Giant Isopod Has Not Eaten for Four Years

Posted February 25th, 2013
Environmental

Fasting Isopod Last Ate on Jan. 2, 2009

Water News in a Nutshell.

 

One of the deep sea’s strangest creatures is the giant isopod, which can live almost indefinitely without food. One in captivity in Japan has not eaten for four years. 

A giant isopod that has been in captivity in Japan since his capture in the Gulf of Mexico, had a big meal of a horse mackerel four years ago but has shown no interest in eating since. He has remained healthy during his long abstinence from food.

Isopods are close relatives of rolly pollies and “pill bugs,” with a few adaptations for living on the ocean floor in the deep, cold waters of the Atlantic and Pacific Oceans. They have seven pairs of legs and four sets of jaws and can grow to more than two feet in length.

They are scavengers that can survive for long periods without food. They are always in a state of semi-hibernation.

Sea and Sky calls the isopod “without a doubt one of the strangest creatures found in the deep sea.”

This giant isopod has refused to eat for over 4 years.

 

 

 

Source:  NPR

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How Water Treatment Is Sized: Meshes and Microns

Posted February 25th, 2013
Water Treatment 101

Meshes and Microns: The Measurements of Water Treatment

by Gene Franks

Water News in a Nutshell.

 The water treatment industry measures size in microns and mesh.  This article puts these concepts into the context of the world we live in.


So much attention is given to the materials of water filter media (coconut shell vs. standard bituminous filter carbon, for example) that the size measurements of filter media are often ignored. Size, however, is very important in water filters. Filter media are usually manufactured substances that are ground to a specific size. The “grind,” usually expressed as a mesh size, greatly affects the performance of the filter.

In large tank-style filters, the general rule is that the smaller the granules of filter media, the more effective the filter will be at reducing contaminants, but the greater the restriction it will offer to the flow of water. Performance must be weighed against flow rate. A filter is of no value if water won’t go through it, nor is it of value if it’s so porous that it won’t remove the targeted contaminant.

The size of the particles in granular filter media is usually expressed as mesh size. Mesh refers to the number of holes or openings per inch in a testing sieve. A 12 mesh screen has 12 holes per inch. A 40 mesh screen has 40 much smaller openings per inch.

Filter media is usually described with a two number designation. Twelve by 40 mesh filter carbon is a common size. If filter carbon is said to be 12 X 40 mesh, it means that the granules of carbon will fall through a screen with 12 holes per inch but be caught by a screen with 40 holes per inch. (Since nothing is perfect, some allowance is made for a small percentage of granules to be outside the size range. The undersized particles that wash out of the filter when water first goes through it are called “fines.” Over-sized chunks are called “overs.”) Eight by 30 mesh carbon is a courser blend than 12 X 40 carbon. It will fall through an 8-mesh screen but be retained by a 30-mesh screen. Water goes through 8 X 30 carbon faster, but for many jobs it is less effective.

In general, the larger the mesh number, the smaller the granules.

The familiar term “granular activated carbon,” or GAC, is used to describe most granular carbon. The technical definition of GAC is carbon of which 90% is retained by an 80 mesh screen. Finer-ground carbon, often compressed into carbon block filters, is called powdered activated carbon. Powdered activated carbon is in the 80 X 325 mesh neighborhood. Powdered carbon is more effective than GAC, but it is much more restrictive.

Microns

As things get tinier, filter makers usually switch to another measurement, the micron.

Here’s the Wikipedia definition: A micrometer or micron , the symbol for which is µm, is one millionth of a meter. It can be written in scientific notation as 1×10−6 m, meaning 1⁄1000000 m. In other words, a micron is a measurement of length, like an inch or a mile.

To put this in context, an inch is 25,400 microns long, or a micron is 0.000039 inches long.

Here are measurements of some common items:

Red blood cell — 8 microns.

White blood cell–25 microns.

An average human hair (cross section) –70 microns.

Cryptosporidium Cyst — 3 microns.

Bacteria — 2 microns.

Tobacco smoke–0.5 microns.

The naked human eye can normally see objects down to about 40 microns in size.

In water treatment, the relative “tightness” of filters is usually expressed in microns. A five-micron sediment filter is a common choice for prefiltration for a reverse osmosis unit or an ultraviolet lamp. A 5-micron filter is one that prevents the passage of most of the particles of five microns or larger. A one-micron filter is much tighter than a five-micron.

