scholarly journals Performance of the first stage of the French system of vertical flow constructed wetlands with only two units in parallel: influence of pulse time and instantaneous hydraulic loading rate

2018 ◽  
Vol 78 (4) ◽  
pp. 848-859 ◽  
Author(s):  
Jorge A. García Zumalacarregui ◽  
Marcos von Sperling
Keyword(s):  
Constructed Wetlands ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Feeding Time ◽  
Vertical Flow ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Vertical Flow Constructed Wetlands ◽  
Removal Efficiencies ◽  
Raw Wastewater

Abstract The technology of vertical flow constructed wetlands – French system for treating raw wastewater depends on several hydraulic factors, one of them being the duration of the pulse feeding and the resulting instantaneous hydraulic loading rate. This paper analyses two scenarios in the same system, the first of a faster feeding by pump and the second of a slower feeding by siphon, both with instantaneous hydraulic loading rate values lower than the literature recommendations. The system treated raw wastewater from a population equivalent of 100 p.e. in Brazil, and was comprised by only the first stage and two units in parallel. The shorter duration of feeding time and higher instantaneous hydraulic loading rate were associated with significantly higher chemical oxygen demand and total Kjeldahl nitrogen removal efficiencies, but with no significant differences in terms of biochemical oxygen demand (BOD) and suspended solids (SS). Oxygen concentrations and redox potential in the effluent were evaluated, together with the effluent flow rate profiles. The removal efficiencies were associated with the accumulation of solids in the upper part of the filter resulting from seven years of operation and to the operating hydraulic conditions, which are important elements in the performance of the system.

Influence of earthworm presence and hydraulic loading rate on the performance of vertical flow constructed wetlands

2020 ◽  
pp. 1-9 ◽  
Author(s):  
Alexandre Atalla ◽  
Catiane Pelissari ◽  
Milina de Oliveira ◽  
Mariana Antonio de Souza Pereira ◽  
Priscila Sabioni Cavalheri ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Loading Rate ◽  
Vertical Flow ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Vertical Flow Constructed Wetlands

Purification Effect of Vertical-Flow Constructed Wetlands with Multi-Size Combined Filter Medium

2013 ◽  
Vol 726-731 ◽  
pp. 1720-1723 ◽  
Author(s):  
Xiang Ling Zhang ◽  
Lu Xu ◽  
Jun Jie Chen ◽  
Liang Hu
Keyword(s):  
Constructed Wetlands ◽  
Loading Rate ◽  
Great Influence ◽  
Filter Medium ◽  
Vertical Flow ◽  
Vertical Flow Constructed Wetlands ◽  
Vertical Flow Constructed Wetland ◽  
Removal Efficiencies ◽  
Single Medium ◽  
Made In

Three columns filled with multi-size combined medium were utilized in the simulative vertical-flow constructed wetland systems to treat wastewater at hydraulic loading rate of 2000-3000 mm/d, that the same kind of media including biological ceramsite, anthracite and zeolite in each column. Comparative analyses were made in treatment performances between multi-size medium and single medium. The results showed that compared with the treatment performances of single medium, the purifying effect had great influence by the multi-size combined medium which were made up of same kind and different size of filter medium. Contrast with the corresponding single medium, the average removal efficiencies of CODCr, Total Nitrogen (TN), and Total Phosphorus (TP) were increased obviously which were purified by the multi-size combined medium. Good performances were achieved in terms of removal of BOD5 and CODCr in the column of multi-size combined biological ceramsite medium. The average removal efficiencies of TN were great in the column of multi-size combined zeolite medium. Good performances were also achieved in terms of removal of TP in the column of multi-size combined anthracite medium.

Constructed wetlands for the treatment of raw wastewater: the French experience

2014 ◽  
Vol 9 (3) ◽  
pp. 430-439 ◽  
Author(s):  
S. Troesch ◽  
F. Salma ◽  
D. Esser
Keyword(s):  
Organic Matter ◽  
Constructed Wetlands ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Vertical Flow ◽  
Small Communities ◽  
Vertical Flow Constructed Wetlands ◽  
French Experience ◽  
Raw Wastewater

Vertical flow constructed wetlands for small communities (<5,000 population equivalent) have been successfully developed in France since the 1990s (currently about 3'000 plants are in operation). This paper summarizes the results and efficiencies of 70 plants designed and built by Epur Nature or SINT. The results show clearly that the design performs well for organic matter removal and nitrification and makes sludge management easy. Therefore if well designed, such systems can achieve an outlet quality of BOD5 < 20 mg/L, chemical oxygen demand <90 mg/L, suspended solids <30 mg/L and TKN < 15 mg/L. In addition, some new configurations involving a French vertical first stage fed with raw sewage, patented by Epur Nature, are presented as an aid to reduce the global footprint.

