Removal efficiency of subsurface vertical flow constructed wetlands for different organic loads

2007 ◽  
Vol 56 (3) ◽  
pp. 75-84 ◽  
Author(s):  
G. Langergraber ◽  
C. Prandtstetten ◽  
A. Pressl ◽  
R. Rohrhofer ◽  
R. Haberl
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Constructed Wetlands ◽  
Specific Surface Area ◽  
Nitrogen Concentration ◽  
Specific Area ◽  
Ammonia Nitrogen ◽  
Vertical Flow ◽  
Design Standards ◽  
Vertical Flow Constructed Wetlands

Using subsurface vertical flow constructed wetlands (SSVFCWs) with intermittent loading it is possible to fulfil the stringent Austrian effluent standards regarding nitrification. For small plants (less than 500 persons) standards for ammonia nitrogen concentration have to be met at water temperatures higher than 12 °C, effluent concentrations and treatment efficiencies for organic matter have to be met the whole year around. According to the Austrian design standards the required surface area for SSVFCWs treating wastewater was 5 m2 per person. Within the first part of an Austrian research project the goal was to optimise, i.e. minimise the surface area requirement of vertical flow beds. Therefore, three SSVFCWs with a surface area of 20 m2 each have been operated in parallel. The organic loads applied were 20, 27 and 40 g COD/m2/d, which corresponds to a specific surface area requirement of 4, 3 and 2 m2 per PE, respectively. The paper compares the effluent concentrations and elimination efficiencies of the three parallel operated beds. It could be shown that a specific area demand of 4 m2 per person is suitable to be included in the revision of the Austrian design standard. Additionally it could be shown that during the warmer seasons (May–October) when the temperature of the effluent is higher than 12 °C the specific surface area might be further reduced; even 2 m2 per person has been proven to be adequate.

Preparation of Adsorbent from Blue Coke Powder and its Application in Coking Wastewater

2011 ◽  
Vol 695 ◽  
pp. 553-556
Author(s):  
Yu Hong Tian ◽  
Xin Zhe Lan ◽  
Qiu Li Zhang ◽  
Juan Qin Xue ◽  
Yong Hui Song ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Removal Rate ◽  
Nitrogen Concentration ◽  
Ammonia Nitrogen ◽  
Raw Material ◽  
Coking Wastewater ◽  
Adsorption Time ◽  
Coke Powder

The low-cost blue coke industrial by-product, blue coke powder was used as raw material for the production of porous carbons adsorbent by steam activating at temperature of 800°C under the atmosphere of N2 for 60 minutes. The specific surface area and pore properties of the adsorbent were characterized by using N2 adsorption-desorption isotherms. Furthermore, the adsorption effects of the adsorbent for ammonia nitrogen in coking wastewater were investigated in terms of particle size, dosage of absorbent and adsorption time. The results show that the specific surface area is 620.94m2/g, the total pore volume is 0.4442cm3/g and the average mesopore size is 4.5808nm, the adsorbent possesses predominant mesoporous structures. In aeration, the removal rate of ammonia nitrogen can reach to 39.5% under the conditions of the ammonia nitrogen concentration of 625mg/L, the dosage of adsorbent 10g/L at the adsorption time of 60 minutes.

Optimization of subsurface vertical flow constructed wetlands for wastewater treatment

2007 ◽  
Vol 55 (7) ◽  
pp. 71-78 ◽  
Author(s):  
G. Langergraber ◽  
Ch. Prandtstetten ◽  
A. Pressl ◽  
R. Rohrhofer ◽  
R. Haberl
Keyword(s):  
Grain Size ◽  
Specific Surface ◽  
Surface Area ◽  
Constructed Wetlands ◽  
Organic Load ◽  
Vertical Flow ◽  
Two Stage ◽  
Main Layer ◽  
Free Drainage ◽  
Stage System

Constructed wetlands (CWs) use the same processes that occur in natural wetlands to improve water quality and are used worldwide to treat different qualities of water. This paper shows the results of an Austrian research project having the main goals to optimize vertical flow beds in terms of surface area requirement and nutrient removal, respectively. It could be shown that a subsurface vertical flow constructed wetland (SSVFCW) operated with an organic load of 20 g COD.m−2.d−1 (corresponding to a specific surface area demand of 4 m2 per person) can fulfil the requirements of the Austrian standard regarding effluent concentrations and removal efficiencies. During the warmer months (May – October), when the temperature of the effluent is higher than 12 °C, the specific surface area might be further reduced. Even 2 m2 per person have been proven to be adequate. Enhanced nitrogen removal of 58 % could be achieved with a two-stage system (first stage: grain size for main layer 1–4 mm, saturated drainage layer; and second stage: grain size for main layer 0.06–4 mm, free drainage) that was operated with an organic load of 80 g COD.m−2.d−1 for the first stage (1 m2 per person), i.e. 40 g COD.m−2.d−1 for the two-stage system (2 m2 per person). Although the two-stage system was operated with higher organic loads a higher effluent quality compared to a single-stage SSVFCW (grain size for main layer 0.06–4 mm, free drainage, organic load 20 g COD.m−2.d−1) could be reached.

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.

