Wetland Units Research Articles

Hydrodynamic Modeling Improves Green River Reconnection with Floodplain Wetlands for Endangered Fish Species Recovery

AbstractWe performed two‐dimensional (2D) hydrodynamic modeling to aid recovery of the endangered razorback sucker (Xyrauchen texanus) by reconnecting the Green River with its historic bottomland floodplain wetlands at Ouray National Wildlife Refuge, Utah. Reconnection allows spring flood flows to overtop the river levee every two to three years, and passively transport razorback sucker larvae to the wetlands to grow in critical habitat. This study includes (1) river hydrologic analysis, (2) simulation of a levee breach/weir, overtopping of river flood flows, and 2D flow through the wetlands using Hydrologic Engineering Center River Analysis System 2D, and (3) modeling flow and restoration scenarios. Indicators of hydrologic alteration were used to evaluate river flow metrics, in particular flood magnitudes, frequency, and duration. Results showed a target spring flow of 16,000 cfs (453 m3/s) and a levee breach elevation of 4,663 ft (1,421 m) amsl would result in a median flow >6,000 acre‐feet (7.4 million m3) over five days into the wetlands, which is adequate for razorback sucker larvae transport and rearing. Modeling of flow/restoration scenarios showed using gated water control structures and passive low‐water crossings between wetland units can provide adequate control of flow movement into and storage in multiple units. Levee breaching can be a relatively simple, cost‐effective method to reconnect rivers and historic floodplains, and hydrodynamic modeling is an important tool for analyzing and designing wetland reconnection.

The use of biochar and crushed mortar in treatment wetlands to enhance the removal of nutrients from sewage.

An experimental study was carried out using in pilot-scale constructed wetland systems, operated in parallel to treat raw sewage. Each system consisted of a vertical flow (VF) unit that was filled with biochar as the main media, followed by a horizontal flow (HF) unit filled with crushed cement mortar. Hydraulic loading (HL) ranged 340-680mm/day was applied on the VF wetland units, where high total nitrogen (TN) mass removal rate (20-23g N/m2d) was obtained, demonstrating that biochar media had a beneficial effect on the degradation of nitrogenous pollutants. Total phosphorus (TP) removal percentage (concentration based) was ≥ 86% in HF wetlands packed with mortar materials. In one system, the flow direction of the sewage was directed by the deployment of downflow pipes and vertical baffles, aiming to facilitate the formation of aerobic and anaerobic zones in the wetland matrices. The effects of such arrangement were analyzed by comparing pollutant removal efficiencies in the two systems. On average, 99, 96, 93, and 86 percentage removals were obtained for ammonia (NH4-N), TN, biochemical oxygen demand (BOD), and TP, respectively, during the experiments. Biochar and crushed mortar proved to be a highly effective combination as media in subsurface flow constructed wetlands for wastewater treatment.

Post-treatment of effluents from UASB reactor treating industrial wastewater sediment by constructed wetland

ABSTRACTThe improvement of water quality parameters by wetland systems is an increasingly global practice. In the present study, the utilization of a treatment method comprising of an upflow anaerobic sludge blanket (UASB) reactor followed by a surface flow (SF) and a vertical flow (VF) wetland (hybrid wetland) in the arrangement has been tested experimentally. Lemna minor was used in wetland units at a planting density about 3 kg wet m−2. The UASB reactor effluents were diluted with tap water to keep the influent chemical oxygen demand (COD) at about 1000 mg L−1 and then fed semi-continuously to lab-scale hybrid wetland system. Removal efficiency ranged from 80 to 93% treatment for COD and biochemical oxygen demand (BOD5), about 92–98% for total phosphorus (TP) treatment and total Kjeldahl nitrogen (TKN), and except Hg (approximately 83%), heavy metal removal was over 90%. Post-treatment of UASB reactor effluents with hybrid wetland provided a high COD, BOD5, TKN, ammonia–nitrogen, TP and phosphate–phosphorus removal and efficiently removed heavy metals (Hg, Cr, Zn, Al, As, Cd, Co, Cu, Pb and Ni). In addition to this, the bioconcentration factor of these heavy metals by the L. minor was also studied in the present study.

