The Removal of Urban Pollutants by Constructed Wetlands During Wet Weather

1999 ◽  
Vol 40 (3) ◽  
pp. 333-340 ◽  
Author(s):  
L. N. L. Scholes ◽  
R. B. E. Shutes ◽  
D. M. Revitt ◽  
D. Purchase ◽  
M. Forshaw

The Environment Agency for England and Wales has developed urban runoff treatment wetlands at two selected sites in Outer London. The systems were monitored for a range of determinands including heavy metals, suspended solids and BOD. Initial analysis of the data indicates that during dry weather, removal efficiencies vary greatly. However, during storm events removal efficiencies are higher with mean values of 71% for Zn, 72% for Cd, 69% for Pb, 66% for Cu, 34% for Ni and 81% for Cr at the Dagenham wetland. Mean removal efficiencies of 20% for Cd, 40% for Pb, 36% for Cu, 34% for Ni and 38% for Cr were monitored during storm conditions at the Brentwood wetland, but an overall increase in Zn was measured. Removal of BOD was greater at both sites during storm events with mean removal efficiencies of 24% and 29% at Dagenham and Brentwood, respectively. Suspended solids are reduced on passing through both wetlands during dry weather, but, during storm events there is an overall increase. The metal removal capability of microorganisms isolated from the rhizosphere of Typha latifolia and Phragmites australis is being investigated. Laboratory experiments are assessing the efficiency of two metal tolerant strains to accumulate Pb and Zn. It is believed that this ability may prove to be an important year-round pollutant removal process in the treatment of urban runoff by constructed wetland treatment systems, and preliminary data are presented.

2021 ◽  
Author(s):  
Vanitha Thammaiah ◽  
Manjunatha Hebbara ◽  
Manjunatha Mudukapla Virupakshappa

Abstract An experiment with different filterbeds and macrophytes was carried-out to study their phytoremediation capacity on the efficiency of domestic wastewater treatment through constructed wetland (CW) during November to March, 2017-18 at University of Agricultural Sciences, Dharwad campus, Karnataka, India. Twenty treatment combinations involving five types of filterbeds (FB-1: gravel, FB-2: gravel-sand-gravel, FB-3: gavel-sand-brick-gravel, FB-4: gravel-sand-charcoal-gravel and FB-5: gravel-sand-(charcoal+brick)-gravel) and four macrophytes (MP-1: Typha latifolia, MP-2: Brachiaria mutica, MP-3: Canna indica and MP-4: Phragmites sps.) were evaluated for treating domestic wastewater. After 120 days from start, across treatment combinations, water electrical conductivity (EC), total dissolved and suspended solids (TDS-TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), sodium, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), bicarbonates, total nitrogen-phosphorus-potassium (N-P-K) and boron (B) were reduced by more than 40 per cent due to wetland treatment. The system enhanced the mineralization of organic nitrogen to ammoniacal nitrogen (NH4+-N) and nitrate nitrogen (NO3-N) fractions. Among filterbeds, Type-5 caused higher reduction in pH, EC, BOD, COD and Organic-N while, Type-4 proved efficient in removing total solids and lowering pH in the sewage effluent. The Type-3 filterbed removed more suspended solids, potassium and ammoniacal nitrogen. Among the macrophytes, Brachiaria (paragrass) removed more nitrogen and potassium while, Phragmites removed more nitrogen, phosphorus and boron. The flexibility of implementation allows the CW to be adapted to different sites with different configurations, being suitable as main, secondary or tertiary treatment stage.


