WASTEWATER - Wastewater refers to all effluent from household, commercial establishments and institutions, hospitals, industries and so on. It also includes stormwater and urban runoff, agricultural, horticultural and aquaculture effluent. Dirty water can be thrown away into gutters, on the land, on flowers and grasses, down into the kitchen drains, bathroom drains or flushed down the toilets. It is never returned in the same way that it was withdrawn. We depend on freshwater a wide range of reasons, but unless we revolutionize the way we deal with dirty water, our needs for fresh water will not be met in the near future. This means a lot of pressure on water resources. The more water we withdraw, the more wastewater we will produce. Wastewater is produced in every dwelling. The discharge of wastewater into the environment poses a serious threat, but it is also a huge opportunity for ecological health, social wellbeing, and green employment.

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Wastewater

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Introduction to wastewater
During the natural cycle of water, from the mountaintops down into the oceans, humans capture and divert a lot of the water for agriculture, industrial and municipal use.

After the water is used, it is returned to the environment in a different condition, usually as dirty water (wastewater).

Depending on where you live, dirty water can be thrown away into gutters, on the land, on flowers and grasses, down into the kitchen drains, bathroom drains or flushed down the toilets.

It is never returned in the same way that it was withdrawn.

We depend on freshwater a wide range of reasons, but unless we revolutionize the way we deal with dirty water, our needs for fresh water will not be met in the near future.

Why are we producing so much dirty water? The reason is a combination of factors: population growth, urbanization, industrialization, and food production.

Global populations are expected to exceed nine billion by 2050. Urban populations may rise nearly twice as fast, projected to nearly double from current 3.4 billion to 6.4 billion by 2050, with numbers of people living in slums rising even faster, from 1 to 1.4 billion in just a decade.

This means a lot of pressure on water resources. The more water we withdraw, the more wastewater we will produce.

Wastewater is produced in every dwelling. In developing countries, less water may be withdrawn and less wastewater may be produced, but they largely have very little infrastructure to treat the wastewater.

The picture is very different in developed countries where there is some level of effort made in treating wastewater.

Every day in the UK over 624,200 kilometres (about 387,860 miles) of sewers collect over 11 billion litres of wastewater from homes, municipal, commercial and industrial premises and rainwater run-off from roads and other impermeable surfaces.

The discharge of wastewater into the environment poses a serious threat, but it is also a huge opportunity for ecological health, social wellbeing, and green employment.

This lesson provides some information and talking points that we can use to learn more about the issue.

What is wastewater?

Wastewater refers to all effluent from household, commercial establishments and institutions, hospitals, industries and so on.

It also includes stormwater and urban runoff, agricultural, horticultural and aquaculture effluent.

Effluent refers to the sewage or liquid waste that is discharged into water bodies either from direct sources or from treatment plants. 

Influent refers to water, wastewater, or other liquid flowing into a reservoir, basin or treatment plant.

Sewage is also wastewater. It is wastewater originating from toilets and bathroom fixtures, bathing, laundry, kitchen sinks, cleaners, and similar dirty water that is produced in households and public places.

Water used to irrigate turf and gardens, swimming pools, roof drainage, surface runoff and stormwater are all wastewater but not classified as sewage.

In simple terms, wastewater is all the dirty water from municipal sources (poop, urine and faecal sludge). This includes black water, gray water and yellow water.

All dirty water from all the schools, restaurants, commercial establishments, hospitals, farms, floodwater and all the possible dirty water you can think of is considered wastewater.

Some wastewater contain hazardous dissolved toxins and chemicals, whiles others contain particles, sediments and suspended matter of all sizes.

Agriculture (irrigation, livestock watering and cleaning, aquaculture) uses about 69% to 90% of global fresh water use, and the bulk of it is returned to the soil, waterways or discharged with added nutrients and contaminants.

Types of wastewater

Wastewater comes in three main types namely Blackwater, Graywater and Yellow water.

Blackwater
This is wastewater that originates from toilet fixtures, dishwashers, and food preparation sinks.

It is made up of all the things that you can imagine going down the toilets, bath and sink drains.

They include poop, urine, toilet paper and wipes; body cleaning liquids, anal cleansing water and so on.

They are known to be highly contaminated with dissolved chemicals, particulate matter and is very pathogenic.

Graywater
This is wastewater that originates from non-toilet and food fixtures such as bathroom sinks, laundry machines, spas, bathtubs and so on.

