Aquatic macrophytes tolerance to domestic wastewater and their efficiency in artificial wetlands under greenhouse conditions (original) (raw)
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In this study, the physicochemical and biological contributions of different macrophytes in horizontal sub-surface flow constructed wetlands (HSSF-CWs) to treat low-strength municipal wastewater operated at high hydraulic loads under a sub-tropical climatic region is investigated. Out of the four identical beds, three were planted with locally available macrophytes (P. australis, Sagittaria, and Iris), whereas one bed was kept as a control. The beds were filled with media and operated in parallel continuously for eight months, with increasing the surface loading rate (SLR) from 0.19 to 2.78 m day−1. The results indicate that the planted beds performed significantly (p < 0.01) better to remove TSS (70% to 78%), BOD5 (66% to 77%), COD (59% to 75%), NO3-N (56% to 64%), NH4-N (41% to 69%), TN (36% to 41%), and TP (44% to 61%) as compared to the unplanted bed for the same parameters (48%, 39%, 40%, 33%, 18%, 20%, and 29%, respectively). The presence of macrophytes in HSSF-CWs was foun...
Journal of Engineering and Engineering Technology (FUTAJEET), 2017
The objective of the study was to evaluate the phytoremediation potential of three aquatic macrophytes (Commelina cyanea, Phragmites australis and Water Hyacinth (Eichhornia crassipes)) for treatment of municipal wastewater collected from Federal University of Technology, Akure (Nigeria). Laboratory scale of three constructed wetlands of dimensions 0.43 m x 0.93 m x 0.36 m in width, length and depth respectively, were developed to mimic natural conditions and was operated for a single experimental run with each macrophte at different retention time of 6, 9 and 12 days. These aquatic macrophytes were planted in separate ponds. Domestic wastewater from undergraduate students' hostel was introduced to the ponds. The raw wastewater sample and treated wastewater samples were analysed using standard laboratory methods for physical (Turbidity and Dissolved solids), chemical (pH, Nitrate, Nitrite, Phosphate, Sulphate Chemical Oxygen Demand and Biochemical Oxygen Demand) and bacteriological (Coliform bacteria) parameters. Results showed substantial diminutions in all parameters treated with the phytoremediators during the course of the study. Asides the three plants effectively removing Nitrate, Nitrite, phosphate and Sulphate pollutants, Phragmites australis gave the highest removal efciency for Phosphate (85.8%), Water hyacinth gave the highest removal efciency for pH (11.5%), Biochemical Oxygen Demand and Coliform bacteria and Commelina cyanea gave the highest removal efciency for turbidity (96.9%) and dissolved solids (82.9%) parameters of the domestic wastewater samples. The overall results of the phytoremediation studies indicate that the purication effectiveness of the three aquatic macrophytes were spontaneous, feasible and remarkable.
Water Science and Technology, 2001
Two highly productive emergent macrophytes, Zizaniopsis bonariensis and Typha subulata were established in experimental subsurface flow, sand-based wetlands receiving anaerobically treated municipal wastewater. The hydraulic loading rate was tested in two levels, sequentially, 6.8 cm.d-1 and 13.6 cm. d-1, for 70 days each. In the 13.6 cm. d-1-loading treatment, among all monitored variables only COD, PO4-Total-P, and Turbidity were removed more efficiently by the planted beds in comparison to unplanted sand beds (P<0.001). When the 6.7 cm. d-1-loading rate was applied no significant improvement in removal was found comparing macrophyte beds to unplanted sand beds, except for PO4-P. T. subulata beds were significantly more efficient than Z.bonariensis beds for most of the variables. The highest significant differences (P<0.001) were related to the main effect of the factor hydraulic loading rate, with decreased removal for increased load when considering the variables Total Col...