Two qualifying words are used to describe the effectiveness of the filter: absolute and nominal. An absolute filter catches virtually all the particles of the specified size, while a nominal filter catches a good portion of them. There is, unfortunately, within the industry a lot of wiggle room in defining what exactly constitutes a nominal or absolute filter rating.

The nominal pore size rating describes the ability of the filter media to retain the majority of particles at the rated pore size. Depending on the standard used, a “nominal” filter can be anywhere from 60% or 98% efficient.

Absolute is a higher standard, but again the term is slippery and its meaning depends on whose definition you accept. The standard water treatment industry’s trade associations, to accommodate marketers, in some cases lower its definition of “absolute” to as little as 85% efficiency. Other standards exist, such as industrial/commercial filtration (98%-99%), US EPA “purifier grade” (99.9%), and very high purity industry standards, e. g. pharmaceutical, (99.99%).

To clarify: a “0.5 micron absolute” carbon block filter sold by an aggressive commercial marketer isn’t necessarily as tight a filter as a 0.9 micron absolute ceramic filter that is designed to purify water by removing bacteria. Marketing standards allow some leeway because the carbon block filter isn’t being sold as a purifier (i.e., bacteria remover).

Here is some common size information regarding water filtration that may be helpful.

Granular tank-style filters are generally assumed to have about a 20 micron particle rating. Some are tighter. A multi-media filter (containing filter sand, anthracite, garnet, etc.) is considered to be about a 10 micron filter. Some of the newer natural zeolite media (Turbidex, Micro Z, for example) are considered 5 micron filters.
Good carbon block drinking water filters, which are manufactured by binding very small carbon particles together, are frequently in the 0.5 and smaller range.  Doulton ceramic filters, which are very effective bacteria reducers, are in the 0.9 micron absolute area.  As you would guess, flow rates are slow and pressure drop is significant.  Newer technologies known as ultrafiltration operate in the 0.1 micron range, and nano filtration (often called “loose reverse osmosis”) goes down to the 0.01 micron range.  Reverse osmosis membranes have a micron rating of around 0.0005 to 0.001 microns–so tight that they reduce the “dissolved solids” (minerals) in water which pass easily through carbon and ceramic filters.

Comparing and converting mesh sizes to microns is most easily done by visiting one of the many web sites that offer conversion charts. Some common equivalents, to give you the idea:

10 mesh equals about 2,000 microns.

100 mesh equals about 149 microns.

400 mesh equals 37 microns.

Source: Pure Water Occasional for June 2011.

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Innovative Billboard Produces Water in the Desert

Posted February 24th, 2013
Shortage

Sign Wrings Water Out of Lima’s Atmosphere

Water News in a Nutshell.

 

In Lima, rainfall is scarce and water is scarce, but the atmospheric humidity is around 98%.  A billboard has been created that pulls 25 gallons of water per day out of the atmosphere. 


Water Producing Billboard in Lima

The Gazette earlier reported on “fog harvesting” in Lima.  Here’s a high tech application of the same principle. The piece below is reprinted from news.discovery.com–Editor.

Billboard Converts Desert Air Into Drinking Water

By Nic  Halverson.

We all know the adage of turning lemons into lemonade. But have you heard the one about the billboard that turned polluted desert air into drinkable water?

Lima, Peru, is the second biggest capital in the world located in a desert. Raindrops are few and far between. The city gets less than an inch a year, forcing many residents to get their water from less than desirable places, such as dirty wells.

However, Lima’s humidity is around 98 percent, so the University of Engineering and Technology (UTEC) teamed up with ad agency Mayo Publicidad to create a billboard that harvests moisture in the air and converts it into purified water that locals can tap at the base of the billboard.

The air goes through a series of five machines inside the billboard, including an air filter, a condenser and a carbon filter, and finally collects in a pipe leading to the foot of the structure. The billboard is expected to generate upwards of 25 galllons (96 liters) of water per day for the neighboring community.

Dust off your Spanish and check out UTEC’s video about the project here.

Source

Simple Sand Dams Provide Water in Semi-Arid Kenya

Posted February 24th, 2013
Dams, Shortage

Simple But Effective Sand Dams Store Water From the Rainy Season for Use During the Dry Season

Water News in a Nutshell.

