Removal of bacteria in subsurface flow wetlands

1997 ◽  
Vol 35 (5) ◽  
pp. 109-116 ◽  
Author(s):  
M. B. Green ◽  
P. Griffin ◽  
J. K. Seabridge ◽  
D. Dhobie
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Diurnal Pattern ◽  
Flow Rates ◽  
Field Surveys ◽  
Total Coliforms ◽  
E Coli ◽  
Secondary Effluents ◽  
Wet Weather ◽  
Reed Bed

Removal of E. coli and total coliforms in subsurface flow constructed wetlands is investigated in field surveys and pilot experiments. Both systems use reed beds with 5-10 mm gravel medium receiving secondary effluents. A diurnal pattern of numbers was indicated in the survey of an operational tertiary reed bed at Leek Wootton. Removals of E. coli and total coliforms were compared in dry and wet periods in surveys on two successive years. Removals of about 1.5 to 2.1 log were found in dry weather. Removals fell in wet weather although no change was detected in removal of BOD5, TSS and amm N. The effect of different flow rates was compared using a pilot reed bed. A trend of increasing removal was seen between retention times of 12, 24, 48 and 120 hrs but variation between samples implied caution. All effluent samples from the pilot had less than 1000 cfu E. coli/100 ml at retention times of 24 hrs or more.

scholarly journals Multistage Horizontal Subsurface Flow vs. Hybrid Constructed Wetlands for the Treatment of Raw Urban Wastewater

2020 ◽  
Vol 12 (12) ◽  
pp. 5102
Author(s):  
José Alberto Herrera-Melián ◽  
Mónica Mendoza-Aguiar ◽  
Rayco Guedes-Alonso ◽  
Pilar García-Jiménez ◽  
Marina Carrasco-Acosta ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Urban Wastewater ◽  
Total Coliforms ◽  
E Coli ◽  
Effect Of Water ◽  
Horizontal Subsurface Flow ◽  
Water Height

In this study, pilot-scale hybrid constructed wetlands (CWs) and multistage horizontal subsurface flow CWs (HF CWs) have been studied and compared for the treatment of raw urban wastewater. In the hybrid CWs, the first stage was a mulch-based horizontal subsurface flow CW and the second stage was a vertical subsurface flow CW (VF CW). The VF CWs were used to determine if sand could improve the performance of the hybrid CW with respect to the mulch. In the multistage HFs, mulch, gravel and sand were used as substrates. The effect of water height (HF10: 10 cm vs. HF40: 40 cm) and surface loading rate (SLR: 12 vs. 24 g Chemical Oxygen Demand (COD)/m2d) has been studied. The results show that the use of sand in the vertical flow stage of the hybrid CW did not improve the average performance. Additionally, the sand became clogged, while the mulch did not. The effect of water height on average pollutant removal was not determined but HF10 performed better regarding compliance with legal regulations. With a SLR of 12 g COD/m2d, removals of HF10 were: 79% for COD, 75% for NH4+-N, 53% for dissolved molybdate-reactive phosphate-P (DRP), 99% for turbidity and 99.998% for E. coli and total coliforms. When SLR was doubled, removals decreased for NH4+-N: 49%, DRP: −20%, E coli and total coliforms: 99.5–99.9%, but not for COD (85%) and turbidity (99%). Considering the obtained results and the simplicity of the construction and operation of HFs, HF10 would be the most suitable choice for the treatment of raw urban wastewater without clogging problems.

scholarly journals Performance of three pilot-scale hybrid constructed wetlands for total coliforms and Escherichia coli removal from primary effluent – a 2-year study in a subtropical climate

2014 ◽  
Vol 13 (2) ◽  
pp. 446-458 ◽  
Author(s):  
Florentina Zurita ◽  
Alejandra Carreón-Álvarez
Keyword(s):  
Escherichia Coli ◽  
Constructed Wetlands ◽  
Pilot Scale ◽  
World Health ◽  
First Year ◽  
Subtropical Climate ◽  
Total Coliforms ◽  
E Coli ◽  
Stage System ◽  
Health Organization

