MAHC Update: Revised Disinfection & Water Quality Module

January 27th, 2014

The revised version of the Disinfection & Water Quality Module of the MAHC continues to recommend ozone, but it does not go far enough. Ozone is effective against threats that chlorine does not touch in many kinds of public aquatics venues, but the MAHC rules do not explicitly recognize it.

The MAHC Process, One More Time

The Model Aquatic Health Code (MAHC) continues its journey through bureaucratic boxes with the January 24th publication of the revised versions of the Disinfection and Water Quality Module and the Regulatory Module. All of the modules as revised will be incorporated into a complete final draft to be released by summer 2014.

The CDC recommends that if you want to make comments in the final public comment session, you should consider using the revised modules to begin your review.  Even though the final complete draft will be somewhat different than the modules to accommodate duplications, cross-references, and so forth, you will have an advantage by starting soon.  The draft full document will only be open for public comment for 60 days.

Disinfection and Water Quality Module

DEL Ozone participated in the drafting of the water quality module, though as you will see, we do wish it was more explicit about the value of secondary disinfection for many (probably most) public aquatics venues. You can find a current draft PDF of the document on the CDC webpage.

The draft best practices still recommend the use of UV or ozone as a secondary disinfection system, and make it mandatory for “increased risk aquatic venues” including those designed for diaper-aged children (less than 5 years old) and therapy pools. Secondary disinfection systems are considered “optional” for other aquatic venues.

Crypto is More Widespread Than That

This formulation underestimates the value of secondary disinfection for public aquatics venues. The purpose of the adoption of secondary disinfection is to address the failure of chlorine to act quickly enough in the presence of Cryptosporidium oocysts to prevent cryptosporidiosis. Defeating Crypto was one of the original triggers that prompted the National Swimming Pool Foundation to sponsor the MAHC process in the first place. In fact, the MAHC recommendations specifically include criteria for a 3-log reduction in Crypto for a given system to meet the standards—the point of it is to kill Crypto.

It should be obvious that the Crypto threat occurs in many more aquatics venues than children-oriented or therapy pools. In fact, you might want to refer to our post on the most recent CDC report on recreational water illnesses, including crypto. Among other things, the CDC reported that 33 out of 57 RWI outbreaks in treated recreational water occurred in hotels or water parks.

It seems to us that you ought to use a secondary sanitation system that works against the threat where the threat actually exists.


CDC Report on RWI: Crypto Outbreaks Increasing

January 14th, 2014

The Center for Disease Control and Prevention (CDC) published its summary report on the incidence of recreational water-associated disease outbreaks for 2009-2010 on January 10th. The CDC qualifies the data, indicating that it understates the number of outbreaks for numerous reasons, ranging from definitional ambiguity to inadequate capacity in local jurisdictions.

Overall, jurisdictions voluntarily reported 81 outbreaks in recreational water-associated diseases, 57 of them from treated recreational water.  In total, these outbreaks resulted in 1,326 cases of illnesses and 62 hospitalizations, but fortunately no deaths.

We found 2 of the findings especially interesting.

First, the overall incidence of reported disease outbreaks has increased significantly since reporting started in 1978. The upward trend includes a spike in 2007 that was caused by just two communities which accounted for 55% of the outbreaks in that year. The CDC chart below describes the trends in both cryptosporidosis and total outbreaks.

CDC-rwi-outbreak-trend-10Jan14
It may be that the trend is increasing simply because the reporting is improving, but obviously there is no way to know that. More relevant, the increases indicate that public aquatics venues (hot tubs and water parks are venues where a disproportionate number of cases occurred) still have a great distance to go in water sanitation practices.

The second trend in the chart is in the increasing frequency of cryptosporidosis. This chlorine-resistant parasite was confirmed as the cause of illness in 27 outbreaks (55% of the total for which etiological data was available), resulting in 422 cases of illness and 14 hospitalizations. This parasite was by far the largest single source of illness among cases where evidence of source could be determined.

Crypto does not need to be causing such havoc. Secondary treatment by ozone would kill this microbiological threat.  We hope the pending adoption of the Model Aquatic Health Code will add motivation to aquatics venue managers to make use of the known sanitation practices that can prevent these serious outbreaks.

 

 

 


Milwaukee Chose Ozone 20 Years Ago

November 22nd, 2013

We ran across an article we filed away a few months ago, and had one of those “doh!” moments.  Why didn’t we report on this sooner?

But the story is still right on the money:  ozone sanitation was chosen over chlorine and other traditional techniques because it kills Cryptosporidium – and chlorine doesn’t. (Ozone also kills all the other dangerous microorganisms lurking in under-treated water, but that’s a different story.)  This story starts with a mystery.

