Why isn’t chlorine treatment of potable water enough to keep water safe?

I had some water utility workers ask me, “Why isn’t chlorine treatment of potable water enough to keep water safe? Why should we worry about cleaning tanks when we already use chlorine?”

Chlorine works great as long as there is not a breach in the tank. When there is a breach like a hole in the top that lets birds and insects inside the tank, the chlorine can not keep up. This is why annual tank inspections are so important. People have died from this scenario, see: “Salmonella Outbreak in Alamosa, Colorado“. According to USEPA officials a sediment build up on the interior floor of a water storage tank is another type of breach. Bacteria like Legionella, protozoa like Cryptosporidium, and a wide range of viruses including Norovirus can hide and GROW in the tank sediment.

Do you know what the #1 cause of municipal water contamination is? According to the CDC it is a microscopic parasite called Giardia. The sediment becomes a perfect habitat providing both shelter and food for Giardia and many other microorganisms to grow. In time, the contaminants can reach a point where they overwhelm chlorine or any other disinfectant you may be using. Keeping tanks clean keeps your drinking water safe.

Giardia- Photo CDC website

Top 10 Causes – Outbreaks in Public Water Systems*

• Giardia
• Legionella
• Norovirus
• Shigella
• Campylobacter
• Copper
• Salmonella
• Hepatitis A
• Cryptosporidium
• E. coli, excess fluoride (tie)

For a complete listing of water-related surveillance data, see CDC’s Surveillance Reports for Drinking Water-associated Disease & Outbreaks.

A professional potable water Dive Crew can remove tank sediment along with everything that is growing in it with minimal water loss.  The diver is sealed in a DRY suit so there is no human contact with the water supply.  Before entering the water system the diver is washed down with a chlorine solution to meet state and federal guidelines. The diver can then enter the tank and make quick work of removing tank sediment and any contaminant that may be hiding in it. It is basic housekeeping! You would not drink out of a dirty glass, no one should drink out of a dirty water storage tank or tower either. If you need a water storage tank or tower cleaned, give us a call toll free at 1-888-481-1768 for a free quote.

For more information on Municipal Water Tank Cleaning see: Ron Perrin Water Technologies web Site: www.rpwt.us.

Content source: Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases

Water Tank Cleaning

Ron Perrin Water Technologies inspects and cleans water storage tanks and towers.  Since 1997 we have been a leader in the tank inspection and cleaning industry.  Our dive crew can remove tank sediment quickly and safely.

Call 1-888-481-1768 for a free inspection or cleaning quote.  See: www.rpwt.us

Can a virus live in your drinking water?

YES. Both bacteria and viruses are microorganisms regulated by EPA’s Maximum Contaminant Levels (MCLs) criteria. Viruses are the smallest form of microorganisms capable of causing disease, particularly those of a fecal origin infectious to humans by waterborne transmission; bacteria are typically single-celled microorganisms that can also cause health problems in humans, animals or plants, despite many form’s ability to aid in water pollution control.

If your water storage tank has an accumulation of sediment on the interior floor you may have undetected microorganisms in your water storage tank.  Sediment can be a safe habitat for a wide range of contaminants this can lead to the disinfectant being overwhelmed and the public served by your system being at risk of disease.

Clean Water Storage Tans and Towers

Keeping your water storage tanks clean and free of sediment is the best way to protect your customers from bacteria, viruses and many other microorganisms that can use the sediment on the floor of your tank to hide, grow and thrive.  Our divers dress in dry suits completely sealed in their own environment, the diver is then washed down with a chlorine solution to meet EPA requirements.  Our dive crew can quickly safely remove all sediment form your water storage tank or tower with a minimal of water loss!  Do not take the risk of bacteria, viruses or other microorganisms growing in your water system. Keep your tanks clean and your water safe to drink.

For a free Quote on your tank cleaning call toll free 1-888-481-1768.

Line-Air Diver – Water Tanks & Towers

Are you looking for something different?  We specialize in the inspection and cleaning of Potable Water Storage (drinking water tanks). We are currently taking applications for a commercially trained Line-Air Diver.  Employment is year round. Pay based on experience. Pre-employment drug screening is required. This position requires frequent out of town travel, paid by company (from Fort Worth, Texas). We are currently seeking qualified applicants that live in or near the DFW metroplex. Please e-mail resume  and use “Resume” on subject line. Call 817-377-4899 to schedule interview M-F 8 to 5.

 

Download an application Here:

RPWT Application_062918_dw

Return application to: tankinspections@aol.com or  Fax: 817-246-1740

For more information see the EMPLOYMENT page at: www.tankdiver.us

 

Inspection & Cleaning Quotes

Water Tank Inspection and Cleaning is our business. This page is supported by Ron Perrin and his company Ron Perrin Water Technologies. If you would like a quote to inspect or clean a water storage tank or tower please call 817-377-4899 or click here.

