scholarly journals Enhancing the quality of arsenic-contaminated groundwater using a bio-sand filter with iron-mixed clay pellets

2018 ◽  
Vol 13 (2) ◽  
pp. 285-294
Author(s):  
Borano Te ◽  
Boonchai Wichitsathian ◽  
Chatpet Yossapol ◽  
Watcharapol Wonglertarak
Keyword(s):  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Plug Flow ◽  
Sand Filter ◽  
Influent Water ◽  
Filter Bed ◽  
Clay Pellets ◽  
Flow Head ◽  
Who Guideline

Abstract Many people in Cambodia consume groundwater with arsenic concentrations above the WHO guideline. In this study, an iron-mixed porous pellet adsorbent was put into a lightweight bio-sand filter to treat arsenic. The filter was intermittently charged daily with 30 L influent water until the effluent arsenic concentration exceeded 10 μg/L. The results indicated that the Morrill Dispersion Index was less than 2.0, implying that the filter had preferential plug flow. Head loss accumulation led to flow rate reduction over a period of 30 days. Arsenic removal efficiency was between 97 and 99% for the influent concentration, being in the range 355 to 587 μg/L. No significant leaching of iron or organic carbon was observed. The high dissolved oxygen concentration is likely to have contributed to the aerobic conditions in the filter bed. The filter removed arsenic more efficiently than was achieved in some previous studies and might be suitable to provide household-scale, arsenic-safe drinking water.

Million Dollar Arsenic Removal Plants in West Bengal, India: Useful or Not?

2006 ◽  
Vol 41 (2) ◽  
pp. 216-225 ◽  
Author(s):  
M. Amir Hossain ◽  
Amitava Mukharjee ◽  
Mrinal Kumar Sengupta ◽  
Sad Ahamed ◽  
Bhaskar Das ◽  
...  
Keyword(s):  
Watershed Management ◽  
Arsenic Removal ◽  
West Bengal ◽  
Arsenic Concentration ◽  
Poor Performance ◽  
Raw Water ◽  
User Friendliness ◽  
Treated Water ◽  
Guideline Value ◽  
Who Guideline

Abstract The effectiveness of arsenic removal plants (ARPs) to provide safe water was evaluated based on a study of 577 ARPs out of 1900 installed in 5 arsenic-affected districts of West Bengal, India. Out of 577, 145 (25.1%) were found in defunct condition. Both raw and filtered water from 305 ARPs were analyzed for total arsenic concentration. Forty-eight ARPs were installed despite raw water arsenic concentrations below the Indian standard (50 µg/L) and in 22 cases even below the WHO guideline value (10 µg/L). Among the 264 ARPs having raw water arsenic above 50 µg/L, 140 (53.1%) and 73 (27.7%) failed to remove arsenic below the WHO guideline value and Indian standard, respectively. The highest arsenic concentration in treated water was 705 µg/L. Analysis of 217 treated water samples for iron showed that 175 (80.6%) failed to remove iron below 300 µg/L. The treated water became coloured on standing 6 to 8 h, for 191 (44.2%) ARPs and 25 (5.8%) produced bad-odoured water. Overall, the study showed that 475 (82.3%) of the ARPs were not useful. The reasons for ineffectiveness and poor performance of these ARPs include improper maintenance, sand gushing problems, a lack of user-friendliness and absence of community participation. A comparative study of ARPs in two different blocks (Domkol in Murshidabad district and Swarupnagar in North 24 Parganas) showed that 39 (80%) and 38 (95%) ARPs, respectively, were not useful. Further study in Gram Panchayet Kolsur, Deganga block, North 24 Parganas, showed that 14 (87.5%) ARPs were not useful. Proper watershed management with active participation from the villagers is urgently required for successful mitigation.

As(III) Removal by Dynamic Adsorption onto Amberlite XAD7 Functionalized with Crown Ether and Doped with Fe(III) Ions

2019 ◽  
Vol 70 (7) ◽  
pp. 2330-2334
Author(s):  
Mihaela Ciopec ◽  
Adina Negrea ◽  
Narcis Duteanu ◽  
Corneliu Mircea Davidescu ◽  
Iosif Hulka ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Fixed Bed ◽  
World Health ◽  
Arsenic Content ◽  
Arsenic Adsorption ◽  
Stage Of Development ◽  
Wide Range ◽  
Health Organization

