Sustainability : Water

Sustainability : Water - Key SQA Definitions

• Wastewater - Water that has been used in the home, in a business, or as part of an industrial process.

In Scotland, we take access to fresh, clean drinking water for granted; it is literally available 'on tap'. However, for others around the world, access to safe drinking water is a daily struggle. 

One in four of people on Earth do not have access to safe drinking water, but as seen previously with food, this average varies greatly from country to country. 

For example, in MEDCs such as Europe, Japan or the U.S., have almost 100% coverage of their population with safe access to water. In countries at the lowest incomes however, such as Chad, the Central African Republic or Sierra Leone, less than 10% of the population have access to safe water. 

In the diagram below, regions that do not have access to safe drinkwater are concentrated in Central Africa, South-East Asia and parts of South America:- 

As global population grows (increasing agricultural, industrial and domestic demands for water), water stress and the risk of water scarcity is now an increasing concern:-

Water Stress is a measure of how sustainable the use of water is in a country, by comparing the volume of water extraction for use to the volume of water replenished through precipitation (rain, snow etc.) 

The videos below shows an introduction to the topic of Water Scarcity & Stress:-

As can be seen in the diagram below, several countries across the Middle East, North Africa & South Asia have extremely high levels of water stress. Many, such as Saudi Arabia, Egypt, United Arab Emirates, Syria, Pakistan, Libya have withdrawal rates well in excess of 100 percent this means they are either extracting unsustainably from existing aquifer sources, or producing a large volume of water from desalinisation (making fresh water from sea water).

Water use in LEDCs

Less economically developed countries (LEDCs), such as Myanmar and Haiti, tend to use less water than more economically developed countries (MEDCs). The majority of water in LEDCs is used in agriculture for watering crops. LEDCs tend to be warmer countries and as such, the water evaporates from the crops and the soil very quickly. Due to this, water must be continually applied to prevent the crops from dying. 

LEDCs obtain a lot of their drinking supplies from wells or open sources. This water can be full of bacteria and can cause disease. Water in LEDCs can also be obtained through rainwater harvesting, sub-surface dams, hand dug wells and boreholes.

Water use in MEDCs

More economically developed countries (MEDCs), such as Japan and South Korea tend to use a lower percentage of their water in the agricultural sector, but because of their larger and more advanced industrial and commercial sectors, much more water is used than in LEDCs. 

MEDCs have sanitation systems and water control regulations. Water is recycled and cleaned in treatment plants and piped to homes.

The relative wealth in MEDCs has resulted in a greater demand for water in the homes. Technology, such as washing machines, dishwashers, air conditioning, central heating, swimming pools and hot tubs, have all dramatically increased the demand for water in the homes. 

Clean Water Supplies : MEDCs

In MEDCs, water is usually provided through a centralised 'mains water' system. This means that it is treated to prevent microbes or other contaminants and then piped directly to homes and businesses.

Water that has been extracted from aquifers, rivers or lakes will be purified prior to use at a water treatment plant : 

Due to this process of purification, water in most MEDCs is safe to drink straight from the tap :

Clean Water Supplies : LEDCs

In LEDCs, most tap water is not safe to drink and in some, mains water is simply not available. 

In the absence of a centralised 'mains water' supply, water is commonly collected from wells, lakes or rivers and undergoes minimal purification before use. 

This can lead to a range of consequences to health, caused by microbes or or other contaminants, but there are steps that can be taken to reduce the risk  : 

Issues arising from Water Use

Both MEDCs and LEDCs experience a range of issues due to water use. 

These include:-

• Industry - water pollution, effluents.

• Agriculture - water pollution and change in water levels as a consequence of water abstraction and irrigation. 

• Domestic - gardening, washing, cooking, heating, sanitary, may lead to water shortages in times of drought and to water-use restrictions. 

• Impacts on public health, contamination and pollution of water supplies, conservation, and tourism and recreation.

• Impact of wastewater, including untreated sewage, on aquatic ecosystems

Impacts on Public Health Case Study : Cholera 

Cholera is an acute diarrhoeal infection caused by eating or drinking food or water that is contaminated with the Cholera bacterium. It is estimated that every year, there are 1.3 to 4.0 million cases of cholera globally, and 21,000 to 143,000 deaths worldwide due to the infection.

Cholera outbreaks can occur anywhere where access to safe drinking water is limited, either by lack of development (as in LEDCs) or in the aftermath of natural disasters or conflicts. 

The symptoms of Cholera can be easily treated using an oral rehydration solution and education about safe water management can help reduce further outbreaks  : 

In modern Scotland the risk of contracting Cholera is negligible, but that wasn't the case in the mid-1800s. 

In 1848-49, a Cholera epidemic swept through the densely crowded cities and fishing towns of Scotland, caused by the lack of access to safe drinking water and poor sanitation. It is thought that over 60,000 people died in 1848 alone, with ~50 % of people who contracted the disease dying. 

The photograph below shows a 'watch-house' over a mass burial pit of Cholera victims in Eyemouth, Scotland. The watch-house is constructed out of headstones from the cemetery which had to be cleared to make room for the pit :

Impacts on Public Health Case Study : Blue-Green Algae 

Where there are high levels of nutrients and warm enough conditions,  the numbers of blue-green algae can increase. Increased periods of growth are called blooms. Blooms can have a negative effect on the appearance, quality and use of the water. It may become green, blue-green or greenish-brown and several species can produce musty, earthy or grassy odours. 

Blue-green algae photosynthesise during the day - adding oxygen to the water - but consume it at night. This means oxygen levels can be very low in the early morning and can suffocate fish and other creatures. Bloom of blue-green algae can produce toxins. These toxins can kill wild animals, livestock and domestic pets. In humans, they can cause rashes after skin contact and illnesses if swallowed. preventing the water body being used for sport or recration activities. 

Impacts of Waterwater Case Study : Combined Sewer Overflows

In Scotland, wastewater is carried from homes and businesses to water treatment plants through a network of combined sewers. A combined sewer is a series of drains and pipes that carry both wastewater and surface water (rainfall drains etc.). 

The diagram below shows how a combined sewer system works in clear weather, rain and then prolonged storm conditions:-

This system is designed such that any overflow from the drain or storm tanks is diluted as much as possible to reduce the impact of the sewage discharge on rivers or the sea. The Scottish Environmental Protection Agency (SEPA) monitors the discharge of pollution into Scotland's rivers and sea, and has the power to fine companies who break the rules on levels of pollution. 

The video below shows a BBC news story covering the release of raw sewage into waterways in England:-

You would use the equipment in a water treatment plant to make water clean and safe for people to drink. You could also process sewage, chemicals and other waste to make it safe. You would use equipment such as sludge processing and pumping stations clean and look after septic tanks, filters and other equipment, add chemicals to treat the water, check and record water and gas levels etc. 

You would need to be willing to work difficult hours, and to follow strict health and safety rules at all times.

Sustainable Water Use

Over the past 100 years, water consumption has steadily risen due to increased demand for water both in people’s homes as well as demand for water for agriculture and industry. Treating water to make it potable (safe to drink) requires a significant amount of energy and other resources and so people are being advised to reduce their water consumption where possible, to allow sustainable water management. This applies to 'Water-Rich' countries like Scotland too. 

Domestic changes that could be made to reduce water consumption include:-