ROV Water Tank Inspection

Water Tank Inspection. Water Tank Cleaning. ROV Water Tank Inspection. Since 1997 Ron Perrin Water Technologies has been a leader in underwater inspection services for potable water storage tanks.  Our inspection methods include Remote Cameras, ROV inspections and Potable Water Diver inspections.

 

Our inspections offer the most information for the lowest cost while never disrupting water service or draining your tank.  Check out our new ROV Tank Inspection Video on youtube.

We have a a fleet of ROV’s to insure we are ready to meet your inspection needs. For a free price quote call Debi at 817-377-4899, or toll free at 888-481-1768.

Visit our new web page at www.watertankinspection.com

 

New water tank inspection video

Water Tank Inspection. Water Tank Cleaning. KEEPING DRINKING WATER SAFE SINCE 1997. Check out our new video at www.watertankinspection.com.

Water Tank & Tower Inspection and Cleaning by Ron Perrin Water Tech.

Ron Perrin Water Technologies performs over 800 Water tank inspection’s every year.

Since 1997 we have performed thousands of inspections for water utilities in 14 states.  Our remote underwater camera inspection is our most popular service.  Since 1997 we have performed thousands of inspections for water utilities in 14 states.

Visit our water tank inspection web site at: http://www.watertankinspection.com

Ron Perrin – http://www.ronperrin.com

Our Remotely operated Vehicle inspection is also popular for larger facilities.  We maintain a feet of three ROV’s to meet our customer demands at any time.  Our reports caver all required State and AWWA inspection points.  Be deliver the completed inspection report back in a notebook/binder for convienient reference and storage.

DEEP TREKKER ROV

Diver inspections are our third method.  Often used when specific inspection goals are required.  Divers also perform inspections after tank cleanings.  The diver is sealed in his own environment and washed down with a chlorine solution to meet all AWWA and EPA requirements.  This allows the diver to enter the water system and move around freely.

 

Potable Water Diver

Water tank & tower inspection and water tank & tower cleaning is our specialty since 1997.  Please visit our web site at www.ronperrin.us or www.watertankinspection.com for more information.  For a free price quote call 817-377-4899.

Do you need a Texas Inspection form? Just Click Here: FORM

 

The face of an American Hero

  by Ron Perrin

I write a lot about drinking water contamination and the importance of keeping water storage tanks and towers clean.  I haven’t written about people that much but this is about both drinking water contamination and a particular person I think is an American Hero.

Pediatrician Mona Hanna-Attisha or Dr. Monica as her young patients call her, did not plan her life to be a hero and I am sure she doesn’t see herself that way now, but she is.  She is the person that made enough noise, would not take, “your wrong” or “everything is ok”, for an answer.  After noticing many of her young Flint, MI patients had lead poisoning, she suspected the water supply.  She is the person at the right place at the right time that stood up to say, something is very wrong here and she was not going to go away. 

Her story was covered on CBS Sunday Morning this past Fathers Day.  I had the opportunity to watch with my son and infant grandson. My son made the comment that she is a REAL AMERICAN HERO. I could not agree more.

I titled this, “The Face of an American Hero”, because Dr.  Mona Hanna-Attisha was born in Iraq and raised in Michigan after her family fled the regime of Saddam Hussein.  Being a true American is not about where you were born but about who you are and who you want to be. It has always been about doing the right thing. The USA has always attracted the best and brightest the world has to offer. I think we are very lucky to count her as one of us, and I wanted to share her story.  

She has written a book,  “What The Eyes Don’t See See“, by Dr. Mona Hanna-Attisha.

https://www.amazon.com/What-Eyes-Dont-See-Resistance/dp/0399590838

If you missed her CBS interview check it out here:

https://youtu.be/pd2qxi2mF_4

 

 

Potable Water Diver / Water Tower Inspector Wanted

ESTABLISHED WATER TANK AND TOWER INSPECTION AND CLEANING COMPANY is seeking a commercial diver. CURRENT SCUBA certification and recent diving physical is required, preference given to ADC certified line air divers. We have a full time opening working out of our Main Office in Ft Worth, Tx. This position requires frequent out of town travel (2-5 days a week, often work on a 4 day work week with 3 days off). A valid Drivers license and good driving record is required. For additional information and application see:

Click Here to Down Load an Application

or www.ronperrin.com/employment.

FOR INTERVIEW Call our Office Manager Debi at 817-377-4899.

Job Type: Full-time

Salary: $125 to $160.00 /day depending on training and experience.

Ron Perrin Water Technologies is a sole owned business established in 1997.  We are a leader in the underwater inspection and cleaning of potable water storage tanks and towers in Texas and surrounding states.  To See more of what we do and how we do it visit our company Facebook page, and give us a like! Call 817-377-4899 to schedule an interview or get a free inspection or cleaning quote.

https://www.facebook.com/ronperrinwatertech

YouTube Channel:

Potable Water Diver

http://www.rpwt.us

CBS 11 i-Team watches as my company inspects and cleans a north Texas water tower.

