Exploring low-cost arsenic removal alternatives in Costa Rica

Author(s):  
L Romero ◽  
J Valverde ◽  
P Rojas ◽  
M Vargas ◽  
J Araya
Keyword(s):  
2021 ◽  
Vol 14 ◽  
pp. 100585
Author(s):  
Amalia Lara Bursztyn Fuentes ◽  
Facundo Barraqué ◽  
Roberto Carlos Mercader ◽  
Alberto Néstor Scian ◽  
María Luciana Montes

2017 ◽  
Vol 18 (1) ◽  
pp. 40-48 ◽  
Author(s):  
Sylvie Kunz ◽  
Luis G. Romero-Esquivel ◽  
Philipp Otter ◽  
Ulrike Feistel ◽  
Thomas Grischek ◽  
...  

Abstract A novel treatment was tested with groundwater to investigate its arsenic removal under natural conditions. The system utilised in-line electrochlorination to oxidise water constituents without the need for external chemical supply. The oxidised arsenic and iron co-precipitated and were filtered via Greensand Plus™. The filter was catalytically active and provided an emergency oxidant. The system had only a few maintenance requirements due to online water quality monitoring. The contaminant removal during the field test in Costa Rica was impaired by strong fluctuations in water quality including low iron concentrations. However, the system removed on average 68% of the arsenic. Mean values of arsenic were 40 ± 23 μg/L in groundwater and 13 ± 6 μg/L in treated water. Iron was removed from an average of 2.8 ± 2.4 mg/L to 0.2 ± 0.2 mg/L (93% removal). Free chlorine produced and available in the treated water tank had a mean concentration of 1.25 mg/L and 0.64 mg/L, respectively.


Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2520
Author(s):  
Jasmina Nikić ◽  
Aleksandra Tubić ◽  
Malcolm Watson ◽  
Snežana Maletić ◽  
Marko Šolić ◽  
...  

Magnetite nanoparticles were synthesized by a simple and ecofriendly method using onion peel (MNp-OP) and corn silk extract (MNp-CS), in order to develop new low-cost adsorbents for arsenic removal from groundwater. As a point of comparison, magnetite nanoparticles were also synthesized with a conventional chemical process (MNp-CO). The antioxidant potential of onion peel and corn silk extracts was determined using ferric reducing antioxidant power (FRAP) and free radical (DPPH) scavenging assays, including the total phenolics, flavonoids and tannins contents. The synthesized magnetite nanoparticles were characterised using different techniques (Scanning electron microscope/Energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) surface area analyzer). The adsorption capacity of MNp-OP and MNp-CS and the arsenic removal mechanism of these novel adsorbents was investigated through kinetic and equilibrium experiments and their corresponding mathematical models. Characterisation of MNp-OP and MNp-CS shows high BET specific surface areas of 243 m2/g and 261 m2/g, respectively. XRD and FTIR analysis confirmed the formation and presence of magnetite nanoparticles. The arsenic adsorption mechanism on MNp-OP, MNp-CS and MNp-CO involves chemisorption, intraparticle and external diffusion. Maximal adsorption capacities of MNp-OP, MNp-CS and MNp-CO were 1.86, 2.79, and 1.30 mg/g respectively. The green synthesis applied using onion peel and corn silk extracts was cost effective and environmentally friendly, and results in adsorbents with a high capacity for arsenic and magnetic properties, making them a very promising alternative approach in the treatment of arsenic contaminated groundwater.


Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1323 ◽  
Author(s):  
TA Siddique ◽  
Naba K. Dutta ◽  
Namita Roy Choudhury

Arsenic (As) removal is of major significance because inorganic arsenic is highly toxic to all life forms, is a confirmed carcinogen, and is of significant environmental concern. As contamination in drinking water alone threatens more than 150 million people all over the world. Therefore, several conventional methods such as oxidation, coagulation, adsorption, etc., have been implemented for As removal, but due to their cost-maintenance limitations; there is a drive for advanced, low cost nanofiltration membrane-based technology. Thus, in order to address the increasing demand of fresh and drinking water, this review focuses on advanced nanofiltration (NF) strategy for As removal to safeguard water security. The review concentrates on different types of NF membranes, membrane fabrication processes, and their mechanism and efficiency of performance for removing As from contaminated water. The article provides an overview of the current status of polymer-, polymer composite-, and polymer nanocomposite-based NF membranes, to assess the status of nanomaterial-facilitated NF membranes and to incite progress in this area. Finally, future perspectives and future trends are highlighted.