Microcosm Wetlands for Wastewater Treatment with Different Hydraulic Loading Rates and Macrophytes
Journal of Environment Quality, 2002
Constructed wetlands (CW) usually require large land areas for ties. Applying any traditional wastewater treatment treating wastewater. This study evaluated the feasibility of applying system to purify these reservoirs would be expensive. CW with less land requirement by operating a group of microcosm wetlands at a hydraulic retention time (HRT) of less than 4 d in In addition, the annual water temperature in southern southern Taiwan. An artificial wastewater, simulating municipal waste-Taiwan ranges from 20 to 32ЊC and under such warm water containing 200 mg L Ϫ1 of chemical oxygen demand (COD), weather conditions treating the polluted water with a 20 mg L Ϫ1 of NH ؉ 4-N (AN), and 20 mg L Ϫ1 of PO 3Ϫ 4-P (OP), was the wetland system becomes a reasonable option. inflow source. Three emergent plants [reed, Phragmites australis In our initial study, we found that a CW system effec-(Cav.) Trin. ex Steud.; water primrose, Ludwigia octovalvis (Jacq.) tively removed nutrients from highly polluted river wa-P.H. Raven; and dayflower, Commelina communis L.] and two floatter (Jing et al., 2001). Removal efficiencies for organics, ing plants [water spinach, Ipomoea aquatica Forssk.; and water letammonia nitrogen (AN), and orthophosphate (OP) tuce, Pistia stratiotes L.] plants were tested. The planted systems were influenced by the health and growth rate of the showed more nutrient removal than unplanted systems; however, macrophytes. The presence of the macrophytes enthe type of macrophytes in CW did not make a major difference in treatment. At the HRTs of 2 to 4 d, the planted system maintained hances several functions in the CW system: assisting greater than 72, 80, and 46% removal for COD, AN, and OP, respecsolids sedimentation, reducing algae production, providtively. For AN and OP removal, the highest efficiencies occurred at ing surface area for microbial growth, improving nutrithe HRT of 3 d, whereas maximum removal rates for AN and OP ent uptake, and releasing oxygen (Brix, 1997). Comoccurred at the HRT of 2 d. Both removal rates and efficiencies were monly used macrophytes in CW systems in the United reduced drastically at the HRT of 1 d. Removals of COD, OP, and States are bulrushes (Scirpus spp.), cattails (Typha spp.), AN followed first-order reactions within the HRTs of 1 to 4 d. The and water hyacinth [Eichhornia crassipes (Mart.) Solms] efficient removals of these constituents obtained with HRT between (Brown and Reed, 1994). However, it was necessary to 2 and 4 d indicated the possibility of using a CW system for wasteidentify domestic macrophytes for potential use in our water treatment with less land requirement. CW system. The treatment efficiency of pollutants in a CW system is usually improved by decreasing the hydraulic loading: Abbreviations: AN, ammonia nitrogen; CCE, surface-covered control experimental system; COD, chemical oxygen demand; CW, constructed wetlands; CW-Co, constructed wetlands planted with day-Shuh-Ren Jing, Ying-Feng Lin, and Der-Yuan Lee, Department of flower; CW-Ip, constructed wetlands planted with water spinach; CW-Environmental Engineering and Health, and Tze-Wen Wang, Depart-Lu, constructed wetlands planted with water primrose; CW-Ph, conment of Pharmacy, Chia
Performances of a constructed wetland treating domestic wastewaters during a macrophytes life cycle
Desalination, 2009