November 7th, 2014, Ginger Allen and the CBS 11 i-Team watches as my company inspects and cleans a north Texas water tower. The tower was cleaned as a normal maintenance procedure. A light- brown dusting of sediment was removed from the interior floor before it could get deep enough to support bacteria and become a problem.   The tower was cleaned by a Commercial Diver who was trained at OCEAN CORP, Houston, Texas. The Diver is sealed in his own environment, then washed down with a chlorine solution. Because we specialize in the inspection and cleaning of Potable Water Storage Facilities, all of our equipment is purchased for, and only used in, potable water. This utility is doing a great job of maintaining their system. However, utility managers across the country struggle to get the funds to properly maintain their systems. The EPA is currently considering a regulation that would require all water storage facilities to be inspected and cleaned at regular intervals. This new requirement could improve the water quality for millions of Americans.

Ron Perrin Speaks to News Crew

The EPA is taking comments on this proposed regulation until the end of the year. We have the contact information posted on our blog, or you can just take our poll at: www.cleanwatertankproject.com. The poll results will be turned in to the EPA at the end of the year.

CBS 11 I-Team Looks At What’s In Your Water Tower

 

 

Chick here to see video Video

http://launch.newsinc.com/embed.html?type=VideoPlayer/Single&widgetId=1&trackingGroup=69016&siteSection=ndn&videoId=28175822

The Written article is here:

http://dfw.cbslocal.com/2014/11/19/watertowers/http://dfw.cbslocal.com/2014/11/19/water-towers/

—–Photos taken by RPWT Office Manager Debi Wheelan

Robert Perrin on com bot talking to the diver

Find us on FACEBOOK  or connect with Ron on Linked-In AND PLEASE SHARE THIS POST AND THE CBS NEWS STORY WITH YOUR FRIENDS EVERYONE DESERVES TO HAVE CLEAN SAFE TAP WATER, Take the Poll at www.cleanwatertankproject.com and we can make this happen!

Now we can add a brain-eating amoeba to the list of contaminants that can be in tank sediment

By Ron Perrin

Removing sediment from the floor of your water tanks and towers may also be removing the habitat that allows bacteria, protozoa and viruses from getting a foothold in your distribution system. Now we can add a brain-eating amoeba to the list of contaminants that the sediment on the floor of your water storage tank can support.

Sediment being Removed from water storage tank

September 16, 2013, NBC News reported: “Deadly brain amoeba infects US tap water for the first time”. The death of a 4-year-old boy near Violet, LA., was linked to the Naegleria fowleri amoeba. The child had been playing on a backyard slip-n-slide that used water from the St. Bernard Parish water system, that was later found to be contaminated with the amoeba. “Tests show it’s present throughout the water supply system in St. Bernard Parish, directly southeast of New Orleans.”

According to the CDC: “Naegleria fowleri (commonly referred to as the “brain-eating amoeba” or “brain-eating ameba”), is a free-living microscopic ameba, (single-celled living organism). It can cause a rare and devastating infection of the brain called primary amebic meningoencephalitis (PAM). The ameba is commonly found in warm freshwater (e.g. lakes, rivers, and hot springs) and soil. Naegleria fowleri usually infects people when contaminated water enters the body through the nose. Once the ameba enters the nose, it travels to the brain where it causes PAM, which is usually fatal. Infection typically occurs when people go swimming or diving in warm freshwater places, like lakes and rivers. In very rare instances,Naegleria infections may also occur when contaminated water from other sources (such as inadequately chlorinated swimming pool water or heated and contaminated tap water) enters the nose. You cannot get infected from drinking water contaminated with Naegleria.”

The CDC also tested nearby DeSoto Parish Waterworks Dist. #1 because it was the near the site of an infection that happened in 2011 from non-potable water (lake or river, etc.). On October 8, 2013, The CDC confirmed the presence of the rare amoeba in five locations in DeSoto Parish Waterworks Dist. #1.

Heat is also a factor, an increase in only ten degrees can double the speed of bacteria growth. As record high temperatures become more common in summer months we see that keeping water distribution tanks free of sediment build up may be more important than ever before. Removing the sediment from your water tank may prevent a disaster before it can ever start.

The new Revised Total Coliform Rule (RTCR) will be fully implemented in 2016. It requires assessment and corrective action when there are indications of coliform contamination. The RTCR no longer includes a monthly maximum contaminant level violation for multiple total coliform detections. Instead, systems that have indicators of coliform contamination in the distribution system must assess the problem and take corrective action.  Well documented tank inspections should be part of assessing your problem.  If there is sediment build up in the tank, cleaning would be a logical corrective action to take.

The fact is, keeping your tanks clean may also prevent you from getting an RTCR violation in the first place. What we have found is this: Once the sediment is removed, our utility customers discover that chlorine costs are reduced because the chlorine is no longer losing the war with the microbes that were growing in the sediment.

