Thursday, January 21, 2016

The Water in Flint Michigan

On January 16, 2016 in response to a request from the Governor Rick Snyder President Obama declared that an emergency exists in the State of Michigan. The President's action is in addition to the State declared emergency and authorizes emergency assistance is to provide water, water filters, water filter cartridges, water test kits, and other necessary items to address the current crisis.

For more than a year the drinking water supply in Flint Michigan has been contaminated first with high levels of microbial contaminants such as viruses and bacteria, and inorganic contaminants such as salts and metals which were a result of inadequate treatment of the water, then high level of lead began to appear in homes and have persisted. Reportedly, the lead is the result of slightly caustic, inadequately treated water leaching lead from the old distribution system. This is a related problem that happened in 1994 in Washington DC and hard experience found the solution.

This all began when the city of Flint decided to switch to the Karegnondi Water Authority (KWA) as the City’s permanent water source in a cost saving measure as wholesale water rates from the old Detroit system kept growing in an attempt to support rising maintenance, repair and operating costs in the Detroit Waster and Sewage system. KWA would supply water to the members by building a new pipeline from Lake Huron. While waiting for KWA pipeline to be completed, the City of Flint planned to use the Flint River as a temporary alternative water source.

This decision to use the Flint River was approved by the Michigan Department of Environmental Quality to proceed with treatment of water from the Flint River in 2014. Here is where the problems began. Though the Flint Water Treatment staff, LAN engineering consultants and the DEQ understood that the Flint River would be subject to variations due to temperature changes, rain events and would have higher organic carbon levels than Lake Huron water and would be more difficulty to treat, they thought that Flint had the equipment (after a Water Treatment Plant upgrade) and the capacity to meet the demands of treating river water. They were wrong.

Flint struggled to meet the Safe Drinking Water Act levels at the water treatment plant. The first problems were with of increased levels of trihalomethanes (disinfection by-products formed when chlorine reacts with organic matter in drinking water) next were increased levels of total coliform and fecal coliform bacteria levels. Just when they were convinced that the finished water from the plant was within Safe Drinking Water Act requirements, the began to appear problems at the tap. Lead levels became highly elevated. This should not have been unexpected. It had happened before.

In 1994 amendments to the Clean Water Act Safe Drinking Water Act to regulate disinfection by-products formed when chlorine reacts with organic matter in drinking water resulted in similar problems in Washington DC when they changed from chlorine to chloramine for disinfection. The amendment regulates the disinfection by-products; the EPA considers these byproducts to be a potential health threat. The treatment process for the Washington DC water supply was changed to add ammonia after primary disinfection to react with the remaining chlorine to prevent the formation of disinfection byproducts (haloacetic acids and trihalomethanes). The change caused cause a lowering of pH in the distribution system, the water became slightly more caustic than it had been, increasing the possibility of corrosion.

Shortly after the change, increasing pipe failures and levels of lead began appearing in the homes of Washington DC residents. It turns out chloramine-treated water picks up lead from pipes and solder and does not release it, resulting in elevated levels and deterioration of the pipes. Extreme lead concentration began appearing in homes. This is similar to what happened in Flint. It should have been considered by the city, the DEQ and the Consultants before the change-a simple literature search would have identified the potential for the problem.

Dr. Marc Edwards a MacArthur Prize winning professor of engineering at Virginia Tech ultimately identified the cause and solution to the problem in Washington DC. The lead problem was addressed by adding orthophosphate and tightly control the pH of the water. Orthophosphate controls corrosion in pipes, service lines, and household plumbing throughout the distribution system. It works by building up a thin film of insoluble material in lead, copper, and iron pipes and fixtures. This thin film acts a barrier to prevent leaching of metals into the water, but only works in a narrow pH range. Calcium hydroxide (lime) is also added to adjust the pH of the water to ensure optimal performance of the orthophosphate.

Last September, Dr. Edwards was hired by Flint to find a solution to their problems. Flint has returned to obtaining its raw water supply from the Detroit water system and will be adding orthophosphate and controlling the pH. It remains to be seen how much of the piping system has been damaged by this adventure in cost cutting. When poorly maintained and old pipe distribution systems subjected to this chemical stress often experience extensive pipe failure next. This all started as a cost savings measure.

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