How Forest Fires Save Water

Posted May 30th, 2018
Environmental

 

Billions Of Gallons Of Water Saved By Thinning Forests

Too many trees in Sierra Nevada forests stress water supplies, scientists say

forestfire

 

There are too many trees in Sierra Nevada forests, say scientists affiliated with the National Science Foundation (NSF) Southern Sierra Critical Zone Observatory (CZO).

That may come as a surprise to those who see dense, verdant forests as signs of a healthy environment. After all, green is good, right? Not necessarily. When it comes to the number of trees in California forests, bigger isn’t always better.

That’s in part because trees use lots of water to carry out basic biological tasks. In addition, they act as forest steam stacks, raking up water stored in the ground and expelling it as vapor into the atmosphere, where it’s accessible to humans and forest ecosystems only when it falls back to Earth as rain and snow.

That process — by which plants emit water through tiny pores in their leaves — is known as evapotranspiration. And according to researchers, excessive evapotranspiration may harm a fragile California water system, especially during prolonged, warm droughts.

New research published this week in the journal Ecohydrology shows that water loss from evapotranspiration has decreased significantly over the past three decades. That’s due in large part to wildfire-driven forest thinning — a finding with important implications for forest and water management.

A century of forest management had kept wildfires to a minimum. But without fire, Sierra forests grew very dense. In recent decades, new policies have allowed nature to take its course, with wildfires helping to thin out overgrown forests.

“Forest wildfires are often considered disasters,” said Richard Yuretich, director of NSF’s CZO program, which funded the research. “But fire is part of healthy forest ecosystems. By thinning out trees, fires can reduce water stress in forests and ease water shortages during droughts. And by reducing the water used by plants, more rainfall flows into rivers and accumulates in groundwater.”

Using data from CZO measurement towers and U.S. Geological Survey satellites, researchers found that over the period 1990 to 2008, fire-thinned forests saved 3.7 billion gallons of water annually in California’s Kings River Basin and a whopping 17 billion gallons of water annually in the American River Basin — water that would otherwise have been lost through evapotranspiration.

Forest thinning has increased in recent decades in an effort to stave off disastrous wildfires fueled by dense forests. This study shows that restoring forests through mechanical thinning or wildfire can also save California billions of gallons of water each year.

“The need for forest restoration is being driven largely by the need to lower the risk of high-intensity wildfires and restore forest health,” said University of California Merced scientist Roger Bales, director of the Southern Sierra CZO and study co-author. “Downstream users who benefit from the increased water yield are an important potential revenue stream that can help offset some of the costs of restoration.”

Forested areas needing restoration are large, Bales said, but potential changes in water availability are significant. The total effect of wildfires over a 20-year period suggests that forest thinning could increase water flow from Sierra Nevada watersheds by as much as 10 percent.

The U.S. Forest Service says that 6 to 8 of the 21-million acres it manages in California need immediate restoration. Another 58 million acres nationally also require restoration. For California alone, restoration costs are estimated at $5 to $10B. But, according to the study authors, the restoration might help pay for itself.

“We’ve known for some time that managed forest fires are the only way to restore the majority of overstocked western forests and reduce the risk of catastrophic fires,” said James Roche, a National Park Service hydrologist and lead author of the new study. “We can now add the potential benefit of increased water yield from these watersheds.”

About The National Science Foundation (NSF)

SOURCE: The National Science Foundation (NSF)

Reprinted from Water Online.

Water Hazards from Swimming Pools

Posted May 24th, 2018
Water and Health

The CDC Recommends: Don’t Drink Pool Water

drinkingpoolwater

From 2000 to 2014, public health officials from 46 states and Puerto Rico reported 493 outbreaks associated with treated recreational water, resulting in more than 27,000 illnesses and eight deaths, according to a report in the May 18 Morbidity and Mortality Weekly Report. Hotel pools and hot tubs were the setting for about a third (32 percent) of the outbreaks, followed by public parks (23 percent), club/recreational facilities (14 percent) and water parks (11 percent).

Most of the infections were from three organisms that can survive chlorine and other commonly used disinfectants: Cryptosporidium, a parasite that can cause gastrointestinal problems, Pseudomonas, a bacteria that causes swimmer’s ear, and Legionella, a bacteria that causes a pneumonia-like illness.

So, what to do? The CDC recommends a few steps before diving in: Don’t swallow pool water. Don’t let children with diarrhea in the water. And use test strips to measure levels of pH, bromine and chlorine in the water. The cleaner the water, the safer to swim.

 

Source: Science News.