Habitat use by secretive marsh birds during spring and fall migration in moist-soil wetlands in Kansas

ABSTRACT Wetlands under moist-soil management are managed using disturbance and water regimes to enhance vegetative production during the growing season and flooded in the fall to accommodate waterfowl; however, little research has investigated the use of such wetlands by secretive marsh birds. Our objective was to determine patterns of habitat use by bitterns (Ardeidae) and rails (Rallidae), “secretive marsh birds,” in relation to habitat structure within and among moist-soil wetlands during spring and fall migration in Kansas. We used call-playback (spring) and flush counts (fall) to survey birds. Of our target species, only American Bittern (Botaurus lentiginosus), Least Bittern (Ixobrychus exilis), Virginia Rail (Rallus limicola), and Sora (Porzana carolina) were detected. Abundances varied markedly between years of our study (2014 and 2015), perhaps because of annual variation in precipitation or drawdown timings. In spring, Sora were found in wetland units with relatively tall Polygonum. No other si...

Industrial wastewater treatment in constructed wetlands packed with construction materials and agricultural by-products

Abstract This paper reports pollutant removal performances from mixed industrial wastewater employing subsurface flow constructed wetland systems in Bangladesh. Two parallel hybrid wetland trains were established; each train included a vertical flow (VF) followed by a horizontal flow (HF) wetland. One hybrid system was packed with construction materials (i.e. recycled bricks), whereas the other system included agricultural by-products (i.e. sugarcane bagasse). All wetland units were planted with Canna indica. The hybrid trains were operated under non recirculation and recirculation phases; input hydraulic loading across each VF system ranged between 219.3 and 438.0 mm/d. Mean nitrogen, organics, solids, phosphorus and color removals across the hybrid systems were 67.5–80.0, 74.0–85.0, 55.0–95.0, 64.0–89.0 and 46.0–83.0% respectively. Lower input biodegradation ratio influenced organics removal routes in wetland systems that employed recycled bricks. In contrast, organic contents of sugarcane bagasse material supported microbial routes in the other system. VF wetland with organic media achieved higher TN removal rates (1.82 g/m2 d), due to internal carbon (C) generation. Higher phosphorus removals (89.0%) were observed in hybrid system packed with recycled brick media, due to adsorption process. HF wetland packed with recycled brick was efficient in removing color compounds, whereas the other HF system (with organic media) showed high sulfate removals. Nitrogen and BOD removal improvement was observed in VF wetland (packed with recycled brick media) during recirculation period; in contrast, effluent recirculation reduced removal rates of such pollutants in VF system that employed organic media. In general, this study shows potential application of particular materials as the main media of wetland systems, to achieve pollutant removals from industrial wastewaters in Bangladesh.

Removal of orgRemoval of Organic Material in Free Water Surface Gravel Bed Filtersanic material in free water surface gravel bed filters

The removal of organic material in free surface gravel bed filters was investigatedand modelled. Two pilot wetland units of 7.5m x 1.5m x 0.7m were constructedadjacent to the University of Dar es Salaam waste stabilization ponds to receivemaximum organic and hydraulic loading rates of less than 185 kg/ha/d and 110l/m 2 /d, respectively. These units received wastewater of domestic characteristicsfrom primary stabilization pond. The entire depth of 0.7 m of the wetland unitswere packed with gravel of size 8 ~ 25 mm and porosity of 35%. Samples werecollected from the influent and effluent of wetland units and were tested forchemical oxygen demand (COD), temperature, dissolved oxygen, pH and otherparameters useful for testing of the model. A semi-empirical model representingthe major processes taking place in the wetland units was developed byincorporating suspended biomass, biofilm biomass, and sedimentation andfiltration components. The model was optimized using computer program. Themodel was successfully developed and showed that biofilm of gravel mediacontributed significantly to COD removal in wetlands.

