Treatment Wetlands

Constructed wetland systems (CWSs) can offer cost-effective wastewater treatment in developing countries like Pakistan. This study focused on optimizing design and operational parameters of CWSs in horizontal surface flow (HSF), vertical surface flow (VSF), and hybrid mesocosms for treating sewage and textile effluents using local hydrophytes: Lemna minor, Typha latifolia, and Eichhornia crassipes. Pollutants and heavy metals (Cd, Cr, Cu, Pb, Ni, and Zn) were removed under different flow configurations, bedding materials, hydrophyte species, and hydraulic retention times (HRT) to optimize the overall contaminant removal efficiency (RE). Key findings indicated that the hybrid CWS achieved a maximum RE of 63.62% for total suspended solids (TSS) and 57.9% for biochemical oxygen demand (BOD) at an HRT of 3 days, with efficiencies declining at longer retention times. Additionally, the hybrid system showed maximum metal removal, with Cd and Cr RE reaching 75.2% and 70.5%, respectively. The study also highlighted the critical role of hydrophyte species and HRT in optimizing RE. Furthermore, the choice of hydrophyte species significantly influenced pollutant removal, with treatment cells containing mixed hydrophytes achieving the highest removal efficiencies (63.62%), followed by Eichhornia crassipes with high Cd (643.33 mgkg-1) and Cr (1103.72 mgkg-1) uptake. A lower HRT of 3 days resulted in the highest overall removal efficiency of 57.5%, which decreased with longer HRTs (from 6 to 9 days). Optimizing design and operational parameters is crucial for maximizing CWS treatment potential.

Two ecological models of nitrogen processes in treatment wetlands have been evaluated and compared. These models have been implemented, simulated, and visualized in the Modelica language. The differences and similarities between the Modelica modeling environment used in this thesis and other environments or tools for ecological modeling have been evaluated. The modeling tools evaluated are PowerSim, Simile, Stella, the MathModelica Model Editor, and WEST. The evaluation and the analysis have been performed using McCall's factors for software quality (McCall et al, 1977), a correlation analysis and the Constant Comparative Method (Glaser & Strauss, 1999). The results show that the modeling tools and the models can both be separated into two categories: Simple Components and Complex Components for the modeling tools, and Simple Models and Complex Models for the models. The major difference between the Simple Components and the Complex Components is the higher possibility of the Complex Components to create and reuse separate components and the higher complexity in these components. The similarities between the categories are that they are consistent, easy to overview and use, if no new components are to be created. The major difference between the Simple Models and the Complex models lies in the number of functions and in the possibility of reuse and expansion. The similarities between all the models are that they are all consequent, logical, valid, specialized, and easy to use if the user has programming skill. To conclude this thesis, the nitrogen decrease in a constructed treatment wetland can well be simulated using the Nitrification/Denitrification model expressed in Modelica and the MathModelica Model Editor. However, some changes to the Model Editor are recommended to make the creation of the model easier. The most important of these changes are the addition of a tutorial, the addition of useful error handling and messages, and the removal of unnecessary Visio features.

Two ecological models of nitrogen processes in treatment wetlands have been evaluated and compared. These models have been implemented, simulated, and visualized in the Modelica language. The differences and similarities between the Modelica modeling environment used in this thesis and other environments or tools for ecological modeling have been evaluated. The modeling tools evaluated are PowerSim, Simile, Stella, the MathModelica Model Editor, and WEST. The evaluation and the analysis have been performed using McCall's factors for software quality (McCall et al, 1977), a correlation analysis and the Constant Comparative Method (Glaser & Strauss, 1999). The results show that the modeling tools and the models can both be separated into two categories: Simple Components and Complex Components for the modeling tools, and Simple Models and Complex Models for the models. The major difference between the Simple Components and the Complex Components is the higher possibility of the Complex Components to create and reuse separate components and the higher complexity in these components. The similarities between the categories are that they are consistent, easy to overview and use, if no new components are to be created. The major difference between the Simple Models and the Complex models lies in the number of functions and in the possibility of reuse and expansion. The similarities between all the models are that they are all consequent, logical, valid, specialized, and easy to use if the user has programming skill. To conclude this thesis, the nitrogen decrease in a constructed treatment wetland can well be simulated using the Nitrification/Denitrification model expressed in Modelica and the MathModelica Model Editor. However, some changes to the Model Editor are recommended to make the creation of the model easier. The most important of these changes are the addition of a tutorial, the addition of useful error handling and messages, and the removal of unnecessary Visio features.

Constructed wetlands systems demand preliminary and primary treatment to remove solids present in greywater (GW) to avoid or reduce clogging processes. The current paper aims to assess hydraulic and hydrological behavior in an improved constructed wetland system, which has a built-in anaerobic digestion tank (AnC), from where GW is distributed to the evapotranspiration and treatment tank evapotranspiration and treatment tank (CEvaT), combined with a subsurface horizontal flow constructed wetland (SSHF-CW). The results show that both the plants present in the units and the AnC improve hydraulic and volumetric efficiency, decrease short-circuiting and improve mixing conditions in the system. Moreover, the hydraulic conductivity measured on-site indicates that the presence of plants in the system and the flow distribution pattern provided by the AnC might reduce clogging in the SSHF-CW. It is observed that rainfall enables salt elimination, thus increasing evapotranspiration (ET), which promotes effluent reduction and enables the system to have zero discharge when reuse is unfeasible.