 

Simple devices called sand dams are being used in semi-arid regions of Kenya to provide year-around water for irrigation and domestic use.  Water is captured during the rainy season for use during the dry season, which lasts for months. The unique feature of  storing water via sand dams is that 60% of what is held is sand and only 40% is water.

In semi-arid regions of Kenya a period of heavy rains, which usually comes in December,  is followed by months of drought.  Kenyans have developed a device called the sand dam to get through the long dry season.

Sand dams are built on seasonal rivers, like the Kaiti in the picture below, to hold water for months after the water in the river itself has disappeared.

 

The sand dams trap water in the river’s sandy riverbed.  The dam holds sand as well as water.  In fact, a well constructed sand dam usually holds a reservoir of about 60% sand and 40% water.

 

To make a dam,  a high concrete barrier is constructed across a seasonal river. When it rains, the water carries sand downstream, depositing it up to the level of the barrier. When the rains finish, water remains trapped in the piled-up sand for up to a kilometer upstream of the dam.

A Community Sand Dam on the Kaiti River in Eastern Kenya

 

In terms of volume,  an average sand dam in a relatively wide stream such as the Kaiti River can hold up to 5,000 cubic meters of water, equivalent to 5 million liters (1.3 million gallons). To boost the volume of water stored, several sand dams can be built along one river.In one region where 1,500 sand dams have already been built, it is estimated that the dams can retain as much as 2 billion gallons of water.

To use the water, community members scoop out sand from the river bed to expose it. It can then be pumped out for irrigation or other uses.

Over 3,000 households are now using water from the dams to grow vegetables, tomatoes, drought-resistant legumes, fruit trees such as grafted mangoes and oranges, and other crops.

The sand dams now provide water in places where residents formerly had to walk miles in hope of finding water in a shallow well during the dry season.

The sand dam technology is believed to be indigenous to Kenya, though it is now being used in other areas such as Zimbabwe, Brazil, and Thailand.  The Kenya project, however, is the first time dams have been built in such large numbers (literally thousands) and as permanent structures.

Building of the dams has been a joint project of NGOs and locals.  The NGO donates cement to eligible groups and offers technical assistance. The self-help group members then have to collect construction materials such as stones, which are locally available, and offer unskilled manual labor during construction.

Typically, 250 people can build a sand dam in a single day. 

Source:  Christian Science Monitor

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South America’s Largest Water Treatment Plant Is In Peru

Posted February 22nd, 2013
Water Treatment

Taboada Plant Will Handle Half Of Lima’s Wastewater

Water News in a Nutshell.

 

Lima residents are now enjoying the benefits of the startup of South America’s biggest water treatment plant.  It  increases sewage treatment capacity from 16% to 75% for the area and it will have great benefit on fishing and  ocean recreation in the area.  An impressive drinking water project is also in the works for the Lima area.


Peru’s  Taboada water-treatment plant, which is now South America’s largest,  will handle sewage for almost half of the 9 million inhabitants of the capital city of Lima.  The plant has just come online and will be running full capacity by July 2013.

At present, only 16 percent of the area’s sewage is treated.  Taboada will boost total sewage treatment capacity in Lima and the neighboring port of Callao to 75.

Fishermen and beach users will benefit as far less raw sewage will be dumped into the ocean.  After solid waste is removed, the residual liquid will be pumped into the sea 4 kilometers off shore.

A large part of the area’s food is harvested from the sea, so the food supply will also benefit from the new plant.

In the Lima area, almost 2 million residents still do not have access to running water.  A $3.3 billion drinking water improvement plan is also in the works.  It will extend over 3 years.

Reference source: Bloomberg

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When Water Flows Through a Pipe, Pipe Size Matters

Posted February 21st, 2013
Water Treatment 101

Pressure, Flow Rate, and Delta P

Water News in a Nutshell.

 

 A 2″ pipe is considerably larger than two 1″ pipes when it comes to flow and pressure drop performance. Water does not flow through pipes uniformly.  It flows faster in the middle than on the sides.


Pushing high flows of water through a small pipe wastes both energy and money. It can also cause corrosion and shorten the life of the pipe.

 

Water flowing through a pipe does not flow uniformly from edge to edge. Water in a pipe flows like water in a river, with water in the middle flowing much faster than water at the edges.  Flow is fast at mid stream, and the water against the wall of the pipe is scarcely moving.