However you choose to do it, just get it done. Do not let it go year after year, out of sight and out of mind.   Knowing what is in your facilities with a good inspection is your first line of defense.  If an accumulation of sediment is found, don’t think of it as “just a little dirt.” Know that it is a broken barrier that can allow contaminants to compromise the entire water supply and the health of the community

About the Author:
Ron Perrin is a Certified Safety and Health Official (CSHO), a member of the Texas Water Utilities Association, AWWA,

Ron Perrin Owner of Ron Perrin Water Technologies

and the owner of Ron Perrin Water Technologies in Fort Worth, Texas. Since 1997 his company has inspected over seven thousand water storage tanks and towers in 14 states. Ron may be contacted through his web site at http://www.ronperrin.com.
Or contact RPWT Office Manager Debi Wheelan:
tankinspections@aol.com

Call: 817-377-4899

Fax 817-246-1740

June 2013 Test of New Remotely Operated Vehicle for Tank Inspections

Our first use of the DEEP TREKKER ROV was successful.   We were able to get to the back of a 500,000 gallon potable water storage tank and see sediment level and interior conditions of roof support Columbus and walls.   The second inspection we did was on a one million gallon ground storage tank. We added a safety rope to protect the tether and found the lighting system caused a little bit of glare when we went into darker parts of the tank, but it was reduced when we got closer to the inspection points we needed to look at. Overall, we found it to be a very good inspection tool!

To learn more about what may be in potable water tanks and towers visit:

“THE CLEAN WATER TANK PROJECT”

For more information on RON PERRIN WATER TECHNOLOGIES click here or visit www.ronperrin.com

Are you linked in?

I have over 600 professional contacts, Find me: Google Ron Perrin on Linked in.  Or just click here if the link works!

WHAT IS IN YOUR POTABLE WATER STORAGE TANKS AND TOWERS?   Do you need a Potable water tank or tower inspected?

Our inspection methods offer the most information for the least cost,  all of our inspection methods include an underwater DVD

allowing you to see what is in your storage tanks.  Remote video camera, ROV or potable water diver we have a method for every budget or need.

Call us toll free at 888-481-1768 or simply fill out the form below:

Contact Name(required)

Email(required)

Phone Number with area code.(required)

Request Tank Inspection Quote

Request a Tank Cleaning Quote

Request Tank Inspection & Cleaning Quote

Utility Name(required)

Mailing Address

Tell us about the tanks you would like to have inspected. Quantity, Size in gallons & Type of tank For Example: 3)-500k GST or 1)-50k elevated and 2)-100K GST. Comments may also go here:

Submit

Ron Perrin Water Technologies, Fort Worth, Texas 817-377-4899

Ron Perrin – Owner Ron Perrin Water Technologies

ronlooks@aol.com

Inspecting and cleaning water storage tanks from Texas to Florida is what we do.   We are here to serve you.  We offer the most comprehensive potable water tank inspections in the industry.   Our professional dive crew offers tank cleaning & repair services.  Our goal is to deliver outstanding service to your water utility with no disruption in service.

Call us today for a proposal to inspect or clean your potable water storage tank or tower.

or send us your contact information along with tanks sizes and types to  tankinspections@aol.com  or

Call us toll free at 888-481-1768 or if you need an inspection quote simply fill out the form below:

Contact Name(required)

Email(required)

Phone Number with area code.(required)

Request Tank Inspection Quote

Request a Tank Cleaning Quote

Request Tank Inspection & Cleaning Quote

Utility Name(required)

Mailing Address

Tell us about the tanks you would like to have inspected. Quantity, Size in gallons & Type of tank For Example: 3)-500k GST or 1)-50k elevated and 2)-100K GST. Comments may also go here:

Submit

(C)Ron Perrin 2013

Another day at work

What we do is really amazing-
Keeping tanks and water towers clean makes sure that bacteria, protozoa or even viruses don’t get a foothold in the water system.  These contaminates can find sediment in the floor of a water storage tank or tower an inviting habitat where they can hide, grow and even thrive.  Keeping the floor of water storage tanks clean reduces the risk of waterborne contamination in public water systems.

For more video of Divers Cleaning Water Storage Tanks see or blog at www.ronperrin.us

This video shows you a diver removing sediment from a water tower and what it looks like coming out!

Potable Water Tank Inspections

Since 1997 Ron Perrin Water Technologies has served the water utility industry providing state of the art inspections with remote underwater cameras.  Our inspection reports are the best in the industry covering all STATE REQUIREMENTS for water tank & tower inspection and meeting all AWWA guidelines. 

Click here for more information about Potable Water Tank Inspections

Our Web site about Potable Water Tank Inspections

or go to www.PotableWaterTankInspection.com 

 

We cover over 30 inspection points.  Our digital photography documents the condition of your tank, our narrated underwater video lets you see first hand what the inside roof walls and floor areas of the tank look like.

 

We offer the most choices for your inspection needs, 

 

* Diver inspection for the most detail

* ROV – Remotely controlled underwater vehicle

                  (specially designed for potable water use)

* Remote underwater video camera

                 (our most popular inspection, includes digital photos & narrated underwater DVD for the lowest cost).