Performance evaluation of a novel open trickling filter for the post-treatment of anaerobic effluents from small communities

2013 ◽  
Vol 67 (12) ◽  
pp. 2746-2752 ◽  
Author(s):  
P. C. Vieira ◽  
M. von Sperling ◽  
L. C. M. Nogueira ◽  
B. F. S. Assis
Keyword(s):  
Loading Rate ◽  
Oxygen Demand ◽  
Post Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Trickling Filter ◽  
Small Communities ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Removal Efficiencies

The objective of the work is to evaluate the performance of an innovative design of a trickling filter for small population sizes, which has been implemented for the post-treatment of sanitary effluent from a UASB (upflow anaerobic sludge blanket) reactor. The unit, named open trickling filter (OTF), operates with no side walls, no perforated bottom slab and no secondary settler. The OTF packing was 3.5 m high, composed of crushed stone, with a fixed distribution system made of channels with V-notch weirs. The OTF was operated with mean surface hydraulic loading rates of 4.1 and 9.3 m3 m−2 d−1, corresponding to population equivalents of approximately 250 and 550 inhabitants, respectively. For the surface hydraulic loading rate of 4.1 m3 m−2 d−1, the median removal efficiencies obtained by the OTF and overall system (UASB + OTF) were, respectively, 24 and 83% for total suspended solids (TSS), 44 and 79% for chemical oxygen demand (COD), 42 and 82% for biochemical oxygen demand (BOD), 40 and 40% for N-ammonia. For the surface hydraulic loading rate of 9.3 m3 m−2 d−1, the median removal efficiencies obtained by the OTF and global system (UASB + OTF) were 14 and 76% for TSS, 28 and 76% for COD, 25 and 86% for BOD, 15 and 15% for N-ammonia. Considering the great simplicity, no mechanization and small footprint of the system, these results can be considered satisfactory, suggesting that the OTF is suitable for small communities, especially in developing countries.

French vertical flow constructed wetlands: a need of a better understanding of the role of the deposit layer

2013 ◽  
Vol 69 (1) ◽  
pp. 106-112 ◽  
Author(s):  
Pascal Molle
Keyword(s):  
Constructed Wetlands ◽  
Organic Layer ◽  
Vertical Flow ◽  
Biological Behaviour ◽  
Positive Role ◽  
Vertical Flow Constructed Wetlands ◽  
Key Factor ◽  
Deposit Layer ◽  
Raw Wastewater

French vertical flow constructed wetlands, treating directly raw wastewater, have become the main systems implemented for communities under 2,000 population equivalent in France. Like in sludge drying reed beds, an organic deposit layer is formed over time at the top surface of the filter. This deposit layer is a key factor in the performance of the system as it impacts hydraulic, gas transfers, filtration efficiency and water retention time. The paper discusses the role of this deposit layer on the hydraulic and biological behaviour of the system. It presents results from different studies to highlight the positive role of the layer but, as well, the difficulties in modelling this organic layer. As hydraulic, oxygen transfers, and biological activity are interlinked and impacted by the deposit layer, it seems essential to focus on its role (and its quantification) to find new developments of vertical flow constructed wetlands fed with raw wastewater.

scholarly journals Vertical flow constructed wetlands subject to load variations: an improved design methodology connected to outlet quality objectives

2015 ◽  
Vol 72 (5) ◽  
pp. 817-823 ◽  
Author(s):  
C. Boutin ◽  
S. Prost-Boucle
Keyword(s):  
Organic Matter ◽  
Constructed Wetlands ◽  
Oxygen Demand ◽  
Nitrification Rate ◽  
Vertical Flow ◽  
Design Standards ◽  
Rural Villages ◽  
Vertical Flow Constructed Wetlands ◽  
Nitrogen Concentrations ◽  
Improved Design

