Arsenic Removal Unit Research Articles

Development of arsenic removal unit with electrocoagulation and activated alumina sorption: Field trial at rural West Bengal, India

In the present study, electrocoagulation (EC) with iron electrodes along with adsorption by activated alumina has been evaluated as a treatment process for arsenic removal from groundwater. Batch scale experiments were performed with iron electrodes to assess the removal efficiency of electrocoagulation. The effects of inter-electrode distance and electro-charge loading (ECL) were evaluated on arsenic removal. EC was able to decrease the arsenic concentration in the aqueous phase below 10 ppb at ECL of 60 coulomb/L with 1 cm inter-electrode distance. The optimal condition was obtained by Response Surface Methodology (RSM) with the help of central composite design (CCD). The regression equation and analysis of variance were originated using Design-Expert software and F value (131.56), p-value (<0.05), and desirability value of 1 were obtained for the optimized model. Activated alumina adsorption has also been shown to be a promising arsenic removal technology (As5+) with 15 min of equilibrium time. An arsenic removal system was designed with EC unit, sand filter, and activated alumina column in series for field application. The field unit was able to deliver safe water to the local community. During the operation, the electrodes were passivated, and calcium-based deposition was found on the cathodes. Periodic electrode reversal was able to minimise the passivation. Due to the accumulation of ferric hydroxide flocs, the pores of the filter bed become clogged and they must be cleaned by backwashing. The Backwash system should be continued until the water runs clear. An arrangement of a suitable soak pit is made to contain the backwash water avoiding any environmental contamination. EC could be able to deliver safe water locally in rural areas at affordable prices due to its high efficiency and low operation and maintenance costs.

Design and Development of Arsenic and Iron Removal Unit for Drinking Water: A Sustainable Approach in Environment

This study elucidated and attempted to design and development of arsenic and iron removal unit for drinking water. The process of reducing iron and arsenic from water has been experimented by developing a unit in the Department of Farm Structure at Bangladesh Agriculture University, Mymensingh. In order to test the performance of the developed unit, arsenic contaminated water with four different concentrations like 0.05, 0.10, 0.15 and 0.20 mg/l were prepared in the laboratory and passed into the developed unit and the respective output concentrations were found to be 0.00, 0.01, 0.025 and 0.05 mg/l. The input and output concentrations of arsenic were tested in the chemical testing laboratory under the Bangladesh Institute of Nuclear Agriculture, Mymensingh. Iron contaminated water were collected from four selected tube wells of local Mymensingh and were also passed into the developed unit with four input concentrations like 0.18, 0.1532, 0.179 and 0.133 mg/l and the respective output concentrations were found to be 0.10, 0.1021, 0.11 and 0.09 mg/l. The concentrations of Iron were tested in the chemical testing laboratory under the Soil Resource Development Institute, Dhaka. The results have revealed that iron and arsenic content brings to allowable limit. The developed unit has the capacity to remove Arsenic and Iron and help to eradicates hazardous problem of people.

Design and Development of Arsenic and Iron Removal Unit for Drinking Water: A Sustainable Approach in Environment

Design and Development of Arsenic and Iron Removal Unit for Drinking Water: A Sustainable Approach in Environment

Performance Evaluation of Existing Community Level Arsenic Removal Plants for Arsenic Free Drinking Water Supply in Jessore and Jhenidah Districts of Bangladesh

The use of groundwater as drinking water in Bangladesh is favoured by its easy availability, microbial safety and absence of proper infrastructure for treatment and distribution of surface water. As a result, millions of people are affected by widespread arsenic poisoning through drinking water drawn from underground sources containing arsenic at concentrations well above the permissible limit of 50µg/L. Since 2000, hundreds of community level arsenic removal plants have been installed in the south-west region of Bangladesh. However, the performance of the plants over time is hindered by lack of information due to the absence of long term water quality monitoring information. The objective of this study is to evaluate the performance of existing community level arsenic removal plants. In this study, we selected five arsenic removal plants (four plants were Arsenic Iron Removal Plant, namely AIRP; and one Granular Ferric Hydroxide Based Arsenic Removal Unit, namely SIDKO) located in Jessore and Jhenidah district. All AIRPs and SIDKO achieved the Bangladesh standard for arsenic in drinking water of 50µg/L. The AIRPs removed 64% of influent arsenic on average. However, the SIDKO removed 80 % of influent arsenic. Treated water quality parameter (such as pH, EC, TDS, PO43-, As, NO3-) of the plants were within the WHO standards, except NH3 (0.01-1.89 mg/L) and Fe++ (1.0 – 1.21 mg/L) for long term uses.

