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Stormwater wet detention ponds hold a permanent pool of water and offer many beneficial uses including flood mitigation, pollution prevention, downstream erosion control, increased aesthetics, and recreational uses. Although the removal of nutrients is generally low for stormwater wet detention ponds in urban areas, floating treatment wetlands (FTWs) can be installed to offer an innovative solution toward naturally removing excess nutrients and aiding in stormwater management. To improve the stormwater reuse potential, this study assessed nutrient, microcystin, and chlorophyll-a interactions in three Florida stormwater wet detention ponds with recently implemented FTWs. Both episodic (storm events) and routine (non-storm events) sampling campaigns were carried out at the three ponds located in Ruskin, Gainesville, and Orlando. The results showed a salient negative correlation between total phosphorus and microcystin concentrations for both storm and non-storm events across all three ponds. The dominant nutrient species in correlation seemed to be total phosphorus, which correlated positively with chlorophyll-a concentrations at all ponds and sampling conditions, with the exception of Orlando non-storm events. These results showed a correlation conditional to the candidate pond and sampling conditions for microcystin and chlorophyll-a concentrations.

Lake Okeechobee, located in south Florida and originated about 6000 years ago during oceanic recession, is the second largest freshwater lake contained entirely within the United States. During recent years, four major hurricanes, Irene (1999), Frances (2004), Jeanne (2004), and Wilma (2005), made landfall near Lake Okeechobee. As a result, the lake's hydrodynamic patterns, water level, and water quality have been extensively influenced by hurricanes in the past decade. The direct landfall of Hurricane Wilma on the Lake Okeechobee area led to a drastic structural change to the ecosystem, resulting in an abrupt population decrease of submerged aquatic vegetation (SAV). During the same time period, south Florida also suffered from intermittent droughts in 2000–2001 and 2006–2008 due to climate variability. Drought stress and hurricane impacts induce complex ecosystem responses, including pervasive changes in species composition and productivity that may persist as changes in habitat, lake trophic state, light penetration depth, water levels, and nutrient cycling. After the 2006–2008 drought, decreased turbidity due to reduced sediment hydrodynamics, along with the increased runoff and nutrient inflows to the aquatic ecosystem, led to a range of ecological responses associated with gradual increases in primary productivity and the recovery of SAV in lake shore environments. The ecosystem then recovered after the population increase of SAV, triggering active ecodynamics among phytoplankton, zooplankton, and fish that had abruptly vanished after successive hurricanes in 2004 and 2005. To address such a unique structural change in the lake ecosystem, this study developed a structurally dynamic model to quantify the ecodynamics of the four main aquatic system organisms (SAV, phytoplankton, zooplankton, and fish) based on a thermodynamics index (exergy) and elucidated the ecosystem recovery pathways under the coupled impact of hurricanes and droughts.

Rapid urbanization and climate variability impacts increase with more extreme precipitation and drought events, challenging stormwater management in terms of both flood control and water quality. Traditional stormwater wet detention ponds have limited capacity to remove nutrient pollutants, specifically nitrogen, and the changing environment may exacerbate the problem. The use of floating treatment wetlands (FTWs) may become a viable best management practice to increase the efficiency for on-site removal of nitrogen pollution from traditional stormwater wet detention ponds before release into neighboring aquatic systems or to the groundwater. This study, which is deemed a companion study of the early ecological engineering practice of FTWs, presents a system dynamics model to improve understanding of the nitrogen cycle in relation to FTWs-based subtropical stormwater wet detention ponds. The model was calibrated and validated based on surface water samples collected in a thorough field campaign with R-squared values of 0.83 and 0.97, respectively. Final simulation runs with sensitivity analysis were conducted to investigate scientific questions about the experimental design and effects of urbanization impacts on the biological nitrogen cycling in stormwater ponds.