2011 ◽  
Vol 64 (8) ◽  
pp. 1692-1699 ◽  
Author(s):  
C. F. Yong ◽  
A. Deletic ◽  
T. D. Fletcher ◽  
M. R. Grace

Pervious pavements are an effective stormwater treatment technology. However, their performance under variable drying and wetting conditions have yet to be tested, particularly under a continuous time scale. This paper reports on the clogging behaviour and pollutant removal efficiency of three pervious pavement types over 26 accelerated years. These pavements were monolithic porous asphalt (PA), Permapave (PP) and modular Hydrapave (HP). Over a cycle of 13 days, the period of which was equivalent to the average annual Brisbane, Australia rainfall (1,200 mm), the pavements were randomly dosed with four different flows. Drying events of 3 h duration were simulated during each flow. Inflow and outflow samples were collected and analysed for Total Suspended Solids (TSS), Total Phosphorus (TP) and Total Nitrogen (TN). To evaluate the rate of clogging, a 1 in 5 year Brisbane storm event was simulated in the 6th, 8th, 12th, 16th, 20th and 24th week. Under normal dosing conditions, none of the pavements showed signs of clogging even after 15 years. However, under storm conditions, both PA and HP started to clog after 12 years, while PP showed no signs of clogging after 26 years. The drying and various flow events showed no effects in TSS removal, with all systems achieving a removal of approximately 100%. The average TP removal was 20% for all flows except for low flow, which had a significant amount of leaching over time. Leaching from TN was also observed during all flows except high flow. The TSS, TP and TN results observed during storm events were similar to that of high flow.


Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3153
Author(s):  
Magdalena Gizińska-Górna ◽  
Krzysztof Jóźwiakowski ◽  
Michał Marzec

The present paper reports pollutant removal efficiencies and reliability for a four-stage hybrid constructed wetland (HCW) consisting of the following sequence of subsurface (SS), vertical flow (VF) and horizontal flow (HF) beds: SSVF-SSHF-SSHF-SSVF. The experiments were carried out over a period of three years, with sampling done in each season: winter, spring, summer and autumn. Grab samples of wastewater collected from different stages of treatment were tested for total suspended solids (TSS), BOD5, COD, total nitrogen (TN) and total phosphorus (TP). The wetland was found to have a very high efficiency of removal of suspended solids and organics, with relatively little seasonal variability. The three-year average TSS removal efficiency was approximately 92.7%. The effectiveness of elimination of organic compounds was very high throughout the study period at 96.6% BOD5 and 95% COD. The effluent from the four-stage system had significantly lower contents of TN and TP compared to the wastewater discharged from the first two beds of this facility.


2009 ◽  
Vol 36 (4) ◽  
pp. 690-700 ◽  
Author(s):  
J. Mena ◽  
R. Gómez ◽  
J. Villaseñor ◽  
A. de Lucas

Synthetic wastewaters simulating physically pre-treated low-loaded winery effluents were treated for four months with five pilot-scale horizontal subsurface flow constructed wetlands (HSSF-CWs) using different plants. Species under study were Phragmites australis (HSSF-CW2), Lythrum salicaria (HSSF-CW3), Cladium mariscus (HSSF-CW4), and Iris pseudacorus (HSSF-CW5). The designation HSSF-CW1 was not planted, and was used as a control. The mean dissolved oxygen and oxidation–reduction potential values in all HSSF-CWs indicated anaerobic conditions in the bulk liquid. High pollutant-removal efficiencies were obtained. Apparently, the species with higher growth (Phragmites, Lythrum, and particularly Iris) improved total nitrogen (TN) and nitrogen as ammonium (N-NH4+) removals, but adversely affected sulphate (SO42–) anaerobic reduction. Chemical oxygen demand (COD) removal efficiencies were high, although there were no clear indications how the kinds of plants might have influenced this parameter. A statistical analysis of variance indicated that only N-NH4+ removal efficiencies were statistically different owing to the influence of the different plants. In a second 6 month experimental period, polyphenols (13 mg L–1) were added to the synthetic wastewater to study possible inhibition effects. The addition of polyphenols did not seem to cause inhibition effects on COD, TN, and N-NH4+ removals, but clearly negatively affected SO42– removal. A new two-way analysis of variance confirmed that only SO42– removal was negatively affected by polyphenols, while the effects of the different plants were only significant for N-NH4+ removal. Polyphenols were nearly completely removed. First order rate constants obtained for COD, TN, SO42–, and polyphenol removals were similar to those reported by other authors.