Arsenic content in groundwater�s present a wide range of concentration, ranging from hundreds of micrograms to thousands of micrograms of arsenic per litter, while the maximum permitted arsenic concentration established by World Health Organization (WHO) is 10 mg L-1. According to the WHO all people, regardless of their stage of development and their social economic condition, have the right to have access to adequate drinking water. The most efficient and economic technique used for arsenic removal is represented by adsorption. In order to make this remediation technique more affordable and environmentally friendly is important to new materials with advance adsorbent properties. Novelty of present paper is represented by the usage of a new adsorbent material obtained by physical - chemical modification of Amberlite XAD polymers using crown ethers followed by iron doping, due to well-known affinity of arsenic for iron ions. Present paper aims to test the obtained modified Amberlite polymer for arsenic removal from real groundwater by using adsorption in a fixed bed column, establishing in this way a mechanism for the adsorption process. During experimental work was studied the influence of competing ions from real water into the arsenic adsorption process.

The Microbial Quality of a Wetland Reclamation Facility Used to Produce an Effluent for Unrestricted non-Potable Reuse

1999 ◽  
Vol 40 (4-5) ◽  
pp. 369-374 ◽  
Author(s):  
R. S. Fujioka ◽  
A. J. Bonilla ◽  
G. K. Rijal
Keyword(s):  
Fecal Coliform ◽  
Heterotrophic Bacteria ◽  
Fecal Indicator ◽  
Potable Reuse ◽  
Wetland Reclamation ◽  
Treated Sewage ◽  
Influent Water ◽  
Human Viruses ◽  
To Receive

An auxiliary Wetland Reclamation Facility (WRF) was constructed to receive stabilization pond treated sewage and further treat it with water hyacinth ponds, chemical flocculation, filtration and ultraviolet light disinfection. This was the first facility in Hawaii which was approved to produce the highest quality reclaimed water using alternative treatment schemes. We assessed the effectiveness of the WRF by monitoring water samples after each of the WRF treatment schemes for five genetically different groups of sewage borne microorganisms (fecal coliform, enterococci, C. perfringens, FRNA phage, total heterotrophic bacteria). The concentrations of all fecal indicator microoganisms, especially FRNA phase were low in the influent water to the WRF indicating that extended pond treatment may be especially effective in removing human viruses from sewage. The WRF treatment scheme was calculated to be able to reduce >99.99% of fecal coliform and therefore was able to produce an effluent meeting the non-potable, unrestricted reuse standard of a geometric means of <1 fecal coliform/100 ml.

scholarly journals Evaluation of Fe-Mg Binary Oxide for As (III) Adsorption—Synthesis, Characterization and Kinetic Modelling

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 805
Author(s):  
Saif Ullah Khan ◽  
Rumman Zaidi ◽  
Feroz Shaik ◽  
Izharul Haq Farooqi ◽  
Ameer Azam ◽  
...  
Keyword(s):  
Arsenic Removal ◽  
Kinetic Modelling ◽  
Arsenic Concentration ◽  
Experimental Studies ◽  
Precipitation Method ◽  
Arsenic Adsorption ◽  
Adsorbent Dosage ◽  
X Ray ◽  
Co Precipitation ◽  
Contaminated Waters

Nanotechnology has received much attention in treating contaminated waters. In the present study, a facile co-precipitation method was employed to synthesize a novel iron and magnesium based binary metal oxide using a stoichiometrically fixed amount of FeNO3.9H2O and MgNO3.6H2O in a proportion of molar concentration 1:1 and was later evaluated in removing As (III) from contaminated waters. Characterization of the prepared nanomaterial was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX) and ultraviolet–visible spectrophotometry (UV-VIS). Experimental studies on batch scale were carried out, examining the effect of varying initial concentrations of metal, adsorbent dosage, application time and initial pH on removal efficiency. Arsenic removal increased on increasing adsorbent dosage (0.1–1 g/L) but trend reversed on increasing initial arsenic concentration attaining qmax of 263.20 mg/g. Adsorption was quite efficient in pH range 4–8. Freundlich fitted better for adsorption isotherm along with following Pseudo-2nd order kinetics. The reusability and effect of co-existing ions on arsenic adsorption, namely SO42−, CO32− and PO43− were also explored with reusability in 1st and 2nd cycles attained adsorptive removal up to 77% and 64% respectively. The prepared nano-adsorbent showed promising results in terms of high arsenic uptake (qmax of 263.20 mg/g) along with facile and cost-effective synthesis. Thus, the co-precipitation technique used in this work is a simple one step procedure without any use of any precursor as compared to most of the other procedures used for synthesis.

