Supplying Water... To the Big Apple...

New York City's water supply system is considered to one of the world’s most extensive urban water systems. This multifaceted system relies on a combination of tunnels, aqueducts and reservoirs to meet the daily needs of 8 million residents and the many visitors. Resulting from its well-protected wilderness watersheds, the Big Apple's water treatment process is simpler than many other American cities. One primary advantage of the system is that 95% of the total water supply is supplied by gravity. 

The remaining percentage needs to be pumped to maintain the desired pressure, which is sometimes increased during times of drought when the reservoirs are at lower than normal levels.

This system has been the purest and most bountiful supply of drinking water in the United States. It utilizes three separate systems of reservoirs which obtain water from some 2,000 square miles of watershed in upstate New York. The three systems include the Croton System, the Catskill System and the Delaware System. 

About 50% of the city’s water comes from the Delaware system, 40% from the Catskill system, and the remaining 10% comes from the Croton system. The city now has 19 reservoirs; the farthest is 120 miles from central Manhattan. This long travel time, which is powered by gravity, results in most of the microbes dying naturally. The water is treated with chlorine to kill organisms, fluoride to prevent tooth decay, sodium hydroxide to raise pH levels, and orthophosphate, a substance that coats pipes, to prevent lead from leaching into the drinking water.

New York City’s water, in the past, has won many awards for it’s taste, and has long been toasted as "the champagne of drinking water" but in years past has been documented that it has "lost it’s sparkle.”

New York’s water system is relatively old and the aging system has to deal with an increasing city population. The 2013 ASCE Report Card for the Nation’s Infrastructure stated that New York state need $27 Billion in infrastructure investments. Currently New York City is constructing a new Water Tunnel No. 3 because the aging two current City tunnels are too old for today’s stress. Water Tunnel No. 1 was completed in 1917 and Water Tunnel No. 2 was completed 1936. Water Tunnel No. 3 was started in 1970 and will be completed in the year 2020.

It's one of the biggest public works projects on earth - 60 miles long - and when it's finished, it will have taken 50 years to build and cost $6 billion dollars. 

As reports, it all starts in upstate New York with a series of mountain reservoirs. There are watershed areas 100 miles north of New York City, with reservoirs at such high elevations that gravity alone carries the water down to the city with enough pressure that no pumps are needed. 

But once the water gets to the city, it flows down into those two aging tunnels that have never been repaired or even fully inspected. 




This is why the urgency for Tunnel No. 3 is so high. 

Work on the new water tunnel has been going on since 1970, but it's far from finished. 

 

Singapore's NEWater...

Singapore is comprised of 63 small islands and has a natural, rainforest climate. Actually, nearly a quarter of Singapore’s land area consists of forests and nature preserves. The country averages more than 90 inches of rainfall every year. However, despite what appears to be a flourishing wet ecosystem and an abundance of annual rainfall, Singapore has faced persistent water shortages throughout its history.

Faced with these water shortages in the year 1974, Singapore began a program of water recycling, which is the action of transforming wastewater into clean potable freshwater. Despite its attractiveness, this experimental treatment plant was closed just a year later when cost and reliability issues proved too problematic to overcome.

In the year 1998, the Public Utilities Board (PUB) and the Ministry of the Environment and Water Resources in Singapore inaugurated a water reclamation study. The aim of this study was to determine whether recycled water and desalination could be viable options to meet the country’s long-term water needs, and whether they would help further reduce Singapore’s reliance on imported water from Malaysia, which had been a source of friction over the years.

This study revealed the promise and potential of recycled potable water. The reclaimed water was given the brand name “NEWater.” NEWater is purified using dual-membrane and ultraviolet technologies in addition to conventional water treatment processes. The water is considered safe for human consumption because of it being a high-grade reclaimed water.

It is produced from treated used water that is further purified using advanced membrane technologies and ultra-violet disinfection, making it ultra-clean and safe to drink.

Developed by PUB after three decades, NEWater has passed more than 65,000 scientific tests and surpasses World Health Organisation requirements, a testimony of its high quality and reliability.

NEWater is living proof that using today's water treatment technologies, water of any quality can be treated into drinking water. This ambitious and innovative solution has put Singapore on the world map for state-of-the-art water management, including winning for PUB the Stockholm Industry Water Award in 2007.

The first NEWater plants were opened in Bedok and Kranji in 2003. The latest and largest NEWater plant at Changi with a capacity of 50mgd was opened in May 2010. Currently, NEWater meets 30% of the nation’s water needs. A small percentage of NEWater is also blended with raw water in the reservoir. The raw water from the reservoir then goes through treatment at the waterworks before it is supplied to consumers as tap water.

By 2060, Singapore plans to triple the current NEWater capacity so that NEWater can meet 50% of their future water demand.

Although NEWater is potable, it is mostly used for industrial processes. Supplied to wafer fabrication, electronics and power generation industries for process use, it is also piped to commercial and institutional buildings for air conditioning cooling purposes. This frees up potable water for domestic consumption. It is delivered via a separate distribution network to industrial and commercial customers.

This, however, will change as water shortages continue and water demand continues increasing.

Kenya's Water Crisis...

