Introduction

All life depends on water. Our Earth, home to all species, remains the only place we know capable of sustaining life. In our search for others amongst the stars, it is water we look for first.

More than 71% of the planet is covered in this resource, but only a small proportion is suitable for human use. 97.5% percent of the world’s water is salt water and of the 2.5% freshwater, nearly 70% is locked in glaciers and the ice caps. The majority of what remains is inaccessible; either as soil moisture, permafrost or deep beneath the ground. All considered, less than 0.03% of global water is viable for human use (US Geological Survey 2014).

With the world’s population is rising at a rate of 80 million people a year, water demands are increasing proportionally (Worldometers no date). In order to sustain over seven billion people, we require more than 200 million litres of clean water per second (Waterwise no date). 67% of this is for agriculture, 22% for domestic, and 11% for industrial use.

Our overstretched resources are very unevenly distributed. Areas with high natural resources are rarely near the urban centres of high demand and this is becoming more severe. For example the top countries for fresh water supplies, Brazil, Russia and Canada, with 30% of the world supply between them, are not areas of highest population growth, India, China and Nigeria take the top spots there (Cohen & Siu 2013).

Water Stress - An Increasing Problem

Water stress occurs when the demand for water exceeds the available amount during a certain period or when poor quality restricts its use (EEA no date). Water stress usually occurs in places with low rainfall and high population density or in areas with intensive agricultural irrigation. It means deterioration of the available freshwater supply both in terms of quantity (from aquifer over-exploitation or drained rivers and lakes) and quality (from eutrophication, saline intrusion, organic matter pollution, heavy metal contamination and other problems).

Causes of water stress and scarcity

Climate Change

Climate change, due to an increasing greenhouse effect, has a direct impact on the hydrological cycle (IPCC 1996). Increased evaporation from water bodies leads to an overall increase in precipitation, but the changing climate also causes this to be distributed more unevenly. This can alter the durations of wet and dry seasons leading to droughts and floods with severe repercussions for water resources (Arnell 2004) . The changing climate makes our need for sustainable water scarcity solutions ever more pressing.

Pollution

Water sources contaminated from agricultural runoff, domestic wastewater, industrial pollutants and from atmospheric pollutants as a result of burning fossil fuels are at risk of eutrophication. Less dynamic water resources, such as lakes, are more susceptible due to longer water residence and through their action as integration sinks for multiple polluted water sources. The high-nutrient load (mainly nitrogen and phosphorus), causes algal blooms which may be toxic and complicate many methods of water purification.

Another increasing issue with water quality is the influx of personal care products and pharmaceuticals. Examples of these pollutants include painkillers, antibiotics and female hormonal birth control (UNEP, ERCE, UNESCO. 2008). Certain compounds may be long lived so accumulate in recycled urban wastewater.

Social and Economic Effects

Water conflict

Water has a long history as a source of conflict and neighboring nations have often been at odds over disputed supplies. As far back as the 3rd millennium BCE, King Lagash, significantly reduced the water flow in the neighboring Umma (modern day Iraq) by building boundary canals around his territory.

There are many types of conflict including but not limited to:

• Disputes over control and development of water resources: water resources, lakes, rivers and aquifers are valuable, interconnected and do not respect state boundaries.
• Military tools and targets. In the first case, water resources or systems are used as a tool or weapon for military action for example diverting supplies to cause flood or provide defence. In the second case, water resources are targets of military actions, deliberately polluting or destroying enemy supplies.
• Use as a political tool. Water resources or systems are controlled by state or non-state actors as a means to achieve political goals.
• Target for Terrorism. Water resources or systems are targeted or threatened and by non-state actors as means of violence and coercion.

Notable current sources of water conflicts are demonstrated in the map below: (Pacific Institute)(Gleick 1994)(Gleick 1998)

In The News

Middle East

Recent developments in the Middle East highlight the importance of water in conflict. Islamic State militants are using water as a weapon against villages that resist their advance by cutting off the supplies. Currently, IS control major parts of Tigris and Euphrates, on which all of Iraq and a large part of Syria rely for food, water and industry (Cunningham 2014) (Vidal 2014). Matthew Machowski, a Middle East security researcher for the UK Parliament and Queen Mary University notes that “It is already being used as an instrument of war by all sides. It can be claimed that controlling water resources in Iraq is strategically more important than controlling oil refineries… cut it off and you create great sanitation and health crises” (Vidal 2014).