Winery wastewater is of great concern due to its complex composition, characterized by high organic content and high amounts of readily and slowly biodegradable and recalcitrant compounds. In the present study, the culturable bacteria from rhizo (interstitial water and substrate) and endosphere (inside roots and shoots) of Iris pseudacorus plants inhabiting a treatment wetland mesocosm receiving winery wastewater, were isolated and identified. The innovative approach combined the use of these plants with a substrate based on used cork stoppers, as a support. Of the 53 bacterial isolates retrieved from the rhizo (interstitial water and substrate) and endosphere (root and shoot) of I. pseudacorus plants, the class γ-Proteobacteria was predominant in the shoot and root tissues (72%), but it was also present in the interstitial water and substrate (28%). In total, 13 different genera were found. Pseudomonas and Bacillus were the most represented genera in the rhizosphere while Rahnella and Pseudomonas were dominant in the endosphere of Iris plants. Plant tissues and the water-substrate shared 31% of the genera. Used cork stoppers supported plant growth and can be valorized as substrate in constructed vegetated systems for wastewater treatment and future bioremediation developments may be assisted by the use of resilient bacteria retrieved from such harsh environments.

• C. glauca vs. T. domingensis, and LECA vs. river stone as substrates were compared. • HSSF wetlands with river stone planted with C. glauca showed the best performance. • k values suggested the importance of plants for pollutant removal. • HSSF wetlands using river stones showed a faster kinetics than wetlands with LECA. • We propose to use C. glauca and river stone in a field-scale HSSF wetland.

• C. glauca vs. T. domingensis, and LECA vs. river stone as substrates were compared. • HSSF wetlands with river stone planted with C. glauca showed the best performance. • k values suggested the importance of plants for pollutant removal. • HSSF wetlands using river stones showed a faster kinetics than wetlands with LECA. • We propose to use C. glauca and river stone in a field-scale HSSF wetland.

Constructed wetlands provide nitrogen removal through a combination of bacterial nitrification-denitrification and plant uptake (Reed et ai, 1988). The dynamics of these two mechanisms will vary depending upon the carbon to nitrogen ratio in the wastewater, plant maturity, and the growing season. The authors studied nitrogen removal from primary effluent using 25-L buckets filled with gravel. The study was conducted over a 37 week period. Club rush vegetation was planted in 12 of the 20 buckets. The average detention time for the batch fed reactors was 7 days for the period from week 5 (after planting) to week 21, with detention time decreasing to 3.5 days for treatment 1 for weeks 21 through 37. Nitrogen removal in the unplanted buckets averaged approximately 50% which the authors attributed to nitrification-denitrification. In the planted buckets, 98% nitrogen removal was achieved which the authors attributed to plant uptake (85%). The authors conclude that plant uptake is the major pathway for nitrogen removal in vegetated submerged bed wetlands. There are two problems with the conclusion that plant uptake is the dominant pathway of nitrogen removal. First, the plants were immature and in a maximum growth phase. In fact, the authors state that the colonizing growth mode continued for 3 years before the plant roots fully occupied the space in the buckets. Under these high growth conditions the plants will compete actively for available nitrogen. Full-sized, mature operating systems, however, must operate with mature plants whose nitrogen uptake will be significantly less than that for young growing plants.

Nutrient impairment of Florida's surface waters due to urban stormwater runoff is a growing concern, resulting in the development of new regulatory policies. Several best management practices (BMPs), such as stormwater retention/detention ponds, help reduce the impact of flooding but may not reduce nutrient loadings sufficiently to meet water quality goals. This paper presents the design and implementation of a floating media bed reactor (FMBR) as a supplementary treatment unit for stormwater wet detention ponds to enhance the removal efficiency of total phosphorus (TP) and total nitrogen (TN). This effort mitigates the adverse effects of stormwater runoff on downstream impaired waterbodies. The FMBR was filled with an engineered mixture of adsorption media made of natural and recyclable materials and operates on a 24 h continuous cycle, powered by a small photovoltaic pumping system. Significant reductions in TP and TN were documented across the FMBR achieving varying degree of removal efficiencies for storm and non-storm events with fluctuating temperatures. The outcome expands the state of the art stormwater treatment technology and encourages stormwater reuse as an alternative source of freshwater.

Nutrient impairment of Florida's surface waters due to urban stormwater runoff is a growing concern, resulting in the development of new regulatory policies. Several best management practices (BMPs), such as stormwater retention/detention ponds, help reduce the impact of flooding but may not reduce nutrient loadings sufficiently to meet water quality goals. This paper presents the design and implementation of a floating media bed reactor (FMBR) as a supplementary treatment unit for stormwater wet detention ponds to enhance the removal efficiency of total phosphorus (TP) and total nitrogen (TN). This effort mitigates the adverse effects of stormwater runoff on downstream impaired waterbodies. The FMBR was filled with an engineered mixture of adsorption media made of natural and recyclable materials and operates on a 24 h continuous cycle, powered by a small photovoltaic pumping system. Significant reductions in TP and TN were documented across the FMBR achieving varying degree of removal efficiencies for storm and non-storm events with fluctuating temperatures. The outcome expands the state of the art stormwater treatment technology and encourages stormwater reuse as an alternative source of freshwater.