Modified Soil Compositions for Removal of Acetaminophen from Wastewater

ACT is a widely used prescriptive drug for analgesic treatment. Due to incomplete conversion of ACT in the body, a significant portion of it is released with human excreta. Most wastewater treatment plants lack the efficiency to treat influent containing ACT residues. As a result, risk of surface and groundwater contamination has been increased. Constructed wetlands (CWs) are one of the widely used natural wastewater treatment technologies, employing soil-plant interactions in treating pollutants through a number of reactions such as plant uptake, ion adsorption and advanced Fenton reaction. In addition, the wetland plants are well-known to generate H2O2 in the surrounding rhizosphere for advanced oxidation process. In this study, the potential of laterite soil in initiating Fenton reactions by its abundant composition of iron (Fe) and its modified structure with activated carbon, cement and crushed shellfish (modified soil) were evaluated for ACT treatment. The induced H2O2 soil environment in the constructed wetland units could remove almost 80% of the ACT present initially. The results showed good occurrence of Fenton process on both natural laterite soil and modified media bed (cement: laterite soil fine: 50% laterite soil coarse: 50% activated carbon).

Water quality implications of hydrologic restoration alternatives in the Florida Everglades, United States

AbstractThe use of models to generate future scenarios is an important tool for restoration planning. We used a scenario modeling approach to examine water quality implications of five options for Everglades hydrologic restoration. In oligotrophic Everglades wetlands, phosphorus (P) inputs exceeding 10 µg/L cause P accumulation in soils and a shift to cattail marsh. Everglades restoration seeks to improve wetland hydrology while ensuring that delivered water contains no more than 10 µg P/L (long‐term average). Outputs from a landscape‐scale ecological model, the Everglades Landscape Model (ELM), showed that P concentrations in new water inputs will be controlled by P uptake by constructed treatment wetlands and by the movement of legacy P. Benthic periphyton responds quickly to changes in P, initiating a eutrophication response cascade, so we used ELM output to drive periphyton response models that predicted abundance, quality, and composition. All five restoration scenarios had similar effects on these three attributes in Everglades National Park, but variable responses across the other wetland units depended on water delivery and legacy P mobilization. Periphyton biomass was considerably reduced in scenarios that maximized freshwater delivery, but predicted values for periphyton total P were below the legal P concentration maximum in most of the Everglades. Benthic algal edibility increased more than 4‐fold, with the greatest increases in the deeper water areas. To meet water quality standards for the five restoration scenarios, we estimated that Everglades restoration should include an additional 105–156 km2 of treatment marshes upstream of surface water inflows to the landscape.

Nitrogen removal and distribution of ammonia-oxidizing and denitrifying genes in an integrated constructed wetland for swine wastewater treatment

This study investigated nitrogen (N) removal process and microbial community distribution in a full-scale integrated constructed wetland (ICW), which was constructed with a bioreactor (R) and three wetland units (W1, W2, and W3) arranged successively along the flow path. For swine wastewater treatment, ICW showed high N removal efficiency with average removal rate of 98% for NH4+-N and 96% for total nitrogen (TN) from August 2012 to July 2014. In ICW sediments, abundance of amoA gene of ammonia-oxidizing archaea (AOA) was 1 order of magnitude greater than ammonia-oxidizing oxidizing bacteria (AOB), and narG gene was 2 orders of magnitude greater than nosZ. The highest amoA gene abundance of AOA and AOB in R were consistent with the most efficient NH4+-N and TN removal compared to W1, W2, and W3. Both W1 and W3 vegetated with Myriophyllum aquaticum had significantly higher AOA abundance than W2 vegetated with Ipomoea aquatica, Zizania latifolia, and Nasturtium officinale (p<0.05). Responding to the increasing NO3−-N concentrations along the flow path, higher narG and nosZ abundance were observed in W2 and W3 than in R and W1. Principal component analysis revealed that there were clear differences in the relative abundance of terminal restriction fragments. These findings demonstrated that environmental factors such as wetland plants and NH4+-N and NO3−-N concentrations had effects on the distri bution of microbial ammonia oxidizers and denitrifiers. Therefore, the responsible development of functional microbial communities could contribute to efficient N removal in the ICW.

