Wastewater Irrigation

In water-scarce developing regions, urban wastewater is used to irrigate agriculture

Some factors contributing to this phenomenon include water scarcity and reliability of waste water supplies.  Also, crops irrigated with wastewater= higher profits.

This is an informal, unplanned, and ungoverned practice.  Officials see wastewater irrigation as a burden to govern and regulate.

The WHO has established guidelines on the usage of waste water for irrigation in attempt to reduce risks to human health and the environment.  However, the stated guidelines for waste water treatment prior to use for irrigation may be too costly for developing countries (at a price of US$125 to prevent one case of infection).

  

Currently, in Pakistan, approximately 32500 ha of land is irrigated directly with wastewater from cities. Crops irrigated with wastewater are mostly vegetables because they can fetch high prices in nearby urban markets (farmers using wastewater irrigation earned approximately $300 more per year than those using freshwater), and also because wastewater is a reliable supply than treated freshwater.

In some cases, wastewater is auctioned by the municipal council to the highest bidder, often a group of wealthier farmers who rent out their fields to poor landless farmers.  Under these conditions, wastewater irrigation is considered a win-win situation for both the authorities, who want to dispose of the wastewater, and the farmers, who get a reliable supply of water with a high nutrient content.

In Vietnam, irrigation with wastewater is a centuries old tradition.  Natural ponds collect wastewater and drainage from cities and discharge wastewater to canal systems. The ponds provide some level of natural treatment process for untreated sewage.  When the supply of irrigation water  is insufficient, city pumps discharge waste water to irrigation canals. Some farmers also use wastewater irrigation (at the tail end of sewage systems) where irrigation infrastructure is inadequate.

To mitigate health risks associated with wastewater irrigation, sprinkler use should be minimized because sprinklers have the highest capacity to spread illnesses.  Instead, the "bubbler, drip, or trickle methods" (localized methods that minimize possible area of contamination) should be used.  Protective clothing should also be worn.  If sprinklers are used, a buffer zone between farms and more urban areas should be set up.

-SEE CASE STUDIES ON NAIROBI, KENYA AND KUMASI, GHANA

citation:

Scott, Christopher, Faruqui, Naser I. and Liqa Raschid, eds. WASTEWATER USE IN IRRIGATED AGRICULTURE Confronting the Livelihood and Environmental Realities. IDRC, 2004. Accessed November 7 2010. http://www.idrc.ca/openebooks/112-4/

Mona Dai

November 19th, 2010

HARVESTING RAIN.

As the name suggests, this practice involves collecting rainwater for
everyday use - drinking water, irrigation, and livestock.

It is especially effective in areas where groundwater is scarce or
contaminated or in places with high population density. It is
conservative of natural resources and takes full advantage of one
natural disaster, floods, to combat another, namely drought.

These benefits have made rainwater harvesting particularly popular in India,
where rainwater harvesting is an ancient tradition and is likely the
primary reason why society could flourish. As far back as 4500 BC,
water has been collected from rivers, floods, monsoons, underground
streams, surface water and deep inside the earth.

While practices differ according to region and climate, this is how
India generally addresses the three steps of rainwater harvesting:

1. Catchment: Water is collected from rooftops and courtyards
(where water is least susceptible to contamination), glaciers, ground
surface coverings that catch monsoon runoff, and river banks.

2. Conveyance: Rain gutters, pipes, and ditch systems.

3. Storage: simple "kuis" or "beris" wells that prevent evaporation
of fallen rainwater, more developed wells known as "kundis" or
"kunds", step-accessible "bundela" and "chandela" tanks (surrounded by
orchards and pavilions)



Eveline Lam
November 19, 2010

Water Use by the Natural Resources Sectors In Alberta

As a whole, the entire natural resources sector in Alberta is responsible for 2% of pollutants released to water in 2003.


The main concern is that high volumes of water are withdrawn, which could create stress in areas where water is scarce. However, the water withdrawn is usually returned to the source quickly, so consumption rates are low.


For oil and gas production, the main issue is that water use could be considered to be consumptive, meaning that it is not returned to the location from which it was withdrawn.  Water is either injected into oil reservoirs or, in the case of the oil sands, held for years in tailings ponds. 


Water use intensity (per unit of energy generation) is highest for hydroelectric installations, followed by nuclear and fossil fuel-fired plants.


Thermal-electric power generationThermal-electric power generation has the highest water withdrawal rate of all natural resources sectors in Canada.  It used 36 345 MCM of water in 2005, or 60 percent of the Canadian total.  Water was used mostly for cooling and thus was not consumed. Gross water use in the thermal-electric power generation industry has increased moderately since 1991. 


