Water and the city

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water and the city

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n 2010 the United Nations General Assembly approved a resolution whereby access to safe and clean drinking water and basic sanitation was considered a human right that is essential to the full enjoyment of life. However, studies into water reserves and use reveal that there is a need for urgent measures in order to guarantee its conservation.

Accustomed as we are to using it as if it were an endless resource, it is time to change our habits and customs.

A Coruña’s Science Museums, in collaboration with A Coruña City’ Council’s Environment Service, EMALCSA and the University of A Coruña’s People-Environment Research Group, are carrying out activities aimed at bringing about greater understanding and collaboration between residents and some of the institutions involved in water management.

What kinds of controls are carried out to guarantee water quality? How do we know if it is drinkable?

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he decree regulating the quality of water for human consumption in Spain states that the parameters for controlling water quality at the consumer’s tap are smell, taste, colour, turbidity, conductivity, pH value, ammonium, coliform bacteria and Escherichia coli bacteria. Other parameters for consideration include chlorine and its derivatives when the water is treated for drinking, and copper, chromium, nickel, iron, lead or other similar elements when the installations include materials of this type. The monitoring programmes include checks at the source of supply, when the water leaves the treatment plants and in the distribution networks. In the case of water obtained from wells and other collection sources, analyses must be carried out in public or private laboratories that hold UNE-EN ISO/IEC 17025 o UNE-EN ISO 9001. standards certificates.

■ How is water made drinkable?

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he water collected in the reservoir that supplies our city is of good quality (pH value, hardness, salinity, etc.). However, before it reaches the supply network it is treated three times. The first process consists of removing large debris (such as leaves or sticks). Then, the water goes through tanks where substances are added so that the suspended particles group together (known as flocculation) and are then deposited on the bottom of the tanks, forming sediments which can then be removed. The final stage consists of filtering the water and adding the chlorine.

■ Why does water taste of chlorine? Is it bad for our health?

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part from eliminating germs, chlorine also helps to remove iron, manganese, sulphides and other substances. It is normally added in two phases; at the start and on completion of the water treatment process in order to neutralise any possible contamination during transportation. It evaporates easily, and therefore the amount present in the water varies depending on the districts and their proximity to the processing plant and the length of time the water remains in the urban tanks.

Failure to use the correct amount of chlorine may cause it to react with natural organic matter and produce toxic substances known as trihalomethanes. Their presence in regulated by the European Union and must not exceed 100 micrograms per litre. According to the World Health Organisation, using chlorine is the best way to obtain safe water.

■ Why does water sometimes look dirty or brown when it comes out of the tap?

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hilst the water remains in the supply network and does not flow, organic matter in suspension collects on the pipe walls.

This matter may come loose when the water flow speeds up or changes direction, which is common in any distribution network. The elements that make the water look cloudy do not affect our health, but, if it is very noticeable, the best thing is to allow the water to flow or leave it to rest for a while in a container before use.

■ How do water filtration jugs work?

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■ Is water wasted due to the poor condition of pipes?

he filters in these jugs contain a type of resins that react with and retain certain substances such as chlorine or mineral salts. This is why they are able to modify parameters such as acidity, hardness, the amount of chlorine or the salt composition; they also appear to be capable of retaining unwanted substances. Spain’s Consumers and Users’ Organisation has warned that the benefits do not meet the claims and that the reduction in the amount of chlorine means that it is essential to ensure that the jugs are spotlessly clean and keep a close eye on the safety of the water stored in these jugs. In the case of water with a low mineral content, such as the water in A Coruña, any smell produced by residual chlorine can be eliminated by storing the water in the fridge.

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ach day in Spain the equivalent of a day’s consumption in a city the size of A Coruña is wasted. According to the latest figures published by the Spanish National Institute of Statistics, water loss (caused by leaks, breakages and burst pipes) in 2011 stood at 776,000 million litres, 17% of the country’s total consumption. Our city has implemented a pipe renewal programme aimed at cutting the number of broken pipes.

The Spanish Ministry of Agriculture, Food and the Environment has established an optimum value of 0.24 pipe breakages per kilometre. In our city the figure stands at 0.18.

In A Coruña response time to a pipe breakage must not exceed 45 minutes

How does the water travel fro

■ How can we take advantage of salt water?