KINERJA SUBSURFACE CONSTRUCTED WETLAND MULTYLAYER FILTRATION TIPE ALIRAN VERTIKAL DENGAN MENGGUNAKAN TANAMAN AKAR WANGI (Vetivera Zozanoides) DALAM PENYISIHAN BOD DAN COD DALAM AIR LIMBAH KANTIN

Wastewater from the canteen is a domestic wastewater that has high concentrations of organic matter that needs to be processed before being released and not contaminating the water stream. The wastewater treatment at canteen SMA Negeri 34 Jakarta begins with collecting basin and aeration basin, and then it is pumped into two reactor that is the subsurface constructed wetland multilayers filtration type flow vertical with Vetiver Grass unit (SCW-MLF) and multilayers filtration type flow vertical unit without plants (MLF) as a control. The purpose of this study was to test the effectiveness of the vetiver grass in wastewater treatment with subsurface constructed wetland unit multilayers filtration type vertical flow with vetiver grass to fulfill effluent standards before it is released into stream water. Metodology of the study was conducted from acclimatization of plants, removal the plant to the SCW-MLF unit, and analyze the quality of wastewater. Flowrate that goes into the processing unit is 6.9615 m3/day. The detention time in SCW-MLF unit was 17.7 hours. The results showed that at steady state COD organic loading on SCW-MLF unit is 917.08 to 4126.84 kg COD/ha/day for the removal efficiency around 69.2 to 80.0%, BOD organic loading is 309.78 to 850,73 kg BOD/ha/day for the removal efficiency 61.2 to 70.8%. K value SCW-MLF unit around 0.55 to 0.71 m/day for BOD, 0.57 to 0.89 m /day for COD. The concentration of the wastewater effluent from WWTP are complied to effluent standart regulation (Pergub DKI Jakarta No. 112 Tahun 2005).

Horizontal subsurface-flow constructed wetland removal efficiency using Cyperus articulatus L.

Constructed Wetlands (CW) are a suite of natural wastewater treatment systems that are governed by biological, chemical and physical processes. These processes, in tandem, regulate the removal of organic and inorganic wastewater pollutants. Both aquatic microorganisms and aquatic macrophytes can transform and uptake contaminants from wastewater and achieve higher removal efficiencies. The aim of this study was to evaluate the effect of Cyperus articulatus, a Colombian native aquatic macrophyte, on removal of dissolved organic matter and nitrogenous compounds from domestic wastewater. Experiments were conducted in replicate pilot-scale Horizontal Subsurface Flow Constructed Wetlands (HSSF CWs). Four (4) wetland treatment units were installed in parallel. Two were planted with C. articulatus and the other two remained as unplanted controls. The experimental system was hydraulically connected to a 760L septic tank, which functioned as a primary treatment module and fed experimental wetland treatment units. Each wetland unit was filled with granite gravel (8mm average diameter and approximately 40% porosity) to a depth of 0.5m. During a period of four-months, each treatment unit was provided with 29Lday−1 of clarified domestic wastewater, ensuring a Hydraulic Retention Time of three (3) days. Wastewater samples from influent and effluents were collected twice each week in order to monitor temporal/spatial changes in concentration of chemical oxygen demand (COD), ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N). At the end of the experiment, plant biomass was collected and dried to constant weight to facilitate calculations and reporting of plant biomass on a dry matter basis. Although this was a preliminary study of short duration, results showed that high organic matter removal efficiency can be achieved (91% in systems planted with C. articulatus, compared with 80% in unplanted wetlands). NH4+-N removal was significantly improved in planted systems, averaging 85% vs. 40% for unplanted systems (p<0.05). Total biomass production by C. articulatus was 5.0 (±0.16) kg.m−2. In conclusion, results obtained in this short duration study indicate that C. articulatus could be a promising species for treating domestic wastewater in the Colombian Caribbean region.

