What are the funtions of water storage facilities?
- Balance between Q_d,max and Q_h,max (fluctuating water quanitites)
- Pressure regulation
- Bridging of operational faults (pipe breakage)
- Provision of a safety reserve
- Provision of extinguishing water
- Settling basin for fine sand and sludge particles (cleaning)
Name distinguishing criteria for the classification of water storage facilites.
- Elevation
- Position in relation to the pipe network
- Type of construction
- Pressure
What are the differences between an elevated tank and a water tower?
Elevated tank (usually below ground level): economical and reliable operation
Water tower (only in unfavorable locations): costs approx. 5 x elevated tank
What are water storage tanks in low position used for?
Lowered/underground tanks are usually suction tanks for pumping stations
Name the different position of wate storage facilites to the pipe network.
- flow-through tank
- counter tank
- central tank
What is the characteristic of a flow-through tank?
Water is only pumped into the water tank
What are the characteristics of a counter tank?
Water is pumped into the water storage tank via the local network
What are the characteristics for a central tank?
Wate storage tank centralized in the local network
What are the advantages and disadvantages of flow-through-tanks?
Advantages:
- Pressure fluctuations in the supply area are minimal
- Water supply is always replaced and thus kept fresh
Disadvantages:
- All water must be raised
- Water only flows into the supply area from one side
What are the advantages and disadvantages of counter tanks?
Advantges:
- Only the water not used in the area needs to be lifted
- Supply to the area from two sides, lower pressure losses
- Greater operational reliability in the event of faults or burst pipes
Disadvantages:
- Greater pressure fluctuations when the tank is filled
- Water replenishment is more difficult
What are the advantages and disadvantages of central tanks?
Advantages
- cheapest and shortest pipe network
- Uniform supply pressure
Disadvantages
- Diddicult to implement
Name the differnt shapes of water towers.
- Cylinder
- Cone
- Cup
- Ellipsoid
- Sphere
Name the different ground plan shaped of unterground tanks.
Rectangular shape:
- Single-chamber tank
- two-chamber tank
Circular shape:
- Single chamber tank
- Three-chamber tank
- Spectacles tank
What are the functions of pressure boosting systems?
- Control (pressure and time-dependent) of pumps (limitation of switching frequency)
- Balancing between inflow and demand quantity
- Pressure increase
How high are the safety reserves in water storage tanks for:
- small WS systems
- up to 500 m³/d
- up to 2000 m³/d?
- small WS systems: generous safety reserves
- 10% of volume
- 6% of volume
What is the rule for extinguishing water reserve and how high are the safety reserves in water storage tanks for:
- Q_d,max <= 2000 m³/d
- up to 500 m³/d
- 500 <= Q_d,max <= 2000 m³/d
- Q_d,max > 2000 m³/d
Rule: Extinguishing wate should be available for 2 hours
- Q_d,max <= 2000 m³/d: Extinguishing water reserve is required
- up to 500 m³/d: 20% of volume
- 500 <= Q_d,max <= 2000 m³/d: See diagramm
- Q_d,max > 2000 m³/d: Extinguising water reserve is not required
What material are most pipes in water supply made of?
Cast iron
What materials are used for pipes?
- gray cast iron (replaced by ductile cast iron)
- ductile cast iron
- steel pipes
- plastic pipes
- fiber cement
What material are most urban drainage systems made of?
Stoneware and Cement