 

As water pressure pushing the flow increases, flow within the pipe becomes more turbulent and “thinner.”  By thinner we mean that there is rapid flow at the center of the pipe but the areas of relatively low flow extend further out from the walls of the pipe.

 

Flow with high turbulence requires far more energy than smooth flow. Thus, to double the flow rate in a pipe by increasing pressure, it takes four times as much energy.Therefore, it is important to limit linear flow when designing a piping  system.

 

There is a general rule that says flow through a pipe should be no more than 8 to 10 linear feet per second.

 

There is a measurement used in pipe and water filter design called “Delta P.”   In general terms,  Delta pressure, or delta P,  most commonly refers to the difference in pressure before and after a fluid filter (oil, hydraulic, or fuel) which indicates when the filter is clogged. Most aircraft have “Delta P” indicators to show this condition.  With water filters a pressure gauge is sometimes mounted in front of a filter and another after. The difference between the readings of the two gauges indicates the delta P.  If the filter is clean, the gauges should read nearly the same, but as the filter takes on contaminants, the difference between the inlet and the outlet gauges, the delta P, increases.

There is a common misconception that pipe capacities increase in direct proportion to the stated size, i.e. that a 2” pipe has twice the carrying capacity of a 1” pipe, and that, therefore, two 1” pipes side by side would have the same fluid carrying capacity as a single 2” pipe. This is not so.  A 2″ pipe actually has the carrying capacity of four 1″ pipes.   The rule of thumb is twice the diameter equals four times the flow.  See How Many 1″ Pipes Will Fit Into a 2″ Pipe?

Without getting too technical, consider these examples of how delta P works:

If you put 10 gallons of water per minute through 100 feet of 1” irrigation pipe, the pressure at the end of the pipe will be 15 psi less than the pressure at the input end. That’s a delta P of 15 psi per 100 feet of pipe.

If you put 10 gallons of water per minute through  100 feet of ¾” irrigation pipe, the pressure at the end of the pipe will be 20 psi less than the pressure at the input end. That’s a delta P of 20 psi per 100 feet of pipe.

If you put the same 10 gallons of water per minute through 100 feet of 1/2”  irrigation pipe, the pressure at the end of the pipe will be 35 psi less than the pressure at the input end. That’s a delta P of 35 psi per 100 feet of pipe.

Another example:

Water flowing through 10 foot section of 4” pipe at the rate of 10 feet per second  will put out 400 gallons per minute.

Water flowing through a 10 foot section of  2” pipe at the rate of 10 feet per second will put out 100 gallons per minute.

Water flowing through a ten foot section of 1” pipe at the rate of 10 feet per second  will put out 25 gallons per minute.

Therefore, a 2″ pipe is much larger than double the size of a 1″ pipe when it comes to flow and pressure performance. 


Indebted to a Water Conditioning  and Purification article, February 2013,  paper issue,  by Chubb Michaud, and to Ryan Lessing and Pure Water Annie, via the article cited above.

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Indian Conference Calls for Better Ways to Dispose of Pharmaceuticals

Posted February 19th, 2013
Pharmaceuticals (and Drugs)

Fifty to Ninety Percent of Drugs Given to People End Up in Wastewater

 

Water News in a Nutshell.

  The Hindu reports that an astonishing 50 to 90 percent of drugs taken by people in India eventually appear in wastewater.  This includes chemotherapy drugs that can kill cells of normal people exposed to the water.  While new forms of water treatment are needed, the urgent need is to find better ways to dispose of drugs. 

Unabsorbed pharmaceuticals in the human body find their way to wastewater streams after being excreted, they develop drug resistance in bacteria and their presence in water may cause mutation in the human DNA. This fact was highlighted by bio-scientist P.P. Bhakre at a national conference on water quality management in Jaipur recently.

Pointing out that 50 to 90 per cent of administered pharmaceuticals are released into waste water, Dr. Bhakre especially warned about the non-metabolised part of chemotherapy drugs that are used for treatment of cancer patients. Such drugs reach wastewater and may kill the normal cells of people who use this water after treatment from water bodies such as rivers and lakes — calling for the development of an alternative system to dispose of the unused pharmaceutical drugs.

The three-day conference discussed the challenges of supplying clean and adequate water to the people of Rajasthan as well as the scope for development of new technologies for purification of water for domestic use. Ninety per cent of the total groundwater in the desert State is used in the agricultural sector and the rest 10 per cent is used for domestic supply.