This paper explores the spatiotemporal patterns of total phosphorus (TP) in Tampa Bay (Bay), Florida, with the aid of Moderate Resolution Imaging Spectroradiometer (MODIS) images and genetic programming (GP) models. The study was designed to link TP concentrations with relevant water quality parameters and remote sensing reflectance bands in aquatic environments using in-situ data from a local database to support the calibration and validation of the GP model. The GP models show the effective capacity to demonstrate snapshots of spatiotemporal distributions of TP across the Bay, which helps to delineate the short-term seasonality effects and the decadal trends of TP in an environmentally sensitive coastal bay area. In the past decade, urban development and agricultural activities in the Bay area have substantially increased the use of fertilizers. Landfall hurricanes, including Frances and Jeanne in 2004 and Wilma in 2005, followed by continuous droughts from 2006 to 2008 in South Florida, made the Bay area an ideal place for a remote sensing impact assessment. A changing hydrological cycle, triggered by climate variations, exhibited unique regional patterns of varying TP waste loads into the Bay over different time scales ranging from seasons to years. With the aid of the derived GP model in this study, we were able to explore these multiple spatiotemporal distributions of TP concentrations in the Tampa Bay area aquatic environment and to elucidate these coupled dynamic impacts induced by both natural hazards and anthropogenic perturbations. This advancement enables us to identify the hot moments and hot spots of TP concentrations in the Tampa Bay region.

Floating treatment wetland (FTW) is one of the emerging best management practices (BMPs) for stormwater treatment where macrophytes provide a suitable root-zone environment for microorganisms that allow the plants to remove nutrients through direct uptake into their tissue. In this study, four floating mats with native Florida aquatic macrophytes were deployed in a 340 m2 subtropical stormwater wet detention pond. A fountain in the pond and peat moss used to hold the substrate for plant species on the floating mats are both assumed to add nutrients to the water column. The aim of this study was to evaluate the performance of nutrient removal through the four floating mats and explore associated effects of simultaneous hydrological and biological controls related to various hydrobiogeochemical processes for nutrient removal in a multimedia pond environment. Nutrient concentrations in both inlet and outlet were monitored continuously over 13 months, with episodic (storm events) and routine (non-storm events) sampling plans carried out in parallel to justify the efficacy of the FTWs. Nutrient values within the water column and the sediment were compared before (Phase I) and after (Phase II) the deployment of the FTWs to prove the proposed hypotheses. An additional phase (Phase III) after the removal of the FTWs was added to enhance the understanding of ecosystem response. For non-storm events, phosphorus removal was substantial because of the increase in the initial concentrations, presumably due to resuspension of nutrients into the water column from the fountain operation; about 47.7% total phosphorus (TP) and 79.0% orthophosphate (OP) were removed. The removal rates of total nitrogen (TN), nitrite– and nitrate–nitrogen ( NO x – N = N O 2 − – N + N O 3 − – N ) , and ammonia–nitrogen (NH3–N) were also calculated as 15.7, 20.6, and 51.1%, respectively. Without the uptake by plants, the nutrient removal decreased to different degrees when comparing those in non-storm events during Phase II. Considering plant species, nutrient uptake and assimilation by soft rush (Juncus effusus) was much higher than that by pickerelweed (Pontederia cordata) through both leaves and roots in this case. For soft rush, uptake rate in spring is much higher than that in fall. About 77.0 g N and 8.8 g P were removed from pond water via uptake and assimilation during the second phase. Despite organic nitrogen accumulation due to the pickerelweed leaf debris sedimentation, the organic nitrogen concentration in pond water was still kept at a low level, which implies that the ecosystem is capable of efficiently managing the withered plants and circulating nutrients.

Stormwater wet detention ponds hold a permanent pool of water and offer many beneficial uses including flood mitigation, pollution prevention, downstream erosion control, increased aesthetics, and recreational uses. The reduction efficiency of nutrients is generally low in stormwater wet detention ponds in many urban areas. To enhance nutrient reduction, floating treatment wetlands (FTWs), which are a new best management practice (BMP) in stormwater management, can be installed in wet detention ponds to offer an innovative solution toward naturally removing excess nutrients and aiding in stormwater management. This study assesses nutrient reduction in three Floridian stormwater wet detention ponds where FTWs have recently been installed. Both episodic (storm event) and routine (nonstorm event) sampling campaigns were carried out at the three ponds located in Ruskin, Gainesville, and Orlando. Most notably, nutrient reduction rates after installation of the FTWs reached levels of 33% for total nitro...

Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt+clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L⁻¹ and decreases in nitrate nitrogen (NO₃⁻–N) from 2.7 mg L⁻¹ to

A next generation septic tank media filter to replace or enhance the current on-site wastewater treatment drainfields was proposed in this study. Unit operation with known treatment efficiencies, flow pattern identification, and system dynamics modeling was cohesively concatenated in order to prove the concept of a newly developed media filter. A multicompartmental model addressing system dynamics and feedbacks based on our assumed microbiological processes accounting for aerobic, anoxic, and anaerobic conditions in the media filter was constructed and calibrated with the aid of in situ measurements and the understanding of the flow patterns. Such a calibrated system dynamics model was then applied for a sensitivity analysis under changing inflow conditions based on the rates of nitrification and denitrification characterized through the field-scale testing. This advancement may contribute to design such a drainfield media filter in household septic tank systems in the future.

In this study, a new-generation subsurface upflow wetland (SUW) system packed with the unique sorption media was introduced for nutrient removal. To explore the interface between hydraulic and environmental performance, a tracer study was carried out in concert with a transport model to collectively provide hydraulic retention time (7.1 days) and compelling evidence of pollutant fate and transport processes. Research findings indicate that our pollution-control media demonstrate smooth nutrient removal efficiencies across different sampling port locations given the appropriate size distribution conversant with the anticipated hydraulic patterns and layered structure among the sorption media components. The sizable capacity for nutrient removal in this bioprocess confirms that SUW is a promising substitute for an extension of traditional on-site wastewater treatment systems.

On-site sewage treatment and disposal systems, commonly referred to as a septic systems, consist basically of a septic tank and soil adsorption field or drainfield. It may represent a large fraction of nutrient loads and pathogen impacts in vadose zone and groundwater systems. It includes not only nitrogen (N) and phosphorus (P), but also pathogen indicators such as fecal coliform and Escherichia coli, which indicate the presence of other disease-causing bacteria flowing into the aquatic system and potentially adversely affecting public health. Constructed wetlands, an effective small-scale wastewater treatment system with low energy and maintenance requirements and operational costs, will cover current needs for nutrient and pathogen removal. In our study, a next-generation subsurface upflow wetland system that is filled with green sorption media (e.g., mixes of recycled and natural materials) along with selected plant species was tested as a substitute for the conventional drainfield in septic ...

Constructed wetlands have been popular in ecological engineering regime; yet, modeling the physical, chemical, and biological processes within these wetlands is a long-standing challenge in the past decades. In concert with our field-scale pilot testing of a new-generation subsurface upflow wetland (SUW) system, this article highlights an advancement of modeling the SUW system with a layer-structured compartmental simulation model. This is the first wetland model of its kind to address the complexity between plant nutrient uptake and medium sorption. Such a system dynamics model using STELLA® as a means for a graphical formulation was applied to illustrate the essential mechanism of the nitrification and denitrification processes within a sorption medium-based SUW system, which can be recognized as one of the major passive on-site wastewater treatment technologies in this decade. Model calibration and validation received fairly good R-squared values of 0.9998 and 0.9644, respectively. Such good a...

Removal of nutrients and pathogens in wastewater effluents is very important for the sustainability of the aquatic ecosystem and environment. On-site sewage treatment and disposal systems commonly referred as septic systems are one of the major sources of nutrients and pathogens in groundwater systems. Drainfields in septic tank systems are normally located in permeable, unsaturated natural soil or imported fill material so that wastewater can infiltrate and percolate through the underlying soil to the groundwater for final disposal. In the past, removal of nutrients in these conventional drainfields was too low to meet the water quality requirements. This article presents a new passive underground drainfield of innovative design with soil amendments (sorption media) for nutrient and pathogen removal in a field-scaled septic tank system. This new system, which is filled with green sorption media consisting of recycled materials mixed with naturally occurring materials, was fully tested in both Ph...

On-site sewage treatment and disposal systems (OSTDSs) are oftentimes used to treat human waste accruing from nearly one-third of the U.S. population. Operation of OSTDS contributes a larg...

