Gray-water systems catching on in Tucson

by Kimberleigh Holsclaw

TUCSON – The green tree python on display at the Reid Park Zoo’s Lee H. Brown Family Conservation Learning Center coils to collect rain.

Visitors who come to this building to learn how such animals adapt to their surroundings, some by conserving water, may not know they are doing the same when they use the center’s sinks and water fountains.

In addition to cisterns that collect rain that hits the roof, channeling it to be used for irrigation, the center, which opened in 2008, features a gray-water system that sends water through underground pipes to water plants outside.

To Les McMullin, Reid Park’s supervisor, the benefits involve more than helping the environment.

“It costs us a lot less, and the city a lot less, to use reclaimed water rather than potable,” he said.

Since 2008, Tucson has required plumbing in new homes to allow homeowners to set up gray-water systems to reuse water from bathroom sinks, showers and tubs as well as washing machines to water plants and lawns. Noting that a third of household wastewater typically can be reused as gray water, the city also offers a $1,000 rebate to homeowners installing permanent gray-water systems.

Since 2008, Tucson has required plumbing in new homes to allow homeowners to set up gray-water systems to reuse water from bathroom sinks, showers and tubs as well as washing machines to water plants and lawns.

Tucson Water has helped fund gray-water demonstration sites at the zoo as well as some businesses, social-service agencies and government offices.

Brad Lancaster, Tucson-based author of the book “Rainwater Harvesting for Drylands and Beyond,” said a gray-water system can reduce an average household’s water bill by 30 percent to 70 percent.

“If they redirected their gray water to the landscape instead of the sewer, they could meet easily over half of their landscape-irrigation needs just with the gray water,” he said.

Lancaster said that Tucson’s population and water consumption are growing but that its water resources are fixed.

“We need to become much more efficient and creative at how we reuse,” he said. “We need to recycle what we have multiple times and do it in the lowest-energy, highest-productive way.”

At his home in Tucson, Lancaster has a multipipe drain system, connected to his outdoor washing machine, that uses gravity to send the water down to his citrus trees. He also has a branched gray-water system that sends water from his bathroom sink and shower outside for irrigation. At any point, he is able to turn a valve and the water is redirected to the sewer.

“It reconnects you with where things come from and where things go,” he said.

Vice Mayor Paul Cunningham said Tucson changed its gray-water regulations a year and a half ago because so few people were installing systems. The city added the rebate and removed a requirement that homeowners obtain permits. Instead of permits, the city requires homeowners to follow a list of best management practices established by the Arizona Department of Environmental Quality.

“I feel Tucson’s long-term sustainability is incumbent on its ability to preserve water,” Cunningham said.

David Arthur Sampson, senior sustainability scientist at Arizona State University’s Global Institute of Sustainability, researched gray water through simulations in 2012 and found that an average household can save 18 to 35 gallons per day by using a gray-water system.

“If you count just the water that’s coming out of washing clothes, showers and baths, that can be almost 80 percent of the water you use in your house,” he said. “If you were able to use that water for irrigation, that would provide a substantial amount of water savings.”

Sampson said gray water hasn’t caught on in the Phoenix area like it has in Tucson, in large part because water rates generally are lower in the Valley.

“Water is too cheap right now,” he said.

The gray-water system at Reid Park Zoo’s Conservation Learning Center complements a catchment system through which rain that hits the roof is used in its toilets, reducing the use of potable water inside by about half. Both systems tie into the zoo’s overall conservation efforts, said Vivian VanPeenen, a zoo spokeswoman.

“The practice of conserving water and other natural resources is definitely effective for the zoo and the species we care for,” she said.

Source:  AZCentral.

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A Practical Guide to Sizing Whole House Water Filters

by Gene Franks

One of the critical factors in determining the size of a “whole house” water treatment system, whether you are removing iron from well water or chemicals from city water, is the rate of service flow you need. To work effectively, the filter must be large enough to handle the volume of water, in gallons per minute (gpm), that you plan to run through it.  Undersizing reduces water pressure, shortens the life of the filter, and compromises quality.

