Benzene Removal in Laboratory Scale Model Wetland under Different Electron Acceptor Conditions Treating Sulfate-Rich Wastewater

2014 ◽  
Vol 955-959 ◽  
pp. 2083-2086 ◽  
Author(s):  
Zhong Bing Chen ◽  
Uwe Kappelmeyer ◽  
Peter Kuschk

Constructed wetlands (CWs) are shown to be suitable for the treatment of water contaminated with benzene. However, due to the high sulfate concentration (around 850 mg/L) in influent, sulfate reduction will be stimulated in CWs. Subsequently, the toxicity of sulfide will be a catastrophe to the plants, and the treatment performance of CWs will be impaired. In this study, nitrite and nitrate were used as competitor with sulfate for electron acceptor to prevent the sulfate reduction. With the inflow benzene concentration ranged from 21.6-103 μg, and the accumulation of sulfide reached up to 39%, the removal efficiency of benzene decreased from 86% to 27%. However, with the addition of nitrite and nitrate, the sulfide accumulation was inhibited successfully, and the benzene removal efficiency recovered to 85%. In conclusion, both nitrite and nitrate can be an option for preventing sulfate reduction and sulfide toxicity in CWs treating sulfate-rich wastewater.

2015 ◽  
Vol 72 (12) ◽  
pp. 2243-2250 ◽  
Author(s):  
J. Y. Choi ◽  
M. C. Maniquiz-Redillas ◽  
J. S. Hong ◽  
S. Y. Lee ◽  
L. H. Kim

This study was conducted to compare the treatment performance of two hybrid constructed wetlands (CWs) in treating stormwater runoff. The hybrid CWs were composed of a combination of free water surface (FWS) and horizontal subsurface flow (HSSF) CWs. Based on the results, strong correlation exists between potential runoff impacts and stormwater characteristics; however, the low correlations also suggest that not only the monitored parameters contribute to stormwater event mean concentrations (EMC) of pollutants, but other factors should also be considered as well. In the hydraulic and treatment performance of the hybrid CWs, a small surface area to catchment area (SA/CA) ratio, receiving a high concentration of influent EMC, will find it hard to achieve great removal efficiency; also a large SA/CA ratio, receiving low concentration of influent EMC, will find it hard to achieve great removal efficiency. With this, SA/CA ratio and influent characteristics such as EMC or load should be considered among the design factors of CWs. The performance data of the two CWs were used to consider the most cost-effective design of a hybrid CW. The optimum facility capacity (ratio of total runoff volume to storage volume) that is applicable for a target volume reduction and removal efficiency was provided in this study.


2021 ◽  
Vol 232 (1) ◽  
Author(s):  
Fátima Resende Luiz Fia ◽  
Antonio Teixeira de Matos ◽  
Ronaldo Fia ◽  
Mateus Pimentel de Matos ◽  
Alisson Carraro Borges ◽  
...  

2013 ◽  
Vol 295-298 ◽  
pp. 1402-1407
Author(s):  
Rui Wang ◽  
Ming Chen ◽  
Jia Wen Zhang ◽  
Fei Liu ◽  
Hong Han Chen

Effects of different electron donors (acetate and hydrogen), acetate and perchlorate concentrations on microbial perchlorate reduction in groundwater were studied. The results showed that acetate and hydrogen addition as an electron donor can significantly improve perchlorate removal efficiency while a longer period was observed for hydrogen (15 d) than for acetate (8 d). The optical ratio of electron donor (acetate)-to-electron acceptor (perchlorate) was approximately 1.65 mg COD mg perchlorate-1. The highest specific reduction rate of perchlorate was achieved at the acetate-to-perchlorate ratio of 3.80 mg COD mg perchlorate-1. The perchlorate reduction rates corresponded well to the theoretical values calculated by the Monod equation and the parameters of Ks and Vm were determined to be 15.6 mg L-1 and 0.26 d-1, respectively.


2020 ◽  
Vol 28 (2) ◽  
pp. 2172-2181
Author(s):  
Thomas V. Wagner ◽  
Fatma Al-Manji ◽  
Jie Xue ◽  
Koen Wetser ◽  
Vinnie de Wilde ◽  
...  

AbstractPetroleum-industry wastewater (PI-WW) is a potential source of water that can be reused in areas suffering from water stress. This water contains various fractions that need to be removed before reuse, such as light hydrocarbons, heavy metals and conditioning chemicals. Constructed wetlands (CWs) can remove these fractions, but the range of PI-WW salinities that can be treated in CWs and the influence of an increasing salinity on the CW removal efficiency for abovementioned fractions is unknown. Therefore, the impact of an increasing salinity on the removal of conditioning chemicals benzotriazole, aromatic hydrocarbon benzoic acid, and heavy metal zinc in lab-scale unplanted and Phragmites australis and Typha latifolia planted vertical-flow CWs was tested in the present study. P. australis was less sensitive than T. latifolia to increasing salinities and survived with a NaCl concentration of 12 g/L. The decay of T. latifolia was accompanied by a decrease in the removal efficiency for benzotriazole and benzoic acid, indicating that living vegetation enhanced the removal of these chemicals. Increased salinities resulted in the leaching of zinc from the planted CWs, probably as a result of active plant defence mechanisms against salt shocks that solubilized zinc. Plant growth also resulted in substantial evapotranspiration, leading to an increased salinity of the CW treated effluent. A too high salinity limits the reuse of the CW treated water. Therefore, CW treatment should be followed by desalination technologies to obtain salinities suitable for reuse. In this technology train, CWs enhance the efficiency of physicochemical desalination technologies by removing organics that induce membrane fouling. Hence, P. australis planted CWs are a suitable option for the treatment of water with a salinity below 12 g/L before further treatment or direct reuse in water scarce areas worldwide, where CWs may also boost the local biodiversity.


2007 ◽  
Vol 56 (3) ◽  
pp. 135-143 ◽  
Author(s):  
D. Weber ◽  
A. Drizo ◽  
E. Twohig ◽  
S. Bird ◽  
D. Ross

In 2003, a subsurface flow constructed wetlands (SSF-CW) system was built at the University of Vermont (UVM) Paul Miller Dairy Farm as an alternative nutrient management approach for treating barnyard runoff and milk parlour waste. Given the increasing problem of phosphorus (P) pollution in the Lake Champlain region, a slag based P-removal filter technology (PFT) was established (2004) at the CW with two objectives: (i) to test the filters' efficiency as an upgrade unit for improving P removal performance via SSF-CW (ii) to investigate the capacity of filters technology to remove P as a “stand alone” unit. Six individual filters (F1–F6) were filled with electric arc furnace (EAF) steel slag, each containing 112.5 kg of material with a pore volume of 21 L. F1–F4, fed with CW treated water, received approximately 2.17 g DRP kg−1 EAF steel slag (0.25 kg DRP total) during the 259 day feeding period. F1–F4 retained 1.7 g DRP kg−1 EAF steel slag, resulting in an average P removal efficiency of 75%. The addition of filters improved CW DRP removal efficiency by 74%. F5 and F6, fed non-treated water, received 1.9 g DRP kg−1 EAF steel slag (0.22 kg DRP in total) and retained 1.5 g DRP kg−1 resulting in a P removal efficiency of 72%. The establishment of the EAF slag based PFT is the first in-field evaluation of this technology to reduce P from dairy farm effluent in Vermont.


2018 ◽  
Vol 123 ◽  
pp. 135-140 ◽  
Author(s):  
Xiaoyan Li ◽  
Aizhong Ding ◽  
Lei Zheng ◽  
Bruce C. Anderson ◽  
Linghua Kong ◽  
...  

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