Milwaukee 1993:  A Collective Gasp

The Milwaukee Journal Sentinel reports that in the spring of 1993 tens of thousands of Milwaukee residents were felled by a relentless diarrhea. Schools closed, city buses ran empty, businesses couldn’t muster a quorum. Medical professionals tested stool samples and found no bacteria and no viruses.

Investigators narrowed the probable cause down to the municipal water system because that was the only common factor in so many cases.  City water officials rigorously tested the treated water, but had the same result:  no infectious microorganisms.

Finally, a Health Department employee named Stephen Gradus decided to test for an unusual organism, the parasite Cryptosporidium.  Almost immediately he found Crypto in stool samples and later throughout the city’s water distribution system.

Ultimately, about 403,000 people suffered from severe diarrhea, made worse for many because they had been drinking extra water for two weeks hoping to rehydrate their systems. 69 people with weakened immune systems died in the Milwaukee area.

In the aftermath of this disaster, the city built a rock-solid water treatment facility that is delivering some of the best water in the nation today. Tests have not detected a single Crypto cyst in one of the treatment plants involved in 1993 since March 1999, when rebuilding was complete.

Ozone Can Kill Crypto

In the new facility, the very first step in the treatment process is with dissolved ozone.  The Journal Sentinel article says it well: “Ozone replaced chlorine as the primary disinfectant because it can kill microorganisms such as Crypto that are left untouched by chlorine. Ozone also controls taste and odor problems.”


Another Place We’ve Heard This Theme

Aquatics professionals are aware that the Centers for Disease Control Model Aquatic Health Code includes ozone as an appropriate secondary treatment for commercial pools for the exact same reason:  it kills Crypto.  And it does a lot of other good things for a commercial pool:  it controls disinfection byproducts, reduces asthma-inducing compounds, kills all microorganisms on contact, and oxidizes organic compounds like fulvic acid.

Ozone is the single best sanitation agent available for your commercial aquatics venue.


Pool Water Quality Rules Tighten Up in California

August 16th, 2013

If you think what happens first in California eventually migrates eastward, listen up. The CA state legislature is discussing making amendments to pool water quality regulations that set quality standards that you must meet, or risk having your pool closed.

Nuts and Bolts of the Regs

For most commercial/public pools, the new law would continue using the minimum standard for free chlorine residual of 1.0 ppm, or 1.5 ppm if a chlorine stabilizer is used.  However, for spas, wading pools and spray features, operators would have to  maintain a minimum of 3.0 ppm free chlorine residual (with or without cyanurates).

The changes in combined chlorine standards are broader, and would affect all commercial venues.  The current requirement is that when the combined chlorine is ½ the residual of total chlorine (free + combined), the water should be replaced or super-chlorinated.  The proposal gets more specific:  you would have to monitor daily for combined chlorine, with the maximum allowable level of 0.4 ppm.

The maximum allowable level of chlorine stabilizer (such as cyanuric acid) would decrease from 100 ppm to 50 ppm.  The allowable pH range would decrease from 7.2 to 8.0 to 7.2 to 7.8.

Taken together, these changes impose a narrower range of permissible water chemistry on operators. They make reliance on chemicals alone even more difficult.

Add Ozone, Make Your Life Easier

The legislation pending in California does not even talk about other issues with chlorine. For example, the Centers for Disease Control’s almost-finished Model Aquatic Health Code recommends that commercial pools use ozone or UV in addition to chlorine to add germicidal capability to the sanitation system.

Why?  In short, because chlorine does not reliably kill Cryptosporidium, even after prolonged contact times.  Ozone and UV do.

But why settle for just killing Crypto?  Ozone, as a potent oxidizer, also helps to keep combined chlorine compounds in check.  It oxidizes them, but UV does not.

We have long recommended using ozone plus chlorine residual as the most effective, and cost effective, water sanitation treatment available for commercial pools. As more and more evidence comes out that chlorine alone is not only insufficient, but can trigger the production of harmful chloramines and other noxious chemicals, the public is going to demand cleaner water free of chemicals.

The perfect “chlorine free” pool is not possible.  But it is absolutely possible to have a pool that smells chlorine free and protects swimmers at the same time. Go ozone.


Model Aquatic Health Code Update

July 3rd, 2013

This is a really short post:  the very last of the 14 MAHC modules is now open for public comment, through August 31. See the Recirculation Systems and Filtration module synopsis, and link from it to more detailed documents.