Arsenic Removal by Solar-Driven Membrane Distillation: Modeling and Experimental Investigation with a New Flash Vaporization Module

A modeling and simulation study was carried out on a new flux-enhancing and solar-driven membrane distillation module for removal of arsenic from contaminated groundwater. The developed new model was validated with rigorous experimental investigations using arsenic-contaminated groundwater. By incorporating flash vaporization dynamics, the model turned out to be substantially different from the existing direct contact membrane distillation models and could successfully predict (with relative error of only 0.042 and a Willmott d-index of 0.997) the performance of such an arsenic removal unit where the existing models exhibited wide variation with experimental findings in the new design. The module with greater than 99% arsenic removal efficiency and greater than 50 L/m2 x h flux could be implemented in arsenic-affected villages in Southeast Asian countries with abundant solar energy, and thus could give relief to millions of affected people. These encouraging results will raise scale-up confidence.

Economic justification and eco-friendly approach for regeneration of spent activated alumina for arsenic contaminated groundwater treatment

In this work, a study has been made on regeneration of activated alumina (AA) and its use in treatment of arsenic contaminated groundwater. We have used 2% NaOH solution for regeneration, since this concentration is optimal upon considering the minimal dissolution of activated alumina granules. We have also studied the effect of pH on activated alumina and found that pH>11.5 is required for arsenic desorption. This technique is cost effective (INR 15 or USD 0.34 approximately per family of 4 people per month) and is capable of treating even 10,000 bed volume of contaminated water with regenerated AA. It is effective even when the predominant species of arsenic in the ground water is As(III). The present study, made during 2004–2007, justifies reduction of pollution load and minimizing financial burden in using regenerated AA at community level arsenic removal unit (ARU).

A Study on Arsenic Methylation by Microorganisms in Sludge Tank of Arsenic Removal Unit

An arsenic removal unit was constructed by the Miyazaki University research group in Bangladesh. The sludge drained from the arsenic removal unit was directed to a sludge tank and allowed to settle down. Then the supernatant in the tank was released to an artificial pond. Biomethylation of arsenic is usually considered as a detoxification of arsenic because toxicity of most organic methylated arsenic is much less than that inorganic arsenic. Microorganisms in the sludge tank were evaluated growth characteristics and arsenic methylation. As a result, dimethylarsinic acid was detected in the broth, and the amount of total arsenic compounds in the broth decreased. It is thought that this loss was contributed by biogenic activity induced by inorganic arsenic biomethylation to gasified volatile organic species, such as monomethylarsine and dimethylarsine. These results suggested that microorganisms in the sludge tank may be utilized for natural attenuation of arsenic sludge from the arsenic removal unit.

人工池でのヒ素の自然浄化

An arsenic removal unit (GSF) was constructed by the Miyazaki University research group in the Marua village in Bangladesh. The sludge drained from the GSF was directed to a sludge tank and allowed to settle down. Then the supernatant in the tank was released to an artificial pond. The water, sediment and sludge samples from the pond and tank were analyzed, and the microbial statuses of the pond and tank were examined. The ORP result was observed to have changed from the reduction state to the oxidation state in the tank within one year from 2005 and 2006. Therewith, the concentration of soluble arsenic and iron in the tank decreased compared with those one year ago. The amount of arsenic included in the entire pond hardly changed in 2005 and 2006. From the result of an enrichment culture using sediment from the pond, monomethylarsonic acid and dimethylarsinic acid were detected in the medium, and the amount of total arsenic compounds in the medium decreased. It is thought that this loss was contributed by biogenic activity induced by inorganic arsenic biomethylation to gasified volatile organic species, such as monomethylarsine and dimethylarsine. These results suggested that the natural attenuation of arsenic in the pond was performed by biologic gasification.