To get a general idea of your service flow requirements, you might refer to this standard sizing chart:

Number of Residents	1-2 Bathrooms	2-3 Bathrooms	3-4 Bathrooms	4-5 Bathrooms
1-2	5 GPM	7 GPM	10 GPM	12 GPM
2-4	7 GPM	10 GPM	12 GPM	14 GPM
5-6	10 GPM	12 GPM	14 GPM	18 GPM
7-8	10 GPM	12 GPM	14 GPM	18 GPM
9-10	12 GPM	14 GPM	18 GPM	20 GPM

The problem starts when you look at a chart of flow rate recommendations for the various filter media. If you have a family of four, for example, and live in a home with two bathrooms, you’ll see from the chart above that you need to size your filter for a 7 gallon-per-minute flow rate. However, if you plan to purchase a Birm filter to remove iron from your well water, the flow rate chart will tell you that a 13” X 54” filter would provide a service flow rate of only 3.9 gallons per minute and even a massive 16” filter would give you only a 5.9 gpm service flow. Note also that to backwash the 16” filter you would need 15.4 gpm, which your well probably isn’t capable of.

Faced with this dilemma, you could install two 13” filters side by side so that each has to handle only half the service flow. This gives you almost 8 gpm. If you backwash the filters separately, they would need only 10 gpm, which your well will handle.

Should you use the two 13″ filters installed in tandem? Probably not, unless your home requires long, sustained service flow rates, and this rarely happens in residential applications.  The reality is that even though 7 gpm is a good figure to keep in mind, most residential water use is at the rate of two or three gallons per minute. It’s also true that you can over-run the recommended rate limit now and then without fear of getting arrested.

The imaginary family of  four in a two-bath home, in fact, usually gets by very well with a 12” X 52” or even a 10” X 54” Birm filter. And it really helps if you use common sense and arrange things so that a dishwasher, a clothes washer, and a shower aren’t in use at the same time. Briefly violating the “speed limit” with an occasional burst of 7 gpm usually doesn’t result in a noticeable bad result.

Chloramine Filters

Among the most troublesome sizing problems are chloramine filters for city water users. Chloramines are hard to remove and require a slower flow rate than chlorine. Recommended flow rates for Pure Water Products’ “Chloramine Catcher,” for example, which were based on  the catalytic carbon maker’s flow rate recommendation, allow only 6.25 gallons per minute for a 13” filter. It would be common, nevertheless, for the hypothetical 7-gpm family to use a 10” X 54” filter, which is recommended for a flow of only 3.25 gpm.  Usually a  12″ X 52″ chloramine filter will perform excellently in this situation.  Going over the recommended rate from time to time might allow less-than-perfect performance from the filter (probably not noticeable), or it might shorten the life of the carbon a bit, but it won’t break anything or get you arrested.

Realize that irrigation doesn’t fall under to the 7 gpm rule. If you plan to run water for hours on end from your well and don’t want iron to stain your driveway, you’ll need to find an alternative solution. The two 13” filters we discussed above won’t handle it.  In fact, filtering water for lawn irrigation and filling large swimming pools fall under a whole different set of rules.

Keep in mind, too, that if you are filtering water for a sustained flow to a dialysis machine or feeding a fish pond with many gallons of water from a chloraminated source, you are advised to follow the rules strictly.

It is easy to provide sufficient service capacity with cartridge-style filters by using them in tandem.  In the installation above, the installer has split the service flow so that each of the filters with a 5 gpm capacity is handling half the service load.  More about this.

Unholy pollution in India’s holy waters

By Victor Mallet in Varanasi

For foreigners and Indians alike, the shocking state of the Ganges is an enduring mystery. If the river is so holy, why do the 450 million people who depend on it for water and food treat it with such contempt?

There cannot be many high priests who understand sewage treatment technology, but in the holy Hindu city of Varanasi it makes sense: every day thousands of devotees bathe in the Ganges from the steps of the city’s famous ghats, convinced not only of the sanctity but also of the purity and medicinal qualities of the river water.

So Vishwambhar Nath Mishra – mahant (religious leader) of the Sankat Mochan temple to Hanuman the monkey god, president of a foundation set up by his father to protect the Ganges and professor of electronics engineering – knows a thing or two about activated sludge plants and faecal coliform bacteria.

