It seems the more we learn about the hazards of recycled water – tertiary treated sewage effluent – the more public announcements are made about its increased use in California. I have written extensively about the use of recycled water in Monterey County to irrigate vegetables consumed raw, but news comes about a major proposed use in Sonoma County to irrigate almost 34 square miles of intensive agriculture land including grape vineyards. While there is major resistance from farmers, landowners, and residents, this behemoth project seems to just keep lumbering along, with its momentum greased by federal and state money plus the lobbying and PR efforts of the recycled water industry.
In quick review, my earlier writings have pointed out the fact that pathogens and harmful organic and inorganic chemicals can pass successfully through a tertiary treatment process. That means that they escape into the environment and are available to do damage. However up to now, the people purveying treated sewage effluent to the public have been fairly successful in obfuscating the discussion by mixing and matching scientific pieces of information and making many believe that the dangers ended at the treatment plant and the effluent is safe.
Current Water Quality Standards Are Inadequate
One of the things I have noticed is that people tend to cease to be alarmed when they are repeatedly assured that projects like the Monterey County’s Castroville Sea Water Intrusion Project (CSIP) are held to standards such as California’s Title 22 water quality standards and rules. What nobody explains is that those standards and rules are inadequate in this area.
Coliforms have been used as indicators for the presence of pathogenic microorganisms in the testing of water. In other words, if coliforms are detected in water, it is assumed that pathogenic microorganisms may also be present, and steps must be taken to protect the public health.
For many years the mere identification of coliforms was thought to be adequate for protecting the public from pathogens in drinking water. Over the past 15 or 20 years however, there has been increasing evidence that coliforms are not adequate indicators for all pathogenic microorganisms. For example, human pathogenic viruses have been detected in treated drinking water that contained no coliforms and met other drinking water standards for turbidity and free chlorine. In addition, numerous scientific studies have shown that many pathogenic microorganisms such as E. Coli 0157:H7 survive in the environment (i.e., soil, water, and air) for much longer periods of time than do the coliforms.
Perhaps the most convincing evidence that coliforms are not the best indicators of the microbiological quality of water are the data on waterborne disease outbreaks in the United States. Despite advances in sanitation practices in this country, the number of reported waterborne disease outbreaks has not decreased in recent years. The number has actually increased. Some of the increase is undoubtedly due to improvements in reporting, but nonetheless, a significant number of waterborne disease outbreaks continue to occur every year. The World Health Organization tells us that waterborne infections account for 80% of all infectious diseases world wide and 90% of all infectious diseases in developing countries.
The World Heath Organization (WHO) put this issue in perspective when they reported in 2003 that: “Analysis of data accumulated over the 20th century has suggested that some of the microbial testing standards (e.g. heterotrophic plate count, total coliforms and thermotolerant coliforms) have little predictive value for public health purposes. It is clear from the scientific literature that previously held beliefs about water testing are now being challenged by emerging pathogens that are resistant to standard water and wastewater treatment processes. These pathogens – such as E. coli 0157:H7 — exhibit extended survival periods in the environment, can adversely affect sensitive subpopulations, and only require extremely low doses – just a few cells — for human infection.”
To get closer to a safer recycled water effluent it will undoubtedly be necessary to have additional advanced wastewater treatment technologies incorporated into tertiary treatment facilities than currently exist in most situations. These advanced treatment methods that provide additional barriers to pathogens include additional filtration technologies (either conventional or membrane) and water disinfection steps using ultraviolet irradiation, chemicals such as ozone, activated carbon, air stripping, chemical oxidation, or membrane technology such as reverse osmosis.
The problem with all these additional treatments that are required to make the water safer for the consumer is that they cost more money, maybe a lot more money. The water recycling industry and the people benefiting from this current practice do not want to pay more for our safety. Once we realize that recycling water if made really safe costs as much or more as other technologies such saltwater distillation, water reuse companies with all this recycled water technology could be left with a technological dinosaur.
So What’s The Problem?
So far the water recycling industry has been succeeding in fooling the general public by pointing to the California Title 22 standards and saying, “No problem here. We’re meeting State of California standards”. If they can make us believe that, 1) the requirements of California Title 22 are truly protecting our safety and; 2) they are following those Title 22 requirements and standards, what’s the problem?
So our response should be that those standards and rules are inadequate for these circumstance and the standards should be changed. But introducing new standards (metrics) into the practices of CSIP farmers and growers has been resisted, well, … like the plague. The “vegetable grower-industrial complex” has hammered on regulators and legislators to not put standards into place that would indeed measure the degree of hazard we are facing.
GAPS in the Metrics
The California growers that have been claiming that they can regulate themselves with their new organization and practices call their standards Good Agricultural Practices (GAP). After the huge financial losses this past Fall with the spinach E. coli 0157:H7 outbreak, the fresh cut industry accelerated work on a set of leafy green “Good Agricultural Practices” (GAP), now called the “GAP Metrics.” The Western Growers Association (WGA) led the coalition of industry and farm groups developing
the GAP Metrics.
In a soon-to-be-published report entitled “E. Coli O157: Preventing Outbreaks”, Dr. Charles Benbrook of the Organic Center has much to say about the deficiencies of the California growers GAP metrics. You might say that Dr. Benbrook points out some “gaps in the metrics.”
Dr. Benbrook states:
“The water testing provisions, collectively, are the most serious flaw in the GAP Metrics. The water testing provisions rely exclusively on testing for generic E. coli. While the presence of generic E. coli is an indicator of possible E. coli O157 contamination, the correlation is not strong, nor sufficiently reliable to judge a water source as safe if it meets the proposed generic E. coli standards. Not only is the basic standard governing water quality based on the wrong organism, the standard applicable to generic E. coli is also unscientific and indefensible. The standard is based on an outmoded recreational water quality risk assessment carried out by EPA in the mid-1980s.”
