of fecal coliforms in CW. Stringent guidelines for pathogens requires disinfection of treated water. Data indicate a 100-fold reduction of fecal coliforms in CW. Stringent guidelines for pathogens requires disinfection of treated water.

24. Advancing the research and academic mission of Florida International University. Constructed Wetland Design Wastewater flow; EPA gives a range of 47-52 gallons per person per day (U.S. EPA, 1980). Wastewater flow; EPA gives a range of 47-52 gallons per person per day (U.S. EPA, 1980). – These values may vary according to the location and country. Climatic data on average monthly temperatures, precipitation in mm/month, peak flow month, ET in mm/month, soil temperatures (at 30 inches), and solar radiation. Climatic data on average monthly temperatures, precipitation in mm/month, peak flow month, ET in mm/month, soil temperatures (at 30 inches), and solar radiation. Expected BOD, TSS, total nitrogen, and total phosphorus. Expected BOD, TSS, total nitrogen, and total phosphorus.

25. Advancing the research and academic mission of Florida International University. Water balance calculations Precipitation (Pr) and evapotranspiration (ET) play a decisive role in CW performance. Precipitation (Pr) and evapotranspiration (ET) play a decisive role in CW performance. – ET significantly reduces the outflow rate, thereby impacting water balance and producing higher HRTs. – ET increases concentration of conservative, non- degradable contaminants such as salts and nutrients, especially phosphorus, in the effluent. – In the wet season superfluous Pr can radically raise water levels in both SSF and SF components, resulting in contaminant dilution.

26. Advancing the research and academic mission of Florida International University. Water balance and mass removal The area-based SSF and SF effluents (m3 d−1) were calculated with respect to Pr and ET (Kadlec and Knight, 1996). The area-based SSF and SF effluents (m3 d−1) were calculated with respect to Pr and ET (Kadlec and Knight, 1996). Q SSF outflow = Q SSF inflow − ET × S SSF + P r × S SSFQ SSF outflow = Q SSF inflow − ET × S SSF + P r × S SSF Q SF outflow = Q SSF outflow − ET × S SF + P r × S SFQ SF outflow = Q SSF outflow − ET × S SF + P r × S SF –S SSF and S SF represent the respective surface areas of the SSF and SF wetland cells (m2), – P r is equivalent to the precipitation rate (mday−1) –ET -rate of evapotranspiration (mday−1) HLR were calculated based on acquired inlet and outflow rates. HLR were calculated based on acquired inlet and outflow rates.

27. Advancing the research and academic mission of Florida International University. Constructed wetland design The most known models for the CW design in temperate climate areas (mainly the U.S.) Campbell & Ogden (1999), Campbell & Ogden (1999), – Campbell, C.S. and M.H. Ogden, 1999. Constructed Wetlands in the Sustainable Landscape. John Wiley & Sons, Inc. – Estimates area for removal of BOD, TSS, ammonia and nitrate in SSF and SF Reed et al. (1995), Reed et al. (1995), – Reed, S. C., Crites, R. W. & Middlebrooks, E. J., 1995. Natural Systems for Waste Management and Treatment (2 ed.). USA: McGraw Hill, Inc. – Estimates area for removal of BOD and P;

28. Advancing the research and academic mission of Florida International University. Constructed wetland design Environmental Protection Agency (U.S. EPA, 2000) Environmental Protection Agency (U.S. EPA, 2000) – Constructed Wetlands Treatment of Municipal Wastewaters.” Office of Research and Development. EPA/625/R-99/010. 2000. – Estimates area for removal of BOD and TSS; Treatment Wetlands Treatment Wetlands – Kadlec, R. H. & Knight, R. L., 1996. Treatment Wetlands. Boca Raton, FL: CRC Press LLC. – Kadlec, R. H. & S.D. Wallace, 2008, (2-nd edition), CRC Press LLC, Boca Raton, FL – Estimates area for removal of BOD, TSS, TP and TN in SSF and SF Lack of information for the wetland design specifically for tropical or dry desert conditions. Lack of information for the wetland design specifically for tropical or dry desert conditions.