In this study, the performance of a combined subsurface vertical and horizontal flow constructed wetlands system, designed for rural domestic wastewaters treatment and with theoretical hydraulic retention time of 2 d and 3.6 d, respectively, was investigated. Several water quality parameters including pH, BOD 5 , COD, TSS, TKN and TP, and faecal bacteria's number in both raw and treated wastewaters were monitored during a macrophytes life cycle. At the same time, the growth of the rooted plants, reeds and cattails was investigated through the measurement of the height and leaves number. The average influent characteristics were as follows: pH (7.98 ± 0.27), BOD 5 (420 ± 144 mg/L), COD (1339 ± 352 mg/L), TSS (798 ± 302 mg/L), TKN (205 ± 70 mg/L), TP (30.7 ± 12.4 mg/L), faecal coliforms ([2.69 ± 4.14] × 10 7 CFU/100 mL) and faecal streptococci ([9.35 ± 1.81] × 10 6 CFU/100 mL). The main treatment performance results showed the following average removal rates: BOD 5 (93 ± 2%), COD (89 ± 3%), TSS (98 ± 1.5%), TKN (38 ± 19%), TP (72 ± 16%). The average bacterial reduction between the inlet and the outlet was of the order of 4 ± 1 logarithmic units for faecal coliforms and 3 ± 1 logarithmic units for faecal streptococci. Analysis of the results reveals a temporal variation in the system's performance depending on the primary treatment operation and on the macrophytes growth rate. Reeds and cattails start their life cycle at the beginning of the spring and continue their development during summer. During the autumn season, the plants reach their optimum growth rate, and after that, they enter the dormant phase. The quality of the treated wastewaters was evaluated according to Tunisian standards. The average effluent pH, BOD 5 , TSS and faecal bacteria were in agreement with the standards, but COD, nitrogen and phosphorus residual loads were still above the values required by the quality criteria.
Performance assessment of aquatic macrophytes for treatment of municipal wastewater
Journal of Environmental Health Science and Engineering, 2014
The objective of the study was to evaluate the performance of three different aquatic macrophytes for treatment of municipal wastewater collected from Taxila (Pakistan). A physical model of treatment plant was constructed and was operated for six experimental runs with each species of macrophyte. Every experimental run consist of thirty days period. Regular monitoring of influent and effluent concentrations were made during each experimental run. For the treatment locally available macrophyte species i.e. water hyacinth, duckweed & water lettuce were selected to use. To evaluate the treatment performance of each macrophyte, BOD 5 , COD, and Nutrients (Nitrogen and Phosphorus) were monitored in effluent from model at different detention time of every experimental run after ensuring steady state conditions. The average reduction of effluent value of each parameter using water hyacinth were 50.61% for BOD 5 , 46.38% for COD, 40.34% for Nitrogen and 18.76% for Phosphorus. For duckweed the average removal efficiency for selected parameters were 33.43% for BOD 5 , 26.37% for COD, 17.59% for Nitrogen and 15.25% for Phosphorus and for Water Lettuce the average removal efficiency were 33.43% for BOD 5 , 26.37% for COD, 17.59% for Nitrogen and 15.25% for Phosphorus. The mechanisms of pollutant removal in this system include both aerobic and anaerobic microbiological conversions, sorption, sedimentation, volatilization and chemical transformations. The rapid growth of the biomass was measured within first ten days detention time. It was also observed that performance of macrophytes is influenced by variation of pH and Temperature. A pH of 6-9 and Temperature of 15-38°C is most favorable for treatment of wastewater by macrophytes. The option of macrophytes for treatment of Municipal sewage under local environmental conditions can be explored by further verifying the removal efficiency under variation of different environmental conditions. Also this is need of time that macrophyte system should be used for treatment of wastewater because their performance is comparable to conventional wastewater treatment plants and also the system has very low O&M costs.