The Ganges at Varanasi

Varanasi, he tells me at the temple after a night-time ceremony of chanted prayers, produces 350m litres a day of sewage, but is able to treat only 100m litres – and even that only partially. But amid the clamour of India’s general election Prof Mishra senses an opportunity to rescue the river from industrial pollution and human waste: Varanasi, also known as Benares, Banaras or Kashi (“the city of light”), has now become the focus of national politics.

“The place where you’re sitting” – he points at the mat on the floor – “Modi was sitting there on the 20th of December.” That was the day Narendra Modi of the Hindu nationalist Bharatiya Janata party, favourite to become India’s next prime minister, went on to address his first mass rally in the city.

“He was a mute spectator. Whatever I was saying, he was just listening,” says Prof Mishra firmly. “I said, ‘Modi-ji, you are going to address a big crowd. It would be nice if you could consider, if you could deliberate on this [Ganges] issue. Most people are not aware of it.’”

On that day and since, Mr Modi has responded handsomely to Prof Mishra’s request, calling the Ganges his mother and promising a clean-up. Seeking Hindu support across India, and eager for votes from the vast population of the city’s hinterland in Uttar Pradesh, Mr Modi is also standing as a member of parliament for Varanasi. Arvind Kejriwal, leader of the anti-corruption Aam Aadmi or Common People party, is doing the same to challenge Mr Modi.

As thousands of rowdy supporters packed Varanasi’s streets last week to glimpse Mr Modi presenting his nomination papers for parliament, the BJP leader praised the cultural glories of Varanasi while lamenting the state of the Ganges. In parts of Uttar Pradesh, he said in his blog, the river’s condition was “pitiable”.

For foreigners and Indians alike, the shocking state of the Ganges along much of its 2,500km between the Himalayas and the Bay of Bengal is an enduring mystery. If the river is so holy, how come the 450m people who depend on it for water and food treat it with such contempt? Why has so much state money for cleaning the river been wasted, stolen or simply never spent?

Varanasi itself provides a clue. Say it softly while you are there, but the holiest city in India is also among the filthiest and most dilapidated. Drains are blocked with garbage. Tour guides blithely discard plastic cups into the Ganges after finishing their tea. When you stumble across yet another heap of rubble in the streets, it is hard to tell if it comes from an ancient building that has collapsed or is destined for another that may – eventually – be built.

This is more than just a lack of civic pride. The river’s sanctity may itself be part of the problem. B D Tripathi, head of environmental science at Banaras Hindu University, has been concerned about the Ganges since 1972, when he bathed with his mother and encountered the floating corpse of a cow. When he spoke of pollution and started measuring it, his mother and others were appalled. “Varanasi is a religious place,” says Prof Tripathi. “They said: ‘You are not a Hindu. The water of Ganga [the Ganges] is the most pure.’”

He is not discouraged. He campaigns against dams that reduce the river’s water flow and claims to be the first to calculate how many human corpses are burnt each year at Varanasi’s main cremation ghats: 32,000, he says, releasing 200 tonnes of half-burnt flesh into the Ganges.

If Mr Modi does become prime minister, and if he is elected in Varanasi, those in the city who care for the Ganges will be quick to hold him to his promises after decades of broken government pledges. Prof Mishra says he will be “the first person to tell him: ‘You made this commitment in Sankat Mochan temple.’ Our objective is that not even a drop of sewage should go into the Ganges.” The devoutly Hindu Mr Modi has been warned.

Source:  Financial Times,

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See this related article.

The Ocean’s Biggest Challenge

by John Christopher Fine

 

Editor’s Note:  The following is excerpted from a longer piece.  It is an excellent overview of the process by which choral reefs are being destroyed.–Hardly Waite.

Nitrogen is a nutrient for algae. Nitrogen, in all of its forms, comes from various sources prevalent in human habitation and activity in Florida. The first is sewage waste. This includes direct dumping of sewage effluent into the ocean as well as treated sewage. While court rulings have ordered municipal sewage treatment facilities to close their ocean pipes, this has not happened.

Removal of nitrogen from sewage effluent is a very costly process. Few municipal budgets can afford the changeover. Many claim that the requirement to divert sewage effluent underground in deep-well injection is already a financial burden. When heavy rains occur sewage treatment facilities bypass deep-well injection and continue to pump sewage into the ocean through their “closed” pipes that run a mile underwater out to the reefs.