2015 ◽  
Vol 72 (10) ◽  
pp. 1796-1802
Author(s):  
Luboš Stříteský ◽  
Radka Pešoutová ◽  
Petr Hlavínek

This paper deals with biological treatment of malt house wastewater using algal-bacterial flocs. During three months of testing, optimisation of growth conditions and biomass separation leads to maximisation of biomass production, improved flocs settleability and increased pollutant removal efficiency while maintaining low energy demand. At a high food to microorganism ratio (0.16 to 0.29 kg BOD5 kg−1 TSS d−1), the biological oxygen demand (BOD5), chemical oxygen demand (CODCr), total phosphorus (Ptot) and total suspended solids (TSS) removal efficiencies were all higher than 90%. At a food to microorganism ratio of 0.06 kg BOD5 kg−1 TSS d−1, BOD5, CODCr, total nitrogen (Ntot), Ptot and TSS removal efficiencies of 99.5%, 97.6%, 91.5%, 97.8% and 98.4%, respectively, were achieved. The study also proved a strong dependence of removal efficiencies on solar radiation. The results suggest the algae-bacteria system is suitable for treatment of similar wastewater in locations with available land and sufficient solar radiation and temperature during the whole year.


Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 520 ◽  
Author(s):  
Anand Jayakaran ◽  
Thorsten Knappenberger ◽  
John Stark ◽  
Curtis Hinman

Porous Asphalt (PA) pavements are an increasingly adopted tool in the green stormwater infrastructure toolbox to manage stormwater in urbanized watersheds across the United States. This technology has seen particular interest in western Washington State, where permeable pavements are recognized as an approved best management practice per the National Pollutant Discharge Elimination System (NPDES) municipal stormwater permit. Stormwater effluent concentrations from six PA cells were compared with runoff concentrations from three standard impervious asphalt cells to quantify pollutant removal efficiencies by porous asphalt systems. Additionally, the effects of maintenance and pavement age on pollutant removal efficiencies were examined. Twelve natural and artificial storms were examined over a five-year period. Street dirt and pollutant spikes were added to the pavements prior to some storm events to simulate high loading conditions. Results from this work show that porous asphalt pavements are highly efficient at removing particulate pollutants, specifically coarse sediments (98.7%), total Pb ( 98.4%), total Zn (97.8%), and total suspended solids (93.4%). Dissolved metals and Polycyclic Aromatic Hydrocarbons (PAH) were not significantly removed. Removal efficiencies for total Pb, total Zn, motor oil, and diesel H. improved with the age of the system. Annual maintenance of the pavements with a regenerative air street sweeper did not yield significant pollutant removal efficiency differences between maintained and unmaintained PA cells.


Author(s):  
Osayomwanbo Osarenotor ◽  
Helen M. K. Essandoh ◽  
Isoken Tito Aighewic

Abstract Slaughterhouses generate wastewater daily and often discharge it to the environment. Many lack wastewater treatment systems, due to such systems' typically high cost and technological demands. In this study slaughterhouse wastewater was filtered through columns of mycelium – Pleurotus ostreatus – grown on sawdust substrates of different particle sizes. The columns' pollutant removal efficiencies were evaluated for color, turbidity, total suspended solids, total dissolved solids, electrical conductivity, dissolved oxygen, biological oxygen demand (BOD), chemical oxygen demand, total nitrogen and total phosphorus. The best color (75%), BOD (88%) and total nitrogen (86%) removal efficiencies were recorded with 2.36 mm particle size and 9 cm depth. Electrical conductivity removal efficiency was best with 2.36 mm particle size but 3 cm bed depth. The study showed that particle size has a significant effect on physiochemical pollutant removal by mycelium-colonized sawdust systems.