Groundwater contamination due to the failure of septic tank systems is a vital concern in environmental health. Active on-site wastewater treatment counts on the use of pumps to sustain the aerobic condition in the process and promote the nitrification which might not be sustainable in terms of energy saving. In current practice, passive on-site wastewater treatment processing is deemed a cost-effective option to improve the nutrient removal. The recirculation filtration tank (RFT) is an intermediate process installed to trigger or promote the proper nitrification/denitrification process between the septic tank and the drain field. However quantification of the nitrification remains difficult. To explore the structure and function of the microbiological community in the RFT, two types of sands—fine and coarse—were used in two consecutive phases for elucidating the nitrification and denitrification effects. With the aid of real-time PCR, the growth of nitrifiers and denitrifiers in sand was monitored in the RFT without adding any external carbon source to the sand. Further, phosphorus removal from the wastewater and the ability of limestone for phosphorus removal were also confirmed in the RFT. Fine sand with limestone mixture performed better in nutrient removal if clogging was overcome by using a grinder pump for dosing. On average, removal efficiencies of 60.54% ammonium, 49.48% total Kjeldahl nitrogen (TKN), 42.57% total nitrogen (TN), 92.06% soluble reactive phosphorus (SRP) and 87.16% total phosphorus (TP) were achieved by the RFT with fine sand. The E. Coli removal efficiency by the RFT was 99.9% in both phases.

Conventional on-site wastewater treatment systems are no longer able to fully meet the needs of coping with the impacts of the variegated pollutants with which they are confronted. Without proper nitrification and denitrification, this implies a large fraction of nutrient loads such as nitrogen and phosphorus will flow into groundwater aquifers adversely affecting the water quality and public health. Constructed wetland, a cost-effective small-scale wastewater treatment system with low energy, maintenance requirements and operational costs may well fill the current gaps. In Phase I of this study, a subsurface constructed wetland system designed as an integral part of a performance-based passive on-site wastewater treatment system was proved effective after receiving septic wastewater flow. Using a suite of selected plant species, it is configured to handle 189 liters per day (50 GPD) of influent for a wastewater treatment and reuse study using green sorption media (recycled and natural materials) at a test center located at the University of Central Florida (UCF). During the three-month test run, the system achieved a removal efficiency of 75.4% in total nitrogen (TN) and 94.9% in total phosphorus (TP). Overall, the removal efficiency of TN and TP in an integrated septic tank and constructed wetland (ST/CW) system became as high as 81.3% and 95.8%, respectively.

Stormwater management was originally intended for flood control and minimal water quality improvement. The systems utilized for on-site treatment, most often stormwater ponds, are now a critical best management practice (BMP) tool for preventing nutrient runoff from urban regions discharging into natural water bodies causing eutrophication. This chapter begins with discussing limitations of traditional stormwater ponds followed by a brief introduction of the FTW as an innovative and additive BMP to avoid copper-based algaecide use and improve the pond nutrient removal. This is supported with a field-scale study in terms of hydrologic record, water quality levels, and sediment nutrient contents. This chapter continues with the development of a system dynamics model associated with FTWs in a stormwater wet pond to entail the coupling, feedback, and cycling embedded in these hydrobiogeochemical processes within. This study eventually leads to a deepened understanding of the nitrogen cycle and ecological phenomena in relation to floating islands for nitrogen removal under current management techniques, which apply copper-based herbicides to control algae blooms resulting from available nutrients. The model was designed to be structurally dynamic to evaluate ecosystem dynamics that compound the biochemical removal mechanisms that may result in the altered nitrogen removal capacity due to copper impact. Simulations were conducted with corresponding scenarios associated with potential use of algaecides for algal bloom control in those stormwater wet ponds.

In this study, a new-generation subsurface upflow wetland (SUW) system packed with a unique sorption media was introduced for nutrient removal in a domestic wastewater treatment process. To explore the interface between hydraulic and environmental performance, a tracer study was carried out in concert with a transport model to collectively provide hydraulic retention time (7.1 days) and compelling evidence of pollutant fate and transport processes. Research findings indicate that our pollution-control media demonstrates smooth nutrient removal efficiencies across different sampling port locations given the appropriate size distribution conversant with the anticipated hydraulic patterns and layered structure among the sorption media components. The sizable capacity for nutrient removal in this bioprocess confirms that the SUW is a promising substitute or an extension of traditional onsite wastewater treatment systems. Constructed wetlands have been popular in ecological engineering regime; yet modeling the physical, chemical, and biological processes within these wetlands with respect to the knowledge gained in a tracer study has been a long-standing challenge in past decades. The second part of this chapter highlights an advancement of modeling the SUW system with a layer-structured compartmental simulation model. This is the first wetland model of its kind in the world to address the complexity between plant nutrient uptake and sorption media. Such a system dynamics model using STELLA® as a means for a graphical formulation was applied to illustrate the essential mechanism of the nitrification and denitrification processes within a sorption media-based SUW system, which can be recognized as one of the major passive onsite wastewater treatment technologies in this decade.