Three pilot-scale two-stage hybrid constructed wetlands were evaluated in order to compare their efficiency for total coliforms (TCol) and Escherichia coli removal and to analyze their performances in two 1-year periods of experimentation. System I consisted of a horizontal flow (HF) constructed wetland (CW) followed by a stabilization pond. System II was also configured with a HF CW as a first stage which was then followed by a vertical flow (VF) CW as a second stage. System III was configured with a VF CW followed by a HF CW. In the first year of evaluation, the HF–VF system was the most effective for TCol removal (p < 0.05) and achieved a reduction of 2.2 log units. With regard to E. coli removal, the HF–VF and VF–HF systems were the most effective (p < 0.05) with average reductions of 3.2 and 3.8 log units, respectively. In the second year, the most effective were those with a VF component for both TCol and E. coli which underwent average reductions of 2.34–2.44 and 3.44–3.74 log units, respectively. The reduction achieved in E. coli densities, in both years, satisfy the World Health Organization guidelines that require a 3–4 log unit pathogen reduction in wastewater treatment systems.

Study of constructed wetlands effluent disinfected with ozone

2014 ◽  
Vol 70 (1) ◽  
pp. 108-113 ◽  
Author(s):  
N. D. Miranda ◽  
E. L. Oliveira ◽  
G. H. R. Silva
Keyword(s):  
Constructed Wetlands ◽  
World Health ◽  
Constant Flow ◽  
Total Coliforms ◽  
E Coli ◽  
Complete Inactivation ◽  
Batch System ◽  
Health Organization ◽  
Almost All ◽  
Concentration Levels

The purpose of this research was to study the disinfection of sanitary effluent from constructed wetlands, evaluating the oxidation of organic matter, the formation of formaldehyde, as well as the efficiency of total coliforms and Escherichia coli inactivation. A constant flow of ozone was applied to the batch system in 5 and 10 mg.O3 L−1 doses with contact times of 5 and 10 min. This study revealed that the average values of formaldehyde formation ranged between 259.00 and 379.00 μg L−1, which means that the values are within World Health Organization recommended values. The total coliforms and E. coli showed complete inactivation in almost all tests. The dose of ozone 5 mg.O3 L−1 and contact time of 5 min were sufficient for a significant reduction of the concentration levels of pathogens in constructed wetlands effluent with similar characteristics, thus allowing for its agricultural reuse.

scholarly journals FILTRAÇÃO LENTA PARA REUTILIZAÇÃO DE ÁGUA EM IRRIGAÇÃO

Irriga ◽  
2003 ◽  
Vol 8 (1) ◽  
pp. 10-20
Author(s):  
Luciana De Resende Londe ◽  
José Euclides Stipp Paterniani
Keyword(s):  
Constructed Wetlands ◽  
Sewage Treatment ◽  
Sand Filtration ◽  
Slow Sand Filtration ◽  
Small Communities ◽  
Total Coliforms ◽  
Total Solids ◽  
E Coli ◽  
Apparent Color ◽  
E Mail

FILTRAÇÃO LENTA PARA REUTILIZAÇÃO DE ÁGUA EM IRRIGAÇÃO  Luciana de Resende Londe José Euclides Stipp PaternianiFaculdade de Engenharia Agrícola, Universidade Estadual de Campinas, Campinas, SP. CEP 13083 970. E-mail: [email protected]  1 RESUMO  O tratamento de esgotos domésticos por leitos cultivados tem se mostrado eficiente, principalmente na diminuição de sólidos, cor e turbidez. Esta tecnologia, porém, matém ainda uma quantidade alta de coliformes totais e fecais e não elimina a necessidade de tratamentos complementares quando pretende-se reutilizar seu efluente. A proposta deste trabalho é a utilização da filtração lenta como tratamento posterior ao de leitos cultivados, possibilitando a reutilização de águas residuárias em atividades rurais, como a irrigação localizada. Os dois sistemas de tratamento possibilitam simplicidade de instalação e operação e custos reduzidos. Portanto, são adequados em pequenas comunidades ou áreas rurais. Para os ensaios realizados com taxa de filtração igual a 3 m3.m- 2.dia-1, o Filtro Lento reduziu, em média, em 64% a turbidez, 38% a cor, 62% os sólidos suspensos totais, em 92,57% os E. coli e em 85,61% os coliformes totais. Nos ensaios com taxa de filtração igual a 6 m3.m-2.dia-1, a redução em média foi de 72% para turbidez, 44% para cor, 67% para sólidos suspensos totais, 83,87% para E. coli e 82,90% para coliformes totais.  UNITERMOS: Leitos Cultivados, qualidade da água, saneamento rural  LONDE, L. de R.; PATERNIANI, J. E. S. SLOW SAND FILTRATION FOR IRRIGATION WATER RE-USING  2 ABSTRACT  Sewage treatment by constructed wetlands has been very efficient to color, turbidity and solid reduction. However, it still remains a high amount of total and faecal coliforms which requires other treatments before water re-using. This study has evaluated the efficiency of slow sand filtration to treat constructed wetlands effluents and intended to make it possible water re-using at rural works, for example at drip irrigation. Both treatment systems, constructed wetlands and slow sand filtration, require simple installation at low costs. They are advisable for small communities or rural area. Results from tests using 3 m3.m-2.day-1filtration rate have shown reductions of 64% turbidity, 38% apparent color, 62% total solids, 92,57% E. coli and 85,61% total coliforms. Tests at 6 m3.m-2.day-1 filtration rate led to 72%, 44%, 67%, 83,87% and 82,90% reduction for turbidity, apparent color, total solids, E.coli and total coliforms, respectively.  KEY-WORDS: constructed wetlands, water quality, rural sanitation.