Arsenic removal by ferric-chloride coagulation – effect of phosphate, bicarbonate and silicate

2011 ◽  
Vol 64 (5) ◽  
pp. 1046-1055 ◽  
Author(s):  
Dóra Laky ◽  
István Licskó
Keyword(s):  
Adverse Effect ◽  
Arsenic Removal ◽  
Linear Regression Analysis ◽  
Arsenic Concentration ◽  
Ferric Hydroxide ◽  
Multiple Linear Regression Analysis ◽  
Ph Values ◽  
Robust Model ◽  
Coagulant Dosage ◽  
Negative Effect

Jar tests with synthetic water were carried out in order to investigate the effect of phosphate, bicarbonate and silicate on arsenic removal efficiency by in-situ formed ferric hydroxide. Above 12 mg C/L inorganic carbon concentration, the adverse effect of bicarbonate was definite, and resulted in higher remaining arsenic concentration. At all pH values (7.5–7.8) and coagulant dosages (0.84–3.00 mg/L Fe) tested, the negative effect of phosphate on arsenic removal was also evident. In the presence of silicate small ferric-hydroxide colloids were formed, which were able to go through the 0.45 μm pore-size membrane. Compared to silicate-free systems, 2.5–3.5 times higher coagulant dose was needed to achieve the target arsenic concentration in the presence of 14–23 mg/L Si. At higher pH values the adverse effect of silicate was even more significant. All data were merged and multiple linear regression analysis was carried out in order to build up a robust model to predict the residual arsenic concentration if the raw water contains 50–60 μg/L initial arsenic concentration. The estimation was based on the following variables: PO4-P concentration, final pH, Si concentration, Fe(III) dose. The most important influencing factors proved to be the silicate concentration and applied coagulant dosage.

scholarly journals A23 Seasonal abundance of chironomid larvae in slow sand filter bed

2002 ◽  
Vol 53 (Supplement) ◽  
pp. 41
Author(s):  
K. Hirabayashi ◽  
N. Nakamoto ◽  
S. Tanizaki
Keyword(s):  
Seasonal Abundance ◽  
Sand Filter ◽  
Chironomid Larvae ◽  
Slow Sand Filter ◽  
Filter Bed

Removal of particulates, natural organic matters, and microorganisms in a surface amended slow sand filter

2002 ◽  
Vol 2 (5-6) ◽  
pp. 387-394
Author(s):  
H.-B. Jun ◽  
Y.-J. Lee ◽  
S.-S. Shin
Keyword(s):  
Surface Treatment ◽  
Raw Water ◽  
Sand Filters ◽  
Water Turbidity ◽  
Turbidity Removal ◽  
Sand Filter ◽  
Organic Matters ◽  
Slow Sand Filter ◽  
Natural Organic Matters ◽  
Filter Bed

Removal characteristics of particulates, natural organic matters, and microorganisms with six slow sand filter units were measured with a diameter of 50 mm and packed with sand to a depth of 50, 150, 300, 600, and two 700 mm, respectively. One of the 700 mm depth filters was amended by covering the surface of the filter bed with a prefilter. The raw water turbidity and pH was in the range of 1.5-2.0 NTU, and 7.0-7.7, respectively. Turbidity in each filter effluent was decreased as the depth of filter medium increased. However, a greater part of influent turbidity was removed within the top layer of the slow sand filters. Turbidity removal in the 700 mm depth filter with prefilter was similar to that without the prefilter, however, the removal of particles smaller than 2 mm was improved with the prefilter. The particles greater than 10 mm could be removed within the upper 50 mm depth in the slow sand filter. A greater fraction of the particles smaller than 2 mm was removed within the upper 50 mm, however, they were also removed in the deeper sand bed. The removal efficiency of DBP precursors represented by DOC and UV-254 absorbance was 9.2-31% and 2-31%, respectively. pH drop in the 50 mm depth filter was 0.12, while that in the 700 mm depth filter was 0.19. The effects of surface treatment with prefilter on UVA and DOC were not apparent.

