Role of Colocasia esculenta L. schott in arsenic removal by a pilot-scale constructed wetland filled with laterite soil

Arsenic (As) is a naturally occurring element in the environment that poses significant risks to human health. Several treatment technologies have been successfully used in the treatment of As-contaminated waters. However, limited literature has explored advanced electrocoagulation (EC) processes for As removal. The present study evaluates the As removal performance of electrocoagulation, electrochemical peroxidation (ECP), and photo-assisted electrochemical peroxidation (PECP) technologies at circumneutral pH using electroactive iron electrodes. The influence of As speciation and the role of oxidants in As removal were investigated. We have identified the ECP process to be a promising alternative for the conventional EC with around 4-fold increase in arsenic removal capacity at a competitive cost of 0.0060 $/m3. Results also indicated that the rate of As(III) oxidation at the outset of electrochemical treatment dictates the extent of As removal. Both ECP and PECP processes reached greater than 96% As(III) conversion at 1 C/L and achieved 86% and 96% As removal at 5 C/L, respectively. Finally, the mechanism of As(III) oxidation was evaluated, and results showed that Fe(IV) is the intermediate oxidant generated in advanced EC processes, and the contribution of •OH brought by UV irradiation is insignificant.

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Enhancing arsenic removal from acidic wastewater using zeolite supported sulfide nanoscale zero‐valent iron: the role of sulfur and copper

Journal of Chemical Technology & Biotechnology ◽

10.1002/jctb.6734 ◽

2021 ◽

Author(s):

Chundi Zhou ◽

Caiyun Han ◽

Xize Min ◽

Ting Yang

Keyword(s):

Arsenic Removal ◽

Zero Valent Iron ◽

Nanoscale Zero Valent Iron ◽

Acidic Wastewater

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Pilot-scale study of vertical flow constructed wetland combined with trickling filter and ferric chloride coagulation: influence of irregular operational conditions

Water Science & Technology ◽

10.2166/wst.2015.077 ◽

2015 ◽

Vol 71 (7) ◽

pp. 1088-1096 ◽

Cited By ~ 4

Author(s):

B. Kim ◽

M. Gautier ◽

G. Olvera Palma ◽

P. Molle ◽

P. Michel ◽

...

Keyword(s):

Constructed Wetland ◽

Phosphorus Removal ◽

Water Saturation ◽

Oxygen Demand ◽

Pilot Scale ◽

Saturation Level ◽

Vertical Flow ◽

Trickling Filter ◽

Operational Conditions ◽

Vertical Flow Constructed Wetland

The aim of this study was to characterize the efficiency of an intensified process of vertical flow constructed wetland having the following particularities: (i) biological pretreatment by trickling filter, (ii) FeCl3 injection for dissolved phosphorus removal and (iii) succession of different levels of redox conditions along the process line. A pilot-scale set-up designed to simulate a real-scale plant was constructed and operated using real wastewater. The influences of FeCl3 injection and water saturation level within the vertical flow constructed wetland stage on treatment performances were studied. Three different water saturation levels were compared by monitoring: suspended solids (SS), total phosphorus (TP), dissolved chemical oxygen demand (COD), ammonium, nitrate, phosphate, iron, and manganese. The results confirmed the good overall efficiency of the process and the contribution of the trickling filter pretreatment to COD removal and nitrification. The effects of water saturation level and FeCl3 injection on phosphorus removal were evaluated by analysis of the correlations between the variables. Under unsaturated conditions, good nitrification and no denitrification were observed. Under partly saturated conditions, both nitrification and denitrification were obtained, along with a good retention of SSs. Finally, under saturated conditions, the performance was decreased for almost all parameters.

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The role of SO42− surface distribution in arsenic removal by iron oxy-hydroxides

Journal of Solid State Chemistry ◽

10.1016/j.jssc.2014.02.026 ◽

2014 ◽

Vol 213 ◽

pp. 145-151 ◽

Cited By ~ 24

Author(s):

S. Tresintsi ◽

K. Simeonidis ◽

N. Pliatsikas ◽

G. Vourlias ◽

P. Patsalas ◽

...