Approaches to Development of a User-Friendly Community Based Arsenic/Iron Removal Unit in Bangladesh

The present stydy focuses on the strategies to modify the design of a community based Arsenic Iron Removal Unit (AIRU) based on the field performance of the AIRU and the feedback from the users. The ultimate aim was to offer a user-friendly and sustainable system. Appropriate modifications in the design of the developed unit reduced the propensities of water head-loss and media clogging, thereby yielding sustained flow rate. Introduction of a simple cleaning procerdure (98% flow-recovery with three successive backwashing sequences) successfully reduced the frequency of requirement of labor-intensive replacement of the whole filter media. Raw water with arsenic concentration up to 200 microgam/L along with high iron content was treated by the AIRU under the field conditions satisfying the Bangladesh standard (50 microgam/L) without using any chemicals. Efficient sludge management was ensured through porper drainage and safe disposal facilities. Simple construction using locally available materials, considerable treatment performance as well as ease of operation and maintenance present the developed system as a promising one

Water For People Receives Award for Arsenic Removal Work

This article announces that Water For People has received a Silver Grainger Award from the National Academy of Engineering for its innovative work in removing arsenic from drinking water in the West Bengal region of India, where millions of people are at risk from naturally occurring arsenic that is prevalent in groundwater supplies. Water For People shared the Silver Award with Lehigh University in Bethlehem, Pennsylvania, which collaborated on the development of the sustainable arsenic removal technology being used by Water For People in India. Each arsenic removal unit serves approximately 300 households. The system is used in more than 160 locations in West Bengal and provides arsenic‐safe potable water to nearly 170,000 villagers in the region.

Iron and manganese amended activated alumina – a medium for adsorption/oxidation of arsenic from water

Research Article| February 01 2007 Iron and manganese amended activated alumina – a medium for adsorption/oxidation of arsenic from water Anuj Kumar Dhiman; Anuj Kumar Dhiman 1Kaveri Infrastructure (P) Ltd, Kaveri House, B-5, Geetanjali Enclave, Malviya Nagar, New Delhi 110017, India Search for other works by this author on: This Site PubMed Google Scholar Malay Chaudhuri Malay Chaudhuri 2Civil Engineering Programme, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan, Malaysia Tel.: +60 5 368 7286 Fax: +60 5 365 6716 E-mail: malaychaudhuri@yahoo.com; malay@iitk.ac.in Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2007) 56 (1): 69–74. https://doi.org/10.2166/aqua.2007.061 Article history Received: January 30 2006 Accepted: July 10 2006 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation Anuj Kumar Dhiman, Malay Chaudhuri; Iron and manganese amended activated alumina – a medium for adsorption/oxidation of arsenic from water. Journal of Water Supply: Research and Technology-Aqua 1 February 2007; 56 (1): 69–74. doi: https://doi.org/10.2166/aqua.2007.061 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex In a laboratory study, iron and manganese amended activated alumina (IMAA) showed promise as an effective medium for removing arsenic [As(III) and As(V)] from groundwater. Batch adsorption/oxidation kinetic test indicated that the effectiveness of the IMAA medium was due to in situ oxidation of As(III) to As(V) and higher adsorption of As(V) by the medium. A home arsenic removal unit, containing 4 L of IMAA or AA and operated at 6 L/h, produced 2400 L and 2340 L or 1392 L and 1320 L of water in two cycles of runs when the influent arsenic concentration was 1.0 mg/L [0.6 mg/L of As(III) and 0.4 mg/L of As(V)]. The IMAA medium should be subjected to field trials to assess the long-term effects on performance, such as loss of medium capacity, attrition of the iron and manganese coating, fouling by organics, and pH and competing ion effects. activated alumina, adsorption/oxidation, arsenic removal, iron, manganese This content is only available as a PDF. © IWA Publishing 2007 You do not currently have access to this content.

Efficiency of Arsenic Removal Unit Working in Bangladesh and Cement Stabilization of Its Sludge

Abstract To supply safe water to the arsenic affected community, an arsenic removal unit, gravel sand filter (GSF), was developed by modifying the pond sand filter (PSF) so that it can be used to overcome the dry season low flow problem of it. Performance data of that arsenic removal unit shows that it can be the most suitable option to solve that problem of the PSF. GSF uses the naturally occurring iron to remove arsenic by coprecipitation. In this process it produces arsenic rich iron sludge. Disposal of this sludge to the nature may pose a risk of secondary contamination to the stratum. Leaching tests of the arsenic rich iron sludge and the solidified sludge with cement indicates that arsenic leaching ratio of sludge ranges between 3 and 13 % and that of cement stabilized sludge is between 1 and 6 %. This means that the arsenic has a strong bond with the iron sludge and its treatment may not be difficult.