scholarly journals Microbiological evaluation of constructed wetlands and solar disinfection in wastewater treatment and reuse

2020 ◽  
Vol 18 (6) ◽  
pp. 1146-1153
Author(s):  
Vinícius B. Santos ◽  
Beatriz S. Machado ◽  
Alexandre Atalla ◽  
Priscila S. Cavalheri ◽  
Fernando J. C. Magalhães Filho
Keyword(s):  
Constructed Wetlands ◽  
Limit Of Detection ◽  
Septic Tank ◽  
Salmonella Spp ◽  
Fecal Indicator ◽  
Total Coliforms ◽  
Solar Disinfection ◽  
E Coli ◽  
Significant Difference ◽  
Shigella Spp

Abstract The objective of this study was to evaluate the removal of fecal indicator bacteria and select bacterial pathogens (total coliforms, Escherichia coli, Shigella spp., Salmonella spp. and Pseudomonas aeruginosa) in vertical flow constructed wetlands (VF-CWs) with earthworms and solar disinfection (SODIS) as post-treatment of effluent from a septic tank. There was no significant difference between them in removing bacteria using a VF-CW with earthworms (VF-CW W/E) and without earthworms (VF-CW N/E). Both VF-CWs did not completely remove pathogens; however, with the SODIS technology receiving the effluent from VF-CW W/E, for E. coli, Shigella spp., Salmonella spp. and P. aeruginosa, the values were reduced below the limit of detection and 4.3 log unit average reduction for total coliforms, with 6 h in SODIS.

Comparison between polishing (maturation) ponds and subsurface flow constructed wetlands (planted and unplanted) for the post-treatment of the effluent from UASB reactors

2010 ◽  
Vol 61 (5) ◽  
pp. 1201-1209 ◽  
Author(s):  
M. von Sperling ◽  
F. L. Dornelas ◽  
F. A. L. Assunção ◽  
A. C. de Paoli ◽  
M. O. A. Mabub
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Typha Latifolia ◽  
E Coli ◽  
Effluent Quality ◽  
Coarse Filter ◽  
In Series ◽  
Subsurface Flow Constructed Wetlands ◽  
Belo Horizonte ◽  
Uasb Reactors

This paper presents the results of a comparison of the performance of two treatment systems operating in parallel, with the same influent wastewater. The investigated systems are (i) UASB + three polishing ponds in series + coarse filter (200 population equivalents) and (ii) UASB + subsurface flow constructed wetlands (50 population equivalents). Two wetland units, operating in parallel, were analysed, being one planted (Typha latifolia) and the other unplanted. The systems were located in Belo Horizonte, Brazil. The wetland systems showed to be more efficient in the removal of organic matter and suspended solids, leading to good effluent BOD and COD concentrations and excellent SS concentrations. The planted wetland performed better than the unplanted unit, but the latter was also able to provide a good effluent quality. The polishing pond system was more efficient in the removal of nitrogen (ammonia) and coliforms (E. coli). Land requirements and cost considerations are presented.