The deliberations also covered chemical and biological aspects of water quality management, contamination in distribution system, domestic devices for water and wastewater treatment. Paediatrician Sunil K. Gupta discussed the health aspects of fluorosis and nitrate toxicity from drinking water and threw light on hazardous effects of nitrates and fluoride content present in water.

There were several presentations on the importance of membrane technologies for purifying water. Since membrane-based technologies are not based on chemical treatment, they can rightly be termed green technologies.

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Aeration: An Effective Treatment for Some Serious Well Water Problems

Posted February 19th, 2013
Water Wells

Aeration Is a Green and Inexpensive Treatment for Common Well Water Problems

Iron, manganese, and hydrogen sulfide are common problems with well water.  There are a variety of ways to treat them, but most involve using an “oxidizer” to prepare the targeted contaminant for removal by a filter. Chlorine, potassium permanganate, and hydrogen peroxide are often used as oxidizers, but one of the very best, the least expensive, and “greenest” is plain old air.  Air can be applied to well water problems in a variety of ways.  Read on for details.

Water News in a Nutshell.

Iron and hydrogen sulfide (H2S) are common well problems that frequently occur together and often lend themselves to similar treatment. Iron corrodes appliances, ruins clothing in laundry, stops up pipes, discolors fixtures; hydrogen sulfide, or rotten egg odor, makes water unpalatable and unpleasant, blackens plumbing fixtures, and can be a health hazard when severe. Where there is iron, there is often manganese, which in very small amounts can cause black staining and odors.

The standard methods used to treat iron, hydrogen sulfide, and manganese are variations on the same three-step principle of oxidation, precipitation, and filtration. An oxidizer is added to the water, which induces precipitation of the iron, manganese and hydrogen sulfide, and the precipitated contaminant is then filtered out of the water.

A variety of filters are used to remove oxidized contaminants, but here we are concerned only with the first step, oxidation.

The Common Oxidizers

The old-standby oxidizers for years have been chemicals like chlorine and potassium permanganate. Ozone and hydrogen peroxide are more natural oxidizers that are gaining in popularity. Another common oxidizer that is being used with ever greater frequency is air.

Oxidizing with Air

Plain air is a powerful oxidizer of iron, manganese, hydrogen sulfide. It has a variety of advantages, including its low cost and its easy availability. Air adds nothing objectionable to water and leaves no undesirable by-products. Air is in plentiful supply and does not have to be transported to the treatment site.

Air can be applied to water treatment in a variety of ways. We’re going to look at the most popular applications here.

Open Air Tanks and Air Stripping

Air stripping is a technique in which volatile organic compounds (VOCs) are transferred from water to air. Typically, air stripping takes place in a packed tower (known as an air stripper) or an aeration tank.

Traditional air strippers vary in height, and the height is correlated to the chemical concentration of the contaminated water. A recent innovation in air strippers is the low-profile air stripper. These units have a number of trays that are set almost horizontally. Water is cascaded over the trays to maximize air-water contact while minimizing vertical space. Because they are not so visible, they are increasingly being used for groundwater treatment.

Strippers are used most often to rid water of volatile organics (VOCs) and gasses like methane and radon. Methane and radon are often “aerated” by simply allowing the water to stand in an open tank.

For residential treatment of iron, manganese, and hydrogen sulfide, compact closed-tank aeration units are used. Below are some examples.

The Venturi System

The simplest of the closed-tank systems is a passive aeration system that requires no outside power. It pulls air into the water line by means of an induction device called a Venturi. The Venturi (sometimes called a “Micronizer” or an educer) is installed in the water line prior to the well’s pressure tank. As water is forced through the venturi while the pressure tank is filling, air is sucked into the water line. The aerated water then enters a small treatment tank where the air is mixed thoroughly with the water and excess air is vented to the atmosphere. The water then passes to a filter, which removes the oxidized contaminants.

The main advantages of the Venturi system are its low cost, its economy of operation, and its simplicity. The main disadvantage is that the Venturi valve itself restricts water flow considerably. The Venturi works by funneling the entire water stream through a very small hole inside the valve in order to create the pressure differential required to pull air into the water line. This restricts water flow and often makes it difficult to size the filters which follow the unit, since iron filters often require significant backwash volume. Consequently, Venturi systems are most often sold as “one size fits all” units that use a standard 8″ X 44″ aeration tank, relatively easy to backwash filter media, and filter tanks no larger than 10″ X 54″.