* Basic inspection- no video no photos.  To meet state regulations for minimal cost.

 

 

 

 

 

Remotely controled vehicle

 

 

If there is a deep sediment build up we offer a underwater cleaning service.  Using certified divers and special equipment we are able to remove the sediment in the floor of the tank with minimal water loss and no disruption in service. Unlike other diving companies who make their money offshore and work in the water utility industry part time, serving water utilities is 100% of our business!   

 

Our gear is purchase for and only used in potable water. 

 

Diving in potable water is an art.  Unlike offshore divers, potable water divers must be able to enter the water system without disrupting sediment on the floor of the tanks,   Our divers are sealed in a dry suit so no part of their body touches the water.  They are then washed down with a 200ppm chlorine solution to meet AWWA and state standards.  The diver is then free to go into the confined space inside the water storage tanks, underwater the diver can do a more detailed inspection or clean the loose sediment from the floor of the tank.  Visit  www.ronperrin.us to see video of divers inspecting & cleaning waterstorage tanks. 

 

We have serviced over 500 customers that include municipal governments, utility districts towns, communities, prisons, military bases and universities.  Our customers all have a few things in common they want the most information for the lowest cost with no disruption in there water system. 

 

Visit  www.ronperrin.com

 

Call toll free today for your no obligation proposal.  1-888-481-1768

 

Inspecting and cleaning your water storage tanks and towers is critical to keeping your drinking water safe.

On June 17th 2002 the USEPA Office of Ground Water and Drinking Water  published a white paper titled: “Health Risks from Microbial Growth and Biofilms in Drinking Water Distribution Systems”.  In section 4 the paper list the types of microbes that may contaminate drinking water tanks.  I have selected this section along with several others for your review.  I also included excerpts from another white paper published on August 15, 2002 “Finished Water Storage Facilities” also reviews contaminants that may be in tank sediment and the importance of tank inspection and cleaning.

——————-  Selections

Health Risks from Microbial Growth and Biofilms in Drinking Water Distribution System

IV. Microbes that May Present a Public Health Risk in the Distribution System

This section of the paper will discuss the potential public health concern that arises when certain microbes and their products become a component of the distribution system biofilm. While some potential health effects are listed in the tables herein, additional health effects are provided in tables on the EPA Office of Ground Water and Drinking Water website. The organisms and toxins discussed are:

C Bacteria

C Viruses
C Protozoa
C Invertebrates
C Algae and algal toxins C Fungi
C Microbial toxins

A number of technical reviews of the literature have been published on biofilm organisms in the water distribution system and factors that influence their survival and growth (Geldreich and LeChevallier, 1999; Geldreich, 1996; van der Wende and Characklis, 1990; LeChevallier, 1989a; LeChevallier et al., 1990a; 1990b; 1999b; Costerton and Lappin-Scott, 1989; Marshall, 1992; Mittelman, 1991; USEPA, 1992b; NRC, 1982).

Any microbe (including some pathogens) present in water may attach, or become enmeshed, in the biofilm. Primary pathogens, which cause disease in healthy humans, may survive for a time in the biofilm. However, the survival time for many pathogens in biofilms is uncertain and likely varies depending on the organism For some pathogens, the distribution system is a physical, chemical, and biological environment unsuited for their growth. However, pathogens may accumulate in the biofilm, and the biofilm may extend the survival of primary pathogens by protecting them from disinfectants. These pathogens may be sloughed from the biofilm into the water column due to changes in the flow rate. The persistence of waterborne disease, or of microbial contamination in a distribution system, long after the cause of the distribution system problem has apparently been corrected suggests that there may be an isolated pocket of static or slow-flowing water or biofilm erosion or sloughing is occurring (i.e. the slow-release mechanism).

Page 19 – 20

D. Entry through contamination of finished water storage vessels

Both covered and uncovered finished water reservoirs provide opportunities for microbial contamination of the distribution system, and the subsequent inclusion in distribution system biofilms. Contaminated stored water can enter water distribution pipes when the water is drawn from the

vessels for distribution. Contamination introduced through earlier points in the distribution system may be amplified during storage (e.g., biofilm growth). Storage vessels may accumulate sediment, enhancing the ability of microbes to thrive during storage.

Microbial contaminants can enter open storage reservoirs by natural phenomena, animals or humans. Birds and other animals can introduce microbial contaminants through their feces, or through general contact with the finished water. Some open finished water reservoirs may also be subject to surface runoff which may be contaminated. The Interim Enhanced Surface Water Treatment Rule (IESWTR) requires that all newly constructed finished water reservoirs, holding tanks and other facilities constructed for surface water systems or ground water systems under the direct influence of surface water serving 10,000 or more people, be covered (Federal Register, December 16, 1998). The Long Term 1 Enhanced Surface Water Treatment Rule (LT1) extended this requirement to surface water systems or ground water systems under the direct influence of surface water serving fewer than 10,000 people (Federal Register, April 10, 2000).