Rain Increases Groundwater Contamination

Posted May 16th, 2018
Bacteria, Turbidity and Suspended Solids, Ultraviolet, Water Treatment 101

Summer Rains Increase Risk of Human Viruses in Groundwater

 

By Kelly A. Reynolds, MSPH, PhD

Gazette note: Below is a truncated version of an excellent article  from the June 2017 issue of  Water Conditioning & Purification.  Dr. Kelly A. Reynolds is a widely recognized authority on water quality issues and especially microbial contamination. The increasing frequency of waterborne disease described in the article explains the growing popularity of point of use and point of entry home treatments like ultraviolet disinfection. 

 

Just as the weather constantly varies, the quality of source water is also ever-changing. Increased rainfall in spring and summer months creates additional challenges to municipal water suppliers and private well owners as water moving over the land and through the soil accumulates added contaminants capable of causing human disease.

 

Heavy rainfall associated with waterborne disease

 

Surveys of extreme precipitation events indicate (rainfall more than two inches a day) and waterborne disease outbreaks (WBDO) in the US are strongly correlated. Retrospective comparison of 548 outbreaks documented by US EPA and precipitation data from the National Climatic Data Center from 1948 to 1994 showed that 68 percent of WBDOs were preceded by extreme precipitation events. Surface water was the most likely to be contaminated and result in an outbreak during the same month as the rainfall event but groundwater outbreaks lagged by about two months.

 

Twenty-four years ago in late March, the largest documented waterborne outbreak in US history occurred in Milwaukee, WI. Before identifying the problem, residents consumed contaminated water for over two weeks. Ultimately, more than 400,000 people were sickened with diarrhea and over 100 died. Cryptosporidium, a protozoan pathogen, caused the outbreak and may have been introduced due to increased precipitation and the presence of nearby cattle farms. Crypto has been found in 64 percent of manure samples from a sampling of 50 livestock farms. Following rain and land runoff, Crypto from nearby farms is readily transported to surface supplies, where associated increases in turbidity further tax treatment works.

 

Groundwater risks

 

Surface water risks are somewhat expected and municipalities have treatment tools, including the use of flocculants, filtration and disinfectants to settle out, filter and inactivate harmful microbes. While federal regulations mandate treatment of surface water, utilities accessing groundwater are not necessarily required to treat. Thus, less obvious and less controlled are groundwater contamination events. The greatest concern with seasonal groundwater contamination are human viruses. Viruses, unlike larger bacteria and protozoa, easily navigate the tortuous path from land surface to underground aquifers. Storms, however, can lead to sewer overflows and contamination of groundwater wells with a variety of microbial hazards.

 

Recently Minnesota and Wisconsin state health departments announced evidence of disease-causing microbes in a high percentage of drinking-water wells. In Minnesota, eight percent of a collection of 478 samples and 37 percent of the 82 public water systems with a groundwater well supply tested positive for human viruses. Eleven percent were positive for Salmonella bacteria. Less is known about household well water supplies. An estimated 34 million households in the US are served by private wells. One Wisconsin study found that out of 50 wells from seven hydrogeologic districts, eight percent were positive for human viruses, including hepatitis A virus, rotavirus, and noroviruses. With summer being Wisconsin’s rainy season, concern this time of year is especially heightened.

 

Most private and public groundwater supplies are not filtered or disinfected. The presence of low levels of human virus genomes in groundwater is common and has been associated with a 30 percent increase in gastrointestinal illness. Up to 63 percent of gastrointestinal illnesses in children were attributed to these tap-waterborne viruses.

Source: Water Conditioning and Purification.

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High Performance Cartridge-Style Chloramine Filter

Posted May 11th, 2018
Chloramine, Water Treatment 101

A Case Where Two Is More than Twice As Much as One

Double_Parallel_CompactWH_withBypassFor a water filter to work well, the water needs an adequate “residence time” within the filter medium. The rate that water flows through the filter affects the filter’s effectiveness (the percentage of the contaminant it removes), the pressure drop (how much the filter reduces water pressure), the longevity of the filter medium, and, consequently, the cost of operation.

We’ve taken the manufacturer’s performance data on a single filter cartridge to illustrate the interesting fact that by doubling the capacity of a whole house filter, installing two identical filters side by side, you more than double the value. The illustration above shows a whole house filtration setup using standard-sized 4.5″ X 20″ filter cartridges.  The water passes through an initial sediment cartridge (sediment filters will handle much higher flow rates than equally- sized carbon filters) then the line splits to go through two carbon filters.  Each of the carbon filters, therefore, handles only half as much water, at half the flow rate, giving each cartridge double the residence time to do its work.