Brazil

One of the world’s most rapidly expanding economies has been affected by droughts this past summer. A major affected area was Sao Paulo, the southern hemisphere’s largest city. Reservoirs of the Cantareira system that supply 45% of the city fell to 9.7% capacity, an unprecedented low. Conflict ignited between Sao Paulo, Rio de Janeiro and Minas Gerais, the country’s three most prosperous – and most severely water stressed – states. Sao Paulo controversially diverted water from the Paraiba de Sul in order to supply the Cantareira system, by reducing the flow of the Jaguari River (a tributary to the Paraiba de Sul). Paraiba de Sul is one of the major water and energy supplies of Rio de Janeiro.

This move violated a federal pact between the three states, made due to fears water transfer to the Cantaneira system may have adverse effect on the environmental, economic and social balance of all three states.

The disagreement recently reached the Supreme Court and eventually concluded with Sao Paulo reducing water flow in two of its dams and Rio de Janeiro reducing water capture from the Paraiba de Sul river basin (International Law Office 2014).

Many conflicts stem from large areas and communities relying on a single, shared water supply. In addition to preventing overexploitation it is helpful to provide communities with alternative, more local purification solutions to empower them and give control of their own resources (Faeth and Weinthal 2012)

Social implications

It is predicted that within the next 15 years, more than half of the world’s population will be living under severe water stress (OECD 2012). So far, water scarcity has been an issue for individuals and families living in poverty, while most in the developed world enjoy reliable, plentiful access to safe water. As the stress increases, it will hit many of us who were previously unaffected but the majority of the hardship will continue to fall on the worlds poorest.

There are further equality issues of equality arising from water accessibility and sanitation. In developing countries significant responsibility for acquisition and distribution of water is placed upon women and children of the family. Difficulties in access result in many hours lost that could instead be used for income generation, caring for family members or education (UNDP 2006). This reinforces the cycle of gender disempowerment and inequality. In rural parts of eastern Africa, women and girls spend significant amounts of their day trying to access water sources. Their journey may take them through treacherous places and increases risk of violence and sexual abuse. Women are more likely to voice concerns regarding water and sanitation compared to their male counterparts. However due to their inferior social standing such concerns often go unheard. (Mengistu 2012).

Water stress can reinforce or increase inequality. Solutions to the water crisis are necessary not just for a healthier, more peaceful world, but also a fairer one.

Economic Implications

Water is a key input in the smallest of businesses and the largest of corporations alike. Without water it is impossible to generate energy or produce goods. Therefore the economic welfare of a state relies on its water resources, it sustains the backbone of the economy. Corporations are increasingly forced to take water availability into account. For example the Coca Cola plant in Mehdiganj, India, chose to close due to the increasing water stress in the region (Guardian 2014). The socioeconomic impacts of water stress are considered in case studies below.

Case Study: BRICs

The BRIC countries (Brazil, India, China and Russia) are large, developing economies, distinguished from other emerging markets by their demographic and developmental potential. These four countries are home to more than 2.5 billion people, 40% of the world’s population, cover 25% of the world’s area, and account for 25% of the global GDP.

Expanding economies such as these require increased energy production which in turn relies significantly on water. One third of global energy needs are currently met by oil, an immensely water-expensive fuel source. Natural gas is currently the most popular alternative to oil due to the “shale gas revolution” and is cleaner in terms of emissions. Shale gas is even more water intensive however and prospective shale-producing countries like China and India will face constraints due to inadequate water supplies (Cohen & Siu 2013).

Additionally, an expanding middle class in these countries causes shifts in dietary preference that have a significant impact on water use and management. Vegetable-oriented diets turn into meat and dairy-oriented ones that are significantly more water intensive increasing stress on water-scarce nations (Cohen & Siu 2013).

Disparities in water also exist on more local levels within these countries. In China, the southern part of the country experiences sufficient precipitation and rich groundwater supplies but the North is particularly drought-prone. With large cities like Beijing and Tianjin situated in the North, water distribution is a pressing concern.