Inadequately secured covered finished water storage vessels may allow microbial contamination to enter the distribution system. When air is drawn through air vents to replace water leaving the vessel, contamination in the air can enter (USEPA, 1992b). Humans and animals can enter inadequately protected covered finished water vessels and introduce contamination. Underground basins are susceptible to bird, animal and human contamination (USEPA, 1992b), while ground level and elevated finished water storage tanks can also become contaminated by humans and birds. A S. typhimurium outbreak in Gideon, Missouri, which caused over 400 cases of illness and seven deaths, was likely caused by bird feces contaminating an elevated storage tank (Clark et al., 1996). More information on contamination of storage vessels is addressed in a separate paper on covered storage.

E. Entry through Improper Treatment of Materials, Equipment or Personnel in Contact with Finished Water

Materials, equipment and personnel introduced to the distribution system also provide pathways for microbial contaminants to enter biofilms. The materials can include filter materials, piping, sealing vials and others (Schaule and Fleming, 1997). Personnel in contact with the water can provide a pathway for contaminant introduction (Schaule and Fleming, 1997) by introducing contaminants during maintenance or repairs of the distribution system or storage vessels. Equipment placed inside water distribution systems, such as tank cleaning equipment or video equipment used to inspect pipelines, can introduce contaminants if not decontaminated prior to use.

F. Entry through inadequate distribution system security

Lack of proper security may result in microbe entry, followed by incorporation of the microbial contaminants into the distribution system biofilm. This may result from intentional security breaches, such as vandalism or terrorism. Also, unintentional contamination can result from unauthorized users tapping into the distribution system and swimmers using storage vessels or reservoirs. Distribution systems can have many

miles of pipe, and many storage tanks and interconnections. Because of this, systems can be susceptible to tampering, allowing contamination

Page 26.

G. Sediment Accumulation

Significant microbial activity may occur in accumulated sediment (USEPA, 1992b). Organic and inorganic sediments can also accumulate in low-flow areas of the distribution system, and enhance microbial activity by providing protection and nutrients (USEPA, 1992b). Biofilms that slough can accumulate in the periphery of distribution systems leading to sediment accumulation and the proliferation of some microorganisms (van der Kooij, 2000). Sediments may be an important source of nutrients in open finished water reservoirs, by accumulating slowly biodegrading materials which are then broken down and released into the water column (LeChevallier, 1999b). The opportunities for biofilm development may be more abundant in storage tanks than in distribution system piping. Frequently, water is drawn from storage tanks only when water demand is high, such as during drought, fire flow, and flushing operations. This intermittent use results in prolonged storage times that may lead to increased sediment accumulation and lack of a disinfectant residual in the finished water storage vessel. Biological and aesthetic effects can be observed following the release of accumulated sediments from low flow areas of the distribution system (Geldreich, 1990).

Many studies have identified microbes in accumulated sediments, including both pathogens and non-pathogens. These include bacteria, viruses, protozoa, algae, fungi and invertebrates. Opportunistic pathogens that have been detected, and can multiply in sediments, include Legionella and mycobacteria (van der Kooij, 2000). Some primary pathogens can also survive for some time in sediments. Hepatitis A virus survived more than four months in sediments at both 5/C and 25/C (Sobsey et al., 1986). Other opportunistic pathogens found in sediments include Pseudomonas fluorescens and Flavobacterium spp. (Berger et al., 1993). Sediments can also release nutrients into the water which stimulate biofilm growth downstream (LeChevallier, 1999b).

VIII. Suitable Measures for Controlling Biofilm Development

Page 34

I. Proper Storage Vessel Management and Alteration

Proper storage vessel management and alteration, when necessary, can prevent contamination of the distribution system. Following TCR violations in 1996 in Washington D.C., one measure that proved effective in bringing the system back into compliance was the cleaning, inspection and disinfection of storage tanks and reservoirs (Clark, et al., 1999). To reduce pathogen presence and biofilm development, systems should have a scheduled program to rehabilitate all water storage facilities (USEPA, 1997). Proper operation and maintenance of storage tanks and reservoirs is listed as a BAT in the TCR (USEPA, 1992b). Storage tanks and standpipes should be pressure flushed or steam cleaned, then disinfected before returned to service (USEPA, 1992b), preferably with a disinfectant solution. This may not only remove microbial contamination from the vessel’s inner surface, but also nutrients that may be present. Proper operation of storage vessels can also reduce excessive residence times, which can lead to microbial survival and growth, and biofilm formation. Properly designed inlets and outlets, and the overall system design can improve problems caused by dead ends (Trussell, 1999). Pathogen contamination due to air introduction can be reduced by installing air filters to guard against pollution entering covered water reservoirs (USEPA, 1992b). Covering finished water reservoirs can protect against contamination from airborne sources, surface runoff, accidental spills and animals, such as insects and birds (USEPA, 1992b). EPA’s Uncovered Finished Water Reservoirs Guidance Manual describes recommended contamination control measures related to birds and other animals, human activity, algal growth and insects and fish (USEPA, 1999b). An understanding of the storage hydraulics and operation is important in reducing contamination of the finished water.