Effects of design and operational parameters on ammonium removal by single-stage French vertical flow filters treating raw domestic wastewater

Four pilot-scale single-stage vertical flow filters (of 2.25m2 each), treating raw domestic sewage, were studied over 20 months in order to assess the impact of different designs and operational conditions on treatment efficiency. One of them was designed and operated as a standard 1st stage “French” vertical flow constructed wetland unit. The other 3 pilots differed from the standard pilot with respect to the filtration depth, the loading rate or the partial replacement of gravel by zeolite (chabazite), respectively. The pilots were monitored by analysing 24-h flow-weighted composite samples for TSS, CODtot, CODd, ammonium, nitrate and carbonate. All pilots showed a high ability to remove TSS and CODtot, with average removal of 81% and 75%, respectively. Increasing the depth of the filtration layer from 40 to 100cm allowed to significantly improve ammonium removal (81%), whereas the simultaneous increase in hydraulic and organic loads resulted in a deterioration of ammonium and CODd removals (44% for both parameters). Using zeolite did not induce any observable improvements in ammonium removal under the conditions of the study.

Continuous removal of Cr(VI) from wastewater by phytoextraction using Tradescantia pallida plant based vertical subsurface flow constructed wetland system

This study investigated the performance of Tradescantia pallida in continuous removal of Cr(VI) from contaminated water using a laboratory scale vertical subsurface flow (VSSF) constructed wetland system. The effect of different hydraulic residence time (HRT), i.e. 1, 2 and 3 day HRT, was first studied at an influent Cr(VI) concentration of 20 mg/L. Later experiments were carried out at different influent pH (7 and 4) and at different influent Cr(VI) concentration (20 and 30 mg/L), but with the same HRT of two days. Best results were achieved for 2 d HRT and for an influent pH of 7 with a maximum Cr(VI) removal efficiency of 97.2–98.3% and a maximum total Cr removal efficiency of 86–88.2%. Cr(VI) was found to be uniformly distributed in different segments of the wetland units. Compared with the control unit in which no plants were grown, the units with the plant biomass showed substantially high amount of Cr(VI) in its soil (63–68%). Bioconcentration factor and translocation factor values ranged from 16.45 to 23.21 and 0.37 to 0.90 respectively, which revealed the excellent Cr uptake potential of T. pallida. The highest accumulated Cr concentration (464.33 mg/kg) was found in plants grown in the system at pH 7.0, whereas the minimum accumulated Cr concentration (249.21 mg Cr/kg) was in plants grown in the system at pH 4.0. Furthermore, 3–4% of the total Cr input into the system was accumulated in the plants at the end of the operation. All these results revealed an excellent performance of the T. pallida plant based constructed wetland system for continuous removal of Cr(VI) from contaminated water.

Effect of operational and design parameters on performance of pilot-scale horizontal subsurface flow constructed wetlands treating university campus wastewater.

Three horizontal subsurface flow (HSF) pilot-scale constructed wetland (CW) units operated for 3years treating municipal wastewater originating from a university campus. The main objective of the study was the evaluation of the performance of these systems under several operational, design, and climatic conditions. Several parameters and factors were investigated, including the influence of temperature, vegetation, and hydraulic residence time. The results were compared to those of a previous study conducted in the same pilot-scale units and under the same operational conditions where synthetic municipal wastewater was used. Results show the satisfying overall performance of the CW units. Performance seems to be influenced by vegetation, temperature, and hydraulic residence time (HRT). The planted units produced better results than the unplanted one while, generally, all units operated better under warmer conditions. In addition, longer HRTs contributed to higher removal efficiencies. Finally, the systems showed higher removal efficiencies in the previous study (synthetic wastewater) regarding organic matter removal, while for the other pollutants, the present study (real wastewater) showed higher or comparable performance in most cases and especially in the planted units. The study also shows the overall good, continuous, and long-term operation of CW systems, since these systems operate for about 13years.