Air Pump Systems

A more aggressive approach to aeration, the air pump system uses a small compressor to pack air into a special aeration tank. This system normally has much more air turnover and therefore requires a more complex venting system than the Venturi system.

Air Pump Used for Water Treatment

A typical air pump setup does not restrict water flow (as does the Venturi system), but it uses a small amount of electricity to run the pump and power the solenoid vent valve. Its initial cost is more than the Venturi system. It is a reliable system and little upkeep is normally needed. Any system, it should be noted, that treats iron needs upkeep because of problems caused by the formation of iron deposits within the system itself. Air pump units are no exception.

The strength of the air pump system is that air is a very rapid oxidizer, so much less retention time is needed as compared with chlorine. Normally, the aeration tank itself provides plenty of holding time for air to do its work. And larger air tanks can be used if more contact time is needed.

Single Tank Systems

Yet another style of aerator that has been around for some time is the one- tank system in which aeration and filtration take place in a single tank. This style is usually marketed as single package without options.

The single tank unit maintains an air pocket in the top of the tank. As the service water passes through the air pocket, iron and H2S are oxidized and the oxidized contaminant is then caught by the filter in the bottom portion of the tank. Air is introduced by venturi draw, but not by an added venturi unit as with the simpler system above. In this type, the unit is controlled by a modified water softener valve which is made to draw air into the tank during the “brine draw” phase of its regeneration cycle.

With this type system manufacturers usually claim effectiveness against six to eight ppm of hydrogen sulfide and 8 or so parts per million iron. Different media are used in the tank depending upon if iron or hydrogen sulfide is the main targeted contaminant.

Single tank systems are relatively expensive because of the sophisticated control head, and they lack versatility. However, they can provide excellent, trouble-free service, and installation is simple.

Pure Water Products Aeration Offerings

We’ve been selling aeration devices since the early 1990s. We currently feature our slightly modified version of a national brand called AerMax. It’s a closed tank system with a small air pump. We stock complete systems, accompanying filters, and all parts. We also offer optional add-ons to the AerMax like the flow switches and a “double aeration” feature for enhanced treatment of hydrogen sulfide.

We have an air pump parts page, offer repair kits and even some reconditioned air pumps. We stock the less expensive Venturi systems and parts, although we don’t have them on our main website.

In the twenty years we’ve sold aeration devices, we’ve never marketed them as “green” products. When you think of it, though, what could be “greener” than a treatment system that uses a renewable resource, requires only minimal energy, keeps chemicals like chlorine and potassium permanganate out the environment, and has no negative environmental impact at the point of use?

More about aeration from the Pure Water Products website.

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What Causes Odors in Water

Posted February 18th, 2013
Water Contaminants

  Finding the Source of Foul Odors in Water and Getting Rid of It

 adapted from a February 2013 article in  Water Technology.

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 Water News in a Nutshell

With the drought much of the U.S. has experienced during the last two years, odor related issues in water have become more severe. Odors can come from excess chlorine, from hydrogen sulfide, from improperly installed equipment–from a variety of causes. Common rotten egg odor usually called hydrogen sulfide can have a variety of causes.  Hot water heaters are often involved.Chlorine and hydrogen peroxide are often used to get rid of unwanted odors. Always read the manufacturer’s instructions and always call a professional if you ever smell something that doesn’t please you.

______________________________________________________________________

Smell is one of the five major senses we have and certainly one we use on a daily basis. Whether it’s the coffee we drink in the morning, the tempeh sandwich for lunch or the weird stench coming from the back of the car, we all use our sense of smell all the time. Some smells we like.  Others we don’t.

Finding the source

Often, a smell will come into a home or office unannounced and finding the cause of that smell is a frustrating task. If you find out the smell is coming from your water, the first thing you should do is contact the professionals or your local water utility board.Poor maintenance can be to blame for some foul odors. If a fixture was improperly installed, then it would be best to call the person who installed it to come and fix the problem.One water treatment expert lists improper maintenance as one of his two reasons for offensive odors in point-of-use (POU) drinking water systems, along with improper contaminant identification and subsequent improper pretreatment techniques.The foul odor associated with water is usually described as a rotten-egg smell. If you’ve ever experienced this problem with water or been around an actual rotten egg, then you probably know the smell.Hydrogen sulfide is normally pegged as the reason for a rotten-egg smell. Sometimes the hydrogen sulfide odor may only be present in the household’s hot water only. This indicates a problem with the water heater. 