Effect of different plant species in pilot constructed wetlands for wastewater reuse in agriculture
Journal of Agricultural Engineering, 2013
In this paper the first results of an experiment carried out in Southern Italy (Sicily) on the evapotranspiration (ET) and removal in constructed wetlands with five plant species are presented. The pilot plant used for this study is made of twelve horizontal sub-surface flow constructed wetlands (each with a surface area of 4.5 m 2) functioning in parallel, and it is used for tertiary treatment of part of the effluents from a conventional municipal wastewater treatment plant (trickling filter). Two beds are unplanted (control) while ten beds are planted with five different macrophyte species: Cyperus papyrus, Vetiveria zizanoides, Miscanthus x giganteus, Arundo donax and Phragmites australis (i.e., every specie is planted in two beds to have a replication). The influent flow rate is measured in continuous by an electronic flow meter. The effluent is evaluated by an automatic system that measure the discharged volume for each bed. Physical, chemical and microbiological analyses were carried out on wastewater samples collected at the inlet of CW plant and at the outlet of the twelve beds. An automatic weather station is installed close to the experimental plant, measuring air temperature, wind speed and direction, rainfall, global radiation, relative humidity. This allows to calculate the reference Evapotranspiration (ET0) with the Penman-Monteith formula, while the ET of different plant species is measured through the water balance of the beds. The first results show no great differences in the mean removal performances of the different plant species for TSS, COD and E.coli, ranged from, respectively, 82% to 88%, 60% to 64% and 2.7 to 3.1 Ulog. The average removal efficiency of nutrient (64% for TN; 61 for NH4-N, 31% for PO4-P) in the P.australis beds was higher than that other beds. From April to November 2012 ET measured for plant species were completely different from ET0 and ETcontrol, underlining the strong effect of vegetation. The cumulative evapotranspiration highest value was measured in the CWs vegetated with P.australis (4,318 mm), followed by A.donax (2,706 mm), V.zizanoides (1,904), M.giganteus (1,804 mm), C.papyrus (1,421 mm).
Aquatic Macrophytes in Constructed Wetlands: A Fight against Water Pollution
Sustainability
There is growing concern among health institutions worldwide to supply clean water to their populations, especially to more vulnerable communities. Although sewage treatment systems can remove most contaminants, they are not efficient at removing certain substances that can be detected in significant quantities even after standard treatments. Considering the necessity of perfecting techniques that can remove waterborne contaminants, constructed wetland systems have emerged as an effective bioremediation solution for degrading and removing contaminants. In spite of their environmentally friendly appearance and efficiency in treating residual waters, one of the limiting factors to structure efficient artificial wetlands is the choice of plant species that can both tolerate and remove contaminants. For sometimes, the chosen plants composing a system were not shown to increase wetland performance and became a problem since the biomass produced must have appropriated destination. We prov...
Role of aquatic plants in wastewater treatment by artificial wetlands
Water Research, 1986
This report describes investigations using artificial wetlands which quantitatively assess the role of each of three higher aquatic plant types, Scirpus validus (bulrush), Phragmites communis (common reed) and Typha lalifola (cattail), in the removal of nitrogen (via sequential nitrification-denitrification), BOD and TSS from primary municipal wastewaters. During the period August 1983-December 1984, the mean ammonia concentration of 24.7mgl-' in the primary wastewater inflow (hydraulic application rate = 4.7 cm day-') was reduced to mean effluent levels of 1.4 mg 1-' for the bulrush bed, 5.3 mg1-I for the reed bed and 17.7mg1-I for the cattail bed, as compared to a mean value of 22.1 mgl-I for the unvegetated (control) bed. For all three vegetated beds, the mean effluent ammonia values were significantly below that for the unvegetated bed and for the inflow. The bulrushes and reeds (in that order) proved to be superior at removing ammonia, both with mean effluent levels significantly below that for the cattail bed. The high ammonia-N (and total N) removal efficiencies shown by the bulrush and reed beds are attributed to the ability of these plants to translocate 0, from the shoots to the roots. The oxidized rhizosphere so formed stimulates sequential nitrification-denitrification. Similarly BOD removal efficiencies were highest in the bulrush and reed beds, both with mean effluent BOD levels (5.3 and 22.2 mg I-', respectively) significantly below that for the unvegetated bed (36.4 mg I-') and equal to or better than secondary treatment quality (30 mg I-'). Our results demonstrate that higher aquatic plants can indeed play a significant role in secondary and advanced (N removal) wastewater treatment by wetland systems, a role that is completely distinct from that associated with their pollutant uptake capacity.