In Estonia many natural/seminatural wetlands have been used for municipal or farm wastewater. During the last decade more than 20 constructed wetlands for wastewater purification were established. In this paper budgets of organic matter (BOD), total N and total P of five systems (a sandlplant filter with vertical flow, a combined overland flow-subsurface flow system on a Phalaris arundinaceaslope, an aquatic macrophyte channela bioditch, a twochamber horizontal-flow sand-plant filter, and a free surface water system as a cascade of 4 serpentine ponds with macrophytes) located in southern Estonia, are analyzed. Except for nitrogen, the efficiency of the vertical flow sandlplant filter was found satisfactory: 82%, 36%, and 74% for BOD5, total N, and total P, respectively. The poor performance with respect to nitrogen may be caused by weak vegetation. In the Phalaris-system, 65% of organic matter, 67% N, and 80% P was removed. The average output concentrations of this system were always lower than the recommended limits (BODs < l 0 mg O2 I-', total N < l 0 mg l.', and total P c 2 mg I-'). Due to high input load, the BOD5, total N, and total P values in the outlet of the bioditch were high and extremely varying: 5-100, 6-16, and 1-4 mg I-', respectively. The horizontal flow sand-plant filter showed satisfactory purification efficiency in terms of SOD and P (66-95% and 63-96%, respectively). In contrast, N removal was relatively low, varying from 12 to 85%. In the free water surface wetland, the most critical parameter is P retention. Mean purification efficiency observed was about 73% for total N, 68% for BOD and only 24% for total P. Purification efficiency in all wetland systems studied did not decrease during the cold season. However, the most critical period for purification efficiency was found in spring.

Performance of constructed wetland systems has been widely variable, particularly with respect to cold climate systems. Phosphorus removal has been particularly challenging in wetland systems, with widely variable removal efficiencies being reported. A subsurface flow constructed wetland is being used at Sunny Creek Estates in Bayside, Ontario, to polish sewage lagoon effluent. A benchmarking study was conducted to gather operational data from within the wetland, to characterize phosphorus dynamics within the system. Samples were collected and analyzed for total and dissolved phosphorus concentrations for a one-year period. Spatial and temporal variations in phosphorus were then investigated, and mass balances were performed. Mass balances conducted on an average annual basis, and on a seasonal basis, indicated a net removal of phosphorus in all cases except the spring season. Segmented phosphorus profiles through the wetland revealed that, regardless of season, there is more phosphorus in shallower wells, and with increasing distance from the influent distribution pipe. Phosphorus masses varied significantly with depth, and in directions both parallel and perpendicular to flow through the wetland. The seasonal and spatial variations illustrate the importance of monitoring within wetlands, and reinforce the limitations of using a black box approach in wetland design.

and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, redistribution , reselling , loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

The trans-boundary area between the Europe Union and other countries is highly susceptible to changes in water quality and variations in the potential pollution load that could influence its eco-systems significantly. The Neris (Viliya) River is one of the biggest surface water bodies in Lithuania and Belarus with an ecologically important area protected by international legislation. The study was aimed at evaluating the impacts of integrated pollution on water quality of the Neris River taking into account different storm-water flows and ecological scenarios. For this purpose, qualitative and quantitative statistical evaluation was set up and calculation was done; different integrated pollution loads of the catchment area were estimated. The evaluation considered a decrease in river discharge due to changes in the regional storm-water flow and technological development that should lead to the growing covered surface and a reduction in the untreated storm-water flows. The obtained r...

Constructed wetlands systems demand preliminary and primary treatment to remove solids present in greywater (GW) to avoid or reduce clogging processes. The current paper aims to assess hydraulic and hydrological behavior in an improved constructed wetland system, which has a built-in anaerobic digestion chamber (AnC), GW is distributed to the evapotranspiration and treatment tank (CEvaT), combined with a subsurface horizontal flow constructed wetland (SSHF-CW). The results show that both the plants present in the units and the AnC improve hydraulic and volumetric efficiency, decrease short-circuiting and improve mixing conditions in the system. Moreover, the hydraulic conductivity measured on-site indicates that the presence of plants in the system and the flow distribution pattern provided by the AnC might reduce clogging in the SSHF-CW. It is observed that rainfall enables salt elimination, thus increasing evapotranspiration (ET), which promotes effluent reduction and enables the ...

The research was driven by a need to increase the knowledge base concerning wetland ecological responses, as well as to identify and evaluate the factors driving the functioning of the Franschhoek Trust Wetland. An ecohydrological study was undertaken in which vegetation cover, depth to groundwater, water and soil chemistry were monitored at 14 sites along three transects for a 12 month period. The parameters used include temperature, pH, electrical conductivity (EC), sodium, potassium,

Nowadays, use of constructed wetlands for wastewater treatment especially in rural areas has become increasingly preferable. The most important reason behind this fact is its relatively low investment cost over other treatment options depending on economical conditions of the country. Nonetheless, due to lower operational costs of constructed wetlands than other conventional wastewater treatment systems, investment costs could be regarded secondary as of importance. Investment costs could show differences even at regional scale in a country. Choosing a constructed wetland system among “Subsurface Horizontal Flow”, “Subsurface Vertical Flow” or “Free Water Surface Flow”; or designing a hybrid system using concurrent systems plays important role when defining costs of the constructed wetland systems. Due to increasing interest for constructed wetlands since 2003, so many constructed wetland systems have been built in rural parts of Turkey and most of these systems have been designed a...