Keyword(s):

Arsenic Removal ◽

Surface Distribution

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Potential use of mangrove plantation as constructed wetland for municipal wastewater treatment

Water Science & Technology ◽

10.2166/wst.2003.0331 ◽

2003 ◽

Vol 48 (5) ◽

pp. 257-266 ◽

Cited By ~ 21

Author(s):

K. Boonsong ◽

S. Piyatiratitivorakul ◽

P. Patanaponpaiboon

Keyword(s):

Wastewater Treatment ◽

Constructed Wetland ◽

Municipal Wastewater ◽

Free Water ◽

Avicennia Marina ◽

Pilot Scale ◽

Natural Forest ◽

Municipal Wastewater Treatment ◽

Detention Time ◽

Bruguiera Cylindrica

The study evaluated the possibility of using mangrove plantation to treat municipal wastewater. Two types of pilot scale (100 × 150 m2) free water surface constructed wetland were set up. One system was a natural Avicennia marina dominated forest system. The other system was a newly planted system in which seedlings of Rhizophora spp., A. marina, Bruguiera cylindrica and Ceriops tagal were planted in 4 strips. Municipal wastewater was retained within the systems for 7 and 3 days, respectively. The results indicated that the average removal percentage of TSS, BOD, NO3-N, NH4-N, TN, PO4-P and TP in the newly planted system were 27.6-77.1, 43.9-53.9, 37.6-47.5, 81.1-85.9, 44.8-54.4, 24.7-76.8 and 22.6-65.3, respectively. Whereas the removal percentage of those parameters in the natural forest system were 17.1-65.9, 49.5-51.1, 44.0-60.9, 51.1-83.5, 43.4-50.4, 28.7-58.9 and 28.3-48.0, respectively. Generally, the removal percentages within the newly planted system and the natural forest system were not significantly different. However, when the removal percentages were compared with detention time, TSS, PO4-P and TP percentages removed were significantly higher in the 7-day detention time treatment. Even though the removal percentages were highly varied and temporally dependent, the overall results showed that mangrove plantation could be used as constructed wetland for municipal wastewater treatment in a similar way to the natural mangrove system.

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The simultaneous removal of bisphenol A, manganese and ammonium from groundwater by MeOx: The role of chemical catalytic oxidation for bisphenol A

Water Science & Technology Water Supply ◽

10.2166/ws.2021.295 ◽

2021 ◽

Author(s):

Yingming Guo ◽

Ben Ma ◽

Jianxiong Huang ◽

Jing Yang ◽

Ruifeng Zhang

Keyword(s):

Oxide Film ◽

Bisphenol A ◽

Dissolved Oxygen ◽

Oxidation Process ◽

Pilot Scale ◽

Simultaneous Removal ◽

Chemical Forms ◽

Synergy Effect ◽

Iron And Manganese

Abstract The iron and manganese oxide filter film (MeOx) were used to research the simultaneous removal of bisphenol A (BPA), manganese (Mn2+) and ammonium (NH4+) in a pilot-scale filter system. We found that 0.52 mg/L of BPA could be removed while consuming 5.44 mg/L of dissolved oxygen (DO). Since the oxidation process of NH4+ and BPA both consume the DO in water, the presence of NH4+ can hinder the removal of BPA. The presence of Mn2+ in water had a synergy effect on the BPA removal. The filter film was characterized by SEM, XRD and XPS. Some substances were generated to block the pores of the oxide film, and a small amount of film was found to crack and fall off. The elemental composition of C and O were both increased by about 9%, the composition of Mn was decreased from 63.48% to 44.55%, and the reduced manganese substance might affect the activity of the oxide film. The main chemical forms of MeOx are Mn6O12·3H2O, MnFe2O4 or Mn3O4. The decrease in the removal efficiency of BPA was mainly due to the C-containing intermediate [−CH2C − H(OH)]n covering the surface of the oxide film and blocking the pore size of the film.

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Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.13.97 ◽

2017 ◽

Vol 13 ◽

pp. 960-987 ◽

Cited By ~ 34

Author(s):

Chinmay A Shukla ◽

Amol A Kulkarni

Keyword(s):

Industrial Process ◽

Pilot Scale ◽

Laboratory Scale ◽

Flow Synthesis ◽

Multistep Synthesis ◽

Synthesis Strategy ◽

Line Separation ◽

Synthesis Approach ◽

Scale Of Operation

The implementation of automation in the multistep flow synthesis is essential for transforming laboratory-scale chemistry into a reliable industrial process. In this review, we briefly introduce the role of automation based on its application in synthesis viz. auto sampling and inline monitoring, optimization and process control. Subsequently, we have critically reviewed a few multistep flow synthesis and suggested a possible control strategy to be implemented so that it helps to reliably transfer the laboratory-scale synthesis strategy to a pilot scale at its optimum conditions. Due to the vast literature in multistep synthesis, we have classified the literature and have identified the case studies based on few criteria viz. type of reaction, heating methods, processes involving in-line separation units, telescopic synthesis, processes involving in-line quenching and process with the smallest time scale of operation. This classification will cover the broader range in the multistep synthesis literature.

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