A rapid assessment of anthropogenic disturbances in East African wetlands

The use of East African freshwater wetlands for agriculture has increased in recent decades, raising concerns about potential impacts on wetlands and the long-term sustainability of such land use trends. WET-health is an indicator-based rapid wetland assessment approach developed in South Africa. It allows determining the conditions of wetlands in four assessment modules (hydrology, geomorphology, vegetation, and water quality) by observing the degree of deviation of a wetland from its anticipated natural reference state. We tested the transferability of the WET-health concept for East African inland valley swamps and floodplain wetlands based on 114 assessment units at four study sites. Due to large wetland areas and different environmental settings in East Africa, we modified the original approach using a random selection of assessment units and an assessment scheme based on disturbance types (Appendices A and B). Estimated WET-health impact scores were matched with biophysical and socioeconomic variables using a generalized linear mixed model. Land use included largely undisturbed wetland units occurring side by side with seasonally cropped or grazed units, and drained, permanently cultivated units. A strong differentiation of impact scores between the four assessment modules was apparent with highest scores for vegetation and lowest scores for geomorphology. Vegetation and water quality responded most sensitively to land use changes. The magnitude of wetland disturbance is predominantly determined by management factors such as land use intensity, soil tillage, drainage intensity, and the application of agrochemicals and influences vegetation attributes and the provision of ecosystem services. The proposed modification of WET-health enables users to assess large wetland areas during relatively short periods of time. While further studies will be required, WET-health appears to be a promising concept to be applied to wetlands in East Africa and possibly beyond.

Marsh accretion and sediment accumulation in a managed tidal wetland complex of Delaware Bay

Wetland impoundments are created to provide ecological benefits such as water quality improvement, mosquito control, and migratory bird habitat. Prime Hook National Wildlife Refuge, located on the southwestern shore of the Delaware Bay, is composed of four interconnected wetland management units. Tidal inflow from Delaware Bay to Units I and IV occurs naturally, whereas flow to Units II and III has been restricted by tidal gates since the mid-1980s. To assess the accretionary status of Refuge marshes and inform an ongoing restoration, we investigated soil physical properties and developed 137Cs and 210Pb radiochronologies for cores collected at twelve sites. Results indicate that marsh accretion is driven by a combination of mineral sediment and organic matter accumulation, the relative proportions of which vary among and within the wetland units. Accretion rates (0.11–0.54cm/y) were found to be significantly correlated with organic matter accumulation but not with mineral sediment accumulation. These relationships demonstrate that biotic contributions to marsh accretion, such as belowground biomass productivity, must be considered in marsh restoration strategies, in addition to the supply of mineral sediment. At eight of the sites, the contribution of mineral sediment to the total volume of the soils has decreased significantly since the early 1900s, predating the impoundment works, perhaps in association with closure of two tidal inlets by natural processes. By comparison, changes in organic soil volume were relatively small over the same time span. At seven of the sites the marsh is accreting at, to just below, the rate of local relative sea-level rise (0.34±0.03cm/y) with potential for submergence on the long term. Additional research at the Refuge is needed to better align measurements of marsh accretion, relative sea-level from tide gauges, and wetland elevation change.

Life on the edge: reproductive mode and rate of invasive Phragmites australis patch expansion

The dynamics of plant invasions from initial colonization through patch expansion are driven in part by mode of reproduction, i.e., sexual (seed) and asexual (clonal fragments and expansion) means. Expansion of existing patches—both rate and mode of spread into a matrix of varying conditions—is important for predicting potential invader impacts. In this study, we used fine-scale genetic assessments and remote sensing to describe both the rate and mode of expansion for 20 Phragmites australis patches in flooded and unflooded wetland units on the Great Salt Lake, UT. We found that the majority of Phragmites patch expansion occurred via clonal spread but we also documented instances of (potentially episodic) seedling recruitment. The mode of patch expansion, inferred from patch edge genet richness, was unrelated to flooding in the wetland unit in the preceding growing season. The rate of Phragmites patch expansion varied from 0.09 to 0.35 year−1 and was unrelated to the mode of spread. In six patches monitored across two years, monoclonal patches stayed monoclonal, whereas patches with higher genet richness had a marked increase in diversity in the second year. The findings of the present study suggest how this partially clonal species can exploit the benefits of both sexual (i.e., genetic recombination, widespread dispersal, colonization of new areas) and asexual reproduction (i.e., stability of established clones suited to local environmental conditions) to become one of the most successful wetland plant invaders. To control this species, both forms of reproduction need to be fully addressed through targeted management actions.