Family filter with iron-coated sand: solution for arsenic removal in rural areas

The presence of arsenic in groundwater is recognised as a threat to public health world-wide and specifically in rural areas of several developing countries due to variety of health-related problems observed in populations ingesting arsenic-containing water. Several arsenic removal technologies suitable mainly for centralised treatment are available or under investigation. However, point-of-use arsenic removal systems, suitable for application at household level appear to be the only feasible solution under conditions prevailing in rural areas of developing countries characterised in general by the absence of centralised water supply systems. Several household level arsenic removal units are commercially available and some of them are currently under testing in Bangladesh. Nevertheless there is still need to develop a more efficient and sustainable point-of-use arsenic removal unit. Very promising results were recently obtained in laboratory experiments with a simple “family filter” with iron-coated sand (ICS) or iron-impregnated granular activated carbon. The objective of this study was to establish methodology for assessment and selection of appropriate ICS for arsenic removal with “family filter”. An additional objective was to optimise and test further “family filter” with selected ICS. Batch and filtration laboratory adsorption experiments were conducted with five types of ICS originating from Dutch groundwater treatment plants and model and natural groundwater with high arsenic concentration. All ICSs tested demonstrated arsenic removal potential with removal efficiencies ranging from 50 to 100%. Short adsorption experiments can be applied to screen the suitability of different ICSs. Adsorption isotherm and filter runs are, however, needed to establish arsenic adsorption capacity of a particular ICS. Contact time was found to be the critical parameter for “family filter” design and performance. The “family filter”, very simple point-of-use treatment unit, equipped with an appropriate ICS demonstrated high arsenic removal potential and could be very attractive for arsenic removal in rural areas of developing countries.

Removal of Arsenic from Ground Water by Manganese Dioxide–Coated Sand

In a laboratory study, manganese dioxide–coated sand (MDCS), prepared by reacting potassium permanganate with manganese chloride under an alkaline condition and in the presence of sand, showed promise as a medium for use in small systems or home-treatment units in developing areas of the world, for removing arsenic(III) and arsenic(V) from ground water. In ten cycles of downflow column tests [bed depth 400 mm; empty-bed contact time 74 min; influent arsenic 0.5 mg As/L of arsenic(III) and 0.5 mg As/L of arsenic(V)], breakthrough bed volumes at the World Health Organization guideline value of 0.01 mg As/L for arsenic in drinking water were in the range of 153–185 per cycle. During regeneration (backwashing with 2 L of a 0.2 N sodium hydroxide solution), 85.0% of the removed arsenic was recovered in the first cycle, and 94.6–98.3% was recovered in subsequent cycles. A low-cost, simple home arsenic removal unit, containing 6 kg (4 L) of the MDCS medium and operated at 6 L/h, produced 740 and 700 L of water in two cycles of runs when the influent arsenic concentration was 0.5 mg As/L of arsenic(III) and 0.5 mg As/L of arsenic(V). No arsenic(III) or leaching of manganese from the medium was detected in the effluent. A detailed study addressing the effects of some important factors (water pH, concentration and type of competing anions, and cations) on the process is needed. The home arsenic removal unit should be subjected to field trials to assess the long-term effects on performance.

Removal of Arsenic from Ground Water by Iron Oxide-Coated Sand

In a laboratory study, iron oxide-coated sand showed promise as a medium for use in small systems or home-treatment units in developing areas of the world, for removing arsenic(III) and arsenic(V) from ground water. A low-cost, simple, home arsenic removal unit (material and fabrication cost: Rs. 200, cost of medium: Rs. 80, and regeneration cost: Rs. 5; 1 U.S. dollar = Rs. 35), containing 6 kg (4 L) of iron oxide-coated sand, produced 625 and 610, and 780 and 760 L of water in two cycles of runs when the influent arsenic(III) or arsenic(V) concentration was 1.0 mg/L. A detailed study addressing the effects of some important factors (selectivity of arsenic(III) and arsenic(V) over one another for removal, water pH, concentration and type of competing anions, and cations) on the process is needed. The home arsenic removal unit should be subjected to field trial to assess long-term effects on performance.