7 of the fourteen modules have been revised based on public comments; 6 more are in committee review and revision following public comment.  The advent of the Model Aquatic Health Code is closing in.

BTW, for those of you who have been lounging by the pool, the MAHC is a best practices guideline for public pool design and operation, developed by committees of experts under the aegis of the Centers for Disease Control.  It will be available to any jurisdiction across the nation that wants to adopt all or parts for local enforcement, possibly as early as next spring or summer.


Pool Water Quality: Funding Decreases vs. MAHC

June 25th, 2013

Here’s an irony for you.  Just as the Model Aquatic Health Code (MAHC) finally, slowly, haltingly makes its way onto the national stage, funding for pool inspections has declined.  Evidence shows that these inspections do make a positive difference. So what happens next?

One outcome to watch is whether the pool industry can organize itself to use known best practices to sanitize pool water.  Or, we may be dependent on pool owners to take charge more actively.   We may not be able to push this responsibility off on inspectors, much as we may like to.

Fewer Inspections = More Illnesses

The headline in the USA Today story explicitly links an increase in Recreational Water Illnesses (RWIs) to reductions in the number of pool inspectors.

The article is not research, but it presents a compelling coincidence.  First, it details how a number of states have reduced the number of funded inspectors in recent years, possibly due to revenue losses during the recent deep recession. One of the states cited was Georgia, which reduced the number of inspectors by about 100 since 2008.  Then, it calls attention to the widely quoted Centers for Disease Control publication in May 2013 that reported finding dangerous microorganisms in public pools in the Atlanta metro area.

It is very plausible that fewer inspections lead to more illnesses. That’s one of the points of inspection, after all – to ensure that public pool water quality meets standards. One shard of information that backs this up is the CDC’s 2010 finding that one in 8 inspections of public pools led to a closure due to a sanitation concern.

It’s the Money that Matters

About a year ago, New Hampshire was debating whether to cut funding for pool inspections. A local news report found that the inspection program had closed 224 pools in the previous 5 years for sanitation violations.  The cuts would eliminate those inspections.

Who should pay for these inspections? It might be counterintuitive, but we see many pool owners – like hotels or motels, private sports associations, schools – actively seeking inspections as a way to help them maintain their pools. The traditional model of using public health agencies to provide these inspections seems to be threatened.

An alternative model of inspections through a professional association funded by pool owners might seem to be an option, but it runs into the problem so many community actions face.  Individual pool owners have an incentive to skip paying for it, hoping to be the one that avoids consequences. This is why public agencies are usually involved in the first place, to make the inspections mandatory.

We don’t have an easy fix for this public problem, but we do know that individual pool owners can make a big difference.

Pool Water Quality Solutions

Pool owners can help themselves with technically modern, aggressive water quality programs.  Of course, we know that ozone and Advanced Oxidation Process sanitation is an effective option to add to a program that combines traditional chlorine sanitation – with a lower level of chlorine – with a secondary sanitizer that can kill the tough bugs like Crypto.  In fact, this sanitation program is at the heart of the MAHC module on water quality.

With or without inspections, pool owners can help to protect the health of swimmers in their pools.


What Can Be Done About Poop in the Pool?

May 29th, 2013

The Centers for Disease Control released a research note in mid-May that spawned stories all over the Internet about poop in the pool.  This was a headline writers could not resist:  Over half of US public pools are poopy!  Even the better media reports took advantage of this grabber even though the research doesn’t actually support the statement.

These dramatic stories were based on the CDC finding e. coli DNA in filter backwash samples of 58% of the 161 public pools it evaluated in the Atlanta metro region in the summer of 2012.  In fact, the research found evidence of frequent contamination by Pseudomonas aeruginosa as well as a small number of cases of other microbial threats including Cryptosporidium and Giardia.  All of these microbes can be linked to Recreational Water Illnesses.

We certainly agree that we need to get these microbes under control.

In fact, the CDC main takeaways are about how a hygiene partnership between swimmers, pool operators, and regulators can help control the presence of microbial contamination in pools:

  • Swimmers need to shower before entering the pool!  And don’t go in the pool with diarrhea!
  • Pool operators need to maintain a proper sanitation program and pH balance.
  • Regulators need to enforce local water quality rules.