Eutrophication is a widespread global scale pollution problem. Agricultural areas are generally the main contributors to eutrophication, whereas sewage and industrial discharges, which usually receive some treatment prior to discharge, are a secondary source. This is mostly the case of the ultra-oligotrophic Florida Everglades, where natural water sources are often enriched by nutrients from large-scale industrial agricultural stormwater runoff. Remediation of these agricultural waters cannot be conducted with the usual environmental engineering solutions, and in this context ecological engineering approaches such as constructed wetlands are much more suitable. Moreover, these wetlands provide other ecosystem services such as carbon sequestration or habitat provisioning. In this paper we have implemented a mechanistic phosphorus model into a time-space-dependent mathematical simulation platform (COMSOL Multiphysics TM) which has been calibrated with wetland mesocosm data. Subsequently we have evaluated different characteristics of constructed wetland physical elements such as internal walls and baffles, different types of inlets, parallel and series operation, and increase in hydraulic retention time (HRT) to study total phosphorus (TP) removal performance and to improve efficiency. Simulation results indicate that wetland mesocosm soils released dissolved organic phosphorus which was washed out together with the effluent, making very difficult to attain a concentration lower than a target of 10 µg TP L-1 , as required to protect the Everglades. Simulations showed that the design based on combination of the bottom inlet together with parallel operation extensively improves efficiency. Target TP concentrations can be achieved with this design together with an increase on 25% of hydraulic retention time. With this study we demonstrate the usefulness of the model for detailed designs, opening the door for its use in field scale applications.

Considering the increasing pressure on freshwater resources due to the constant increase in water consumption and insufficient wastewater control and treatment, recovering wastewater is a path to overcoming water scarcity. The present work describes the potential of reusing treated wastewater (reclaimed water) for irrigation and production of microalgae biomass in an integrated way, through experimental evaluation of plant and microalgae growth, and creation of an application model. First, two parallel experiments were conducted to evaluate the use of reclaimed water produced by a constructed wetland filled with a mix of solid waste: the irrigation of a set of small pots filled with soil and planted with Tagetes patula L., and the cultivation of microalgae Chlorella sp. and a mixed microalgae population with predominant species of the genus Scenedesmus sp. in shaken flasks and tubular bubble column photobioreactors. Results indicated no negative effects of using the reclaimed water ...

• C. glauca vs. T. domingensis, and LECA vs. river stone as substrates were compared. • HSSF wetlands with river stone planted with C. glauca showed the best performance. • k values suggested the importance of plants for pollutant removal. • HSSF wetlands using river stones showed a faster kinetics than wetlands with LECA. • We propose to use C. glauca and river stone in a field-scale HSSF wetland.

The study was aimed at analyzing the effect of an increase of municipal effluent discharge quality on the water restoration of an urbanized karst stream, in order to define specific criteria and strategies to safeguard the water quality and to improve and control of the chemical characteristics of the effluent from municipal WWTP, prior to being discharged into the stream. A case study referred to an urbanized surface water body having locally a relevant role for nature, historical and social aspects, was examined. Water quality was examined in several scenarios in function of the treatment options. Wastewater discharge and water stream quality were verified by using models available in literature. Results showed a practical and real application of such a technology to the full scale.

and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, redistribution , reselling , loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

This work compares the performance of vertical subsurface flow treatment wetlands (VSSF TWs) for wastewater treatment, planted with Zantedeschia aethiopica (Za), here operated simultaneously under two different climate conditions, arid and Mediterranean. The experimental setup was divided into two treatment lines for each climate condition: three VSSF TWs planted with Schoenplectus californicus (Sc) (VSSF-S), as the control, and three VSSF TWs planted with Zantedeschia aethiopica (Za) (VSSF-Z), as the experimental unit. The four treatment systems were operated at a hydraulic loading rate of 120 mm/d during spring and summer seasons, in two locations, Iquique (Atacama Desert, Chile) and Talca (Central Valley, Chile). The water quality in effluents, plant development, and water balance were used as performance measures. In terms of the water quality, the influents’ characteristics were similar in both climates and classified as “diluted”. For the effluents, in both climate conditions,...

Eutrophication has been an issue of the Baltic Sea for a long time, causing de-creased water clarity due to enhanced growth of algae and oxygen depletion dur-ing the decomposition of algae. The study investigated the free water surface wetland Vilhelmsberg that treats agricultural runoff before the water reaches the Baltic Sea. The area of the wetland Vilhelmsberg (1.6 ha) corresponds to 0.1 % of its catchment area, in which the natural waterbody Maren is located upstream of the wetland. The main objectives of this study were to quantify the phospho-rus (P) accumulation, evaluate the possibility of recycling the sediment and as-sess the risk of internal loading. Therefore, sediment cores were collected in both waterbodies and analysed for (i) total P and P fractions, (ii) metal content, (iii) plant available P and (iv) particle size distribution. Results showed that the wetland Vilhelmsberg had a low sediment accumulation rate of 0.5 cm yr 1 and a low P accumulation of 13 kg ha 1 yr...