The cartridge in question is a top quality chloramine cartridge from Pentair. It is a unique radial flow carbon with a very low pressure drop and a high chloramine capacity. (It is also expensive, as cartridge prices go.) Note from the chart that as the flow rate is cut in half, the gallons-treated capacity more than doubles, and the pressure drop falls to less than half. And note, significantly, that the operating cost per gallon for the two filters installed in parallel is about 1/3 the cost of a single filter processing water at the same flow rate. (Costs are based on our current retail price for the cartridge, without considering volume discount, which makes using the double system even more economical.)

 

Format Pressure Drop Cartridge Life Removing Chloramine Operating Cost Per Gallon of Water Treated
Single Filter @ 5.0 GPM Service Flow 2.5 psi 10,000 gallons $0.0168  -1 2/3 cents per gallon.

 

Single Filter @ 2.5  GPM Service Flow

 

 1 psi 25,000 gallons $0.0067 –2/3 cent per gallon.
Parallel Installation of 2 Filters @ 5 gpm Service Flow 1 psi 50,000 $0.0067 –2/3 cent per gallon.

The example given would serve a small family–2 or 3 people–living in a home with one or two bathrooms. The same proportions can be applied, however, to other types of treatment and other filter applications.The double filter setup also gives extra capacity should you needed it. Although the unit is sized for 5 gpm service use, it would easily accommodate a 10 gpm demand should the need arise.  A word of caution, however, concerning tank-style backwashing filters. When you increase the size of backwashing filter, you also increase its backwash water requirement, plus oversizing can actually hurt performance. Tank-style filters actually have a minimum flow rate that should be observed.

CRFC20-BB

Pentek’s CRFC20-BB cartridge is a nominal 25 micron radial flow granular carbon cartridge that has minimal flow restriction. 10,000 gallons of chloramine reduction at 5 gpm; 25,000 gallons of chloramine reduction at 2.5 gpm; 200,000 gallons of chlorine reduction at 4 gpm. Pressure drop is only 2.5 psi at 5 gpm.

Chemical Contamination Caused by Water Treatment Itself

Posted May 11th, 2018
Emerging Contaminants, Water Treatment 101

Flaw Found In Water Treatment Methods

 Gazette Introductory Note: It took us several decades after public water suppliers started using chlorine as a disinfectant to figure out that the disinfection process was creating a seemingly countless group of pretty nasty chemicals that we refer to collectively as “disinfection byproducts” and regulate as THMs. It should not surprise us, then, than when we apply hydrogen peroxide and UV light to eradicate water contaminants we create “presumably less harmful chemicals” that the article below refers to as “transformation products.” Nature is about change. We know that when we “remove” something from water we are often just changing it to something “presumably less harmful.”  Chlorine doesn’t go away: it becomes chloride. So who knows what phenols from personal care products might morph into when exposed to oxidation?

Public water quality has received a lot of attention in recently years as some disturbing discoveries have been made regarding lead levels in cities across the country. Now, a new study from the Johns Hopkins University pinpoints other chemicals in water that are worth paying attention to — and in fact, some of them may be created, ironically, during the water treatment process itself.

To rid water of compounds that are known to be toxic, water treatment plants now often use methods to oxidize them, turning them into other, presumably less harmful chemicals called “transformation products.” Though earlier studies have looked at the byproducts of water treatment processes like chlorination, not so much is known about the products formed during some of the newer processes, like oxidation with hydrogen peroxide and UV light, which are especially relevant in water reuse.

“Typically, we consider these transformation products to be less toxic, but our study shows that this might not always be the case,” says lead author Carsten Prasse assistant professor in the Department of Environmental Health and Engineering at the Johns Hopkins Whiting School of Engineering and the university’s Bloomberg School of Public Health. “Our results highlight that this is only half of the story and that transformation products might play a very important part when we think about the quality of the treated water.”

Prasse, along with colleagues from the University of California, Berkeley, chose to look at phenols, a class of organic chemicals that are among the most common in the water supply, as they’re present in everything from dyes to personal care products to pharmaceuticals to pesticides as well as in chemicals that are naturally occurring in water.

To determine what compounds the phenols transform into during treatment, the team, whose results are published in Proceedings of the National Academy of Sciences, first oxidized phenols using peroxide radicals, a process often used by water treatment plants. Next, they borrowed a clever method from biomedicine: They added amino acids and proteins to the mix. Depending on what chemical reactions took place, Prasse and his team could do some backwards calculation to determine what compounds the phenols must have turned into in the earlier step.