The chlorine effect

But, say experts, the most common cause of odor in drinking water comes from chlorine. Chlorine is added by municipalities to disinfect water by killing bacteria and harmful viruses.“If your home uses water supplied by a public water treatment plant, the level of chlorine will be higher the closer you are to the treatment plant rather than a water user located several miles further away,” says one expert.

“The chlorine dissipates in the water lines and the treatment plant must ensure users the furthest away have an adequate chlorine level for disinfection. Also, at times the treatment plant may add higher levels than normal of chlorine due to maintenance or water related issues.”The disruption caused by the use of chlorine may be annoying and seem unpleasant to drink, but it is usually deemed safe by utility departments using this process.On occasion some municipal systems may experience a loss of chlorine residual which can result in a rapid increase in microbial activity. In the presence of sulfates accompanied by a loss of chlorine residual, nascent levels of sulfate reducing bacteria can grow exponentially and produce hydrogen sulfide gas from sulfates. Generally speaking, the higher the levels of combined sulfates and total organic carbon (TOC), the greater the potential for this occurrence.This becomes more of a problem during warm weather seasons. As the water heats up microbial activity increases, causing a foul odor smell.This phenomenon can occur either in the water mains, or more often it happens after the fact once the water has been dechlorinated by the point-of-entry (POE) or POU system.

Metallic odors may be due to the kind of piping used, while chemical odors may be due to flux used in soldering. Most of the time, the odors subside as water flows through the heater and over time.Lastly, another common cause of taste and odor issues comes from geosmin and 2-methylisoborneaol (MIB). These are naturally occurring compounds produced by blue-green (cyan bacteria), diatoms and actinomycetes.During the summer these organisms multiply in warm surface water, then die. The geosmin and MIB are then released into the water causing an odor, typically described as Earthy-musty.

These compounds do not affect human health, but can be detected by human senses at parts per trillion (ppt) levels.As you can see, there are many reasons why we experience odors in our water. Finding the source of that smell is very important, and usually something that should be done by a professional.

Dealing with foul odors

Now that we know some of the causes of water related odors, the next step is to figure out how to eliminate them. We talked to a couple different experts on the subject who offer varying views on how to treat foul odors.As mentioned above, good maintenance is the best way to reduce and prevent odors. This is especially true when dealing with hydrogen sulfide in a POU device. In this case, the first line of attack is proper maintenance.

Good maintenance is very simple and most often prescribed in detail by the manufacturer. Always refer to the manufacturer’s recommendations for maintenance.Other methods are frequent filter changes along with sanitizing the system. Properly sanitizing with sodium hypochlorite or hydrogen peroxide with help eliminate odors.Activated carbon is another solution to help reduce odors.

Remember, during the summertime municipalities increase their chlorine dosage so it’s important to replace the activated carbon in the spring time before it becomes over saturated with contaminants.Activated carbon systems excel at removing all of these odors. Granular activated carbon should be used for whole house point-of-entry systems, and carbon blocks or granular activated carbon for point-of-use systems. For hydrogen sulfide odor, a special surface-enhanced activated carbon is recommended.

Surface-enhanced activated carbons are specifically made to handle hydrogen sulfide odor more effectively than traditional activated carbons.That leads us back to the rotten-egg smell. Customers that are experiencing this issue can choose between temporary and more lasting treatment options.Peroxide is a temporary fix to rotten-egg odor in all situations, but the next time the heater sits idle, odor will return.

Chlorine bleach can also be used, but it is much more dangerous. The bacteria that cause the odor, otherwise harmless, are anaerobic, which means oxygen kills them. Both peroxide and bleach provide that oxygen. But, peroxide does not have to be flushed out of the system after use.Some odors are wrongfully blamed on the water heater. If a person has odor in one bathroom, but not another, then application of chlorine bleach to drains and sink overflows will probably make a difference.Another solution for rotten-egg odor issue is to remove the sacrificial anode, but this will void the warranty for every water heater made in the U.S. and it reduces its lifespan.

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Psychiatric Drugs Are Changing Fish Behavior

Posted February 17th, 2013
Pharmaceuticals (and Drugs), Water and Health, Water Contaminants

Pharmaceuticals Are Getting into Water and Changing the Way Fish Act

Water News in a Nutshell.