The trans-boundary area between the Europe Union and other countries is highly susceptible to changes in water quality and variations in the potential pollution load that could influence its eco-systems significantly. The Neris (Viliya) River is one of the biggest surface water bodies in Lithuania and Belarus with an ecologically important area protected by international legislation. The study was aimed at evaluating the impacts of integrated pollution on water quality of the Neris River taking into account different storm-water flows and ecological scenarios. For this purpose, qualitative and quantitative statistical evaluation was set up and calculation was done; different integrated pollution loads of the catchment area were estimated. The evaluation considered a decrease in river discharge due to changes in the regional storm-water flow and technological development that should lead to the growing covered surface and a reduction in the untreated storm-water flows. The obtained r...

The objective of the study was to determine the kinetic model that best fit observed nitrate removal rates at the mesocosm scale in order to determine ideal loading rates for two future wetland restorations slated to receive pulse flow agricultural drainage water. Four nitrate removal models were investigated: zero order, first order decay, efficiency loss, and Monod. Wetland mesocosms were constructed using the primary soil type (in triplicate) at each of the future wetland restoration sites. Eighteen mesocosm experiments were conducted over two years across seasons. Simulated drainage water was loaded into wetlands as batches, with target nitrate-N levels typically observed in agricultural drainage water (between 2.5 and 10 mg L −1). Nitrate-N removal observed during the experiments provided the basis for calibration and validation of the models. When the predictive strength of each of the four models was assessed, results indicated that the efficiency loss and first order decay models provided the strongest agreement between predicted and measured NO 3-N removal rates, and the fit between the two models were comparable. Since the predictive power of these two models were similar, the less complicated first order decay model appeared to be the best choice in predicting appropriate loading rates for the future full-scale wetland restorations.

Light greywater (GW L) is the fraction of domestic sewage originating from sinks, shower, bath and laundry activities. Natural systems can be used for GW treatment, for arrangements regarding both uni-residential as well as condominial systems. Green spaces in urban areas improve the local microclimate, benefiting public health and reducing energy consumption, and the use of gray water for developing such spaces, as well as for irrigating private areas, should be considered. For this purpose, a modified constructed wetland system is proposed, aimed at low operation and maintenance. This system, named "EvaTAC", is a combination of an evapotranspiration and treatment tank (CEvaT) with an inbuilt anaerobic chamber (AnC), followed by a horizontal subsurface flow constructed wetland (HSSF-CW). The anaerobic chamber was chosen for its capacity to digest organic matter and retain coarse material, as the intention was to eliminate the septic-or sedimentation tank for pre-treatment, in order to reduce or even avoid problems like clogging and odours. To better understand the capacity of the AnC to equalise daily variations of flow and organic load in the system, we performed two 24-hour and one 8-day monitoring profiles. The results show that the two units complement each other. The 8-day profile shows that, within the CEvaT, the AnC presents the highest removal efficiency of the studied parameters. The HSSF-CW operates as an efficient polishing unit, with the effluent average turbidity of 8 NTU. During the 3 years of operation, no sludge withdrawal was necessary and no maintenance in the distribution pipe (inlet) of the HSSF-CW was required. The implemented system at full scale was quite acceptable to the householders, not disturbing their routine, rendering a green site totally integrated into the garden, without the use of potable water for irrigation.

This work compares the performance of vertical subsurface flow treatment wetlands (VSSF TWs) for wastewater treatment, planted with Zantedeschia aethiopica (Za), here operated simultaneously under two different climate conditions, arid and Mediterranean. The experimental setup was divided into two treatment lines for each climate condition: three VSSF TWs planted with Schoenplectus californicus (Sc) (VSSF-S), as the control, and three VSSF TWs planted with Zantedeschia aethiopica (Za) (VSSF-Z), as the experimental unit. The four treatment systems were operated at a hydraulic loading rate of 120 mm/d during spring and summer seasons, in two locations, Iquique (Atacama Desert, Chile) and Talca (Central Valley, Chile). The water quality in effluents, plant development, and water balance were used as performance measures. In terms of the water quality, the influents’ characteristics were similar in both climates and classified as “diluted”. For the effluents, in both climate conditions,...

Subsurface oxygen availability tends to be one of the main rate-limiting factors for removal of carbonaceous and nitrogenous compounds in subsurface flow (SSF) wetlands used for domestic wastewater treatment. This paper reviews the pertinent literature regarding oxygen transfer and consumption in subsurface flow treatment wetlands, and discusses the factors that influence oxygen availability. We also provide first results from a pilot-scale research facility in Langenreichenbach, Germany (15 individual systems of various designs, both with and without plants). Based on the approach given in Kadlec and Wallace (2009), areal-based oxygen consumption rates for horizontal flow systems were estimated to be between 0.5 and 12.9 g/m 2 -d; for vertical flow systems between 7.9 and 58.6 g/m 2 -d; and for intensified systems between 10.9 and 87.5 g/m 2 -d. In general, as the level of intensification increases, so does subsurface oxygen availability. The use of water or air pumps can result in systems with smaller area requirements (and better treatment performance), but it comes at the cost of increased electricity inputs. As the treatment wetland technology envelope expands, so must methods to compare oxygen consumption rates of traditional and intensified SSF treatment wetland designs.