Monitoring of a pilot GFO filter for removal of low-concentration arsenic in water

2016 ◽  
Vol 11 (4) ◽  
pp. 702-711 ◽  
Author(s):  
Collivignarelli Maria Cristina ◽  
Canato Matteo ◽  
Sorlini Sabrina ◽  
Crotti Barbara Marianna
Keyword(s):  
Water Treatment ◽  
Ferric Oxide ◽  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Specific Treatment ◽  
Cost Effective ◽  
Water Treatment Plants ◽  
Groundwater Arsenic ◽  
Treatment Stage ◽  
Iron And Manganese

Many water treatment plants (WTPs) were designed to remove ammonia, iron, and manganese simultaneously using biofilters. In some cases (especially in the Pianura Padana area, in Italy) such plants were designed without a specific treatment stage for arsenic removal because its concentration in the groundwater (i.e. 10 to 20 μg/L) was lower than the previous maximum contaminant level (MCL) of 50 μg-As/L; therefore, specific treatments for arsenic removal must be introduced or upgraded in WTPs. In this work, the results of a 19-month monitoring campaign are reported for a pilot granular ferric oxide (GFO) filter installed in an Italian WTP as a polishing stage. The aim was to investigate the performance of GFO with low arsenic concentrations. The results show that, if the groundwater arsenic concentration is close to the MCL, GFO treatment can be cost effective (approximately 80,000 bed volumes have been treated). It was confirmed that GFO can be effective for the removal of both As(III) and As(V) species.

Effects of several water quality parameters on arsenic removal by coagulation: laboratory experiments and a pilot-scale study

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
D. Laky ◽  
B. László ◽  
I. Licskó
Keyword(s):  
Potassium Permanganate ◽  
Ferric Chloride ◽  
Laboratory Experiments ◽  
Inorganic Carbon ◽  
Arsenic Removal ◽  
Research Work ◽  
Arsenic Concentration ◽  
Pilot Scale ◽  
Organic Content ◽  
Manganese Concentration

In laboratory experiments a traditional drinking water treatment method, coagulation/flocculation followed by solid/liquid phase separation has been applied in order to decrease arsenic concentration below 10 μg/L (which is the new Hungarian standard for arsenic). The goal of the research work was to examine the transition of the dissolved arsenic to solid form, to determine the factors which have significant effect on arsenic removal efficiency. The organic content of the water highly affected the arsenic removal process. The difference in the required coagulant dosage can be order of one magnitude depending on the organic content of the water. The phosphorous content also increases the required coagulant dose, since ferric phosphate precipitates are formed, decreasing the amount of coagulant available for arsenic removal. pH also proved to have significant influence when experiments were carried out at wide pH range. However, under more realistic conditions (pH is between 7.5 and 8), the effect of pH was not that significant. The inorganic carbon content at some extent favors the liquid/solid transition of arsenate, since it contributes to the buffering capacity of the water, therefore enhances the metal hydroxide formation process. However, the excess inorganic carbon has disadvantageous effect, since it competes with the arsenate ions for the free sites of metal hydroxides. Two oxidants (chlorine and potassium permanganate) and two coagulants (ferric chloride and aluminum sulfate) were studied in pilot scale experiments. The pilot plant was operated at Hajdúbagos, where the arsenic, iron and manganese concentration of the raw water is above the standard. In the experiments it was found the potassium permanganate + ferric chloride combination was the most efficient.

Removal of cyanobacterial metabolites through wastewater treatment plant filters

2012 ◽  
Vol 65 (7) ◽  
pp. 1244-1251 ◽  
Author(s):  
Lionel Ho ◽  
Daniel Hoefel ◽  
Charlotte Grasset ◽  
Sebastien Palazot ◽  
Gayle Newcombe ◽  
...  
Keyword(s):  
Drinking Water ◽  
Wastewater Treatment ◽  
Activated Carbon ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Filter Medium ◽  
Sand Filtration ◽  
Sand Filter ◽  
High Nutrient

Wastewaters have the potential to proliferate excessive numbers of cyanobacteria due to high nutrient levels. This could translate to the production of metabolites, such as the saxitoxins, geosmin and 2-methylisoborneol (MIB), which can impair the quality of wastewater destined for re-use. Biological sand filtration was assessed for its ability to remove these metabolites from a wastewater. Results indicated that the sand filter was incapable of effectively removing the saxitoxins and in some instances, the effluent of the sand filter displayed greater toxicity than the influent. Conversely, the sand filter was able to effectively remove geosmin and MIB, with removal attributed to biodegradation. Granular activated carbon was employed as an alternative filter medium to remove the saxitoxins. Results showed similar removals to previous drinking water studies, where efficient removals were initially observed, followed by a decrease in the removal; a consequence of the presence of competing organics which reduced adsorption of the saxitoxins.

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