2017 ◽  
Vol 17 (5) ◽  
pp. 1249-1259 ◽  
Author(s):  
Nao Kamei-Ishikawa ◽  
Nami Segawa ◽  
Daisuke Yamazaki ◽  
Ayumi Ito ◽  
Teruyuki Umita

The down-flow hanging sponge (DHS) reactor was used for continuous As removal treatment of As-contaminated water. The treatment scheme was: (1) As(III) in contaminated water is oxidized by arsenite-oxidizing bacteria fixed in the sponges in the reactor; (2) Fe(II) naturally existing in the water is oxidized by dissolved oxygen; (3) Fe(III) is precipitated as iron hydroxide and As(V) is co-precipitated with the iron hydroxide; and finally (4) the co-precipitates are fixed in the sponges. This system could remove As from As-contaminated water on a small scale and at low cost. The results showed that, after using the DHS reactor, As and Fe concentrations in the treated water were lower than water quality standards for drinking water when Fe(II) concentration in the influent was lower than 10 mg/L and the Fe/As ratio was higher than 6.67–8.42, with dependence on the Fe concentration. Additionally, even if Fe concentration is higher than 10 mg/L, the treatment system is still applicable if the pH of the influent is higher than 7 or the retention time is longer than 2 h.


2010 ◽  
Vol 62 (11) ◽  
pp. 2702-2709 ◽  
Author(s):  
D. van Halem ◽  
S. G. J. Heijman ◽  
R. Johnston ◽  
I. M. Huq ◽  
S. K. Ghosh ◽  
...  

The principle of subsurface or in situ iron and arsenic removal is that aerated water is periodically injected into an anoxic aquifer through a tube well, displacing groundwater containing Fe(II). An oxidation zone is created around the tube well where Fe(II) is oxidised. The freshly formed iron hydroxide surfaces provide new sorption sites for soluble Fe(II) and arsenic. The system's efficiency is determined based on the ratio between abstracted volume with reduced iron/arsenic concentrations (V) and the injected volume (Vi). In the field study presented in this paper, the small-scale application of this technology was investigated in rural Bangladesh. It was found that at small injection volumes (<1 m3) iron removal was successful and became more effective with every successive cycle. For arsenic, however, the system did not prove to be very effective yet. Arsenic retardation was only limited and breakthrough of 10 μg/L (WHO guideline) was observed before V/Vi=1, which corresponds to arrival of groundwater at the well. Possible explanations for insufficient arsenic adsorption are the short contact times within the oxidation zone, and the presence of competing anions, like phosphate.


2008 ◽  
Vol 58 (10) ◽  
pp. 2009-2015 ◽  
Author(s):  
U. Rott ◽  
H. Kauffmann

Arsenic in groundwater is a huge problem in numerous regions of the world. Many people are exposed to high arsenic concentrations and consequently risk getting ill or even die as a result of arsenic poisoning. There are several efficient technologies for the removal of arsenic but often these methods have disadvantages, e.g. high costs for installation and/or operation, the need for chemicals or the production of arsenic contaminated filter sludge. These disadvantages can make the application difficult, especially in poor regions. Under suitable ancillary conditions the subterranean (in-situ) treatment, which is often used for iron and manganese removal from groundwater, can also be applied for the removal of arsenic and can be a cost-effective treatment technology. A field trial was carried out with a low-cost in-situ treatment plant in West Bengal/India which is described in this paper, in order to investigate whether this treatment technology is also applicable under the boundary conditions there. As for the in-situ treatment technology besides oxygen no additives are required and no arsenic contaminated filter sludge is produced this technology could be a suitable method for arsenic removal especially in poor regions.


Author(s):  
Sofía Miranda-Durán ◽  
Luis Porras-Reyes ◽  
Alexander Schmidt-Durán

Agro-industrial residues correspond to all the materials generated from activities that involve the transformation of both crops and livestock to obtain processed or semi-finished products. In Costa Rica, the primary sector of economy generates more than 6.3 trillion tons of organic residues per year. The daily generation of this residues pose environmental and economic problems. In recent years, biotechnological-based alternatives have emerged with the purpose of taking advantage of the high nutritional content of these residues to cultivate microorganisms capable of producing compounds with high demand at a commercial level. The present study evaluates six agro-industrial residues produced in Costa Rica, in order to growth Bacillus subtilis 168.  An optimization of the culture medium was carried out under a complete factorial design 23, where the variables evaluated were carbon, nitrogen and phosphorus sources. Molasses at 10% m/v, wheat bran at 0.5% m/v, and K2HPO4 at 0.01%, as a carbon, nitrogen, and phosphorus sources, respectively, were identified as optimal for the growth of Bacillus subtilis 168.


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