Natural wastewater treatment (NWT) systems may be a most suitable and economical solution method to ensure a cleaner environment and sustainable production in control of water pollution. Therefore, in this study, a NWT system was designed to reduce existing pollution in overpolluted Kızılca creek (Nigde, Turkey). Combined system consists of a settlement basin (SB), free water surface constructed wetland (FWS-CW) planted with Phragmites communis, and overland flow (OF) system planted with Italian ryegrass, respectively. The system was installed on the edge of the creek in 2014. Over-polluted creek water was treated by passing through the system, and the treated water was discharged into the creek. Total suspended solid (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total phosphorus (TP) parameters were analyzed on samples taken from the inputs and outputs of all stages of the system. During an operating period of about 18 months, it was observed that the pollutant parameters were reduced to a great extent. Despite the high organic loading, it was determined that the treatment system could remove the TSS and the BOD up to 85%, and the TP up to 49%.

The creation of ponds and wetlands has the potential to alleviate stream water quality impairment in catchments affected by diffuse agricultural pollution. Understanding the hydrological and biogeochemical functioning of these features is important in determining their effectiveness at mitigating pollution. This study investigated sediment and nutrient retention in three connected (on-line) ponds on a lowland headwater stream by sampling inflowing and outflowing concentrations during base and storm flows. Sediment trapping devices were used to quantify sediment and phosphorus accumulations within ponds over approximately monthly periods. The organic matter content and particle size composition of accumulated sediment were also measured. The ponds retained dissolved nitrate, soluble reactive phosphorus and suspended solids during baseflows. During small to moderate storm events, some ponds were able to reduce peak concentrations and loads of suspended solids and phosphorus; however, ...

Phosphorus (P) is an essential nutrient, which in excessive concentrations from sewage treatment systems can cause eutrophication of waterways. The use of adsorption substrates is becoming a common method for Premoval from wastewater. To achieve sustained P-removal from passive wastewater treatment systems, such as constructed wetlands, it is essential to select substrates with a high capacity to retain P which can be replaced when saturated. An enriched hemp biochar substrate was added to experimental constructed wetland cells to treat domestic wastewater. Hemp feedstock was treated with hematite, melanterite and dolomite prior to pyrolysis at 400°C. The amount of P which was present in the wastewater from the biochar wetlands cells after treatment was compared to gravel control wetland cells. During the 7-month study period, the wetlands containing the enriched biochar consistently reduced PO 4-P concentrations in primary treated sewage to lower levels than in the control wetlands, with an average inlet P concentration of 15.5 mg/L, to below 2 mg/L. Various analytical methods were used to characterise the changes in the biochar substrate. Concentration of P in the substrate increased by 77% over the test period. X-ray photoelectron spectroscopy (XPS) analysis revealed iron phosphate formation. Scanning electron microscopy together with energy dispersive X-ray spectroscopy (SEM-EDX) showed P captured on the biochar surface was associated with aluminium, silica, iron, magnesium and calcium-rich mineral phases. This study showed that an enriched biochar can be used as a substrate to capture phosphorus in passive wastewater treatment.

Due to increasing population and the improved water supply systems the quantity of greywater generated from the village ponds has increased to a large extent. This has in turn degraded the quality of the receiving water body. Excessive generation of greywater and absence of any village level wastewater treatment mechanism has severely affected the quality of the water in village ponds. So a research has been undertaken to suggest a low cost mechanism for treatment of storm water and grey water found in rural ponds or water bodies. The research conducted includes the study of ten rural catchments in the radius of around sixty kilometres in Doaba region of Punjab. Ponds were used as the disposal points for the greywater generated in the villages. It is worth mentioning that limited quantity of greywater was generated in the villages and hence the self-cleansing capacity of the pond was sufficient to treat the wastewater being disposed of in it. Talking of last few decades the quantity...

As combined sewer systems and centralized wastewater treatment facilities age, many communities in the world are challenged by management of combined sewer overflow (CSO). Constructed wetlands are considered to be one of the green infrastructure solutions to CSOs in the US. Despite the wide application of constructed wetlands to different types of wastewaters, the stochastic and intermittent nature of CSO presents challenges for design and performance assessment of constructed wetlands. This paper reviews the application status of CSO constructed wetlands in the US, assesses the benefits of CSO constructed wetlands, identifies challenges to designing CSO constructed wetlands, and proposes design considerations. This review finds that constructed wetlands are effective in CSO treatment and relatively less expensive to build than comparable grey infrastructure. Constructed wetlands not only remove pollutants, but also mitigate the event-associated flow regime. The design challenges include incorporating considerations of green infrastructure into permit requirements, determining design capacity for highly variable flows, requiring pretreatment,