Study of Gamma Alumina Synthesis – Analysis of the Specific Surface Area

2014 ◽  
Vol 87 ◽  
pp. 54-60 ◽  
Author(s):  
A.H. Munhoz ◽  
H. de Paiva ◽  
L. Figueiredo de Miranda ◽  
E.C. de Oliveira ◽  
Raphael Cons Andrades ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Ageing Time ◽  
Precursor Solution ◽  
Specific Area ◽  
Gamma Alumina ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dta And Tg

Different samples of pseudoboehmite (PB) were synthesized through the sol-gel process, using aluminum nitrate as precursor. The influence of variables on the synthesis and calcinations of the PB on the specific area of the obtained gamma-Alumina were studied. The variables were the ageing temperature (25 and 130o C), addition or not of polyvinyl alcohol to the precursor solution and the ageing time of the PB. The pH adjustment of the precursor solution was made by using ammonium carbonate. The products, which were obtained on different conditions, were then characterized by x-ray diffraction, specific area measurements through the BET process, and by thermal analysis (DTA and TG). After characterization, the synthesis products were calcined at 500°C; during this process the gamma-Alumina transformation was observed. The calcination products were characterized by the same methods (x-ray diffraction, BET, DTA and TG) and the desorption-absorption curves were obtained as well, in order to measure the pore volume of the samples. Finally, the results were analyzed through an experimental factorial planning, which showed that high specific surface area gamma-Al2O3 (around 330m²/g) can be obtained through this process.

Assessment of Effective Specific Surface Area for Free Water Surface Constructed Wetlands

1999 ◽  
Vol 40 (3) ◽  
pp. 83-89 ◽  
Author(s):  
N. R. Khatiwada ◽  
C. Polprasert
Keyword(s):  
Organic Matter ◽  
Specific Surface ◽  
Surface Area ◽  
Constructed Wetlands ◽  
Specific Surface Area ◽  
Kinetic Models ◽  
Water Surface ◽  
Free Water ◽  
Organic Matter Degradation ◽  
Biofilm Bacteria

Biofilm bacteria attached to submerged surfaces play a major role in organic matter degradation in free-water-surface(FWS) constructed wetlands used for wastewater treatment. Effective specific surface area (as) available for the biofilm bacteria is an important parameter in organic matter degradation and in describing the biofilm kinetic models used in the design and operation of constructed wetlands. In this study, kinetic models based on two possible biofilm geometries were developed for the determination of as and its non-dimensionalised value or area factor (δ). The as and δ values were estimated for a laboratory FWS constructed wetland treating domestic wastewater based on the chemical oxygen demand (COD) removal performance and other kinetic parameters. With the assumption of slab geometry for the biofilm, the values of as and δ were found as 3.15 m2/m3 and 2.2 for the lab unit having 80% mass COD removal, whereas by considering the cylindrical geometry for the biofilm attached on the lateral roots higher values of as and δ were obtained.

A Study on the Influencing Factors on the Dry-Shrinkage Performance of Phosphate Cement

2011 ◽  
Vol 99-100 ◽  
pp. 838-841
Author(s):  
Chun Ping Tang
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Magnesium Oxide ◽  
Influencing Factors ◽  
Specific Surface Area ◽  
Specific Area ◽  
Dry Shrinkage

Aiming at the characteristics of phosphate repairing materials, the influences of retarder, specific surface area of magnesium oxide and content of fly ash on the dry-shrinkage performance of phosphate cement were studied in this paper. The results showed that greater content of retarder would result in greater dry-shrinkage value within a certain range, greater specific area of magnesium oxide would result in greater dry-shrinkage value while the increase of content of fly ash would cause the dry-shrinkage value to be decreased correspondingly within a certain range.

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.

scholarly journals High-Level Oxygen Reduction Catalysts Derived from the Compounds of High-Specific-Surface-Area Pine Peel Activated Carbon and Phthalocyanine Cobalt

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3429
Author(s):  
Lei Zhao ◽  
Ziwei Lan ◽  
Wenhao Mo ◽  
Junyu Su ◽  
Huazhu Liang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
High Performance ◽  
Low Cost ◽  
Specific Area ◽  
High Specific Surface Area ◽  
High Catalytic Activity

Non-platinum carbon-based catalysts have attracted much more attention in recent years because of their low cost and outstanding performance, and are regarded as one of the most promising alternatives to precious metal catalysts. Activated carbon (AC), which has a large specific surface area (SSA), can be used as a carrier or carbon source at the same time. In this work, stable pine peel bio-based materials were used to prepare large-surface-area activated carbon and then compound with cobalt phthalocyanine (CoPc) to obtain a high-performance cobalt/nitrogen/carbon (Co-N-C) catalyst. High catalytic activity is related to increasing the number of Co particles on the large-specific-area activated carbon, which are related with the immersing effect of CoPc into the AC and the rational decomposed temperature of the CoPc ring. The synergy with N promoting the exposure of CoNx active sites is also important. The Eonset of the catalyst treated with a composite proportion of AC and CoPc of 1 to 2 at 800 °C (AC@CoPc-800-1-2) is 1.006 V, higher than the Pt/C (20 wt%) catalyst. Apart from this, compared with other AC/CoPc series catalysts and Pt/C (20 wt%) catalyst, the stability of AC/CoPc-800-1-2 is 87.8% in 0.1 M KOH after 20,000 s testing. Considering the performance and price of the catalyst in a practical application, these composite catalysts combining biomass carbon materials with phthalocyanine series could be widely used in the area of catalysts and energy storage.

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