Water Quality

Update on Total Trihalomethane (TTHM) Levels- June 2010

In November 2008, February 2009, May 2009, and August, 2009 the Newport Water Division issued notices that the EPA standard for TTHM level was exceeded as reported for the fourth quarter of 2008, first quarter of 2009, second quarter of 2009 and third quarter of 2009, respectively.

The standard or maximum contaminant level (MCL) established by the EPA for TTHMs is 80 parts per billion (ppb) for a four quarter running average. Compliance for TTHM is based on an arithmetic average, computed quarterly, of quarterly averages of the eight samples that Newport Water analyzes. Please note that Newport Water is required to analyze the water samples for TTHM levels within the first two weeks of each quarter.

Newport Water returned to compliance for TTHM levels in the fourth quarter of 2009 with a reported level of 72.47 ppb. Newport Water continues in compliance with TTHM levels through the second quarter of 2010.

Many water systems treat water with a chemical disinfectant, such as chlorine, in order to inactivate pathogens that cause disease. While disinfectants are effective in controlling many harmful microorganisms, they react with organic and inorganic matter in the water to form disinfection by products (DBPs), some of which pose health risks at certain levels.

Some people who drink water containing TTHMs in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous system, and may have an increased risk of getting cancer. The public health benefits of chlorine disinfection practices are significant and well recognized. Consequently, one of the most complex questions facing water supply professionals is how to reduce risks from disinfectants and DBPs while providing increased protection against microbial contaminants.

The Newport Water Division has taken the following steps to lower TTHMs in your drinking water:

1. Continue to adjust and optimize chlorine and chlorine dioxide levels to provide adequate disinfection while reducing the potential to form TTHMs. There is a fine balance which must be maintained in drinking water to provide appropriate disinfection while not chlorinating too heavily, which tends to form TTHMs.
2. Installed mixing systems in the Reservoir Rd and Goulart Lane water storage tanks. The mixing system reduces the average age of the water in the distribution system. Older age of the water can produce higher TTHM levels.
3. Upgraded the Lawton Valley Sedimentation Basin #1. The sedimentation basins are the first part of the plant treatment which removes organics from the raw water supply. High organic levels can lead to high TTHM levels.
4. Installed an aeration system in the Lawton Valley Reservoir. The aeration system has the potential to reduce algae blooms in the raw water reservoirs. Algae blooms tend to lead to higher organic levels in the treated water.
5. Alter the strategy to treat the reservoirs with copper sulfate for algae blooms by being more aggressive in treating prior to onset of an active bloom. Algae growth in the reservoirs plays a significant role in the formation of high organic levels in the water that enters the treatment plants.

The Newport Water Division has also committed to constructing a new water treatment plant to replace the existing Lawton Valley Plant and to upgrade the existing Station 1 Plant by December 31, 2014. The Water Division has retained a City Advisor to provide professional services for the procurement, design, and construction phases of the major capital improvements for the Water Treatment Plants. A Design Build procurement process is proceeding to implement the water treatment plant improvements.

In April 2010, the City Council endorsed the recommendation to include an advanced water treatment process as the preferred approach to control TTHM levels with the water treatment plant improvements. The use of an advanced water treatment process (nanofiltration or post carbon contactors) is the best long term treatment alternative in the interest of providing safe drinking water into the future to all our customers. Additional pilot testing is being completed during the summer 2010 in order to complete the information to be included in the Request for Proposals anticipated to be issued to pre-qualified contractors in October 2010.

The following are the reported levels for TTHMs for 2007 to date:

*- MCL Violation

Source Water Assessment Report

The Source Water Assessment Report for Newport Waters water supply is now available. The assessment was conducted by the URI Cooperative Extension, Nonpoint Education for Municipal Officials Program in cooperation with the RI Department of Health, with funding from the USEPA.

As required under the Safe Drinking Water Act, all public water supplies in Rhode Island were evaluated. The focus of the assessments is on identifying threats from land use so that it can be used to plan source protection efforts by the City. The results of the assessments show that Newport Waters Aquidneck Island and Mainland supplies are at Moderate Risk to contamination. Protection efforts are important to assure continued water quality.

Summary fact sheets of the assessments are available on the URI website. The direct link is www.uri.edu/ce/wq/RESOURCES/dwater/Assessments/index.htm#summary. The full report is available for review at Newport Water's office at 70 Halsey Street.

Manganese

Customers of the Newport Water Division may at times receive water with a yellow to brown color. This is occasionally due to the level of the naturally occurring mineral manganese in the water. This occurs mainly in the summer and fall. At times the water in the reservoirs of our system has elevated levels of manganese which do not respond to treatment at the water treatment facilities.

The EPA has not established requirements for Manganese as a primary drinking water regulation. The EPA has established secondary drinking water regulations for contaminants such as manganese which are recommended goals. The secondary drinking water regulations are related to contaminants that primarily affect the aesthetic qualities (taste, color, and odor) of drinking water.

The Water Division must balance the treatment processes to meet both the enforceable levels of the primary drinking water regulations with the goals of the secondary drinking water regulations.

When we experience elevated levels of manganese leaving the treatment facilities, the operating staff adjusts treatment processes as much as possible and changes the reservoir water source. In order to remove the treated water with the elevated levels the staff flushes the distribution system.

The Water Division regrets the inconvenience of the colored water and works diligently to avoid these situations by maintaining all drinking water standards and goals. The following EPA website is provided for additional information.

www.epa.gov/safewater/mcl.html