29. Advancing the research and academic mission of Florida International University. CW design approach CW system, Cavalry Base, El Salvador Flow 150 m 3 /day (40,000 gpd) from Basin 1 to the SSF CW Flow 150 m 3 /day (40,000 gpd) from Basin 1 to the SSF CW Two primary variables were considered: hydraulic loading rate (HLR) and inlet concentrations (Ci). Two primary variables were considered: hydraulic loading rate (HLR) and inlet concentrations (Ci). Water treated by CW flowed by gravity from the SSF to SF and then discharging point or stored in a lagoon for irrigation Water treated by CW flowed by gravity from the SSF to SF and then discharging point or stored in a lagoon for irrigation

30. Advancing the research and academic mission of Florida International University. CW system, Cavalry Base, El Salvador SSF SF FL (Basin 1)

31. Advancing the research and academic mission of Florida International University. CW design approach Calculations assumed: Calculations assumed: – Temperature of 20.4 0 C, – Gravel bed depth and porosity for the SSF wetland of 2 ft and 0.4, respectively. – Similarly, depth and porosity for the SF wetland were 18 inches and 0.65, respectively. – The OW sections of 1.2 meters deep planted with submerged Elodea spp.

32. Advancing the research and academic mission of Florida International University. Case study- Cavalry Base, El Salvador. Plants Distribution

33. Advancing the research and academic mission of Florida International University. SSF Inlet water from facultative pond

34. Advancing the research and academic mission of Florida International University. SSF - Phragmites australis Newly planted Plant growth in a year

35. Advancing the research and academic mission of Florida International University. Newly planted SSF- Brachiaria mutica Plant growth in 11 months Fast growing plant, can be used as a fodder for horses and cows; proved proficient with N and P uptakes

36. Advancing the research and academic mission of Florida International University. SSF- Thalia geniculata Newly planted Plant growth in 4 months; Thalia requires frequent trimming and after an initial prolific stage tends to undergo senescence

37. Advancing the research and academic mission of Florida International University. SF- Cyperus alternifolius Cyperus required high maintenance; not tolerating water levels greater than 15– 20cm during the growth period. Plant growth in 11 months

38. Advancing the research and academic mission of Florida International University. SF-Middle open water segment OW segments were planted with Elodea sp. Lemna sp. overtook the OW; lower temperatures were recorded in Lemna sp.-covered open water due to shading effect.

39. Advancing the research and academic mission of Florida International University. Crop irrigation with reclaimed water CW effluent is a valuable source of many crop-essential nutrients and minerals

40. Advancing the research and academic mission of Florida International University. Conclusions CW performance proved reliable under the extremes of tropical conditions CW performance proved reliable under the extremes of tropical conditions SSF should be used cautiously to treat FL effluents due to algae bloom, the leading cause of SSF clogging SSF should be used cautiously to treat FL effluents due to algae bloom, the leading cause of SSF clogging Brachiaria, Phragmites (SSF) and Typha (SF) were the most effective CW plants for organic and nutrients removal; Brachiaria, Phragmites (SSF) and Typha (SF) were the most effective CW plants for organic and nutrients removal; Brachiaria provided the added benefit of serving as a source of fodder and was harvested in 30-45 day intervals. Brachiaria provided the added benefit of serving as a source of fodder and was harvested in 30-45 day intervals.

41. Advancing the research and academic mission of Florida International University. Conclusions Typha produced the best dry season results within the SF component. Typha produced the best dry season results within the SF component. Inlet/Phragmites/Typha) performed better year-round Inlet/Phragmites/Typha) performed better year-round The best results were observed for TN, TSS and fecal coliform The best results were observed for TN, TSS and fecal coliform CW operation did not in any way interfere with military base performance CW operation did not in any way interfere with military base performance

42. Advancing the research and academic mission of Florida International University. Benefits of constructed wetlands Solve environmental problems Solve environmental problems Low energy and maintenance requirements Low energy and maintenance requirements Provide research and educational opportunities Provide research and educational opportunities Vegetation can serve as a source of fodder (Brachiaria); no additional agricultural territory was required Vegetation can serve as a source of fodder (Brachiaria); no additional agricultural territory was required Agricultural reuse of treated water Agricultural reuse of treated water Groundwater recharge if treated water meets standards Groundwater recharge if treated water meets standards

43. Advancing the research and academic mission of Florida International University. Benefits of constructed wetlands Sludge from lagoons can serve as an excellent fertilizer for industrial crops Sludge from lagoons can serve as an excellent fertilizer for industrial crops Irrigation using reclaimed water of non-food or renewable energy crops such as bamboo holds promise for significant economic benefits and environmental sustainability Irrigation using reclaimed water of non-food or renewable energy crops such as bamboo holds promise for significant economic benefits and environmental sustainability

