Enhancing arsenic removal from groundwater at household level with naturally occurring iron

Abstract

A supply of drinking water low in Arsenic (As) prevents arsenic poisoning. The presence of high concentrations of iron (Fe) in groundwater under the alluvial plains of the large rivers in Southeast Asia is a prerequisite for the simple removal of As. This study investigated the mechanisms and possibilities for enhancing As removal with naturally occurring Fe in a reliable, low cost and sustainable way. The results of the study show that As removal with Fe is greatly enhanced by the addition of an oxidizing agent (preferably KMnO4) immediately after the pumping of groundwater. Further enhancement of As removal in the presence of Fe can be achieved by adding a small volume of a concentrated basic solution of MnO4- and AlO2-, which has a combined oxidation, coagulation and buffering capacity. Best results were obtained when this solution was mixed with the groundwater immediately after its pumping until a pale pink color appeared. Maximum required reaction time was 10 minutes and subsequent filtration of the water was able to reduce the As concentration to near zero. Concentrations of MnO4- and AlO2- can be varied in the solution to achieve sufficient As removal to suit different Fe/As ratios and the presence of interfering co-occurring anions.

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

“…Arsenate (As(V)) can be removed readily due to its positive charge. Because of this consideration, the As(III) concentration in the samples was measured by determining the total arsenic (As tot ) remaining in water filtered through SERDOLIT ® resin, which is selective for As(V) (McNeill & Edwards 1995;Sharma et al 2016).…”

Efficiency of Arsenic and Iron Removal Plants (AIRPs) for Groundwater Treatment in Rural Areas of Southwest Bangladesh

“…The larger aeration tank and a small filtration tank contain coarse sand, charcoal, and brick chip media [24]. Several investigations revealed that naturally occurring Fe plays a crucial role in the removal of As [25,26]. A study reported that groundwater containing iron Fe (II) levels (2.33 ± 0.03 mg L −1 ) adsorbed 91% As in anoxic conditions compared to 61% of As in oxic conditions [14].…”

“…A study reported that groundwater containing iron Fe (II) levels (2.33 ± 0.03 mg L −1 ) adsorbed 91% As in anoxic conditions compared to 61% of As in oxic conditions [14]. However, Holm and Wilson [27] found that the As removal rate was only Several investigations revealed that naturally occurring Fe plays a crucial role in the removal of As [25,26]. A study reported that groundwater containing iron Fe (II) levels (2.33 ± 0.03 mg L −1 ) adsorbed 91% As in anoxic conditions compared to 61% of As in oxic conditions [14].…”

Water safety: one of the primary objectives of our time

“…For instance, this was the case with arsenic, whose limit for human consumption was recently reduced to 10 µg L -1 from its previous limit of 50 µg L -1 . After application of the functionality tests to the already-operating plants, the new limit for arsenic was achieved, sometimes through targeted structural upgrading in the treatment chain, sometimes with simple plant adaptations to new requirements (for example, by using an existing unit operation for a different process purpose), sometimes even with only the introduction of dosing and control systems without changing the process chain Sharma et al, 2016). However, the facilities already subject to "monitoring/functionality tests" were the first to implement the new WSP procedure.…”