Performance evaluation of planted and unplanted subsurface-flow constructed wetlands for the post-treatment of UASB reactor effluents

2009 ◽  
Vol 60 (12) ◽  
pp. 3025-3033 ◽  
Author(s):  
Filipe Lima Dornelas ◽  
Matheus Boechat Machado ◽  
Marcos von Sperling
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Typha Latifolia ◽  
Post Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Horizontal Subsurface Flow ◽  
Subsurface Flow Constructed Wetlands ◽  
Belo Horizonte

A system comprised by a UASB (Upflow Anaerobic Sludge Blanket) reactor followed by two horizontal subsurface-flow constructed wetlands in parallel was evaluated for the treatment of the wastewater generated in the city of Belo Horizonte, Brazil (50 inhabitants each unit). One unit was planted (Typha latifolia) and the other was unplanted. Influent and effluent samples were collected for a period of seven months. The systems were able to produce final effluents with low concentrations of organic matter and suspended solids, but showed not to be efficient in the removal of nutrients. Mean effluent concentrations for the planted and unplanted units were, respectively: BOD: 15 and 19 mg/L; COD: 42 and 64 mg/L; TSS: 3 and 5 mg/L; TN: 27 and 33 mg/L; N-NH3: 25 and 29 mg/L; P Total: 1.2 and 1.5 mg/L. The planted wetland presented effluent concentrations and removal efficiencies significantly (Wilcoxon matched-pairs test, 5% significance level) better than the unplanted unit for most constituents. The study shows that horizontal subsurface-flow constructed wetlands can be effectively used as a post-treatment option for the effluent from UASB reactors.

Performance and behaviour of planted and unplanted units of a horizontal subsurface flow constructed wetland system treating municipal effluent from a UASB reactor

2013 ◽  
Vol 68 (7) ◽  
pp. 1495-1502 ◽  
Author(s):  
Jocilene Ferreira da Costa ◽  
André Cordeiro de Paoli ◽  
Martin Seidl ◽  
Marcos von Sperling
Keyword(s):  
Suspended Solids ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Post Treatment ◽  
Filter Medium ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Horizontal Subsurface Flow

A system composed of two horizontal subsurface flow constructed wetlands operating in parallel was evaluated for the post-treatment of UASB (upflow anaerobic sludge blanket) reactor effluent, for a population equivalent of 50 inhabitants per unit. One unit was planted with cattail (Typha latifolia) and the other was unplanted. The study was undertaken over a period of 4 years, comprising monitoring of influent and effluent constituents together with a full characterization of the behaviour of the units (tracer studies, mathematical modelling of chemical oxygen demand (COD) decay, characterization of solids in the filter medium). The mean value of the surface hydraulic load was 0.11 m3m−2d−1, and the theoretical hydraulic retention time was 1.1 d in each unit. Using tracer tests with 82Br, dispersion number (d) values of 0.084 and 0.079 for the planted and unplanted units were obtained, indicating low to moderate dispersion. The final effluent had excellent quality in terms of organic matter and suspended solids, but the system showed low capacity for nitrogen removal. Four-year mean effluent concentration values from the planted and unplanted units were, respectively: biochemical oxygen demand (BOD5): 25 and 23 mg L−1; COD: 50 and 55 mg L−1; total suspended solids (TSS): 9 and 9 mg L−1; N-ammonia: 27 and 28 mg L−1. The COD decay coefficient K for the traditional plug-flow model was 0.81 and 0.84 d−1 for the planted and unplanted units. Around 80% of the total solids present in the filter medium were inorganic, and most of them were present in the interstices rather than attached to the support medium. As an overall conclusion, horizontal subsurface flow wetlands can be a very suitable post-treatment method for municipal effluents from anaerobic reactors.

scholarly journals From start-up to heavy clogging: performance evaluation of horizontal subsurface flow constructed wetlands during 10 years of operation