Floating treatment wetland (FTW) is one of the emerging best management practices (BMPs) for stormwater treatment where macrophytes provide a suitable root-zone environment for microorganisms that allow the plants to remove nutrients through direct uptake into their tissue. In this study, four floating mats with native Florida aquatic macrophytes were deployed in a 340-m 2 subtropical stormwater wet detention pond. A fountain in the pond and peat moss used to hold the substrate for plant species on the floating mats are both assumed to add nutrients to the water column. This chapter presents the basic performance evaluation of nutrient removal through the four floating mats and explores associated effects of simultaneous hydrological and biological controls related to various hydrobiogeochemical processes for nutrient removal in a multimedia pond environment. Nutrient concentrations in both inlet and outlet were monitored continuously over 13 months, with episodic (storm events) and routine (nonstorm events) sampling plans carried out in parallel to justify the efficacy of the FTWs.

The major causes of nutrient problems are widely acknowledged to be nonpoint sources of pollution from both urban and rural areas, including conventional septic tanks or onsite sewage treatment and disposal systems (OSTDS). In this chapter, an extensive literature review of the myriad of alternative passive and non-passive technologies available leads to a new constructed wetland technology that is designed as a subsurface upflow wetland (SUW) with innovative subsurface hydraulic flow patterns, green reactive sorption media, and various plant species. The biosorption-activated media (BAM) are used before the standard drainfield design, and the SUW is used to replace the conventional drainfield. The SUW must have a seepage area for the effluent if reuse of the water is not planned. The SUW system installed at Central Florida underwent intensive sampling for system performance, modeling of the processes, pollutant transport and fate measures, and an assessment for integration of the planning, design, installation, maintenance, and management functions for future implementation and certification testing. Such an SUW system has proven advantageous relative to the conventional OSTDS. The average effluent nitrates are less than 10 mg L − 1 and fecal and E. coli data indicate that their removal is significant for all cases in the field campaign.

Stormwater infiltration basins, one of the typical stormwater best management practices, are commonly constructed for surface water pollution control, flood mitigation, and groundwater restoration in rural or residential areas. These basins have soils with better infiltration capacity than the native soil; however, the ever-increasing contribution of nutrients to groundwater from stormwater due to urban expansion makes existing infiltration basins unable to meet groundwater quality criteria related to environmental sustainability and public health. This issue requires retrofitting current infiltration basins for flood control as well as nutrient control before the stormwater enters the groundwater. An existing stormwater infiltration basin in north-central Florida was selected, retrofitted, and monitored to identify subsurface physiochemical and biological processes during 2007-2010 to investigate nutrient control processes. This implementation in the nexus of contaminant hydrology and ecological engineering adopted amended soil layers packed with biosorption activated media (BAM; tire crumb, silt, clay, and sand) to perform nutrient removal in a partitioned forebay using a berm. This study presents an infiltration basin-nitrogen removal (IBNR) model, a system dynamics model that simulates nitrogen cycling in this BAM-based stormwater infiltration basin with respect to changing hydrologic conditions and varying dissolved nitrogen concentrations. Modeling outputs of IBNR indicate that denitrification is the biogeochemical indicator in the BAM layer that accounted for a loss of about one third of the total dissolved nitrogen mass input.