All water that comes to earth from rain and run-off from all manner of human activities eventually finds its way into storm drains. In Florida, where the land is flat and is composed of sand with a limestone base and geology, run off creates major pollution problems. Recently, signs have been posted on storm sewers that read “No dumping. Drains into Lake Worth.” Or into whatever waterway is convenient to get rid of the water.

Evaporation also brings high nitrogen loaded rain back to earth. Elements that evaporate do not disappear into outer space and remain gone forever as some would hope. Evaporated liquids are retained in clouds until rainfall occurs. Florida is a major cattle and animal feedlot. Animal waste evaporates. Some is drained and efforts are made to treat it. Evaporation causes it to remain in clouds then return to earth in rain.

Everything else that is put on Florida’s lawns and golf courses likewise washes off and ends up in storm drains with tropical rains. Signs that proclaim danger to humans and animals and warn not to walk on sprayed lawns make the danger obvious. Compound that posted danger by the fact that all of it, in one way or another, ends up in the environment. Run off goes into storm drains, then into the Intracoastal Waterway. At tide change it is carried out into the ocean. Consider that in Florida all lawns consist of two inches of sod grass with imported top soil placed atop sand and limestone substrate. Anything that soaks down goes into the water table somewhere.

In Florida the sugar industry has been blamed for creating vast wastelands of ocean and estuarine areas. The culprit has been nitrogen rich fertilizers and sprays used to make sugar cane grow. Sugar growers have been cooperating with government but the impact on Florida Bay and other critical marine areas have been evident by coral death and underwater wastelands. Algae is the culprit. Inland run offs of pesticides and herbicides used in many forms of agriculture including citrus, have created harm to the environment in many ways.

 

Water managers control a vast system of canals across Florida. In the coastal region the waters of Lake Okechobee are controlled by the U.S. Corps of Engineers and the South Florida Water Management District.

Lake Okeechobee is dammed to retain water. With the influx of people into Florida and widespread development in western areas that were once everglades and swamps, water managers have been given the task of preventing flooding that would devastate homes and shopping centers. These areas were developed after swamps and wetlands were drained. They stay dry only because water is retained in the lake and controlled by canals.

When it rains too much, water managers open canal gates and the water pours into the Intracoastal Waterway thence into the Atlantic Ocean. Canal water contains the nitrogen burden of agriculture, human and animal waste that directly affects algae growth.

Nitrogen rich waste is food for algae. The marine plants thrive and grow in such abundance that they choke other forms of life. Gorgonian soft corals, like sea fans and many other varieties of soft corals, have been killed along with other species. The result is that divers remark that once magnificent and pristine South Florida reefs look dead.

The preventative solution could have been taken many years ago. It is not that officials didn’t know that harm would be caused to the marine environment by dumping sewage and agricultural waste into the ocean. Government, with greedy developers, decided on their juggernaught without adequate planning to handle the amount of waste that would be produced by all of these people and their ancillary activities.

A byproduct of development is that people require water. Florida has been in drought for many years. While water managers throw fresh water away to respond to a need to prevent flooding over-developed swamp and everglade areas, they have not provided adequate storage of potable water for increased population.

“The reef here comes up twenty feet off the bottom. Look under the coral ledges. You’ll see sea turtles resting under there and all kinds of marine life. Delray Ledge is one of the most beautiful reefs in the world,” Captain Craig Smart told his divers. Unfortunately algae is killing coral on this and other reefs.

A second dive was made just south of the Boynton Beach Inlet. The reef, like others in the chain, is about a mile offshore. Inlet dredging, with an automatic boom to keep the channel clear, throws out murky muck in the county’s Inlet Park Beach south of the jetty. It is not a pleasant sight for bathers and beach goers but the channel will sand up if it is not dredged. This drainage ditch, from Intrtacoastal to the Atlantic, was never designed as a passage out into the ocean for boats. The inlet, as yellow warning signs proclaim, is drainage for the Intracoastal Waterway. Without drainage at tide change the Intracoastal would be a noisome, polluted sewer.

The reefs near the Boynton Inlet have been hard hit with algae. Coral is dead. Marine life has decreased food supply. Marine turtles return to this area every winter to mate then lay eggs on Florida’s beaches to continue the chain of life that has been going on for eons. Sponges and other food turtles eat are covered with algae. The chain of life is being adversely affected.