This study surveyed four campsites and four rural villages of major tourist interest, called tourist-interest or ti-villages, that were monitored for several years, generating over 70 performance balances for vertical flow constructed wetlands (VFCWs) that were intentionally scaled down for experimental trials. The wastewater effectively qualifies as domestic sewage, although relatively concentrated, with the campsites presenting particularly high nitrogen concentrations (122 gTKN L–1) (TKN: total Kjeldahl nitrogen). The applied daily loads were also particularly high, with some combinations of load parameters (hydraulic load, organic matter, TKN) leading to 400% overloading. Even under those drastic conditions, the quality of effluent remained excellent on the characteristic organic matter parameters, with removal performances always over 85%. Analysis of the dataset points to two major design thresholds: for campsites, in order to maintain a 73% nitrification rate even at the height of the summer season, the load applied onto the first stage filter in operation could achieve up to 600 gCOD m–2 day–1 (COD: chemical oxygen demand). For tourist-interest villages, in order to maintain an 85% nitrification rate, the load applied onto the second stage filter in operation could achieve up to 22 gTKN m–2.day–1. Here, VFCWs were demonstrated to robustly handle a massive increase in loads applied, providing the construction and operation stringently follow design standards and practices.

Contaminant removal in septage treatment with vertical flow constructed wetlands operated under batch flow conditions

2015 ◽  
Vol 73 (4) ◽  
pp. 909-915 ◽  
Author(s):  
Valerie Siaw Wee Jong ◽  
Fu Ee Tang
Keyword(s):  
Constructed Wetlands ◽  
Palm Kernel ◽  
Oxygen Demand ◽  
Vertical Flow ◽  
Contaminant Removal ◽  
Efficient Operation ◽  
Palm Kernel Shell ◽  
Second Stage ◽  
Vertical Flow Constructed Wetlands ◽  
Study Results

Individual septic tanks are the most common means of on-site sanitation in Malaysia, but they result in a significant volume of septage. A two-staged vertical flow constructed wetlands (VFCWs) system for the treatment of septage was constructed and studied in Sarawak, Malaysia. Raw septage was treated in the first stage wetlands, and the resulting percolate was fed onto the second stage wetlands for further treatment. Here, the effects of a batch loading regime on the contaminant removal efficiency at the second stage wetlands, which included palm kernel shell within their filter substrate, are presented. The batch loading regime with pond:rest (P:R) period of 1:1, 2:2 and 3:3 (day:day) was studied. The improvement of the effluent redox condition was evident with P:R = 3:3, resulting in excellent organic matters (chemical oxygen demand and biochemical oxygen demand) and nitrogen reduction. The bed operated with P:R = 1:1 experienced constant clogging, with a water layer observed on the bed surface. For the P:R = 3:3 regime, the dissolved oxygen profile was not found to decay drastically after 24 hours of ponding, suggesting that the biodegradation mainly occurred during the first day. The study results indicate that a suitable application regime with an adequate rest period is important in VFCWs to ensure efficient operation.

scholarly journals Effectiveness of septage pre-treatment in vertical flow constructed wetlands

2017 ◽  
Vol 76 (9) ◽  
pp. 2544-2553 ◽  
Author(s):  
Beata Karolinczak ◽  
Wojciech Dąbrowski
Keyword(s):  
Constructed Wetlands ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Vegetation Period ◽  
Ammonia Nitrogen ◽  
Vertical Flow ◽  
Municipal Wastewater Treatment ◽  
Vertical Flow Constructed Wetlands ◽  
Hydraulic Load ◽  
Pre Treatment

Abstract Septage is wastewater stored temporarily in cesspools. A periodic supply of its significant quantities to small municipal wastewater treatment plants (WWTPs) may cause many operational problems. In the frame of the research, it has been proposed to utilize vertical flow constructed wetlands for pre-treatment of septage prior to its input to the biological stage of a WWTP. The aim of the work was to assess the effectiveness of pre-treatment in relation to factors such as: seasonality, hydraulic load, pollutants load of the VF bed and interactions between these factors. The results proved that application of a VF bed to septage pre-treatment can significantly reduce the concentration of pollutants (biochemical oxygen demand (BOD5): 82%, chemical oxygen demand (COD): 82%, total suspended solids (TSS): 91%, total nitrogen (TN): 47%, ammonia nitrogen (NH4-N): 70%), and thus decrease the loading of the biological stage of a WWTP. The mathematical models of mass removal process were created. They indicate that in case of all analysed parameters, removed load goes up with the increase of load in the influent. However, with the increase of hydraulic load, a decrease of the removed BOD5, COD, TSS and total phosphorus, and in vegetation period an increase of TN, can be observed in terms of load. There are no statistically significant effects of seasonality.

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