2018 ◽  
Vol 7 (4.35) ◽  
pp. 499
Author(s):  
Akhilash Aravind ◽  
Chow Ming Fai ◽  
Chua Kok Hua

A pilot study utilizing ornamental plants as a pollutant removal agent with varying attributes such as plant density and water conditions was conducted in Universiti Tenaga Nasional, Bangi, Malaysia. Lily canna was selected in this study for its abundance and suitable growth due to ideal Malaysian tropical climates. Lily cannas were placed on floating rafts through a 6-week experimental period in water samples collected from Ringlet Reservoir, Cameron Highlands, Pahang. This study was carried out to investigate the relationship between density of lily canna plants with its corresponding pollutant removal efficiencies. The efficiency of pollutant removal was evaluated in terms of percentage removal of several parameters such as Total Suspended Solids (TSS), Turbidity and Nitrate Concentrations. The results obtained showed that removal efficiencies of up to 83.3% for TSS, 97.8% for Turbidity, 90.7% for Colour, and 85.7% for Nitrate Concentrations could be achieved within the experimental period. The tests were conducted with compliance to standard laboratory tests such as Total Suspended Solids Test, Turbidity Test and Nitrate Cadmium Reduction Method for the determination of nitrate concentrations. To conclude, the quality of treated water proved that lily canna has promising abilities to remove pollutants from water bodies in small communities.


2001 ◽  
Vol 44 (11-12) ◽  
pp. 571-578 ◽  
Author(s):  
R.B.E. Shutes ◽  
D.M. Revitt ◽  
L.N.L. Scholes ◽  
M. Forshaw ◽  
B. Winter

This paper compares the performance of an experimental highway runoff treatment system, incorporating a subsurface flow constructed wetland, with that of a vegetated balancing pond. Both systems are located on the same major road in the UK which opened in November 1998. Copper, chromium and nickel total aqueous metal concentrations, although low, have been consistently removed (maximum efficiencies of 67.3, 69.8 and 87.0% respectively in the constructed wetland), particularly in the summer. Zinc showed the highest aqueous metal concentrations and the generally positive removal by the constructed wetland system (maximum efficiency of 60.6%) correlates with the expected metal uptake by Typha latifolia and Phragmites australis. Sediment levels for these metals and for lead progressively decreased over the one year monitoring period. For the two storm events monitored in the constructed wetland system, all metals showed evidence of removal (removal efficiencies of 24.2 to 99.4%) except for copper. Lead and cadmium demonstrated the highest removal efficiencies followed by nickel and zinc. For both storms, the wetland acted as a source of copper (removal efficiencies of -88.4 to -97.1%), which may be explained by the die-back of aquatic plants and consequent release of organically bound copper.


2014 ◽  
Vol 71 (3) ◽  
pp. 373-381
Author(s):  
Siping Niu ◽  
Kisoo Park ◽  
Youngchul Kim

In this study, the effect of sampling duration on the performance estimate for a stormwater wetland over both rainy and dry days was evaluated for the appropriate design of sampling duration. As the cumulative percentage volume (Vp), the ratio of cumulative stormwater volume concerning time to the total stormwater volume, varied between 60 and 100%, generally, the inflow total suspended solids, turbidity and total chemical oxygen demand (TCOD) event mean concentrations (EMCs) did not vary significantly, whereas the total nitrogen (TN) and total phosphorus (TP) EMCs were relatively stable. Compared to the inflow, the corresponding outflow EMCs changed much less as Vp changed. And these variations both from inflow and outflow EMCs did not result in significant changes in the removal efficiencies. The investigation during the dry days between two consecutive storm events showed that outflow pollutants did not change to a considerable extent after 1 day of the previous rainfall event. This study identifies the possibility of shortening the rainy sampling duration, because the performance of stormwater wetlands is usually estimated based on removal efficiencies rather than pollutant concentrations. Also, the sampling during dry days should be performed at least 1 day after a rainfall event.


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