2019 ◽  
Vol 79 (7) ◽  
pp. 1231-1240 ◽  
Author(s):  
Gabriel Rodrigues Vasconcellos ◽  
Marcos von Sperling ◽  
Roberta Silva Ocampos
Keyword(s):  
Constructed Wetlands ◽  
Overland Flow ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Start Up ◽  
Horizontal Subsurface Flow ◽  
Subsurface Flow Constructed Wetlands ◽  
Pre Treatment

Abstract The objective of this work is to evaluate the performance of two horizontal subsurface flow constructed wetlands, one planted with cattail (Typha latifolia) and the other unplanted. The distinguishing feature of this study is that it spans a period of more than 10 years, from start-up to a final operation with heavy clogging and full overland flow. For most of the time, starting in June 2007, the system received municipal sewage previously treated in an upflow anaerobic sludge blanket (UASB) reactor, but for one specific period, the pre-treatment was comprised of the UASB reactor and a trickling filter in series. The two constructed wetlands worked in parallel, each serving approximately 50 p.e. and continuously receiving a flow around 7.5 m3 d−1 for most of the time. The beds had a length of 25 m and a width of 3 m and were filled with blast furnace slag. For most of this long operational period, performance was very good in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS), with median effluent concentrations of 19/18, 46/52 and 12/8, respectively (planted/unplanted units). Clogging was noticeable in the first years of operation, soon leading to overland flow. However, treatment performance was still successful, even when the system's hydraulics were strongly deteriorated. The type of pre-treatment and the applied loads influenced more the performance of the units than the period of operation itself, evidencing the robustness of the system.

Evaluation of clogging in planted and unplanted horizontal subsurface flow constructed wetlands: solids accumulation and hydraulic conductivity reduction

2013 ◽  
Vol 67 (6) ◽  
pp. 1345-1352 ◽  
Author(s):  
André Cordeiro De Paoli ◽  
Marcos von Sperling
Keyword(s):  
Hydraulic Conductivity ◽  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Typha Latifolia ◽  
Surface Flow ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Operational Problem ◽  
Horizontal Subsurface Flow ◽  
Comparative Results

This study aimed to evaluate the behaviour of two horizontal subsurface flow constructed wetland units regarding solids build up and clogging of the filter medium. In order to analyse the causes of this process, which is considered the major operational problem of constructed wetlands, studies were carried out to characterize accumulated solids and hydraulic conductivity at specific points of the beds of two wetlands (planted with Typha latifolia and unplanted units) receiving effluent from an upflow anaerobic sludge blanket reactor treating sanitary sewage (population equivalent of 50 inhabitants each unit). The experiments were performed after the units were operating for 2 years and 4 months. This study presents comparative results related to the quantification and characterization of accumulated solids and hydraulic conductivity along the length and width of the filter beds. Approximately 80% of the solids found were inorganic (fixed). Near the inlet end, the rate interstitial solids/attached solids was 5.0, while in the outlet end it was reduced to 1.5. Hydraulic conductivity was lower near the inlet of the units (as expected) and, by comparing the planted wetland with the unplanted, the hydraulic conductivity was lower in the former, resulting in larger undesired surface flow.

Comparison of simple, small, full-scale sewage treatment systems in Brazil: UASB–maturation ponds–coarse filter; UASB–horizontal subsurface-flow wetland; vertical-flow wetland (first stage of French system)

2014 ◽  
Vol 71 (3) ◽  
pp. 329-337 ◽  
Author(s):  
M. von Sperling
Keyword(s):  
Sewage Treatment ◽  
Subsurface Flow ◽  
Full Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Plant Management ◽  
Anaerobic Sludge ◽  
Vertical Flow ◽  
Coarse Filter ◽  
Horizontal Subsurface Flow

