more work in the world must be done on how to reuse water - explain this statement by giving examples
Answers
"Water is a precious resource and if not spent wisely, it will not be long before we have to face crisis.
The world has to come together in this endeavour to reuse water by adopting the following ways:
• Collect rain water and use that for watering your garden. Let the municipal water be.
• Save water from washing vegetables
• Reuse excess water from drinking
"
Wastewater reuse
On-site wastewater reuse can reduce water use in both urban and rural households. At present, most homes use potable (drinkable) water for practically everything in the house and garden.
We are literally flushing our drinking water down the toilet!
The articles Reducing water demand, Rainwater and Outdoor water use also have information on reducing potable water use.
Opportunities to reuse wastewater and regulation of its treatment vary according to where you live. Urban households typically have a connection to a centralised, or reticulated, sewage system, whereas rural households manage their wastewater on site. Check with your local council or state health authority for advice on the regulations in your area.
Two types of wastewater are created in a home: greywater and blackwater.
Greywater is wastewater from non-toilet plumbing fixtures such as showers, basins and taps.
Blackwater is water that has been mixed with waste from the toilet. Because of the potential for contamination by pathogens and grease, water from kitchens and dishwashers should be excluded from greywater and considered as blackwater.
Each wastewater type must be treated differently and can be used in various ways. Greywater is ideal for garden watering, with the appropriate precautions, such as using low or no sodium and phosphorus products and applying the water below the surface. Appropriately treated greywater can also be reused indoors for toilet flushing and clothes washing, both significant water consumers.
Blackwater requires biological or chemical treatment and disinfection before reuse. For single dwellings, treated and disinfected blackwater can be used only outdoors, and often only for subsurface irrigation. Check with your local council or state health department on local requirements.
A diagram of a wastewater reuse system showing greywater feeding out of the bathroom and laundry, being filtered by a coarse filter and surge tank, then through a sand filter with reeds. The greywater then undergoes UV disinfection before being stored in a roof tank for further use in the toilet or outdoors. Excess greywater runs into the sewer or a septic tank.
Advantages of reuse
By using wastewater as a resource rather than a waste product you can:
reduce water bills
use fewer water resources
irrigate the garden during drought or water restrictions
cut down the amount of pollution going into waterways
help save money on new infrastructure for water supplies and wastewater treatment
decrease demand on infrastructure for sewage transport, treatment and disposal, allowing it to work better and last longer.
Disadvantages of reuse
The disadvantages of reusing wastewater also need to be considered. Currently, the main disadvantage for most households is the financial cost of installing and maintaining a reuse system. The attractiveness of the investment would depend on:
the extent of centralised wastewater treatment services available
the price of water in your area (urban) or scarcity of water (rural)
whether you are replacing an existing system or starting from scratch
the length of time you intend to live in your current house
the type of system — annual operating and maintenance costs vary between systems
whether a restriction free, reliable water supply is valuable to you — wastewater reuse is often a much more reliable secondary source of water than common rainwater tank installations (see Rainwater).
If your house is frequently unoccupied for a fortnight or more, for example a holiday home, select carefully to find a reuse system that can cope with intermittent use. Most systems that include biological treatment do not function properly if used intermittently.
Calculating wastewater volume
The table indicates the approximate amount of wastewater produced by one person each day in an average home with Water Efficiency Labelling and Standards (WELS) scheme 3 star rated fixtures (see Reducing water demand).
Wastewater produced in an average home with WELS 3 star rated fixtures
Wastewater type
Wastewater source
L/person/day
Blackwater
Toilet
20
Greywater
Shower
63
Hand basin
6
Washing machine
13
Laundry tap
2
Other wastewater
Kitchen tap
12
Dishwasher
5
Total greywater
84
Total wastewater
121