Eventually all waste water will have to be processed in ways in which nitrogen and other damaging elements are removed before it is dumped into the ocean. It is a costly process to implement. Meanwhile the 900 million or so gallons of sewage produced every day in Palm Beach County has to go somewhere.

It was only one diver that voiced concern after surfacing. Had a ship containing oil broken apart, had an oil rig cracked causing oil to wash up on shore, the outcry would have come from many voices. The quiet menace of algae pollution is unseen save by a few divers and unreported except through dedicated environmental organizations. Their message goes unheeded as uncritical. If life in South Florida is to be enjoyed by future generations then systems must be put in place to preserve this last frontier, the only reef structure in the Continental U.S.

Source: Epoch Times

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I was struck by a statistic I read in a research report the other day. There’s a commodity that we use every day without thinking about it. We rarely consider it as an investment either.

And yet, a basket of stocks related to this commodity has outperformed gold, oil and gas, and global stocks over the past ten years.

What is this miraculous substance?

Water.

Have we hit ‘peak water’?

 

 

We’ve covered water as an investment theme in MoneyWeek magazine on several occasions in the past. It may seem an odd choice – after all, water is not a globally traded commodity, like oil.

But in fact, it makes a lot of sense. There is always good profit potential in any area where there is an imbalance between supply and demand. You can make usually make good money from the companies working to correct that imbalance.

And with water, these two forces are more acute than in perhaps any other substance.

Demand is high and rising. Water is necessary for life. There’s no substitute. As the global population grows, and we all (hopefully) become wealthier, there will be more and more demand for it.

Meanwhile, supply is limited. Fresh water – water we can use – accounts for just 2.5% of all water in the world. And a big chunk of that is locked up in ice. So there’s actually not that much water to go around. The other problem is that the water often isn’t where it needs to be – ie where the people are. It’s surprisingly hard stuff to transport.

Bank of America Merrill Lynch reckons we may even have reached ‘peak water’. Now, ‘peak’ has become something of an investment world cliché. But you take their point. There’s a lot of stress on the water supply.

The UN reckons that around a fifth of the world’s population lives in areas where there is a physical shortage of water. Another quarter faces “economic water shortage”. This is where water is physically present, but the infrastructure isn’t there to get it from the source to the people who need it.

And this situation is only going to get worse. Between water pollution and depletion of underground aquifers, and the risks of extreme weather events becoming more frequent, the danger is that even as demand grows, supply is going to become more scarce.

In short, water poses a problem. And you can make money from the companies involved in solving this problem.

Source: MoneyWeek

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Water agencies should invest in cancer prevention

Editor’s Note:  The piece below illustrates not only the important issue of Chromium 6 but also the dilemma faced by water suppliers around the world in the face of public demand for safe but inexpensive water.–Hardly Waite.

Treatment of drinking water to comply with the new standard for hexavalent chromium proposed by the California Department of Public Health could more than double water rates in the Coachella Valley.

In the long run, if it prevents higher rates of cancer, it would be worth it. The proposed standard of 10 parts per billion (ppb) is the first state limit on hexavalent chromium in the nation.

Hexavalent chromium, also known as chromium-6, is a carcinogen. The 2000 movie “Erin Brockovich” focused attention on the toxic heavy metal that tainted the water through industrial pollution in the Mojave Desert town of Hinkley. But in parts of the Coachella Valley, chromium-6 seeps into our aquifer naturally as serpentine rock along the San Andreas Fault erodes.

Local water officials say 100 wells in the valley exceed the new standard. Every well in Indio and Coachella and about half of the Coachella Valley Water District wells exceed the standard. In Desert Hot Springs, three of the Mission Springs Water District wells exceed it. The Desert Water Agency appears to be unaffected. More than 100 water systems in the state will need to upgrade water treatment.

CVWD officials estimate the cost of building treatment plants could reach $500 million. It will be the largest public works project in the valley’s history, according to Steve Bigley, CVWD’s director of environmental services. Leaders vow to keep costs as low as possible, but it is expected to add between $7 and $50 to monthly water bills. The average monthly bill is now $35.

Where to set the standard

State officials have been debating the chromium-6 maximum containment level for years. The year after “Erin Brockovich” came out, the California Legislature enacted a law requiring the standard be set by Jan. 1, 2004. The debate continued far beyond that deadline until, in 2012, a judge ordered the state to set a new standard by August.