This study presents an integrated k-means clustering and gravity model (IKCGM) for investigating the spatiotemporal patterns of nutrient and associated dissolved oxygen levels in Tampa Bay, Florida. By using a k-means clustering analysis to first partition the nutrient data into a user-specified number of subsets, it is possible to discover the spatiotemporal patterns of nutrient distribution in the bay and capture the inherent linkages of hydrodynamic and biogeochemical features. Such patterns may then be combined with a gravity model to link the nutrient source contribution from each coastal watershed to the generated clusters in the bay to aid in the source proportion analysis for environmental management. The clustering analysis was carried out based on 1 year (2008) water quality data composed of 55 sample stations throughout Tampa Bay collected by the Environmental Protection Commission of Hillsborough County. In addition, hydrological and river water quality data of the same year were acquired from the United States Geological Survey's National Water Information System to support the gravity modeling analysis. The results show that the k-means model with 8 clusters is the optimal choice, in which cluster 2 at Lower Tampa Bay had the minimum values of total nitrogen (TN) concentrations, chlorophyll a (Chl-a) concentrations, and ocean color values in every season as well as the minimum concentration of total phosphorus (TP) in three consecutive seasons in 2008. The datasets indicate that Lower Tampa Bay is an area with limited nutrient input throughout the year. Cluster 5, located in Middle Tampa Bay, displayed elevated TN concentrations, ocean color values, and Chl-a concentrations, suggesting that high values of colored dissolved organic matter are linked with some nutrient sources. The data presented by the gravity modeling analysis indicate that the Alafia River Basin is the major contributor of nutrients in terms of both TP and TN values in all seasons. With this new integration, improvements for environmental monitoring and assessment were achieved to advance our understanding of sea–land interactions and nutrient cycling in a critical coastal bay, the Gulf of Mexico.

Soil beneath a stormwater infiltration basin receiving runoff from a 23 ha predominantly residential watershed in north-central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop an innovative stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO(3)(-)/Cl(-)) ratios for the shallow groundwater indicates that prior to using BAM, NO(3)(-) concentrations were substantially influenced by nitrification or variations in NO(3)(-) input. In contrast, for the new basin utilizing BAM, NO(3)(-)/Cl(-) ratios indicate minor nitrification and NO(3)(-) losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest that NO(3)(-) losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by the increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO(4)(3-)) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO(4)(3-)/Cl(-) ratios for shallow groundwater indicate predominantly minor increases and decreases in PO(4)(3-) with the exception of one summer sample that indicated a 50% loss. Differences in nutrient variations between the unsaturated zone and shallow groundwater may be the result of the intensity and duration of nutrient removal processes and mixing ratios with water that had undergone little biogeochemical transformation. Observed nitrogen and phosphorus losses demonstrate the potential, as well as the future research needs to improve performance, of the innovative stormwater infiltration basin using BAM for providing passive, economical, stormwater nutrient-treatment technology to support green infrastructure.

Excessive nutrients, which may be represented as Total Nitrogen (TN) and Total Phosphorus (TP) levels, in natural water systems have proven to cause high levels of algae production. The process of phytoplankton growth which consumes the excess TN and TP in a water body can also be related to the changing water quality levels, such as Dissolved Oxygen (DO), chlorophyll-a, and turbidity, associated with their changes in absorbance of natural radiation. This paper explores spatiotemporal nutrient patterns in Tampa Bay, Florida with the aid of Moderate Resolution Imaging Spectroradiometer or MODIS images and Genetic Programming (GP) models that are deigned to link those relevant water quality parameters in aquatic environments.

Soil moisture and evapotranspiration (ET) is affected by both water and energy balances in the soilvegetation- atmosphere system, it involves many complex processes in the nexus of water and thermal cycles at the surface of the Earth. These impacts may affect the recharge of the upper Floridian aquifer. The advent of urban hydrology and remote sensing technologies opens new and innovative means to undertake eventbased assessment of ecohydrological effects in urban regions. For assessing these landfalls, the multispectral Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing images can be used for the estimation of such soil moisture change in connection with two other MODIS products - Enhanced Vegetation Index (EVI), Land Surface Temperature (LST). Supervised classification for soil moisture retrieval was performed for Tampa Bay area on the 2 kmx2km grid with MODIS images. Machine learning with genetic programming model for soil moisture estimation shows advances in image processing, feature extraction, and change detection of soil moisture. ET data that were derived by Geostationary Operational Environmental Satellite (GOES) data and hydrologic models can be retrieved from the USGS web site directly. Overall, the derived soil moisture in comparison with ET time series changes on a seasonal basis shows that spatial and temporal variations of soil moisture and ET that are confined within a defined region for each type of surfaces, showing clustered patterns and featuring space scatter plot in association with the land use and cover map. These concomitant soil moisture patterns and ET fluctuations vary among patches, plant species, and, especially, location on the urban gradient. Time series plots of LST in association with ET, soil moisture and EVI reveals unique ecohydrological trends. Such ecohydrological assessment can be applied for supporting the urban landscape management in hurricane-stricken regions.