This paper presents a comparison between three simple sewage treatment lines involving natural processes: (a) upflow anaerobic sludge blanket (UASB) reactor–three maturation ponds in series–coarse rock filter; (b) UASB reactor–horizontal subsurface-flow constructed wetland; and (c) vertical-flow constructed wetlands treating raw sewage (first stage of the French system). The evaluation was based on several years of practical experience with three small full-scale plants receiving the same influent wastewater (population equivalents of 220, 60 and 100 inhabitants) in the city of Belo Horizonte, Brazil. The comparison included interpretation of concentrations and removal efficiencies based on monitoring data (organic matter, solids, nitrogen, phosphorus, coliforms and helminth eggs), together with an evaluation of practical aspects, such as land and volume requirements, sludge production and handling, plant management, clogging and others. Based on an integrated evaluation of all aspects involved, it is worth emphasizing that each system has its own specificities, and no generalization can be made on the best option. The overall conclusion is that the three lines are suitable for sewage treatment in small communities in warm-climate regions.

Diversity and Abundance of Ammonia-Oxidizing Bacteria in Horizontal Subsurface-Flow Constructed Wetlands with Different Vegetation and Substrate

2014 ◽  
Vol 522-524 ◽  
pp. 136-140
Author(s):  
Xue Cen Yu ◽  
Ming Xiao Zhang ◽  
Yue Wen ◽  
Qi Zhou
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Typha Latifolia ◽  
Ammonia Oxidizing Bacteria ◽  
Gravel Bed ◽  
Scirpus Validus ◽  
Different Types ◽  
Hybrid Substrates ◽  
Horizontal Subsurface Flow ◽  
Subsurface Flow Constructed Wetlands

The diversity and abundance of ammonia-oxidizing bacteria was investigated in three different types of horizontal subsurface flow constructed wetlands, reed (Phragmites australis)/gravel bed (W1), hybrid vegetation {reed, cattail (Typha latifolia), bulrush (Scirpus validus)}/gravel bed (W2) and reed/hybrid substrates bed (gravel, zeolite, slag) (W3). The investigation of community structures of ammonia-oxidizing bacteria revealed that the types of macrophytes , substrate and space distributions had significant influence on the microbial community. The ammonia-oxidizing bacteria detected were all inculturable, and belonged to Nitrosomonas spp.

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.

scholarly journals Difficulties and modifications in the use of available methods for hydraulic conductivity measurements in highly clogged horizontal subsurface flow constructed wetlands

2017 ◽  
Vol 76 (7) ◽  
pp. 1666-1675 ◽  
Author(s):  
Mateus Pimentel Matos ◽  
André Baxter Barreto ◽  
Gabriel Rodrigues Vasconcellos ◽  
Antonio Teixeira Matos ◽  
Gustavo Ferreira Simões ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Constructed Wetlands ◽  
Subsurface Flow ◽  
The Other ◽  
Good Representation ◽  
Horizontal Distance ◽  
Conductivity Measurements ◽  
Construction Time ◽  
Horizontal Subsurface Flow ◽  
Subsurface Flow Constructed Wetlands

Despite the fact that several authors consider the available measurement methods of hydraulic conductivity (ks) suitable for a good representation of the bed condition and clogging potential in horizontal subsurface flow constructed wetlands, others have questioned their adequacy. In this work, hydraulic conductivity measurements with conventional and modified methods were undertaken in two small full-scale units, one planted with cattail (Typha latifolia) and the other unplanted. Both units had already been operating for seven years and showed a high degree of clogging. It was observed that the use of the falling head method, with the introduction of the tubes during the test, provided results without a clear spatial trend. On the other hand, tests done on monitoring wells inserted during construction time showed, as expected, ks increasing with the horizontal distance from the inlet, but without reflecting actual field conditions. It was observed that, as the bed became more clogged, the use of the reported methods became more complex, suggesting the need of other methodologies. The use of planted fixed reactors (removable baskets installed in the bed) with evaluation of ks at constant head in the laboratory showed potential for the characterization of the hydrodynamic properties of the porous medium.

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