Pollution of water supplies is also a significant issue faced by countries. According to the UN, only 28% of wastewater is Russia is properly treated and just 20% in Brazil. This contaminates freshwater supplies and can make otherwise safe water non-potable. A recent survey by the Chinese Ministry of Land and Resources states that only 22% of the countries groundwater supply is safe for human consumption (CMLR 2013) (Cohen & Siu 2013).

Case Study: California

California is the USA’s most populous state containing one eighth of American people. More than 90% of the region is under severe water stress (US Drought Monitor 2014).

The widespread drought is likely to worsen due to climate change, Diffenbaugh (2014) notes: “Research finds that extreme atmospheric high pressure in this region – which is strongly linked to unusually low precipitation in California – is much more likely to occur today than prior to the human emission of greenhouse gases that began during the Industrial Revolution in the 1800s”.

The ramifications could be severe. The drought is estimated to cost more than $2.2 billion to the Californian economy, with 17,100 part-time and seasonal jobs being lost (Howit 2014).

At present, California relies on groundwater reserves in order to replace surface water losses. If the drought continues for more than 2 years it will lead to significant groundwater depletion. and increasing costs of groundwater. This increase is not predicted to impact the prices of commodities and so would be translated as loss of revenue for farmers (Howitt et al 2014).

Case Study: London

With 164 days of precipitation per year, one might not imagine our home city, London as suffering water stress. Yet it ranks as the 15th most water stressed city in the world (edieWater 2014). With a population of more than 8.3 million, water demand is high and supply is tightly regulated. The situation is again predicted to become more severe as climate change causes rainfall to become more seasonal with summers being drier and winters wetter.

The London sewage system is old, having been constructed in the mid-1800s. Emergency overflows into the Rivers Thames prevent overflowing into the cities streets and with around 60 such discharges every year, the water quality of the river is particularly poor (Greater London Authority no date).

Sustainable Water Management

Sustainable Water Management (SWM) is the considered use and distribution of water resources accounting for the needs of both present and all future users. During the international Conference on Water and the Environment (ICWE) the following principles were devised to frame discussion on SWM

1. Freshwater is a finite and valuable resource that is essential to sustain life, the environment and development
2. The development and management of our water resources should be based on a participatory approach, involving users, planners and policy makers at all levels
3. Women play a central role in the provision, management and safeguarding of water resources.
4. Water has an economic value and should therefore be seen as an economic good.

Concepts emerging from a SWM approach include:

Management of Water and Wastewater at Source

Water purification can be implemented at community scale and industrial wastewater treatment can occur on site. Focus should be on treatment as close to the site of origin or use as possible, rather than transferring water and wastewater long distances, making the methods more sustainable and environmentally friendly (Abra & Simms no date).

Low Impact Wastewater Treatment

Recycling wastewater is essential for sustainable management of water supplies. Effort should be made however to reduce the input of chemicals and fossil-fuel energy into these processes (Abra & Simms no date).

Decentralising the Water Supply

Centralised water and wastewater treatment have been of critical importance for water resource management in the development of societies since the 1800s. Although centralised systems have served us cheaply and reliably so far, recent socioeconomic developments - population growth, increasing use of water for agricultural irrigation, increasing need for sustainable water management - call for new approaches (Gikas & Tchobanoglous 2009). Decentralised water and wastewater management can play an important role in the future of water resource management. Factors driving this change include:

Capacity Limitations

The continuous growth of urban areas has exerted increasing pressure on their water management systems. Whilst treatment facilities might have been initially located in remote areas, residential and commercial development has often started enveloping them. That makes potential for expansion limited to impossible.

Rapid Growth

Population growth equates to increased demand for potable water. Current surface and groundwater resources are stretched thin so new urban developments depend on new water purification and recycling systems. Decentralised facilities can more rapidly and adaptably meet changing demand.

Homeland Security and Disaster Mitigation

As previously discussed, centralised water systems are attractive target for potential terrorist activities. Damage can impact the lives of the many people residing in the large areas dependent on them. Additionally, natural disasters such as floods and earthquakes can knock out centralised facilities causing huge disruption. Decentralised water management systems are more resilient. Disruption is likely to affect a smaller area and temporary supplies can be diverted from nearby functioning facilities.

Wastewater Recycling

Society no longer has the luxury of using water only once (Levine 2004).