ENERGY PRODUCTION FROM WASTEWATER USING HORIZONTAL AND VERTICAL SUBSURFACE FLOW CONSTRUCTED WETLANDS

2014 ◽  
Vol 13 (10) ◽  
pp. 2517-2523 ◽  
Author(s):  
Jose Villasenor Camacho ◽  
Maria del Carmen Montano Vico ◽  
Manuel Andres ◽  
Rodrigo Rodrigo ◽  
Francisco Jesus Fernandez Morales ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Energy Production ◽  
Subsurface Flow ◽  
Subsurface Flow Constructed Wetlands

Field-Scale Studies of Subsurface Flow Constructed Wetlands for Stormwater Quality Enhancement

1997 ◽  
Vol 32 (1) ◽  
pp. 101-118 ◽  
Author(s):  
Q.J. ROCHFORT ◽  
W.E. Watt ◽  
J. Marsalek ◽  
B.C. Anderson ◽  
A.A. Crowder
Keyword(s):  
Organic Carbon ◽  
Constructed Wetlands ◽  
Suspended Solids ◽  
Nutrient Loading ◽  
Subsurface Flow ◽  
Reaction Rates ◽  
Pollutant Removal ◽  
Order Kinetic ◽  
Dissolved Metals ◽  
Subsurface Flow Constructed Wetlands

Abstract Two subsurface flow constructed wetlands were tested for pollutant removal performance in conjunction with an on-line stormwater detention pond, in Kingston Township, Ontario. The 4.9 m2 wetland cells were filled with 9 mm limestone gravel, and planted with cattail, common reed and spike rush. Changes in nutrient (total organic carbon, PO43- and NH4+), suspended solids and metal (Cu, Pb, Zn) concentrations were used to assess performance. Contaminant removal occurred through a combination of physical, chemical and biological means. As with any biological system, variation in performance of stormwater wetlands can be expected to occur as a result of fluctuations in contaminant loading, contact time and ambient environmental conditions. Storm pond effluent was delivered in continuous flow through the wetlands (during baseflow and event conditions), with a detention time of 1 to 3 days. The wetlands were able to maintain removal rates of up to 39% for orthophosphate even during the more severe conditions of fall dieback. Average removal of suspended solids (46%) and dissolved metals (Cu 50%) remained similar throughout all tests. Organic carbon was reduced by less than 10% during these tests. Low nutrient levels in the pond effluent were supplemented by spiking with sources of carbon, nitrogen and phosphorus during pulsed loading conditions. Daily sampling produced a time series, which illustrated the rates of decline in concentration of nutrients. First order kinetic assimilation rates ranged from 1.7 d-1 for NH4002B to 0.12 d-1 for organic carbon, which were noticeably lower when compared with municipal and industrial wastewater treatment rates. Three methods of sizing stormwater wetlands (impervious surface area, volumetric load and kinetic reaction rates) were compared using the same design storm and data from this study. From this comparison it was seen that the kinetic sizing approach proved to be the most versatile, and allowed for adaptation to northern climatic conditions and anticipated nutrient loading.

Enhancement of nitrogen removal in subsurface flow constructed wetlands employing a 2-stage configuration, an unsaturated zone, and recirculation

1995 ◽  
Vol 32 (3) ◽  
pp. 59-67 ◽  
Author(s):  
Kevin D. White
Keyword(s):  
Constructed Wetlands ◽  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Subsurface Flow ◽  
Great Promise ◽  
Effluent Recirculation ◽  
Wetland Treatment ◽  
Subsurface Flow Constructed Wetlands ◽  
Inlet Zone ◽  
Bod Removal

Constructed wetland technology is currently evolving into an acceptable, economically competitive alternative for many wastewater treatment applications. Although showing great promise for removing carbonaceous materials from wastewater, wetland systems have not been as successful at nitrification. This is primarily due to oxygen limitations. Nitrification does occur in conventional wetland treatment systems, but typically requires long hydraulic retention times. This paper describes a study that first evaluated the capability of subsurface flow constructed wetlands to treat a high strength seafood processor wastewater and then evaluated passive aeration configurations and effluent recirculation with respect to nitrogen treatment efficiency. The first stage of a 2-stage wetland treatment system exhibited a relatively short hydraulic retention time and was designed for BOD removal only. The second stage wetland employed an unsaturated inlet zone and effluent recirculation to enhance nitrification. Results indicate that organic loading, and thus BOD removal, in the first stage wetland is key to optimal nitrification. Passive aeration through an unsaturated inlet zone and recirculation achieved up to 65-70 per cent ammonia nitrogen removal at hydraulic retention times of about 3.5 days. Inlet zone configuration and effluent recirculation is shown to enhance the nitrogen removal capability of constructed wetland treatment systems.

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