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he drinking water used for certain activities could be replaced by salt Examples water. include leisure and recreation facilities such as swimming pools, water parks, fountains and ponds.

Today, desalination plants are able to obtain water for consumption from the sea, although the procedure is costly, as it requires a lot of energy.

■ How is water treated? Is the process reliable?

Where does the wastewater go?

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ater is treated in Wastewater Treatment Plants. The plants in our city are located in the district of Bens. The first stage consists of a primary filtering process to remove large waste materials, followed by a finer filtering process to remove any particles. The next stage involves adding substances that cause the oils, fats and substances in suspension to coagulate. Then microbial degradation is carried out on the organic material, forming a sludge which is then removed. The final stage eliminates other organic substances, as well as nitrogen and phosphorus compounds and inorganic salts. Finally, the treated water flows through an underwater pipeline located in Suevos, which extends several hundred metres out to sea. However, public company Augas de Galicia claims that in some wastewater treatment plants the disinfection processes do not reach acceptable standards.

■ Are the drains cleaned to prevent flooding in the city?

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he city has a rainwater collection system consisting of a maze of pipelines concealed beneath the ground that form a network that runs as far as the Bens Wastewater Treatment Plant and other discharge points. The slope of the terrain and rainfall patterns are key factors in the design of this network. Maintenance teams are in charge of carrying out any repairs to the network, as well as cleaning the drain grills and sewers. They also handle any work needed to prevent the water from overflowing in the event of heavy rainfall. In addition, a fleet of lorries is on hand to keep the pipes in good condition.

■ How much water does a person consume each day?

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ccording to the Spanish National Institute of Statistics, in 2011 water consumption per person and day in Spain stood at 142 litres. Consumption in Spain has fallen steadily in recent years: in 2004 it stood at 171 litres per person and day. In Galicia the figure for 2011 was 133 litres per day, and 132.5 in the case of A Coruña. The recommended average household consumption issued by the World Health Organisation is around 100 litres per day.

m the reservoir to our homes?

■ How is the water kept clean while it flows through the pipes?

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water supply network requires a series of characteristics that enables the pipelines to be kept clean.

For instance, the pipes and joints must be made of non-contaminating materials, fit for their purpose and completely watertight. In the case of A Coruña they are made from cast iron or plastic, and have gradually replaced the former fibre cement option. In addition, the supply network must have a ‘grid type layout, whereby all the branch pipes are connected, thereby ensuring the constant flow of water, preventing any possible blockages. The water supply network should also be constructed at a considerable distance from and above the wastewater network. The small chlorine content in the water, required by law, helps to keep the water clean and fit for consumption.

■ Could there be a water shortage in A Coruña?

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he amount of water available depends on the rainfall, which supplies the reservoirs, and the way the stored water is managed. Various consecutive months of unforeseen drought may lead to a shortage of this resource. There are plans to connect Meirama Lake with Cecebre Reservoir, which would increase the amount of stored and reserved water in the event of need, although current demand is amply met by the capacity of the Cecebre Reservoir and standard rainfall patterns.

The Aqueduct on Paseo de los Puentes. A project designed by Fernando Casa Nóvoa in 1722 in response to the water shortage suffered by the city at the time

Photograph: Courtesy of the Municipal Archives

■ How do fountains work?

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Coruña has more than 60 fountains, ponds and waterfalls.

They are normally treated with a process of hyper-chlorination to prevent algae from spreading uncontrollably and the outbreak of microorganisms such as those that cause legionnaire’s disease. This means that the water in ornamental fountains is not potable. The fountains in A Coruña operate on a closed circuit of pumps, although they do have a supply system to replace the water lost due to evaporation, the wind or maintenance work.

■ Why is it so expensive?

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ater management companies claim that water rates do not cover the cost of the service.

Remember that for as little as € 0.80 our homes can be supplied with a thousand litres of potable water, and that rates are lower than in other European cities. Of all the Spanish provinces, the price per cubic metre for domestic use in A Coruña is the fifteenth cheapest: Murcia is the most expensive province and Palencia the cheapest. The price of water fluctuates depending on the natural and topographical features of each city. For instance, in the case of A Coruña, each litre of water has to be pumped 1.4 times, which makes it more expensive than in other cities where the water does not have to be pumped so much.