Water consumption levels are low in plants with open-loop cooling systems.  However, the volumes of withdrawal are high. Withdrawal levels could be decreased with closed loop systems, with the effect of increasing consumption due to evaporation


Most of the cost for thermo-electric generation originates from the construction, operation, maintenance of machinery used to withdraw, circulate, treat water.


Oil and Gas Industries From 2001 to 2005, the amount of water allocated to oil and gas industry in Alberta increased by 54% and accounted for 7% of Alberta’s total water allocations.  However oil/gas companies usually use significantly less than the amount they are allocated.Surface-mining oil sands production uses 3.0 to 4.5 barrels of water (net)/ barrel of bitumen produced. In-situ oil sands production: uses ~1 barrel of water (net) per barrel of bitumen produced.


Currently, Natural Resources Canada scientists at CanmetENERGY (formerly CANMET Energy Technology Centre) are working with oil sands mining companies to develop technology that may reduce the water consumed by tailings ponds. Their goal is to decrease the net water use in mining operations to 2 barrels of water/barrel of bitumen.  This would result in dry tailings, eliminating the need for extensive tailings ponds and their associated environmental risk.


By 2015, oil sands productions expected to increase by two times.  The resulting increases in water 
requirements will place pressure on availability of water in Athabaska region.  Some companies have committed to improving their water-use efficiency so they can expand their operations without increased water allocations.

The oil refining industry uses water primarily for cooling, condensing and steam, with a relatively small amount consumed.  In 2005, the petroleum- and coal-products manufacturing industry used 869 MCM of water, 58% of it in the form of recycled water.  The industry requires high-quality water for its operations---41 % ($210 million) of its total water costs in 2005 were devoted to the treatment of intake water. 

Citation:
Natural Resources Canada. “Water Use by the Natural Resources Sectors - Facts” last modified October 14th, 2010,http://www.nrcan-rncan.gc.ca/com/resoress/publications/wateau/energ-eng.php



Mona Dai Nov 19, 2010

Desalination: the process that removes excess salt and other minerals from water.

Water is desalinated in order to convert salt water to fresh water so it is suitable for human consumption or irrigation. Sometimes the process produces table salt as a by-product. The main interest in using this process is focused on developing cost-effective ways of providing fresh water for human use in regions where the availability of fresh water is, or is becoming, limited.

Large-scale desalination uses extremely large amounts of energy as well as specialized, expensive infrastructure, making it very costly compared to the use of fresh water from rivers or groundwater.

The world's largest desalination plant is the Jebel Ali Desalination Plant in the United Arab Emirates. It is a dual-purpose facility that uses multi-stage flash distillation and is capable of producing 300 million cubic metres of water per year.

Methods:

1. The traditional process used in these operations is vacuum distillation—essentially the boiling of water at less than atmospheric pressure and thusa much lower temperature than normal. Thus, because of the reduced temperature, energy is saved.

2. The principal competing processes use membranes to desalinate, principally applying reverse osmosis technology. Membrane processes use semi-permeable membranes and pressure to separate salts from water. Reverse osmosis plant membrane systems typically use less energy than thermal distillation, which has led to a reduction in overall desalination costs over the past decade.

3 Multi-stage flash distillation (MSF) is a water desalination process that distills sea water by flashing a portion of the water into steam in multiple stages of what are essentially counter-current heat exchangers. Multi-stage flash distillation plants produce over 85 percent of all desalinated water in the world.

Anne Sewell

4:13 pm November 19

heres our bob the architect if anyone is curious...

credit to evy~

Vegetarians Vs. Water Crisis

Not all foods are alike when it comes to water, some take more to produce than others. This was the point that John Anthony Allan, a Professor at the University of London, was trying to make when he gave a lecture in Dubai, on November 8, 2010, addressing the water crisis of the Middle-East. In order to educate on foods impact on water he presented the following proactive idea; Because raising your food requires a significant amount of water, altering your diet to include less meat can help conserve water. But how much? Well the vegetarian american consumes half the amount of water that a meat eating american consumes. For example, beef requires 15,500L of water per kilogram and chicken requires 3900L of water per kilogram. All toll, the water necessary to produce food is more than all other uses, specifically agriculture requires 80 to 90% of the worlds water resources and therefore by altering your agricultural practices you will have an enormous impact on the world allowing people who are eating less water intensive foods more room to expand as they inevitably will.
In support of this idea, the animal right organization PETA, has launched a campaign displaying shower curtains which read, “Clean Your Conscience: Go Vegan! 1 lb. of Meat Equals 6 Months of Showers.” Although it’s really not known how accurate this statement is the overall point is there: Animal agriculture accounts for over half of the fresh water consumption. This comes from the water which animals drink as well as the accumulation of water used in the crops they eat. Americans eat on average a half, pound of meat a day and for 1 pound of beef, you use between 435-2500 Gallons of water. The demand for meat on a global scale is expected to have doubled by 2050. This increase is unsustainable, but by switching to a diet/lifestyle with a smaller animal consumption, you move towards sustainability. To put this into measurable figures, an omnivore diet uses 4200 gallons a day, a vegetarian diet uses 1200 gallons a day, a vegan diet uses 300 gallons a day.




