Lecture 1: Water management in general Flashcards
Water use in private danish households (2019):
101 L/person/day
Total water consumption in DK
172 L/person/day
Mention 5 important aspects/parameters of the water cycle
o Evaporation
o Precipitation
o Vapor transport
o Percolation/ ground water
o Runoff
Explain the catchment approach
Lets say that we have a stream running through an area. This stream is receiving water from several sources in its catchment area; this could be runoff from fields, groundwater discharge, sewer systems etc.
What are the challenges of getting water in and out of a city?
- Proper Infrastructures (pipelines, …)
- Surface sealing
- Collection/storage for rainwater
What technologies do we use to overcome the challenges?
- Drain systems
- Filter/sewage systems
- Pumps system
How does the water use in a city affect the water cycle and the water catchments natural balance?
- The consume of water affects the level/availability of water in the water cycle of the catchment area.
- We don’t take care of what we put down the drains (e.g., food waste and hygienic products)
- Pollutants that might be not treated effectively by WWTPs
Mention the challenges effecting the water resources
1) Water scarcity
o Increasing water use due to increase in world population
o 2 billion people live in areas of water scarcity
o Water availability is changing due to climate change and urbanization.
o Overuse/no management and pollution is also a critical factor to water scarcity.
2) Changing weather
o More extreme weather –> More severe rain events which effects the water resources.
o Droughts –> increasing water stress.
Example: Cape Town: until 1. February 2019: 87 L/person/day. Now it is down to 50 L/person/day.
3) Rising sea level
4) Pollution
o DK has a strategy to protect groundwater from pollution. Pollution has been a major focus since 1970.
o Increasing concentrations of different substances
5) Increasing ground water level
Which initiatives are used for handling the problems about rising sea level?
o Dikes –> protecting build-up areas against floods.
o Fixed barriers around infrastructure
o Elevated quayside in harbors
o High water walls at harbors –> protecting cities from flooding.
o Locks (in danish: sluse) –> The locks can be closed when the sea level reaches a critical level. This is done to minimize the flooding
o Storm surge gate –> ability to close an entire fjord during an storm surge (not sure that this is used in DK)
The amount of rainwater is rising in DK. How can we solve this problem in a private household:
Use rainwater as a substitute for drinking water for purposes other than drinking water
o Simple and logical way to protect the environment
o Saves money
Solutions:
o Rainwater tanks, surfaces or collection from roofs. This water can be used for:
- Laundry
- Toilet flushing
- Garden watering
- Carwash
We are operating with 3 types of wasterwater. Which?
o Domestic wastewater – is generated by the population
o Industrial wastewater – is generated by the industries
o Storm wastewater – is generated by the weather conditions
Explain how wasterwater in general is handled in a danish WWTP
o Firstly, there is a mechanical process to sort out the bigger elements in the waste.
o Secondly the water is moving to a tank where the sludge and gases can be released from the water
o Thirdly a biological cleaning process, removing fat, sand and gravel.
- Bacterial cleaning
o Lastly the water is almost clean but still contains the bacteria cultures that helped cleaning. This is removed in tanks where the sludge falls to the bottom, leaving clean water on top and moved to the last holding and finally released to the environment + other uses