The GAP
Dr. Benbrook goes on to conclude:
“Clearly, new science and more thought needs to be devoted to how to set the standard for both generic E. coli and pathogenic E. coli in irrigation water. In the interim, the Metrics should be revised to require the testing of irrigation water for E. coli O157. Water with detectable levels of E. coli O157 should not be used to irrigate fresh cut leafy greens. Period.” (Emphasis added)
I couldn’t agree with him more. I have been adamant about the risk of projects like Monterey County’s recycled water project they call “Castroville Sea Water Intrusion Project (CSIP)”. Until the recycled irrigation water is regularly tested at what scientists call “point of use” (POU), the safety of leafy green consumers cannot be assured. For irrigation projects like CSIP and Sonoma County’s, that necessary testing site is not at the treatment plant, it is at the irrigation sprinkler head.
Biofilms and Bacterial Re-growth
The sprinkler is where the biofilm material will exit the irrigation system and contaminate the growing crops. Remember from my earlier articles that many of us in science are realizing just how important biofilms are in the transmission of disease. The 45 miles of buried pipeline from the sewage treatment plant in Monterey’s CSIP is a perfect repository for pathogen-containing biofilms just waiting to become dislodged from their resting place in the pipeline system to spew periodically onto the growing vegetation. In the case of lettuce and spinach eaten raw, it is like a loaded gun for the consumer.
In a recent article in the Capital Times, author Elizabeth Larson interviewed farmers who were very concerned about Sonoma County Water Agency’s proposed Northern Sonoma County Agricultural Reuse Project that would supply tertiary treated wastewater for use in irrigation and frost protection on 21,500 acres of agricultural lands in the Alexander, Dry Creek and Russian River valley areas. The $385 million plan calls for 19 storage reservoirs and 112 miles of transmission pipelines and pump stations.
Larson interviewed farmer Richard Rued who said he uses wastewater for frost protection on one of his ranches. He said the water caused algae and weeds to grow and plug up his sprinklers. He spent a day cleaning the sprinklers and he said afterward his hands swelled up and hurt for two weeks. “I don’t know what caused it, but I suspect there’s something in the wastewater,” he said.
Without knowing it, much of what Rued was cleaning from his sprinklers was biofilms. While it has been mostly unreported, there is the anecdotal and empirical evidence from the people working like Rued in this hazardous environment every day. Can you imagine the opportunity for pathogen biofilm buildup in Sonoma’s 112 miles of pipelines? Now that’s a profile of a potential disaster.
In a previous article I spent time describing what many now believe is the true Achilles heel of the efforts to dispose of treated sewage effluent by irrigating food crops – biofilms and bacterial re-growth. If there is anything that can get the attention to a discussion with the recycled water industry, it is the mention of “biofilms” and “bacterial re-growth”.
Many in the science world are just starting to grasp the magnitude of the role of biofilms in disease. It has been said that 85% of all infectious disease emanates from biofilms. That’s a powerful source of misery that needs to be understood. Oh, that plaque on our teeth they clean off periodically to prevent tooth decay? Yup, it’s biofilm.
As we have found, these colonies of bacteria are living groups of organisms that have collectively built a system of protection that includes inter-cell communication, food transport and defense barriers systems. A biofilm consists of about 15% bacteria and 85% nutrient for food used by the colony. These wily organisms have their own nutrient storage system. What could be better for them than to be inside a pipeline nutrient-enriched with concentrations of their food — nitrogen, phosphorus, ammonia and organic matter? That pipeline description nicely fits the environment of a wastewater distribution pipeline like that in the Monterey County CSIP and the proposed Northern Sonoma County Agricultural Reuse Project with its 112 miles of pipeline.
For a wonderful description of biofilms I recommend that you read Dr. Bill Costerton’s “BioFilms . . . A Growing Problem”.
And for a graphic depiction of the pathogen environment in a pipeline, take a look at this.
The biofilm life cycle consists of three steps: attachment, growth of colonies, swarming phenomenon and detachment in clumps or “seeding dispersal.” For a visual, take a look at this.
Biofilm bacteria can move in a pipeline numerous ways: Collectively, by rippling or rolling across the surface, or by detaching in clumps or individually, through a “swarming and seeding” dispersal. This is an illustration of how that happens.
I have written that the subject of bacterial re-growth in pipeline distribution systems still baffles the water reuse industry as they desperately and quietly try to find a solution to the problem their recycled water systems have helped create. Dr. A.K. Camper at Montana State University has published research that says that biofilm bacteria require organic carbon in order to metabolize and grow. In research reported by her in 2004 she said Biodegradable Organic Carbon (BDOC) and Assimilable Organic Carbon (AOC) tests are commonly used to measure the organic carbon concentration in water distribution systems. Her research found that the BDOC and AOC tests may greatly underestimate the amount of carbon available for biofilm growth and resultantly their potency in a pipeline. This means that another set of tests upon which water treatment professional rely could be invalid.
We are surrounding by mountains of evidence that a deadly situation exists of our own making and yet so far, little has been done to rectify the situation. It would appear that not enough people have been sickened and died to force the taking of appropriate actions to protect the health of US citizens.
Frank Pecarich retired from the Washington, D.C. headquarters of the US Bureau of Reclamation in 1987. During his 26 year federal career he worked as a soil scientist with the USDA on the now- published Soil Survey for Monterey County. He lives in Ventura County.
Related articles that have been published by the California Progress Report by Mr. Pecarich can be found under the topic of Food Safety . http://www.californiaprogressreport.com/food_safety/index.html