They discovered that the phenols converted into products including 2-butene-1,4-dial, a compound that is known to have negative effects, including DNA damage, on human cells. Interestingly, furan, a toxic compound in cigarette smoke and car exhaust, is also converted into 2-butene-1,4-dial in the body, and it may be this conversion that’s responsible for its toxicity.

To test the specific effects of 2-butene-1,4-dial on biological processes more fully, the team exposed the compound to mouse liver proteins. They found that it affected 37 different protein targets, which are involved in a range of biological processes, from energy metabolism to protein and steroid synthesis.

One enzyme that 2-butene-1,4-dial was shown to bind is critical in apoptosis, or “cell suicide.” Inhibiting this compound in a living organism might lead to unchecked cell proliferation, or cancer growth. And other compounds that 2-butene-1,4-dial interferes with play key roles in metabolism. “There are a lot of potential health outcomes, like obesity and diabetes,” says Prasse. “There’s a known connection between pesticide exposure and obesity, and studies like ours may help to explain why this is.”

The results are exciting since this is the first time these methods have been applied to water treatment, Prasse says. In time, they may be expanded to screen for other types of compounds beyond phenols.

Water purification is extraordinarily challenging, since contaminants come from so many different sources — bacteria, plants, agriculture, wastewater — and it’s not always clear what’s being generated in the process. “We’re very good at developing methods to remove chemicals” says Prasse. “Once the chemical is gone, the job — it would seem — is done, but in fact we don’t always know what removal of the chemical means: does it turn into something else? Is that transformation product harmful?”

Prasse and his team point out that by the year 2050, it’s been estimated two-thirds of the global population will live in areas that rely on drinking water that contains the runoff from farms and wastewater from cities and factories. So safe and effective purification methods will be even more critical in the coming years.

“The next steps are to investigate how this method can be applied to more complex samples and study other contaminants that are likely to result in the formation of similar reactive transformation products,” says Prasse. “Here we looked at phenols. But we use household products that contain some 80,000 different chemicals, and many of these end up in wastewater. We need to be able to screen for multiple chemicals at once. That’s the larger goal.”

Coauthors on the study were Breanna Ford and Daniel K. Nomura of the Department of Nutritional Sciences and Toxicology at the University of California, Berkeley. The senior author was David L. Sedlak of the Department of Civil and Environmental Engineering at the University of California, Berkeley.

This research was supported by the National Institute for Environmental Health Sciences Superfund Research Program (Grant P42 ES004705) at the University of California, Berkeley.

SOURCE: Johns Hopkins University

Source: Water Online.

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Texas Leads the Nation in Water Quality Violations

Posted May 8th, 2018
Uncategorized

Which State Has The Most Drinking Water Quality Issues?

by Sarah Jerome

Texas is struggling with regulatory compliance at drinking water plants, and by some standards, it is having more trouble than any other state in the nation.

“More than 310 public drinking water systems in Texas — nearly 4.5 percent of the state’s regulated public water systems — have quality issues that haven’t been adequately addressed, federal officials told the Texas Commission on Environmental Quality (TCEQ) this year. That is the highest percentage in the nation, according to the Environmental Protection Agency,” the Texas Tribune reported.

A letter from the federal EPA listed plants that may need enforcement attention. But Texas officials are not so sure the federal numbers truly represent the state’s track record on tap water quality.

“TCEQ officials say the federal estimate is outdated and high; by their account, about 4 percent of systems have issues that need more attention. The agency said it has dramatically stepped up its enforcement in the past year, training more staff and pursuing more than 100 public water systems in recent months for clean water violations,” the Tribune reported.

There may not be enough resources for the state to keep up with the issue.

“The EPA’s concerns and additional data suggest that keeping up with the 7,000 public water systems subject to state regulation in Texas has been a huge challenge. The TCEQ’s enforcement division now has 107 full-time employees, compared with 117 in 2007, though its annual expenses have stayed relatively constant at about $5.5 million,” the Tribune reported.

Robert Doggett, general counsel for Texas Rio Grande Legal Aid, which serves areas that have violated enforcement rules, said resources could stand to be increased.

“There could be more resources brought to bear,” he said to the Tribune.

Midland, in western Texas, is among the areas that has drawn the attention of regulators, according to the Midland Reporter-Telegram.

“The Texas Commission on Environmental Quality struck the city of Midland with four water contaminant violations in 2013, as revealed in its annual water quality report released [in July]. The city was found in violation of high levels of arsenic, fluoride and selenium, according to the water report. The three inorganic contaminants were discovered within one of its two water entry points,” the report said.

From Water Online.

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