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    • Rights: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
    Published 12 March 2020 Referencing Hub media
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    All household wastewater from pipes connected to urban homes, businesses and schools goes to a wastewater treatment plant. (A small percentage of people have composting toilets and alternative greywater systems.)

    Once we have used water, it must be treated before being returned to the environment. Like water treatment for supply, this process has a cost, and the more water we use in our houses, schools and businesses, the more water there is to treat.

    In rural areas, household wastewater is treated in wastewater treatment systems and septic tanks and disposal fields in the soil.

    Wastewater must be treated to reduce bacteria1, nutrients2 such as phosphate in faeces3 and detergents and nitrogen4 in urine. Nutrients increase the growth of plants in waterways, and this can lead to eutrophication5.

    There are a number of conservation6 measures that we can take in our schools, businesses and homes to help reduce the amount of wastewater.

    Transcript

    DR ELOISE RYAN

    There are many different types of wastewater, especially in the Waikato region. For example, we have geothermal7 wastewater from our geothermal power stations, and that wastewater is hot and full of heavy metals8. So if you put that into a river, it impacts it. The other main source of wastewater in this region is sewage or effluent9. That is treated, but it has an impact as well by increasing nutrients, sediment10 and bacteria in our waterways.

    So a lot of our wastewater or sewage discharge11 companies have permits called resource consents that require them to treat the water, and every year, the technology gets better and better at treating our wastewater. For example, a lot of the wastewater treatment plants now discharge zero bacteria, and technology is improving to remove nutrients such as nitrogen and phosphorus12.

    Acknowledgements

    Dr Eloise Ryan
    Waikato Regional Council
    Footage of Ngatamariki Power Station, Chris Sisarich

    Acknowledgement

    This video has been developed in partnership with the Waikato Regional Council as part of the Rivers and Us resource.

    1. bacteria: (Singular: bacterium) Single-celled microorganisms that have no nucleus.
    2. nutrient: A substance that provides nourishment for growth or metabolism.
    3. faeces: The excreted waste product of digestion in animals – poo.
    4. nitrogen: A non-metal – symbol N, atomic number 7. Nitrogen is essential for life. It is a component of many molecules that make up cells, including DNA and proteins.
    5. eutrophication: A process where waterways, lakes and shallow sea areas receive excess nutrients that stimulate excessive plant or algae growth. This excessive growth depletes the available oxygen in the water and causes other organisms to die off.
    6. conservation: The protection, preservation and careful management of a species, habitat, artifact or taonga.
    7. geothermal: Geothermal energy is energy produced from the heat of the Earth.
    8. heavy metals: Elements that exhibit metallic properties. Often refers to toxic heavy metals that can cause serious illness in organisms. Waste-derived fuels are especially prone to containing toxic heavy metals.
    9. effluent: The outflowing of water from a system – often refers to the discharge of sewage, but can also be natural, for example, the outflowing of a river to the sea. Agricultural effluent refers to the treated and untreated wastewater collected during the management of livestock.
    10. sediments: Material that settles to the bottom of a liquid. In geology, it describes the solid fragments of inorganic or organic material that come from the weathering of rock and are carried and deposited by wind, water or ice.
    11. discharge: 1. The conversion of chemical energy to electric energy. 2. A flowing out or pouring out.
    12. phosphorus: A chemical element with the symbol P and atomic number 15. Phosphorus is essential for life, playing a critical role in cell development and in producing ATP, DNA and lipids in plants and animals.

    Appears in

    INTERACTIVE

    Our use of water – impacts on water quality

    Find out how some of our daily interactions can impact our local waterways.

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      bacteria

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      2. (Singular: bacterium) Single-celled microorganisms that have no nucleus.

      nitrogen

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      3. A non-metal – symbol N, atomic number 7. Nitrogen is essential for life. It is a component of many molecules that make up cells, including DNA and proteins.

      geothermal

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      4. Geothermal energy is energy produced from the heat of the Earth.

      sediments

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      5. Material that settles to the bottom of a liquid. In geology, it describes the solid fragments of inorganic or organic material that come from the weathering of rock and are carried and deposited by wind, water or ice.

      nutrient

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      6. A substance that provides nourishment for growth or metabolism.

      eutrophication

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      7. A process where waterways, lakes and shallow sea areas receive excess nutrients that stimulate excessive plant or algae growth. This excessive growth depletes the available oxygen in the water and causes other organisms to die off.

      heavy metals

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      8. Elements that exhibit metallic properties. Often refers to toxic heavy metals that can cause serious illness in organisms. Waste-derived fuels are especially prone to containing toxic heavy metals.

      discharge

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      9. 1. The conversion of chemical energy to electric energy.

      2. A flowing out or pouring out.

      faeces

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      10. The excreted waste product of digestion in animals – poo.

      conservation

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      11. The protection, preservation and careful management of a species, habitat, artifact or taonga.

      effluent

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      12. The outflowing of water from a system – often refers to the discharge of sewage, but can also be natural, for example, the outflowing of a river to the sea. Agricultural effluent refers to the treated and untreated wastewater collected during the management of livestock.

      phosphorus

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      13. A chemical element with the symbol P and atomic number 15. Phosphorus is essential for life, playing a critical role in cell development and in producing ATP, DNA and lipids in plants and animals.

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