Water supply sustainability implies a balance between the rate of withdrawal and the rate of water replenishment. Additionally, the water returned should be of the same quality as the water withdrawn. Due to the huge water demand however, it is difficult to replenish supplies by natural means. Additionally, the distribution of water by use of dams, reservoirs alongside "other shifts in land-use patterns alters the rate, extent and spatial distribution of freshwater consumption and replenishment" (Levine 2004).

In order to achieve sustainable water use it is necessary to turn to methods that ensure that we replenish the water we use, for fresh - and groundwater replenishment this means water recycling via wastewater reclamation and treatment (Dolnicar 2009).

Wastewater recycling has been on the rise for the past two decades as our societies become increasingly urbanised. There are two different categories of water reuse: direct and indirect. As an example of indirect water reuse, Oxford and Reading are upstream of London on the River Thames. Sewage originating from these cities mixes with the water that ends up in the London water supply. Direct reuse is more controversial and has been mainly employed to provide water for irrigation. For example in the state of Florida, more than 56000 acres of golf courses, 200,000 residencies, 500 parks and 250 schools are irrigated by reclaimed water. St. Petersburg, FL is home to one of the largest dual distribution systems in the world, operating since the 70’s it provides water for landscape irrigation for cooling and other industrial applications. The state also reuses water for agricultural irrigation. The Water Conserv II project irrigates 3,000 acres of citrus orchard every year. Reused water provides great advantages for the growers, containing the correct amounts of boron and phosphorous to give optimum soil pH.

Considerations

Wastewater treatment and recycling can be challenging and controversial to implement. From a survey of industry experts by the Global Water Research Coalition, Miller (2005) describes “key factors of success” to be considered in design and implementation of water recycling systems. These include:

• A particularly clear definition of the project objectives and limitations.
• Cost competitive pricing. Recycled water must be carefully priced to be viewed as a viable alternative. Cheaper, more efficient technologies in water recycling are desperately needed.
• Chemical and microbiological safety. It is important to have technologies that ensure the removal of chemical contaminants, particularly endocrine disruptors such as pesticides, heavy metals and pharmaceuticals and removal or inactivation of microbiological pathogens. Water utilities must be able to reassure the public that the recycled water is completely safe for its intended use.
• Public perception and acceptance. While the public is generally accepting of recycled water as a mean for landscape irrigation, for potable use, reactions are more negative.

Improving Public Acceptance

Many studies have charted the perception and acceptance of recycled water over the years (Bruvold and Ward 1970; Bruvold 1972, 1979 and 1988, Nancarrow 2003, Dolnicar and Schäfer 2006, 2007 and 2009; Dolnicar and Hurlimann 2010; Hurlimann and Dolnicar 2010). Whilst levels of acceptance vary with time and location a few conclusions are consistently drawn:

1. In general, public knowledge on the subject of water treatment and the advantages and disadvantages of different processes is relatively low.
2. General perception of recycled water is that, whilst it is an environmentally friendly solution, there are public health concerns.
3. Recycled water is considered acceptable for tasks such as gardening and car washing. When it comes to close body use (bathing and showering) there are reservations due to fears of residual wastewater in the recycled water.
4. Perception is very dependant on the particular source and treatment of the water.
5. Choice matters: in places where alternative sources of water were available, people were more sceptical of water reuse than in regions with water shortages.

Education about the necessity and safety of recycled water is paramount for improving public perception and must accompany the technological implementation. A recent survey conducted by Guardian, posted alongside an article about Thames Water plans to introduce recycled water for potable use to meet demand by 2040, revealed a promising 63% of Londoners would be happy drinking recycled water (Saner 2014). As 100% of Londoners need to be drinking it by that date however, perception must catch up.

Conclusions

Our planet’s natural water resources continue to be unsustainably exploited; as a result, we are faced with the challenges of water stress and scarcity. Climate change, population growth and urbanisation fuel the worsening crisis. To avert disaster we must rethink the way we process and use our water supplies. Promisingly, solutions are emerging but significant technological and sociological issues need to be addressed. Water treatment systems are becoming decentralised which makes the system more reliable and adaptable. Supply can be better expanded to meet changing demands and systems can be more tailored to local supplies though improvements are needed to make smaller scale plants more cost effective. Recycled wastewater is becoming an increasingly important component of our water supplies, indirect reuse is common and direct reuse, whilst initially confined to irrigation, is becoming more common. Innovations are needed to improve quality and cost as well as public confidence in the process.

References