Technically it is sewage that does not contain poop or urine. Graywater is treated very differently from Blackwater and is usually suitable for re-use.

Yellow water
This is basically urine collected with specific channels and not contaminated with either blackwater or graywater.

Sources of wastewater

Domestic Sewage
This includes all wastewater generated by home dwellings, public restrooms, hotels, restaurants, motels, resorts, schools, places of worship, sports stadiums, hospitals and other health centers, apartments and the like. They all produce high volumes of wastewater.

Non-sewage
These include water from floods (stormwater), runoff (rainwater running through cracks in the ground and into gutters), water from swimming pools, water from car garages and cleaning centers.

They also include laundromats, beauty salons, commercial kitchens, energy generation plants and so on.

Wastewater is also generated from agricultural facilities. Water used for cleaning in animal farms, washing harvested produce and cleaning farm equipment.

How is wastewater harmful?

In certain parts of the world, especially in developing countries, wastewater is pumped directly into the sea or into fresh water bodies without any form of treatment.

In other parts of developed countries, lack of adequate wastewater treatment infrastructure, maintenance and outdated systems heavily compromise wastewater treatment efforts.

The effects of this (either treated or partly treated) can be classified in the following:

Water pollution:
Fresh water bodies and marine waters into which wastewater is discharged may be polluted and rendered unsafe for human use.

Depending on what is discharged, aquatic life may be harmed too.

Water security:
There is water scarcity in many places in the world.

Wastewater discharged on lands can leach into underground water tables and potentially contaminate aquifers and underground water.

If discharged in freshwater bodies, it may render water sources unsuitable for use.

Ecosystem services:
All ecosystems are connected and they all ultimately depend on water. Similarly, all water (surface and underground) is connected.

This means careless wastewater discharge can have some serious ripple effect.

One common effect of wastewater is the eutrophication of fresh water bodies and oceans. 

If one part of the ecosystem chain is destroyed, it can upset its entire food chain.

Agriculture / Fisheries / Tourism:
Wastewater for irrigation may contain unsuitable chemicals and higher concentrations of nutrients needed for crops. This can result in delayed and under yielding.

Wastewater used for animal farming may also contain harmful things and chemicals dissolved in them.

Animals may die, and there is a chance that humans that eat such animals may be harmed too. In some places, faecal sewage is discharged directly into the sea.

The discharge contains pathogens and harmful dissolved chemicals which can affect fishing in that area. The smell and such behavior does not encourage tourism to that area.

Health of urban and rural populations:
Wastewater is a big health issue, as it carries and transports a myriad of diseases and illnesses.

It is believed that about 2.2 million people die each year (globally) from diarrhoeal disease. (WHO) At least 1.8 million children under five years die every year due to water related disease, or one every 20 seconds (WHO, 2008).

Management of wastewater

Smart wastewater management is key to poverty reduction. It will sustain ecosystem services; improve food security, health and ultimately the economy.

Good wastewater management efforts will enforce existing policies and introduce new and relevant policies, funding, legislation, encourage voluntary agreements, engage private and public sectors and expand education on the issue.

These five areas must be emphasized:

1. Preventive practices:
Laws, policies and advocacy should be designed to encourage all stakeholders to reduce the generation of wastewater. This will reduce the volume of wastewater that we have to eventually deal with.

2. Capture the wastewater immediately:
Appropriate technology and practices must be laid to capture wastewater straight from its source and directed to the right places for treatment.

This part will involve significant investment, but the long-term benefits will be worth it. It may involve laying different underground pipes to carry different types of wastewater.

3. Treatment:
In many rural dwellings all over the world, the sun, vegetation, soils and bacteria are able to take care of wastewater naturally if discharged into the environment with little or no treatment. It is possible because the volumes are very small.

In urban centers the amounts of wastewater produced is staggering and simply impossible for nature to take care of. This is why we need to treat wastewater using appropriate and relevant technology before discharging into the environment.

4. Recycle and re-use water:
This involves the use of physical, biological and chemical principles to remove contaminants from wastewater. The type of wastewater will determine the kind of principle to apply.

Water recycle, reuse and reclaim are often used to mean the same thing. An example is water that is used over and over again for cooling purposes in an energy plant.

Another example is to capture gray water (those from sinks, shower and laundry drains) and reused for landscaping, construction and concrete mixing purposes.

5. Education, Awareness, Advocacy and Stewardship:
Stakeholders should provide a friendly background for the development of new ideas and technologies to managing the issue.