Ozone Disinfection Works:  Here’s Why

DEL cannot make swimmers take showers, or get regulators to do their jobs (or get them funded), but we do know something about pool water quality maintenance. Our ozone and Advanced Oxidation Process pool sanitation systems apply advanced technology to helping pool owners and professionals do their part to maintain water quality.  These systems have several important properties that enhance pool sanitation:

  • Ozone kills microbial contaminants:  We will not overload you with research reports, but there is a lot of academic and 3rd party testing that shows that ozone is an effective antimicrobial agent.
  • DEL Ozone systems inject powerful oxidizers that kill contaminants in the return line downstream of the pump and filter, where the contaminants collect.
  • DEL systems are automatic in the sense that they generate oxidizers on demand whenever the pump runs, without further intervention.
  • DEL Ozone systems are compatible with and supplement traditional chlorine-based sanitation programs to make them more effective.

Ozone Kills Microbial Contaminants

Here’s some data about ozone effectiveness.  Of course, actual results depend on the concentrations and time of contact, but these variables are controlled in these tests.  In fact, microbial concentrations are almost never as high as found in these tests, and ozone begins to destroy them on contact.

Actual Microbial Reductions in 30 Seconds to Six  Minutes

E. coli                    4.7 log (>99.99%)
Staphylococcus aureus        4.7 log (>99.99%)
Pseudomonas aeruginosa        3.2 log (>99.9%)
Trichophyton mentagrophytes    4.0 log (99.99%)
Candida albicans            4.7 log (>99.99%)
Cryptosporidium parvum        3.0 log (>99.9%)

Downstream of the Filter, Where the Microbe Killing Matters

In DEL Ozone pool sanitation systems, the ozone and/or hydroxyl free radicals are injected into the pool return line under vacuum, downstream of the filter and pump.  You may have noted above that the CDC research used filter backwash as the source of their samples, and for a good reason.  That’s where contaminants collect.

Therefore, the DEL systems inject powerful oxidizers at the point where the pool water needs to be disinfected before returning to the pool.  Even the most chlorine-resistant microbes, like Cryptosporidium, are wiped out before entering the pool water body.  Unlike UV-only systems, ozone actually puts a small, temporary residual of ozone into the pool water for continuing disinfection.

Needless to say, even a powerful ozone system cannot completely eliminate e. coli if a bather is unclean and infected.  You will want to maintain a small residual of chlorine in the pool for that first line of defense.  But ozone and AOP, unlike UV only systems, will work actively and effectively to help you maintain clean pool water in the real world of real people.


Is Ozone Really a Threat?

February 19th, 2013

No.

Or more exactly, it is not a threat in all circumstances.  And it is very important to make the distinction.

Ozone is one of the most beneficial chemical disinfectants known to humans, when properly applied.  When it forms in the ground level atmosphere because of tailpipe emissions from burning fossil fuels, it’s a problem.

Confusing the two kinds of ozone could reduce our use of ozone in beneficial applications like wastewater treatment, pool sanitation, and food safety.  In those applications, ozone is not only safe, it is an effective disinfectant that has no side effects or environmentally dangerous consequences.  The byproduct of oxidation disinfection by ozone is ordinary oxygen.

We would benefit from more of this ‘good’ ozone, not less.  Good reporting needs to make this clear.

Ozone as Bad Weather News

Practically every day in Southern California, a news report or reporter warns people, especially those with compromised lungs, about high ozone levels in the lower atmosphere.  Recently, a Wall Street Journal article (access restricted) reported on a link between ground level atmospheric ozone and problems for pregnant women, specifically pre-eclampsia, based on research done in Sweden.

In fact, the study that is cited by WSJ, which is titled Air Pollution Exposure in Early Pregnancy and Adverse Pregnancy Outcomes (download PDF), makes numerous references to a woman’s exposure to traffic pollution during the first trimester of her pregnancy as being related to subsequent pre-term delivery and/or pre-eclampsia. It also cites previous research that tends to confirm the relationship between air pollution and problem pregnancies:  “Thus, a study from Southern California reported that traffic-related air pollution was positively associated with pre-eclampsia, and a Dutch study showed a positive association between such pollution and pregnancy-induced hypertension.”

Whether or not these studies of the link between traffic air pollution and problem pregnancies are confirmed, the reports do influence readers to associate ozone with bad health outcomes. It is not a stretch to think that the negative connotations about ozone due to the WSJ article will influence the attitudes of readers toward the use of ozone in beneficial applications as well.

We Agree:  Traffic Air Pollution is a Real Problem

The causal factor in these studies is traffic air pollution due to burning fossil fuels. Researchers have known for many years that ozone is a byproduct of the chemical chain reaction set in motion when nitrogen compounds created in combustion interact with other chemicals in the air, especially in the presence of sunlight. Exposure to these pollutants, especially for pregnant women early in pregnancy and for asthmatics, can have serious health consequences.  All of these problems deserve attention and action, beginning with making the transportation system cleaner and more efficient.