Groundwater contamination due to the nutrients from a septic tank system is a vital concern in environmental health. Active OSTDS also know as on-site wastewater treatment is dependent on the use of pump to sustain the aerobic condition in the process and promote the nitrification which might not be sustainable in terms of energy saving. Experiments have been conducted over the past three years to find a cost-effective, passive on-site wastewater treatment process to improve nutrient removal. The inclusion of recirculation sand filter (RSF) might be a suitable intermediate process to trigger the proper nitrification/denitrification process between the septic tank and the drain field. This option may be adopted for these existing traditional septic tank systems as a retrofit project. Yet the science question as to how effectively the nitrification and denitrification can be fostered in an RSF remains unclear. Three types of medium: fine sand, course sand, and green sorption media (i.e. denoted as options 1, 2 & 3 in this study) were used to assess the performance of the RSF. In particular, phosphorus removal from the wastewater was one of the key concerns, and the capability of using limestone for phosphorus removal was also investigated and confirmed. It can be concluded that fine sand with limestone mixture had better performance for nutrient removal if clogging issue can be overcome by using a grinder pump when dosing. On average, the septic tank and RSF system with fine sand removal efficiencies were: 60.54% ammonium, 49.48% total Kjehldahl nitrogen (TKN), 42.57% total nitrogen (TN), 92.06% soluble reactive phosphorus (SRP) and 87.16% total phosphorus (TP). The E. Coli removal efficiency by RSF was 99.9% in all cases. However, the addition of green sorption media is not favored due to insufficient hydraulic residence time (HRT). If the size of the RSF can be increased, the use of green sorption media in combination with limestone might be beneficial. Keyword: Wastewater treatment, Nutrient removal, Real-time PCR, Environmental health

The conventional decentralized sewage collection, treatment, and disposal systems are no longer able to fully respond to the needs of handling removal of nutrients.. Without proper sorption and nitrification/denitrification, a large fraction of nutrient loads such as nitrogen and phosphorus flowing into aquatic system may adversely affect the water quality and public health. Constructed wetland, a cost-effective small-scale wastewater treatment system with low energy and maintenance requirements and operational costs, may well fit the current needs. A subsurface constructed wetland system as designed as a performance-based passive on-site sewage treatment and disposal system (OSTDS) was proved effective after receiving septic wastewater flow. With the aid of a suite of locally adapted and selected plant species, such an OSTDS was configured to handle 189 cubic meters per day (50 GPD) influent using green sorption media at the test center located on the main campus of University of Central Florida (UCF). During the test run, results indicate that wetland 1, which was planted with Canna, achieved the best removal efficiency of 97.1 %, 98.3 %, 99.98 % and near 100.0 % for TN, TP, fecal coli and E.Coli, respectively. Keyword: Wastewater treatment, Nutrient control, Ecological engineering, Sustainability engineering, Green Technology, Environmental health

When urban regions gradually expand due to regional development, centralized sewage collection, treatment, and disposal is often unavailable for both geographic and economic reasons. As a consequence, about a quarter of the residences in the United States relied on decentralized treatment of wastewater. Household wastewater contains high concentration of nutrients (mainly nitrogen and phosphorus), disease-causing organisms and viruses, and some toxic chemicals. Nation wide, wastewater effluent from on-site wastewater treatment (OWTS) can represent a large fraction of nutrient loads to groundwater aquifers. Phosphorus and nitrogen compounds are the most frequent measurements to indicate nutrient loadings. Some aquifers may discharge into springs or other surface waters adversely affecting public health. Hence, on-site wastewater effluent disposal has contributed significant adverse impacts to the dynamics of the natural environment. Nowadays, due to widespread septic tank failure, scientists, engineers, and manufacturers in the wastewater treatment industry have developed a wide range of alternative passive technologies designed to address increasing hydraulic loads, energy saving requirement, and water contamination by nutrients and pathogens in OWTS. This paper aims to present an innovative design of the underground drainfield with soil amendments (sorption media) in a pilot septic tank system. The new system located at the OWTS test center, University of Central Florida (UCF) was tested and proved costeffective in the initial test run in fall 2008.