Each person and all groups of people should be adequately informed about the threat and the need to reduce wastewater and welcome the potential in managing them with socially and culturally appropriate methods and technology.

Wastewater is a resource

Wastewater is a huge resource that if harnessed properly, can bring a lot of health and economic benefits, increase food production, reduce poverty, enhance fishing, tourism, rural and urban livelihoods. Here are a few points to note:

Irrigation and Agriculture:
urban runoff and effluent from animal farms can be captured for irrigation and other farming needs.

This kind of wastewater is usually high in nutrients (nitrogen, phosphorus, potassium, micronutrient and organic matter) and farmers love it. They are able to save on fertilizer cost and also preserve surface and underground water that they would have otherwise used.
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In the US state of California, 31% of reclaimed water is used for crop or landscape irrigation. In Mexico, most of the wastewater from Mexico City is used in irrigation districts surrounding the city, notably the Tula valley.

Note that sludge from treatment sites are also used in composting sites and also sent to rural agricultural fields.

Energy and Construction:
The waste materials (sludge) collected from a treatment plant can be biodegraded in a controlled environment and then combusted (burnt at high temperatures) to release Methane (A gas similar to natural gas).

This can be used in boilers at homes and in buildings, as well as for cooking and heating purposes.

Note that this digester kind of biodegrading can contain contaminants and so the process has to be done properly. The sludge from treatment plants can also be combusted to produce electricity.

Note that there are different types of sludge. Sludge could be faecal (from human and animal poop flushed down the drains) and regular sludge, from rubbish and garbage that get into drains and sewage systems.

Faecal sludge is high in contaminants and must be treated well before discharge.

Household:
Smart thinking by rural and urban dwellers can offer some real benefits to households too. For example, water use in the kitchen can be collected and used to water flowers and lawns.

A couple of gallons each day means a significant saving on water by the end of the year! Families can also reduce the amount of wastewater they produce by smart use of bathrooms.

Facts an figures of wastewater

Water related diseases:
Globally, two million tons of sewage, industrial and agricultural waste is discharged into the world’s waterways and at least 1.8 million children under five years-old die every year from water related disease, or one every 20 seconds.

Wastewater treatment in California USA:
In California, 100,000 miles of sanitary sewers and more than 900 wastewater treatment plants manage the approximately 4 billion gallons of wastewater generated every day by the state’s citizens, businesses and visitors, according to the 2012 California Infrastructure Report Card prepared by the American Society of Civil Engineers (ASCE). “This engineered wastewater infrastructure serves their ratepayers and customers and visitors very well in their mission to protect public health and the environment,” the report card noted in an excerpt.
ISBN-13: 978-1-61948-003-2 – Abridged Edition, California Wastewater
Prepared by the Water Education Foundation

    USA daily wastewater processing:
Most homes and businesses send their wastewater to a treatment plant where many pollutants are removed from the water. Wastewater treatment facilities in the United States process approximately 34 billion gallons of wastewater every day.
The Sources and Solutions: Wastewater. http://www2.epa.gov/nutrientpollution/sources-and-solutions-wastewater

   Global wastewater treatment:
Globally, only 20% of wastewater produced receive proper treatment. (UNESCO 2012). Treatment capacity typically depends on the income level of the country, thus treatment capacity is 70% of the generated wastewater in high-income countries, compared to only 8% in low-income countries.
Wastewater Management A UN-Water Analytical Brief
http://www.unwater.org/fileadmin/user_upload/unwater_new/docs/UN-Water_Analytical_Brief_Wastewater_Management.pdf

       Car wash water use
On the average, a self-serve facility uses 20 gallons of water per vehicle with 3-5 gallons of water loss through evaporation and carryout. Tunnel car wash facilities can wash from 100 to 1,000 cars a day, using an average of 80 gallons of water per car. Page 5,7, Guide to Best Management Practices. Florida Department of Environmental Protection, Pollution Prevention Program and Industrial Wastewater Section.

       The Great Lakes Sewage Dump:
A study by Sierra Legal found that more than 90 billion litres of untreated sewage were dumped into the Great Lakes each year. That’s the same as dumping over 100 Olympic swimming pools of raw sewage into the Great Lakes, every day!
Page 9, Wastewater treatment, SDWF
www.safewater.org/PDFS/resourcesknowthefacts/WastewaterTreatment.pdf

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