Proper turnover of the water in finished water storage facilities eliminates what amounts to dead ends and can reduce the extent to which biofilms develop, minimize nutrient availability and prevent the accumulation of sediments. To accomplish this systems can exercise valves to reduce stagnation, and eliminate excess storage (Crozes and Cushing, 2000).

Systems can exercise additional control over biofilm accumulation and microbial growth in finished water storage vessels by preventing sediment accumulation. This can be accomplished through periodic flushing (Crozes and Cushing, 2000) and cleaning.

__________________________________________________________

EPA White Paper #2

Office of Water (4601M)

Office of Ground Water and Drinking Water

Distribution System Issue Paper

Finished Water Storage Facilities   August 15, 2002   

Additional Information

The paper is available at the TCR web site at:

http://www.epa.gov/safewater/disinfection/tcr/regulation_revisions.html

Page 2

2.1.1 Sediment

Sediment accumulation occurs within storage facilities due to quiescent conditions which

promote particle settling. Potential water quality problems associated with sediment

accumulation include increased disinfectant demand, microbial growth, disinfection by-product

formation, and increased turbidity within the bulk water. Instances of microbial contamination

and disinfection by-product formation due to storage facility sediments are described in the

Pathogen Contamination and Microbial Growth section and the Disinfection By-Product

formation section, respectively.

2.1.2 Pathogen Contamination and Microbial Growth

Prepared by AWWA with assistance from Economic and Engineering Services, Inc. 3

Microbial contamination from birds or insects is a major water quality problem in storage tanks. One tank inspection firm that inspects 60 to 75 tanks each year in Missouri and southern Illinois reports that 20 to 25 percent of tanks inspected have serious sanitary defects, and eighty to ninety percent of these tanks have various minor flaws that could lead to sanitary problems (Zelch 2002). Most of these sanitary defects stem from design problems with roof hatch systems and vents that do not provide a watertight seal. Older cathodic protection systems of the hanging type also did not provide a tight seal. When standing inside the tank, daylight can be seen around these fixtures. The gaps allow spiders, bird droppings and other contaminants to enter the tank. Zelch (2002) reports a trend of positive total coliform bacteria occurrences in the fall due to water turnover in tanks. Colder water enters a tank containing warm water, causing the water in the tank to turn over. The warm water that has aged in the tank all summer is discharged to the system and is often suspected as the cause of total coliform occurrences. Storage facilities have been implicated in several waterborne disease outbreaks in the United States and Europe. In December 1993, a Salmonella typhimurium outbreak in Gideon, Missouri resulted from bird contamination in a covered municipal water storage tank (Clark et al. 1996). Pigeon dropping on the tank roof were carried into the tank by wind and rain through a gap in the roof hatch frame (Zelch 2002). Poor distribution system flushing practices led to the complete draining of the tank’s contaminated water into the distribution system. As of January 8, 1994, 31cases of laboratory confirmed salmonellosis had been identified. Seven nursing home residents exhibiting diarrheal illness died, four of whom were confirmed by culture. It was estimated that almost 600 people or 44% of the city’s residents were affected by diarrhea in this time period. A 1993 outbreak of Campylobacter jejuni was traced to untreated well water that was likely contaminated in a storage facility that had been cleaned the previous month (Kramer et al. 1996). Fecal coliform bacteria were also detected in the stored water. In 2000, a City in Massachusetts detected total coliform bacteria in several samples at one of their six finished water storage facilities (Correia, 2002). The tank inspector discovered an open access hatch and other signs of vandalism. This tank was drained and cleaned to remove several inches of accumulated sediment. Three other finished water storage facilities were cleaned in 2001 without being drained and removed from service. The tank closest to the filtration plant was found to contain two to three inches of accumulated sediment and the tanks in outlying areas contained four to six inches of sediment. Shortly after the tanks were returned to service, the City experienced widespread total coliform occurrences in the distribution system (Correia, 2002). The City’s immediate response was to boost the free chlorine residual in the distribution system to 4.0 mg/L (including at tank outlets). Also, the distribution system was flushed continuously for two days to remove the contaminated water. These measures resolved the coliform bacteria problem. A boil water order was not required. To prevent the problem from recurring, the City has instituted a tank cleaning program in which all tanks are cleaned on a three year cycle. City engineers are planning to improve water turnover rates by separating the tank inlet and outlet piping.

In 1995, a water district in Maine traced a total coliform bacteria occurrence in the distribution system to two old steel tanks with wooden roofs (Hunt 2002). Upon inspection, many roof shingles were missing and large gaps were present in the tank roofs. After the tanks were Prepared by AWWA with assistance from Economic and Engineering Services, Inc. 4 drained, an interior inspection found two feet of accumulated sediment, widespread coating failure on the tank sidewalls, and evidence of human entry. The tanks were cleaned and the distribution system was flushed and disinfected. A boil water order was in place until system water quality was restored. The tanks have since been replaced with a modern preload concrete tank.