Standards have long been established for total chromium-3, which is good for you, and chromium-6, which is not. The U.S. Environmental Protection Agency standard is 100 ppb and California’s current standard is 50 ppb. In 2011 the Office of Environmental Health Hazard Assessment established a “public health goal” of 0.02 ppb specifically for chromium-6. The standard of 10 ppb is 500 times greater than that goal. The level of 10 ppb is roughly 10 drops in a 10,000-gallon pool.

Brockovich, the former legal clerk whose crusade against Pacific Gas & Electric led to a $333 million settlement in the 1990s, expressed dismay that the state didn’t set the limit at 0.02 ppb. Other environmental groups agree.

State Public Health Director Ron Chapman issued a statement saying, “The drinking water standard for hexavalent chromium of 10 parts per billion will protect public health while taking into consideration economic and technical feasibility as required by law.”

Does it cause cancer?

In a meeting with The Desert Sun editorial board last year, local water officials pointed out that Coachella Valley residents have been drinking the water for a century and there has been no evidence of higher cancer rates. Higher rates weren’t found in Hinkley, either.

However, in 2008 the National Toxicology Program concluded there was clear evidence that chromium-6 caused cancer in lab rats. A toxicology review by the EPA concluded that chromium-6 in drinking water is “likely to be carcinogenic to humans.” It is listed as one of 800 suspected cancer-causing chemicals in California’s Safe Drinking Water and Toxic Enforcement Act of 1986.

A report by the World Health Organization released in February estimated that cancer rates would surge 57 percent over the next two decades. Steps to slow that rise make sense.

Give us time and work together

The Office of Administrative Law has 30 days to approve the standard. Once approved, it will take effect on July 1. The state needs to give the water districts enough time to design and build the treatment plants.

Fortunately, CVWD is already using ion-exchange technology in a plant to remove arsenic near Mecca. That process also removes chromium. And the district is conducting two federally funded research projects to test new technologies.

All the Coachella Valley water agencies should work together to meet this challenge and protect the health of our residents.

More about Chromium 6 from Pure Water Products.

Source:  The Desert Sun.

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Indigenous protesters occupy Peru’s biggest Amazon oil field

Fracking compared to slavery at debate

But Josh Penry defends the practice during oil and gas forum

4/25/2014

By Peter Marcus

“Slavery had a lot of economic benefits, but it had an ethical problem. Bringing fossil fuels is an ethical problem…”

“Most of the water of the world is… groundwater. What we’re doing is destroying the future in a very real sense.” 

 

Reverse Osmosis and Refrigerators: A Perfect Match, with a Few Problems

by Gene Franks

As refrigerators get more complex and offer features such as cold water dispensers, it is becoming more common to feed them with high quality water from an undersink reverse osmosis (RO) unit. The challenge in such hook-ups is how to provide sufficient water pressure for the refrigerator, especially since many of the newer refrigerators and ice machines require more feedwater pressure than older models.

With simple filters, just teeing into the undersink filter’s faucet tube works fine, since filters put out essentially the same pressure as the tap water source. With reverse osmosis units,  however, a standard system puts out only about 2/3 of the tap water pressure when the RO storage tank is full, and, of course, less as water is taken from the storage tank.

If city water pressure is strong–say, 60 psi or more–a standard reverse osmosis unit will usually rise to the occasion and supply plenty of water pressure for the refrigerator.  Important variables are distance between the RO unit and the refrigerator and the size of tubing used. Pressure loss is considerably less with 3/8″ tubing than with 1/4″, and shorter the distance between to the refrigerator the better.  With low city pressure or with well systems that have variable pressure, however, the RO unit may need some help.

Various devices are used to enhance pressure output of RO units when they send water to a remote point of use like a refrigerator. Here’s a look at the most common of these.
1. Booster Pumps.  The most commonly known of these are the popular Aquatec 6800 and 8800 booster pumps. These are electric pumps that increase the water pressure going into the RO unit. Increased inlet pressure, in addition to making the unit run more efficiently, increases the pressure coming out of the storage tank, but the out-of-tank pressure is limited to about 40 psi when the storage tank is full.  (There are tank switches that will run the pressure up to 60 psi, but we don’t recommend them for most residential users.)

