Skip navigation

As.jpg

In 1972, along with a graduate student assistant, I undertook a study of the removal of arsenic from drinking water. We focussed on the adsorption of arsenic (V) on aluminum and ferric hydroxides largely because this was consistent with the treatment provided in most conventional water treatment plants.

 

At the time, since the MCL for arsenic was set at 50 micrograms per liter and there were no well-established, widely-available chemical means for determining arsenic in drinking water at or below such concentrations, there were also no reported violations of the arsenic drinking water standard in the U.S.

 

To oversome analytical difficulties, the study employed an arsenic radiotracer. This allowed a quick and reproducible assessment of the removal of arsenic by orders of magnitude.

 

The results of the studies, published in the Journal of the American Water Works Association in 1973, showed that arsenic could be readily removed to a high degree (> 90%) by conventional dosages of both iron and aluminum coagulants. Iron precipitates were found to be particularly effective in adsorbing or co-precipitating arsenic.

 

With the development of advanced analytical capabilities, the issue of arsenic in drinking water had reemerged on the national and world scenes in dramatic fashion by the year 2000, leading both to modification of regulations and a renewed search for arsenic removal methods.

 

The attached series on Arsenic in Drinking Water examines some of the developments that occurred after the health effects of arsenic in drinking water were assessed.

Copper Corrosion Problem in Household Plumbing: A Case Study

 

Pit Happens 1.jpg

 


Beginning in March 2001, the City of Kearney, Missouri, began receiving reports of leaks in household plumbing. Over succeeding months, owners of at least sixteen homes reported the development of pinhole leaks in copper piping. The majority of the homes affected were in a localized subdivision where homes were on the order of 10 to 14 years old.


A common feature of the reported leaks was that they occurred almost exclusively in the copper lines used in recirculating hot water systems. Cold water lines were generally not affected, although one homeowner reported the need to also replace cold water lines.

 

Damage to those homes experiencing leakage was significant owing to the pinpoint spray in spaces hidden by drywall or ceiling.

 

Questions were raised about the nature of the pipe failures, the plumbing methods used, and the quality of the copper pipe used. Questions were also raised about the quality of the water delivered by the City of Kearney. Was it corrosive to copper and, if so, what remedial steps could be taken to reduce the rate of corrosion in the future?

 

The engineering report is available in the two attached pdfs.