Mapping and Hydrologic Attribution of Temporary Wetlands Using Recurrent Landsat Imagery

In areas with a high density of ephemeral wetlands, traditional mapping protocols may underestimate occurrence of wetlands when single-date base-imagery is utilized. In the Pleistocene Sand Dunes Ecoregion in Oklahoma, National Wetland Inventory (NWI) maps created using base-imagery from a dry year omitted large numbers of ephemeral wetlands. To improve the likelihood of capturing inundated depressions, we classified water pixels from 51 Landsat images (3 images per year: pre/early, peak, and late/post growing season) from 1994 to 2011. Several image classification methods were tested but decision tree analysis with training pixels from multi-season imagery provided the greatest accuracy. Accuracy was determined through manual comparison of two Landsat images with concurrent aerial imagery (Kappa =0.96 and 0.93 for the two images). Wetland polygons were created from water/non-water rasters and given hydroperiod designations based on the number of inundated periods. Landsat-derived wetland maps identified 3156 wetland units, 718 more than the original 1980s NWI, with only 33.9 % agreement between the two maps. Finally, one meter LiDAR data were combined with classified Landsat images to determine the volume of water in wetlands during each image date. These wetland maps can assist with estimating the availability of inundated habitat during wet, dry, and average rainfall periods.

Multistage hybrid constructed wetland for enhanced removal of nitrogen

Hybrid constructed wetlands (HCWs) are very efficient in removal of total nitrogen. So far hybrid-constructed wetlands have been composed of various combinations of wetland units but most common combination is vertical flow–horizontal flow system. Also, multistage HCWs have recently been used. The present study describes the use of three-stage HCWs for treatment of municipal sewage. The system consists of saturated vertical flow, free-drain vertical and horizontal flow units in series. The experimental system with a total surface area of 10.1m2 has been operated for 19 months between March 2009 and October 2010. The results proved that multistage hybrid constructed wetland was able to remove efficiently organics, suspended solids and nitrogen. The overall removal efficiency amounted to 92.5%, 83.8%, 96.0%, 88.8% and 79.9% for BOD5, COD, TSS, NH4-N and TN, respectively. The aerobic vertical flow stage provided high degree of nitrification (removal rate of 4.17g NH4-Nm−2d−1) while remaining anaerobic stages (first and third) provided suitable conditions for denitrification (removal rates of 0.83g N-NO3m−2d−1 and 0.47g N-NO3m−2d−1, respectively). The outflow NH4-N concentrations were below 5mgl−1 throughout the monitored period including winter period when the air temperature dropped below −20°C. Plant biomass sequestered 28% and 26% of phosphorus and nitrogen inflow load, respectively.

GREYWATER MANAGEMENT OF PANTAI BARU PANDANSIMO KABUPATEN BANTUL FOR CREATING ZERO WASTE ZONE

The beach which is experiencing the current developments in the districts of Bantul is Pantai Baru Pandansimo. This area is an area that has been declared by the Bantul regent as zero waste zone. The development of Pantai Baru Pandansimo will give some impact. Thing that can arises is the environmental pollution from trading activity at restaurants around Pantai Baru Pandansimo. Every restaurant produce washing waste (greywater) had only absorbed into the ground or yard restaurants because do not have access to treatment plant. The main objective of this research is plan alternative system management for greywater that corresponding to Pantai Baru Pandansimo area so can creating sustainable zero waste zone. The results of the analysis obtained that alternative management unit greywater that appropriate and can be used at Pantai Baru Pandansimo is subsurface constructed wetland because easy to understand society and easy maintenance. Application of processing units that had been planned to reduce the BOD load in the amount of 41% depending on the extent of the unit to be used and reduce greywater is discharged into the environment 60% -80% of waste. From calculations obtained, wetland unit dimensions used by the average discharge within one week of 276.25 liters / day is 1 x 0.5 x 0.8 m3 with detention time (td) 0,5 day. Wetland that is used can be used as a park around the culinary of Pantai Baru Pandansimo and can encourage people to be more aware of the concept of zero waste.