 

Gazette’s Summary: Mind-altering drugs taken by humans are being excreted into lakes and steams.  Swedish scientists studied the effects of these drugs on fish and found that they alter fish behavior and as a consequence change the environment. Read on for full details.

Psychiatric medicines that are excreted by humans and find their way into waterways can change the behavior of fish in rivers and streams, scientists report in a new study. 

Researchers found that wild European perch exposed to the anxiety-moderating drug oxazepam in an experimental pond in Sweden were less fearful and are more aggressive feeders.

Ecologists worry that such changes in fish behavior could lead to unexpected ecological consequences, including changing the composition of species in waterways and increasing the risk of potentially toxic algal blooms.

“This is only one of hundreds of kinds of [pharmaceutical drugs] that are passed through wastewater plants, and we don’t know what their environmental effects will be,” said study coauthor Micael Jonsson, an ecologist at Sweden’s Umea University. 

The new study, detailed in this week’s issue of the journal Science, also found that water downstream from sewage treatment plants in Sweden contain concentrations of Oxazepam that experiments have shown are capable of changing fish behavior. 

The findings add to a growing body of evidence that pharmaceutical drugs can do more than just poison fish or change their physical characteristics. An earlier study conducted by scientists in Minnesota at St. Cloud State University showed that fathead minnows exposed to various antidepressants in the laboratory were slower at avoiding predators.

This latest study expands the list of mood altering chemicals to a different class of drugs – those used to treat anxiety disorders.

Wild European Perch

“Before this, people had talked at [scientific] meetings about how you would expect this kind of drug to affect fish behavior, but what these researchers have done is show, very elegantly, how fish behavior has changed, and not just one aspect either, but several aspects,” said Patrick Phillips, a hydrologist with the U.S. Geological Survey in Troy, N.Y., who was not involved in the study. 

Perch are normally shy and hunt in schools. But Jonsson and his team found that those exposed to Oxazepam were bolder, less interested in hanging out with the group, and more likely to strike out on their own to explore novel, potentially dangerous areas.

“We were actually a bit surprised because [Oxazepam] is supposed have a soothing effect. Humans usually become calmer. But we saw the opposite in fish,” Jonsson said.

Normally, perch are constantly on the lookout for larger predator fish. The researchers speculate that the medicated perch are bolder because they are calmer.

“When they get exposed to this drug, they lose that inhibition, so they don’t care anymore,” Jonsson said.

Not only were the medicated perch braver, they also ate faster. In the long term, this combination of fearlessness and a larger appetite could lead to ecological disturbances that are hard to predict, scientists warn. Perch feed on tiny microorganisms called zooplankton, which in turn feed on algae.

“If the zooplankton decrease in number, the algae might increase, and you could have a situation where you have more algal blooms,” Jonsson said.

Alternatively, the perch population might actually decrease because drugs have made them foolhardy towards predators. But then again, “we don’t know how larger fish will react to this kind of medication,” Jonsson said.

There is also worry that some drug effects on wildlife won’t be apparent for years or decades.

“We’re just beginning to understand what the ultimate consequences may be from these kinds of exposures,” said research hydrologist Dana Kolpin, of the USGS Toxics Substances Hydrology Program, who also did not participate in the study.

According to scientists, it’s also likely that the ecological changes they worry about are already happening.

“It’s not all of a sudden that [medicines] are in the environment,” Kolpin said. “There are papers going back to the 1970s that say pharmaceuticals are potential environmental contaminants. We just didn’t have the analytical tools until more recently [to prove it].”

Most studies have shown that humans are unlikely to be affected by trace amounts of drugs in drinking water, but Kolpin suggests more research is needed.

“We just do not know enough about aspects such as sensitive populations” – including infants and pregnant women – “or effects from chronic exposures to complex chemical mixtures,” Kolpin said.

Jonsson and his team stressed that the solution to the problem is not to stop medicating ill people, but to develop ways for sewage treatment plants to capture environmentally hazardous drugs.

Experts say technology exists that can reduce, if not fully purge, drugs from waste water, but upgrading every waste treatment plant would be prohibitively expensive.

A more sensible, and realistic, approach would be to identify those classes of medicines that are most harmful to wildlife.

“We are realizing that some compounds are worse actors than others, and if we can identify those, then we can be more targeted in our approach for preventing their release into the environment,” Kolpin said.

Source: Inside Science.

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