44. Advancing the research and academic mission of Florida International University. Future considerations Examine trends in vegetation nutrients uptake in dry and wet seasons Examine trends in vegetation nutrients uptake in dry and wet seasons Revise hydraulic design to reconcile operation under extreme conditions during the wet and dry seasons Revise hydraulic design to reconcile operation under extreme conditions during the wet and dry seasons Conduct helminthes analyses and eggs viability if treated water is to be used for irrigation Conduct helminthes analyses and eggs viability if treated water is to be used for irrigation Use a larger gravel size of 1”-2” can to increase SSF system permeability and prevent clogging Use a larger gravel size of 1”-2” can to increase SSF system permeability and prevent clogging Improve the distribution and drainage system design to prevent CW pipes clogging Improve the distribution and drainage system design to prevent CW pipes clogging Minimize the effects of excessive evaporation and transpiration during the dry period Minimize the effects of excessive evaporation and transpiration during the dry period

45. Advancing the research and academic mission of Florida International University. References Arceivala, S.J. 1981. Wastewater Treatment and Disposal. Marcel Dekker. New York. Arceivala, S.J. 1981. Wastewater Treatment and Disposal. Marcel Dekker. New York. Batchelor, A. and Loots, P. 1997. A critical evaluation of a pilot scale subsurface flow wetland: 10 years after commissioning. Wat. Sci. Tech. 35, p.337–343. Batchelor, A. and Loots, P. 1997. A critical evaluation of a pilot scale subsurface flow wetland: 10 years after commissioning. Wat. Sci. Tech. 35, p.337–343. Halverson, N.V. 2004. Review of Constructed Subsurface Flow vs. Surface Flow Wetlands. U.S. Department of Energy. WSRC-TR-2004-00509. Halverson, N.V. 2004. Review of Constructed Subsurface Flow vs. Surface Flow Wetlands. U.S. Department of Energy. WSRC-TR-2004-00509. Kadlec, R., 2006. Free surface wetlands for phosphorus removal: The position of the Everglades Nutrient Removal Project. Ecological Engineering, 27, 4, p.361-379 Kadlec, R., 2006. Free surface wetlands for phosphorus removal: The position of the Everglades Nutrient Removal Project. Ecological Engineering, 27, 4, p.361-379 Katsenovich, Y., Shapovalova, L., Boot, L., Izhitskaja, M., 2008. Evaluation of biological pond system modified with submerged planted dams, Ecological Engineering, 33, p.1-7 Katsenovich, Y., Shapovalova, L., Boot, L., Izhitskaja, M., 2008. Evaluation of biological pond system modified with submerged planted dams, Ecological Engineering, 33, p.1-7 Katsenovich, Y., Hummel-Batista, A., Ravinet, A. J., Miller, J.F., 2009. Performance Evaluation of Constructed Wetlands in a Tropical Region. Ecological Engineering Journal, 35, p.1529-1537. Katsenovich, Y., Hummel-Batista, A., Ravinet, A. J., Miller, J.F., 2009. Performance Evaluation of Constructed Wetlands in a Tropical Region. Ecological Engineering Journal, 35, p.1529-1537. Kivaisi, A. K., 2001. The potential for constructed wetlands for wastewater treatment and reuse in developing countries: a review, Ecological Engineering, Volume 16, Issue 4, p. 545-560 Kivaisi, A. K., 2001. The potential for constructed wetlands for wastewater treatment and reuse in developing countries: a review, Ecological Engineering, Volume 16, Issue 4, p. 545-560 U.S. Army Corps of Engineers. June 23, 2003. Applicability of Treatment wetlands for Army Installations. Washington, DC. Public Works Technical Bulletin 200, p.1-21 U.S. Army Corps of Engineers. June 23, 2003. Applicability of Treatment wetlands for Army Installations. Washington, DC. Public Works Technical Bulletin 200, p.1-21 Vymazal, J., 2004. Removal of phosphorus in constructed wetlands with sub-surface flow in the Czech Republic.. Water, Air, and Soil Pollution, Volume 4, pp. 657-670. Vymazal, J., 2004. Removal of phosphorus in constructed wetlands with sub-surface flow in the Czech Republic.. Water, Air, and Soil Pollution, Volume 4, pp. 657-670. Vymazal, J., 2005. Horizontal sub-surface flow and hybrid constructed systems for wastewater treatment. Ecol. Eng., Volume 25, pp. 478-490. Vymazal, J., 2005. Horizontal sub-surface flow and hybrid constructed systems for wastewater treatment. Ecol. Eng., Volume 25, pp. 478-490.

46. Advancing the research and academic mission of Florida International University. Acknowledgments Funding for this project was provided by the Office of the Assistant Secretary of the United States Army for Installations and the Environment (OASA I&E) under contract no. W74V8H-04-C-0064. Funding for this project was provided by the Office of the Assistant Secretary of the United States Army for Installations and the Environment (OASA I&E) under contract no. W74V8H-04-C-0064.