2. Permeate Pumps.  These non-electric pumps do not increase inlet pressure but they isolate the RO unit from the back pressure from the storage tank, allowing it to run much more efficiently.  They can be installed with or without a hydraulic shutoff valve.  Without the shutoff valve they will put more pressure into the storage tank, but there are pros and cons to this type installation that should be considered.

The permeate pump runs on water pressure from the RO drain line and needs no electricity. In addition to sending higher pressure to the refrigerator, it improves the RO unit’s efficiency so that it uses less water.

3. Demand, or Deliver Pumps.  These electric pumps are installed after the RO unit and they push water directly from the output of the RO unit to the point of use–e. g., the refrigerator. They can deliver water with pressures up to 80 psi. They work on demand. When the icemaker calls for water, or if you activate the drinking water dispenser, the pump comes on and sends water to the refrigerator.

 

Pros and Cons
1. The booster pump is the best choice if your RO unit is starved for pressure.  If you have, let’s say, tap water pressure of 40 psi.  A standard RO unit will run on this pressure, but not well. What’s worse, it will put only 2/3 of that into the storage tank–25 psi or so even when the tank is “full”–so your refrigerator won’t get much water.  The booster pump will run the RO unit excellently and you’ll have a strong 40 psi of pressure in your full storage tank. Booster pumps are quiet and usually trouble-free.

2. With the same 40 psi inlet pressure, the permeate pump, if installed without the shutoff system (the pump itself will take over the shutoff function) will put almost 40 psi in the storage tank. It will also refill the tank much more quickly when water is taken from it. The permeate pump is trouble-free and needs no electricity. The model used with membranes that produce fewer than 50 gallons per day are very quiet. The over-50 gpd model makes a thumping noise that can be troublesome while the unit is producing water.

3. The demand pump will deliver 60 to 80 psi to the refrigerator regardless of the pressure in the tank (that is, unless the tank runs out of water, which can happen if the RO unit is a low producer).  The downside is that the pump won’t actually improve the performance of the RO unit as the other pumps do, but will simply increase the pressure to the refrigerator. Another issue is a phenomenon called “pump chatter.”  This doesn’t always happen, but if it does you won’t be able to ignore it. Pump chatter can be described as the pump turning on when no demand for water is made, running briefly–a couple of seconds usually–then turning back off.  This problem can be cured by installing a second RO tank between the pump and the refrigerator.  The tank provides the pump with constant back pressure which keeps it turned off.  It has the added advantage of giving you a couple more gallons of water, stored at maximum pressure and ready to supply the refrigerator.

As a final note, you can often improve flow to the refrigerator significantly by simply installing a second storage tank in the feed line near the refrigerator. This simple practice can improve pressure and the amount of water available to the refrigerator significantly.

More information you might like to look at:

How Permeate Pumps Work.

A Practical Guide to Water Treatment Pumps.

How Reverse Osmosis Booster Pumps Work.

How Small Demand or Delivery Pumps Work.

This article appeared originally in the Pure Water Occasional.

California water recycling facility reaches milestone

Modern Water Treatment Facility in El Segundo, CA

Water recycling is key for water companies in drought-stricken areas. Facilities that have been forward-looking enough in previous years to develop a water recycling process can now reap the benefits of having a reliable source of water to cover various municipal needs. The city of El Segundo, Calif., has already achieved this, as it was recently announced that its West Basin Municipal Water District (West Basin) has managed to recycle 150 billion gallons of water at its Edward C. Little Water Recycling Facility.

The milestone for the facility was reached in February this year. The total amount of water recycled is sufficient to meet the needs of 3.7 million people for a year, the West Basin Water District explained in a statement. In fact, the facility provides about 50 percent of the water used in El Segundo.

According to Donald Lear, vice president of the West Basin Board, the facility is one of a kind because it produces five different types of recycled water, with different properties and applications. Some of the recycled water is used for irrigation and is tertiary disinfected, while some of it is nitrified to be used as cooling tower water. The facility also recycles water to be used as low-pressure or high-pressure boiler feedwater, with the proper single pass or double reverse osmosis, and as indirect drinking water, which goes through microfiltration, reverse osmosis and UV light disinfection.

Source: Processing Magazine.

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