3.3 Tank Inspections  Page 10

Like water quality monitoring, tank inspections provide information used to identify and evaluate current and potential water quality problems. Both interior and exterior inspections are employed to assure the tank’s physical integrity, security, and high water quality. Inspection type and frequency are driven by many factors specific to each storage facility, including its type (i.e. standpipe, ground tank, etc), vandalism potential, age, condition, cleaning program or maintenance history, water quality history, funding, staffing, and other utility criteria. AWWA Manual M42, Steel Water Storage Tanks (1998) provides information regarding inspection during tank construction and periodic operator inspection of existing steel tanks. Specific guidance on the inspection of concrete tanks was not found in the literature. However, the former AWWA Standard D101 document may be used as a guide to inspect all appurtenances on concrete tanks. Concrete condition assessments should be performed with guidance from the tank manufacturer. Soft, low alkalinity, low pH waters may dissolve the cementitious materials in a concrete reservoir causing a rough surface and exposing the sand and gravel. The concern is that in extreme cases, the integrity of reinforcing bars may be compromised. Sand may collect on the bottom of the storage facility during this process. Routine inspections typically monitor the exterior of the storage facility and grounds for evidence of intrusion, vandalism, coating failures, security, and operational readiness. Based on a literature review and project survey, Kirmeyer et al. (1999) suggested that routine inspections Prepared by AWWA with assistance from Economic and Engineering Services, Inc. 11 be conducted on a daily to weekly basis. Where SCADA systems include electronic surveillance systems, alarm conditions may substitute for physical inspection.

Periodic inspections are designed to review areas of the storage facility not normally accessible from the ground and hence not evaluated by the routine inspections. These inspections usually require climbing the tank. Periodic inspections, like routine inspections, are principally a visual inspection of tank integrity and operational readiness. Based on a literature review and project survey, Kirmeyer et al. (1999) suggested that periodic inspections be conducted every 1 to 4 months.

Comprehensive inspections are performed to evaluate the current condition of storage facility components. These inspections often require the facility to be removed from service and drained unless robotic devices or divers are used. The need for comprehensive inspections is generally recognized by the water industry. AWWA Manual M42 (1998) recommends that tanks be drained and inspected at least once every 3 years or as required by state regulatory agencies. Most states do not recommend inspection frequencies thereby leaving it to the discretion of the utility. States that do have recommendations are Alabama (5 years), Arkansas (2 years), Missouri (5 years), New Hampshire (5 years), Ohio (5 years), Rhode Island (external once per year; internal, every five years), Texas (annually), and Wisconsin (5 years). Kirmeyer et al.(1999) recommend that comprehensive inspections be conducted every 3 to 5 years for structural condition and possibly more often for water quality purposes.

Uncovered finished water reservoirs have unique problems. Consequently, water utilities have ceased constructing such facilities. As noted previously, the IESWTR prohibits construction of new uncovered finished water reservoirs in the U.S. Under the LT2ESWTR, existing uncovered finished water reservoirs will be managed in accordance with a state approved plan, if the facility is not covered subsequent to the rule’s implementation. Flexible membrane covers are one means of enclosing uncovered reservoirs and these types of facilities also require specific routine, periodic, and comprehensive inspections to ensure the cover’s integrity.

3.4 Maintenance Activities  Page 11

Storage facility maintenance activities include cleaning, painting, and repair to structures to maintain serviceability. Based on a utility survey conducted by Kirmeyer et al. (1999), it appears that most utilities that have regular tank cleaning programs employ a cleaning interval of 2 to 5 years. This survey also showed that most tanks are painted (exterior coating) on an interval of 10 to 15 years.

4.0 Summary

Microbiological, chemical, and physical water quality problems can occur in finished water reservoirs that are under-utilized or poorly mixed. Poor mixing can be a result of design and/or operational practices. Several guidance manuals have been developed to address design, operations, and maintenance of finished water reservoirs. Water quality issues that have the potential for impacting public health include DBP formation, nitrification, pathogen contamination, and increases in VOC/SOC concentrations. Elevated DBP levels within storage facilities could result in an MCL violation under the proposed Stage 2 Disinfectants and Disinfection Byproduct Rule, based on a locational running annual average approach. A separate White Paper on Nitrification indicates that nitrite and/or nitrate levels are unlikely to approach MCL concentrations within the distribution system due to nitrification unless finished water nitrate/nitrite levels are near their respective MCLs. Pathogen contamination from floating covers or unprotected hatches is possible. Recommended tank cleaning and inspection procedures have been developed by AWWA and AWWARF to address these issues.

Inspecting and cleaning your water storage tanks and towers is critical to keeping your drinking water safe.  For a free inspection or cleaning quote call 817-377-4899.