Arsenic

Drinking water in several regions of the world contains geologically sourced arsenic in concentrations that are harmful to humans.  Aqua Clara International has been evaluating processes and engineering structures to formulate cost effective systems that remove arsenic contaminants from drinking water sources.  The ACI technique involves both filtration and adsorption and methods which, in turn, permit both bacterial and arsenic contaminant reductions in water that are superior to the presently accepted, universal standards.  And, these selected systems are more cost effective than alternatives.

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Modelled global probability of geogenic arsenic contamination in groundwater for (a) reducing groundwater conditions, and (b) high-pH/oxidizing conditions where arsenic is soluble in its oxidized state. Source: Royal Society of Chemistry

Source:  United States Geological Service

Source: United States Geological Service

To support this performance ACI, in cooperation with Michigan State University,  identified and developed  an improved  method for evaluating the arsenic reduction performance of adsorbents in water;  developed adsorbent/ sand mixtures in reactors that, in turn, support both high reduction efficiencies of contaminants and economically useful clean water through-put rates; developed filtration techniques that permit the processing of contaminated surface waters and the sequential reductions of bacterial pathogens and arsenic based ions in an integrated, economically acceptable, simple engineering system; and employed a simple, environmentally sound method for the disposal of spent adsorbents.

Based on this laboratory development work, two water purifier systems for arsenic contaminant reduction have been designed, constructed and are operating in the field.

A household filter, first installed in 2010 in the La Carona region of Nicaragua in collaboration with El Porvenir.  There are now 19 filters installed and providing arsenic-free  clean water for a group of  families living in an area where arsenic contamination ranges from 30-60ppb.

The performance of these units has been monitored over time via ACI plus the Department of Chemistry of the National Engineering  University in Managua.  The on-going performance of these units, as evaluated by the University, has been approximately zero ppb of arsenic in the output water (results of this testing are presented in the Evaluation and Research section)

First home to receive a filter

First home to receive a filter

New filter producing clean water

New filter producing clean water

Constructing arsenic-remediation filters in 2013

Constructing arsenic-remediation filters in 2013

New filters awaiting placement

New filters awaiting placement

A school filtration system that incorporates a sand-prefilter, a 15 μ  roughing filter two 10” 0.2 μ hollow membrane filters and our arsenic remediation media. The sand pre-filter and roughing filter remove the normal water borne contaminants found in surface waters, eg, parasites, worms, sediments, fungi, and plant species, prior to the adsorption and removal of arsenic ions from the water to be purified. The two hollow fiber, 0.2 μ membrane filters that are placed in series essentially eliminate the bacterial pathogens and the general level of bacterial species; the actual reduction in such species via this design is log 6 (99.9999).

Four such systems have been installed in collaboration with the Rotary Club of Gauhati South, Assam, India; the schools are located in the Nalbari region.  The Rotary Club installed a new hand pump well at each site (there being no available electricity) and built a filter house that contained the ACI filtration system which was designed to process water borne, arsenic levels of 250 ppb and generate water with an approximately zero level of arsenic in the clean water for at least 2.2 years.

Filter house and new hand-pump well next to school

Filter house and new hand-pump well next to school

ACI bacteria and arsenic remediation system

ACI bacteria and arsenic remediation system

The initial tests conducted by an independent testing agency of the water produced in these schools have confirmed the design performance: the systems are producing highly clean, potable water with no arsenic contamination.