Constructed wetlands are commonly used for sewage treatment. However, as the natural processes operate, these artificial ecosystems can also be used to enhance the equalization of water features to those of the receiving environments, thus reducing the impacts of the treated water on the natural systems. Here, we studied, by a year-round survey, the simultaneous and separated operation of two subsurface wetlands that were used as a tertiary treatment to enhance the naturalization of wastewaters that had already been treated in a waste water treatment plant (WWTP). These wetlands were operating serially, with the first wetland being covered by the riparian plant Helosciadum nodiflorum, which has not been described so far as being used in treatment wetland, whereas the second was covered by Typha latifolia. The changes in the concentrations and transformation among the different types of pollutants and other physical and chemical parameters, as well as in the bacterial abundance and activity, were studied under different operational conditions of serial cooperation or of separately-operating wetlands. Both wetlands were differentially efficient in the reduction and transformation of the remaining pollutants, with very active nitrification and denitrification processes, which reduced the ammonium concentrations by more than 65%, although they changed according to the operational status of each wetland. They also reduced the already low organic matter contents by around 30% and promoted slight shifts in the dominant types of dissolved organic matter to less labile compounds. To a certain extent, the Typha-covered wetland also contributed to phosphorus removal, by up to 35%. Noticeably, both of the wetlands contributed greatly to the reduction of bacterial abundance, which was even 50% lower after the wetland transit, although the resulting community increased its activity, thus keeping the capacity for pollutant removal and transformation. Overall, the wetlands' operation increased the similarity between the poured waters and those of the receiving stream, thus diminishing its environmental impact.

Constructed wetlands have not been commonly used in Vietnam due to the lack of information in the selection of proper types of constructed wetlands, type of reeds, design parameters and performance efficiency, in tropical climates. This paper focuses on Canna generalis, which is a common reed and easy to grow both in water and wet land conditions. Two kinds of hybrid constructed wetlands were employed, including Facultative pond combined with free water sub-surface constructed wetlands system and horizontal subsurface flow combined with Aerobic pond system. It was found that the ponds played an important role in the hybrid system performance and enhanced the performance of constructed wetlands. The pollutant removal efficiencies of the hybrid systems were all higher than the single constructed wetlands. The BOD5, TSS, NH4-N and PO4-P removal efficiencies averaged 81%, 85%, 93% and 77%, respectively for the hybrid horizontal subsurface flow constructed wetlands system operated at a h...

The enormous increase in the generation of waste water on account of rapid growth of industrialization and urbanization has posed serious threat on human and natural resources. Wastewater has become a significant issue in urban areas especially in developing countries. Developed countries have the capacity to bear the water purification cost but developing countries don’t have that capacity in as much as that they dispose untreated wastewater in to the open source water bodies. The authors of the present paper thus focus on land treatment of wastewater which is economical among other conventional methods which is viable solution for the treatment and disposal of water particularly for the developing countries including India.

Cultural eutrophication stimulated by anthropogenic-derived nutrients represents one of most widespread water quality problems worldwide. Constructed wetlands (CWs) have emerged as an aesthetic, sustainable form of wastewater treatment, but, although they have shown adequate levels of organic matter removal in wastewaters, the effectiveness of nutrient removal has been less successful. An eleven-month monitoring program was undertaken in a horizontal subsurface flow CW (HSSF-CW) treating domestic wastewater from a village in Centre Region of Portugal, to evaluate the influence of climatic conditions (Continental-Mediterranean Climate region) and seasonal variations on removal. This CW uses gravel and sand as substrate and Phragmites australis as wetland plants. Samples were collected at the inlet and outlet from wetland bed and analyzed for pH, TN, Org-N, NH 4 +-N, NO x-N, TP and DP. The removal efficiencies (RE) of nitrogen and phosphorus compounds were relatively poor, but the results allow us to conclude that season had a significant (p < 0.05) effect on the RE of TN, NH 4 +-N, NO x-N, TP and DP, with higher values in warmest period (10.4%, 10.4%, 3.4%, 27.5% and 26.1%, respectively) than in coldest period (0%, −7.7%, −9.8%, 12.9% and 0%, respectively). Although lower hydraulic loading rate (HLR) generally resulted in better RE of all N and P compounds analyzed, no significant linear relationship was observed between these two variables. TN and NH 4 +-N concentrations in the effluent tend to significantly (p < 0.05) decrease with increasing respective incoming mass load rates for whole monitoring period and during spring-summer period, while the correlation between outlet TP concentrations and the inlet loading rate are not significant. The results indicate that the system is not effective for removal of nutrients, probably because it operated on overload and with a low hydraulic retention time (HRT) (average = 2.4 days). The results also showed that the RE of N and P followed seasonal trends, with higher values during spring-summer period.

The creation of ponds and wetlands has the potential to alleviate stream water quality impairment in catchments affected by diffuse agricultural pollution. Understanding the hydrological and biogeochemical functioning of these features is important in determining their effectiveness at mitigating pollution. This study investigated sediment and nutrient retention in three connected (on-line) ponds on a lowland headwater stream by sampling inflowing and outflowing concentrations during base and storm flows. Sediment trapping devices were used to quantify sediment and phosphorus accumulations within ponds over approximately monthly periods. The organic matter content and particle size composition of accumulated sediment were also measured. The ponds retained dissolved nitrate, soluble reactive phosphorus and suspended solids during baseflows. During small to moderate storm events, some ponds were able to reduce peak concentrations and loads of suspended solids and phosphorus; however, ...