Responsible Reporting Acknowledges ‘Good’ Ozone

Creating an association between ozone and disease without highlighting the actual causes diverts attention from the real issues.  Ozone in the lower atmosphere is a byproduct of burning fossil fuels.  That’s the underlying point that needs to be made.

At the same time, responsible reporting on ozone-related studies must always make the distinction between the ‘good’ and ‘bad’ ozone.  Good uses of ozone benefit human life, and we should encourage their use.


Whither the Model Aquatic Health Code?

October 4th, 2012

Tom Lachocki writing for the National Swimming Pool Federation, which was an original sponsor of the Model Aquatic Health Code (MAHC), has called for the adoption of the Code.  He correctly cites the need for a standard, scientifically justified code.

But the MAHC has a long and winding road to travel before implementation. Remember that the Code is not a law:  it is a compendium of science-based best practices to help pool operators provide safe and healthy water, in a safe and healthy environment.  Various jurisdictions may choose to adopt part or all of the Code for public health regulation – or they may not.

Industry Support or Opposition Will Make a Difference

An AI article calls our attention to another impediment to adoption.  Kendra Kozen’s piece addresses an industry complaint about the MAHC Facility Design & Construction module which requires a minimum depth at the starting blocks of a competition pool of 6 feet 7 inches for a length of 20 feet. It’s not surprising that existing pool operators see this as a huge problem due to the cost of retrofitting pools to this standard.  Kozen also writes that there are several compromise positions that could facilitate the acceptance of this standard, or one aiming to achieve the same thing (safety for diving into the pool to start a race or lap).

But that’s not the point: the industry simply has to be on board for these standards or public health jurisdictions will not adopt them. The costs of the various best practices recommended in the Code will be weighed against their benefits, and support or opposition will be in proportion.

The Public Role in the Adoption Process

It’s far too early to know how the MAHC adoption process will go, but the role of the public may be important.  Increasing publicity in news media for disease outbreaks or sanitation system failures ensure some degree of constant pressure.

Added to this, the Centers for Disease Control (the home agency for the MAHC) has begun to spread the news about the Code and how it can help make swimming safer. The MAHC Factsheet, published in mid-August 2012, promotes the adoption of the Code by noting how it can help prevent consumers’ diseases, injuries or medical problems, and how it will help prevent aquatic venue closings.

We support the adoption of the Model Aquatic Health Code because it will make swimming a safer form of healthy exercise and play for millions of people.  But standards whose cost-benefit ratio is poor could hold up or prevent the adoption of the good parts of the Code (full disclosure: like secondary sanitation).  Those lower value standards, like the one for depth at the starting blocks, need to be revised or dropped.


Chlorination Byproducts and Hepatitis C

August 14th, 2012

A recent article by Nicole Cutler at Hepatitis Central called our attention to how pool chemicals can be especially dangerous for people with Hepatitis C.  She focuses on the organic byproducts of the interactions between primary sanitizers – especially chlorine – and organic material in the pool. These byproducts can increase the toxin load on Hepatitis C victims whose damaged livers are already taxed trying to cope with ordinary threats.

Cutler recognizes that the linkage between disinfection byproducts (DBPs) and liver disease is not yet clinically proven, but the biological pathway that raises her concern is valid. Finding less toxic ways to disinfect swimming pools reduces risks for everyone.

Ozone Oxidizes both DBPs and their Precursors

We published a series of blog posts about a year ago that dealt in some detail with  disinfection byproducts, including both definition and evidence issues. The limited but important research on these elements supports our concern, even for swimmers not challenged by the extra burden of Hepatitis C.

Fortunately, ozone sanitation is an excellent option for addressing some of the concerns raised by Cutler and others.

Ozone helps to prevent the formation of disinfection byproducts.  For example, ozone, unlike UV, oxidizes urine and perspiration, either of which can combine with chlorine in noxious forms.

Ozone is capable of destroying disinfection byproducts like chloramines without materially affecting the free available chlorine needed to keep a pool safe.

Ozone oxidation, unlike superchlorination, is effective against organic chloramines as well as inorganic ones.

Ozone Helps Prevent the Problem

The presence of DBPs in pool water – or in the air just above it — depends on many factors. Ventilation, bather load, bather practices, and the chemical sanitation program can all affect the level of DBPs in the water. However, it is quite certain that making ozone part of the sanitation program can help to prevent the formation of disinfection byproducts.

When DBPs are prevented, so are their unintended health consequences.