http://www.greenprophet.com/2010/11/vegetarians-solve-water-crisi/

http://animals.change.org/blog/view/worried_about_the_global_water_crisis_stop_eating_meat

Those of us who live in North America may not realize that we are among the richest of the world. What we don't know is suddenly put into perspective if the world were a village of 1000 people.

The majority and minorities of the worlds ethnic groups become clearer.
584 would be Asians, 123 would be African, 95 would be East and West Europeans, 84 would be Latin Americans, 55 would be Soviets, 52 would be North Americans, 6 would be Australians and New Zealanders.

The world would have trouble communicating with each other.
165 would speak Mandarin, 86 would speak English, 83 would speak Hindi/Urdu, 64 would speak Spanish, 58 would speak Russian, and 37 would speak Arabic. The other half speak Bengali, Portuguese, Indonesian, Japanese, German, French and 200 other languages (in descending order).

There would be 300 Christians, 175 Muslems, 128 Hindus, 55 Buddhists, 47 Animists and 210 of all other religions, including atheists.

A third of the people would be children. Only half of them will be properly immunized. 60 will be over the age of 65. Only about half of the married women will have access to and be using modern contraceptives. 28 babies will be born each year. 1 person will be infected with HIV.
Every year, 10 people will die, 3 of which die from lack of food and 1 from cancer. 2 of the deaths will occur to a baby before it turns 1.

Of the money within this community, 200 people will receive 75% of the income, while another 200 will receive only 2%.
Only 70 people will own a car.
Of the 670 adults, only half would be able to read.

If we shrink down the Earth to this size, each person would get 6 acres of land, creating a total of 6000 acres. Of these 6000 acres:
700 acres of cropland;
1400 acres of pasture;
1900 acres of woodland;
2000 acres of desert, tundra, pavement, and other wasteland.

83% of the fertilizer would be concentrated on 40% of the cropland owned by the top 270 people. The excess would run off and cause pollutants in lakes and wells. The other 60% of cropland would produce 28% of the food and feed 73% of the village.

About a third will not have access to clean, safe drinking water.


--

But how much water does a SINGLE PERSON use in a day in North America?

Water covers 70.9% of Earth's surface, of which 97% is salt water and is therefore unusable. 2% are ice bergs, glaciers, ice caps.
Only 1% of the water on Earth is usable fresh water, needed for drinking, eating, processing etc. Unfortunately, a portion of this 1% of fresh water is unusable because it is unattainable (under water reservoirs), which leaves .33% of the Earth's water USABLE.

Logo!

Desalination

My topic.

Anne Sewell.

November 19, 1:30 pm

Microhydro power generation

That's my topic!
Mona Dai
Nov 19th, 2010

PlayPump in Africa

Instead of using a hand pump for drawing up clean water, there is a new system in Africa that uses a merry-go-around to pump water.

While children have fun spinning on the PlayPump, clean water is pumped from underground into a 2,500L tank, standing seven meters above the ground. A tap on the others side makes it easy for people to draw water. The Excess is diverted from the storage tank back down into the borehole.

The design of the water system makes it highly effective, easy to operate and very economical, keeping costs and maintenance to the minimum.

The Play Pump is:

1. able to produce up to 1,400L of water per hour

2. at 16rpm

3. able to work from a depth of 40m up to 100m.

Emily Li

Water For People, the current of change. "How PlayPump Works." http://www.waterforpeople.org/extras/playpumps/how-playpumps-works.html (accessed November 19, 2010).

Harvesting Rain

My topic is set. :)

Tsz Wai Eveline Lam

Using The Sun to Sterilise Water

Pastor Moses Kwanga is leading a project with other Ndolela villagers in Tanzania to sterilize their drinking water. The piped water supply is not always functioning and when it is not always drinkable. The solution is both simple and cost effective.

Forty houses in the village are now using solar water purification. The process is simple:

1. Paint roof black
   
2. Put water in clear plastic water bottles
3. Put water bottles on the roof
4. Wait eight hours

After eight hours the water is safe to drink. The heat and UV radiation are sufficient to kill bacteria in the water.

BBC News, "Using the sun to sterilise water." March 22, 2006.http://news.bbc.co.uk/2/hi/africa/4786216.stm (accessed November 9 ,2010).

Waste/Grey Water Irrigation

Charles Ye

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