A pilot project of one constructed subsurface flow wetlands to treat sewage from family Subandi house has been built in Bandung Indonesian in February 1999. The water samples from both influent and effluent (COD, BOD5, NO3-N, NO2-N, NH4-N, PO4-P, pH, and settleable solids, and O2) were taken twice a month and analyzed. Fecal coliforms bacteria was determined by MPN method. The objective of this study was to install one constructed subsurface flow wetlands with vertical flow to treat sewage from private house. The treatment efficiency of this constructed wetlands was already relatively high, although this constructed wetlands was just only eleven months in operation. The results were very promising and give a possibility of constructed wetlands to be installed and developed in tropical countries, especially in Indonesia, as a viable alternative to conventional wastewater technology, because this system is and simple and cost effective. Keywords: Constructed wetlands, wastewater treat...

Due to increasing population and the improved water supply systems the quantity of greywater generated from the village ponds has increased to a large extent. This has in turn degraded the quality of the receiving water body. Excessive generation of greywater and absence of any village level wastewater treatment mechanism has severely affected the quality of the water in village ponds. So a research has been undertaken to suggest a low cost mechanism for treatment of storm water and grey water found in rural ponds or water bodies. The research conducted includes the study of ten rural catchments in the radius of around sixty kilometres in Doaba region of Punjab. Ponds were used as the disposal points for the greywater generated in the villages. It is worth mentioning that limited quantity of greywater was generated in the villages and hence the self-cleansing capacity of the pond was sufficient to treat the wastewater being disposed of in it. Talking of last few decades the quantity...

Methods, system, compositions for a green sorption media for bioretention soil amendments in drainfields for on-site waste water systems filled with the green sorption media to foster an anaerobic or anoxic environment saturated. The green sorption media includes one or more recycled materials, including tire crumb, sawdust, orange peel, coconut husks, leaf compost, oyster shell, soy bean hulls and one or more naturally occurring materials including peat, sands, zeolites, and clay. The wastewater filtration system for a passive drainfield includes the green sorption material mixture, a cell including baffled compartments and a riser, the cell filled with green sorption material mixture to provide an alternating cycle of aerobic and anoxic environments, an influent distribution system to distribute the influent over the cell, and a piping system arranged for dosing the cell to sustain the functionality of the green sorption material mixture to remove nutrient content in wastewater.

Methods, system, compositions for a green sorption media for bioretention soil amendments in drainfields for on-site waste water systems filled with the green sorption media to foster an anaerobic or anoxic environment saturated. The green sorption media includes one or more recycled materials, including tire crumb, sawdust, orange peel, coconut husks, leaf compost, oyster shell, soy bean hulls and one or more naturally occurring materials including peat, sands, zeolites, and clay. The wastewater filtration system for a passive drainfield includes the green sorption material mixture, a cell including baffled compartments and a riser, the cell filled with green sorption material mixture to provide an alternating cycle of aerobic and anoxic environments, an influent distribution system to distribute the influent over the cell, and a piping system arranged for dosing the cell to sustain the functionality of the green sorption material mixture to remove nutrient content in wastewater.

Iron removal in three Pennsylvania wetlands constructed to treat acid mine drainage was evaluated. All wetlands were constructed with a mushroom compost substrate and were planted with Typha spp. Performance was evaluated by calculating area-adjusted iron loadings and removals as Fe g day-1 m-2 (gdm). An initial model of the iron removal capabilities of constructed wetlands was also evaluated. Relationships between pH, concentration, flow, loading and removal were considered. At the Somerset Site (avg. influent pH=4.0), influent iron loading, which was primarily a function of concentration, was considerably more variable than iron removal. The relationship between the two appeared asymptotic, with removal being independent at loadings above 15 gdm (avg. removal = 10.6 gdm) and averaging 54% of loading at loadings less than 15 gdm. Conversely, at the Latrobe Site (avg. influent pH=3.0), variation in iron loading was primarily a consequence of flow variation. Removal averaged 2.7 gdm at flows > 100 L min-1 and 4.3 gdm when flow < 100 L min-1. The overall average removal was 3.6 gdm. A significant relationship between loading and removal was not found. At the Friendship Hill Wetland, influent pH was 2.7, and iron removal averaged 3.3 gdm. The narrow range of loadings at this site prevented detailed analysis of loading:removal relationships. Overall, these data were used to develop preliminary wetland sizing criteria based upon iron loadings. In situations where mine drainage has flow > 50 L min-1 and iron concentration > 50 mg L-1 , loading-based criteria result in significantly larger wetlands than conventional flow-based criteria.

Nitrogen runoff in locations that rely almost exclusively on septic systems for wastewater management is causing water quality issues in local bodies of water, like ponds, lakes and watersheds. This excess nitrogen causes plant life to die, allows bacteria and algae to thrive and gives bodies of water a murky green discoloration. Orleans, Massachusetts has drafted several plans to solve this problem, but they keep getting voted down at town meetings due to high costs. The purpose of this project is to find and develop efficient and cost effective methods to augment these drafted plans and reduce costs to a level which meets public approval. The method we recommend is the use of microbial fuel cells (MFCs). These cells clean wastewater, remove between 60 and 90 percent of the nitrogen, use little energy to operate, and create some electricity in the process. This means when implemented in a centralized treatment plant, MFCs can significantly reduce the long term cost of a wastewater ...