There are about 40 million people living in Kenya today and within that number about 17 million (43 PERCENT!!!) do not have access to clean water. For decades, water scarcity has been a major issue in Kenya, caused mainly by years of persistent droughts, poor management of its water supply, contamination of the available water, and a sharp increase in water demand resulting from the moderately high population growth.

 The lack of rainfall affects also the ability to acquire food and has led to eruptions of violence within the African Nation. In many areas, the shortage of water in Kenya has been amplified by the government’s lack of investment in water, especially in rural areas. Kenya is a relatively dry country with about 80 percent of the country being arid and semi-arid.

The high potential/fertile agricultural land only amounts to a mere 17 percent, which sustains 75 percent of the population. 

The average annual rainfall in Kenya is about 630 millimeters (mm) with a variation from less than 200 mm in Northern Kenya to over 1,800 mm on the mountain slopes of Mt. Kenya. Over the past decade Kenya and most of East Africa has experienced a severe drought leaving many dead. 

Global warming is one of the critical factors that has prolonged the drought killing millions as a result and of the Kenyans that have survived are unable to grow their crops and keep their livestock alive. Because most Kenyans rely directly or indirectly on agriculture, when severe droughts occur, many Kenyans are left to starve unless food aid prevents a famine.

Another main reason why droughts have prolonged as a long as they have is due to deforestation. The largest forest in Kenya is Mau,  which distributes water to six lakes plus eight wildlife reserves, and some 10 million people depend on its rivers for a living. However, loggers and farmers have destroyed a quarter of Mau’s 400,000 hectares. The problem with deforestation is that it almost always leads to increased surface water runoff, which has negative implications in both the rainy season as well as the following dry season.

The inability to maintain clean water in Kenya is another main reason for the constant worsening of the water crisis in Kenya and the rest of East Africa. 

Most Kenyans use wells to obtain domestic groundwater and also use pit latrines that are often close in distance to the wells. This causes contamination of the wells because the microorganisms travel from the pit latrines to the wells. The wells should be placed in elevated areas (at least 2 meters above the water table) and at least 15 meters from pit latrines, which however is not the case in most overcrowded urban slums.

At the global level about 1 billion people are sealed out of having access to safe water due to poverty, inequality and government failure. It is also clear that not having access to clean water is a main driver and cause of poverty and inequality. In Kenya, largely due to recurrent droughts, millions of families that rely on crops and livestock are threatened and thousands of people die each year as a result of thirst and hunger. According to the World Bank (2010), the mortality rates of adult males, adult females, children under five, and infants has increased from 1990 to 2008.

Rainwater Harvesting....

Rainwater harvesting is the capture, storage and utilization of rainwater for a meaningful purpose. There has been a huge spike in rainwater harvesting systems across the United States as a result of drought, increasing population and aging infrastructure. Rainwater harvesting offers many benefits, which include conservation of groundwater, low on salts, gravity systems help to conserve energy and can reduce flooding and erosion. 

Commonly, rainwater harvesting methods are isolated into two categories, passive and active systems. Passive systems utilize no moving parts and generally use the landscape for rainwater diversion to a desired locality. The water is stored in the soil rather than a containment object for a Passive System. Passive systems include rain gardens and permeable pavements.

The design of rainwater harvesting systems will vary for each building type. A usual system will consist of three components, which include the catchment, the detention basin, and the conveyance system, but the most important element is the catchment, which is used to collect the rainfall. The catchment can be on the roof depending if it is flat. 

If the roof were sloped then there would be some form of collection area or gutter on the overhangs that will lead to the detention basin. Since, rainwater is considered, in terms of it being potable, in between groundwater and surface water then passing it through a sand filter will sufficient and adding baking soda to increase its pH to the desired level will work as well.

An example of a complex rainwater harvesting system that is used is the HighDRO system. This system consists of a flush filter, rainwater collection tank and an advanced water filtration/disinfection system. This system can help a building achieve Net-Zero Water, but it could cost the building in becoming a Net-Zero Energy building if the energy requirement is high.

Rainwater harvesting shows great potential to reduce municipal water supply costs and protect adjacent ecosystems. The U.S. EPA reports that “reducing [municipal] potable water demand by 10 percent could save approximately 300 billion kilowatt-hours of energy each year” in the U.S. alone.

Best practices for designing rainwater-harvesting systems use relatively simple, little technological methods for collection and the storage. Water should enter the cistern near the bottom of the tank where it is subsided by means of a diffuser to avoid disturbing sediment in the tank.

Rainwater harvesting systems have the potential for incorporation into a wide number of other building systems. “They are ideally suited for incorporation into on-site stormwater management strategies, allowing temporary storage after storm events and helping to reduce runoff.” They are also ideal for use in landscape irrigation, counteracting the need for potable water.

 Further occasions may exist to integrate rainwater cisterns into both active and passive solar systems by providing a potential location for storage of thermal energy. Large storage tanks may both provide or require additional structural support so careful attention is needed when designing them either on or near other structures. Finally, catchment and conveyance systems may be integrated into both interior and exterior spaces of a building in such a way that they provide a valuable connection between occupants and the natural water cycles outside the building.