Cecebre Reservoir

■ How is water used in the city?

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he water from Cecebre Reservoir supplies homes in the city as well as in the other boroughs that make up the metropolitan area. It is also used for non-domestic purposes and in the Port of A Coruña. In 2013, 51% of the water made drinkable supplied the municipality of A Coruña. 48.9% went to the boroughs of Arteixo, Abegondo, Culleredo, Oleiros, Bergondo, Sada and Carral.

■ ls tap water as good as bottled water?

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ike tap water, bottled water has to meet a series of health standards. The mineral content means that some are more recommendable than others. For example, those with a low mineral content are suitable for preparing baby food and for people with kidney complaints, whilst those with low levels of sodium are recommendable for people with blood circulation problems. The characteristics and composition of tap water varies in accordance with the area. In A Coruña for instance, the water is soft, somewhat acidic with a low mineral content and is considered to be of good quality.

■ Are the gardens watered with drinkable or recycled water?

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t the moment drinkable water is used. Work is currently underway on the installation of a smart remote control system in order to improve the process. It will use sensors to detect irrigation requirements in real time, based on factors such as the degree of humidity. These data will be included in a system for comparison with other information, such as any forthcoming events, the weather forecast or the level of the city’s water tanks in order to adjust the irrigation conditions.

■ What measures have been adopted to save public spending on water?

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ssentially practices aimed at reducing consumption, control methods and awareness raising campaigns. A country’s water assets will undoubtedly become one of its most valuable resources in the future, and will be even more important than its energy sources. A Coruña plans to monitor its water supply, install a remote meter reading system and apply a smart watering system. Work will also begin on the automated management of the sanitation network in order to monitor spills and guarantee that the water treatment systems function correctly at all times.

1,500 litres of water ■ How can we to produce 1 kilo save water? of wheat n agriculture, which is • the sector that con2,000 litres of water to sumes most water, drip produce 1 kilo of paper would cut water irrigation • by up to 90%. consumption 52,500 litres of water In addition, optimising irrito produce 1 gation times and installing rain mid-sized car sensors would save 30%. Industry is the second sector in terms of water consumption; in this case, what we need are production systems that consume less water.

One example is the Estrella Galicia brewery, which in the last 20 years has reduced the amount of water required to produce a litre of beer from almost 20 litres to just 8. In addition to the careful use of the water we obtain from the tap, one of the best ways of saving this resource is to consume less: for instance, it takes 2,700 litres of water to produce a single cotton T-shirt.

It t ak es …

The former San Andrés Fountain and the current Illuminated Fountain in Cuatro Caminos

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■ A survey to measure environmental and water management awareness among the residents of A Coruña

51.5% of residents in A Coruña claim they regularly consume tap water, whilst one in three normally drinks bottled water.

Museos Científicos Coruñeses

Source: Sondaxe 2013

■ How is the price of water calculated? What factors influence our water bills?

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■ How can we raise people’s awareness about the need to save water?

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he world is currently experiencing a water and sanitation crisis. One response has been the international campaign for the 2005-2015 decade entitled “Water, a source of life”. Other actions include World Water Day, which is commemorated each year on 22nd March with activities such as the filming of documentaries, conferences, round-table debates, workshops and exhibitions. A Coruña City Council has implemented an environmental awareness campaign targeting almost 7,000 schoolchildren each year.

he most important factors that affect the price of water are the processes involved in making it potable, together with transportationMuseos and storage.

Specifically, Científicos Coruñesesthe price is determined according to the sum of a number of concepts. One is the supply service, which is related to the size and capacity of the meter that measures consumption. Others include water consumption, which is paid for in blocks: the first corresponds to the initial 18 cubic metres, and is cheaper than the following blocks in order to prevent wastage. The rate applied depends on the use the water will be put to: domestic or industrial. Water bills also include other concepts, such as the sewage and water treatment sysMuseos Científicos Coruñeses tems, as well as a council charge for refuse collection, for domestic waste materials only, and a regional tax that is levied to fund protection measures for this valuable resource as well as new infrastructures for rendering water drinkable, storage and sanitation.

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