Even some Wisconsin residents are being forced to pour out their water.

How about a glass of water with that arsenic?
Contaminated water isn’t just a concern in India, Pakistan, Bangladesh and other developing countries. Parts of the United States, including Wisconsin, have potentially unsafe drinking water.

Arsenic is a poisonous element widely dispersed throughout the Earth’s crust. It seeps its way into water through the separation of minerals and ores and as a result of erosion from local rocks. Liquid industrial waste is another source of this metalloid—an element having properties of both metals and nonmetals. Consequently, arsenic can also be found in plants, fish and shellfish.

The health problems associated with human exposure to arsenic can be grotesque if not deadly. Immediate symptoms of acute arsenic poisoning include vomiting, abdominal pain and bloody diarrhea. Complications relating to long-term exposure include cancer of the skin, lungs, bladder and kidneys. It also has a negative effect on the reproductive system and is linked to black foot disease. Despite these harmful effects, not every country has the means or capital to treat arsenic in water.

“Common treatment technologies used in arsenic removal for piped water supply is costly,” said Jim Park, Civil and Environmental Engineering Professor at UW-Madison. “It’s estimated at two million dollars of capital cost for each million gallons per day cleansed.”

After three years of research and development, Professor Park and his team of students have created a metal oxides nano-particle impregnated mesoporous silicate absorbent, which has a significantly greater adsorption capacity and rate compared to the commonly used activated alumina. It has a $600,000 price tag for each million gallons per day purified. This makes it more affordable to developing countries that have not been able to afford previous treatment.
The way his product works is quite simple. Imagine a large column with nothing but the media substance inside. Groundwater is then pumped into the column. Any arsenic in the water is trapped within the media and the natural water flows through to the drinking water distribution system.

When the media are saturated with arsenic, the natural water is drained from the column, leaving the arsenic-saturated media behind. A solution of sodium hydroxide is then poured into the columns, which releases the arsenic from the media. The contaminated solution is then transferred to another container where the liquid is evaporated, leaving a pure arsenic substance on the bottom.

The cleaned media can be used again in the process. Any remaining pure arsenic can be reused as wood preservatives or in production of lead-acid batteries and semiconductors used in computers and electronic applications. The distinctive properties of the media are what make this process efficient and economical.

This novel absorbent has a significantly large surface area of more than 1000 square meters per gram. The large surface area combined with the media’s chemical and other physical properties gives it a higher adsorption rate than activated alumina.

Lab apparatus Professor Park's team used to develop and test his new aresenic removal media.

Let’s assume activated alumina is a basketball. Professor Park’s research team erected cans on the surface of the basketball in a highly-ordered fashion, thereby increasing the surface area significantly. Then, lanthanum oxide was impregnated on the surface. “These treatments allow it to adsorb ten times greater adsorption at 15 times faster rate than activated alumina,” stated Professor Park.

It is more efficient because the media are specially formulated to have greater affinity to arsenic particles, whereas the alumina resolvant method removes other minerals and elements as well.

The fact that it can accumulate a larger amount of arsenic in a shorter contact time (ten seconds to one minute) than other methods makes it an economical method of extraction. The amount of arsenic that may pass through the process is well below the future regulatory limits of five to ten parts per billion (ppb).

The U.S. Environmental Protection Agency (EPA) sets the U.S. standard for arsenic in water. Currently it is set at 50 ppb, but by 2006, every drinking water provider must abide to ten ppb. The EPA estimated that the 5 ppb standard would cost $1.5 billion annually and requires $14 billion in capital investments, which translates into water bill increases of as much as $1,900 per customer annually.

Professor Park and his team of students took three years to develop these efficient and economical media for reducing arsenic in water. It has been funded through University Industry Relationship (UIR) and Wisconsin Groundwater Research Council and patented through the Wisconsin Alumni Research Foundation (WARF.) Currently, Professor Park is in the process of working with Clack Corporation in Windsor, Wisconsin to handle the commercial production and distribution of the product. It is scheduled to hit the market in two years.