Streamline - Fall 2012 - (Page 25)
The Inspector Found What?
BY ERIKA HENDERSON, DIRECTOR OF RESEARCH PITTSBURG TANK & TOWER
SHOCK AND DISBELIEF were probably the first two things that went through the city officials’ minds when 24 dead rats were pulled from their water tank in Maryland. In Georgia, a fish swam by the camera during a robotic inspection of a water tank. Although insects and birds are the most common intruders found in water tanks, they are not the only intruders. Human remains used to be found in water reservoirs regularly, although the number has dramatically decreased thanks to newer and stricter regulations. However, there are still some cases of human remains being found in water tanks.
Fish, mussels, snakes, turtles and a signiﬁcant amount of mud and aquatic life have been discovered in water tanks that receive their water from lakes.
Fish, mussels, snakes, turtles and a significant amount of mud and aquatic life have been discovered in water tanks that receive their water from lakes. These tanks should be cleaned more frequently than others. In New York, more than 50,000 gallons of mud and aquatic life were cleaned out of a 2-million gallon tank, and 68,000 gallons of mud was cleaned out of a Kentucky tank. These are examples of why it is crucial to have each tank inspected and cleaned regularly. America Water Works Association (AWWA) states that, “Tanks should be washed out and inspected at least once every three years, and where water supplies have sediment problems, annual washouts are recommended.” (AWWAM42-88) If part of the water tank is used for fire protection, then it must also follow National Fire Protection Association (NFPA) regulations. The NFPA25 states that, “The interior of steel tanks without corrosion protection shall be inspected every three years, and the interior of all other types of tanks shall be inspected every five years.” (NFPA25-31) If vents, manways, overflow and inlet/outlet pipes are checked regularly, these types of intruders can be avoided. Safety ladder cages and locks should also be inspected regularly to avoid unauthorized access on or in the water tank. When water problems occur, the water tank which stores that water is the best place to start an investigation. Cloudy or dirty looking water may indicate an excess amount of sludge. The outlet pipe may need to be extended farther up the tank to allow water to be taken from the middle of the tank instead of the bottom where sediment settles, or an over-the-top fill or mixing system may need to be installed to help prevent stagnation. The solution could be as simple as having
it inspected and cleaned. Until just a few years ago, to inspect a water tank it had to be taken out-of-service. Time constraints and the expense of water loss due to draining and filling the tank proved problematic; as a result, many delay water tank inspections until a problem occurs. Today, however, this is not so. Now, by using a ROV (Remote Operated Vehicle), a complete tank inspection can be done with no problem. The tank can now be completely inspected and cleaned without draining the tank. A written inspection report is furnished which includes a detailed evaluation, photographs, recommendations of needed repairs, code updates and a detailed cost estimate for each item. After an inspection has been performed and the condition of the tank has been determined, address the issues. Structural repairs are priority and should be repaired on an emergency basis. A tank with structural repairs could collapse under certain conditions and lives could be at risk. Special attention should be given to the floor and roof on ground storage tanks, and the bowl, riser and windage rods on elevated tanks. AWWA, NFPA and OSHA regulations should be properly addressed and manways need to be the appropriate size. The inspection report alone is not enough to insure a safe and healthy environment to store water, but it does provide crucial information needed to do so.
Twenty-four dead rats were pulled from a water tank in Maryland.
Table of Contents for the Digital Edition of Streamline - Fall 2012
From the President
From the Executive Director
A Day ( or Two) in the Life of a Circuit Rider
The Necessary Evolution of Water and Wasterwater Utilities
Craig-New Castle PSA: One Small System's Giant Leap into the Future
Poor planning on your part does not constitute an emergency on our part
Extra Highlights from 2012 VRWA Conference
Virginia Department of Transportation Work Zone Traffic Control Update
FOG (Fat, Oil and Grease): Sewer Public Enemy No.1
The Inspector Found What?
Ergs, Joules & Such
Understanding your Job as a Board or Council Member?
Throwing My Loop
Do You Know What Your VRWA Benefits Are?
Welcoming New Members
Board Of Directors
Index to Advertisers/Ad.com
Streamline - Fall 2012