Greywater Harvesting: A Novel Way To Conserve Water
Walk into the restroom of one of the upmarket malls in Delhi, you come across a board which tells you to not feel disgusted if you see yellow water the moment you flush because it is treated and reused water. Known as greywater harvesting, the waste water generated from cleaning utensils, bathing and washing clothes is treated and reused. After rainwater harvesting, greywater harvesting is fast catching up among urban dwellers.
What is greywater?
Greywater is the waste water generated by households and commercial set-ups sans the faecal contamination. For instance, the water used for cleaning utensils, bathing and washing clothes can be termed as greywater. When compared with the other domestic wastewater, greywater can be easily treated and reused because it has less pathogens, hence, less contaminated.
This kind of used water makes up for 50-70 per cent of the released by a household. Once recycled, it can save an average of 50 litres of potable water per family per day.
What are the uses of greywater?
Greywater, when treated, can be used for:
- Toilet flushing
- Watering plants (both food and non-food plants)
- Cleaning cars
What are the benefits of re-use?
- It helps conserve fresh water because this water can be used for other household activities which consume the maximum water.
- It also cuts down on water bills.
- It reduces the amount of wastewater that enters the sewage system.
How is greywater treated?
There are various ways in which greywater can be treated. These range from a makeshift household system to technologically sophisticated systems. There are a few ways in which you can treat or use waste water without much effort.
- Direct-use system: Here you don't have to treat water but ensure that you use the waste water in no time. For example, if you have a huge garden, just connect the pipe to the external waste pipe and use the water quickly, on a daily basis, because untreated water breeds harmful bacteria. This kind of system is best suited if you have a huge garden to maintain and it consumes a fair amount for water. Make sure you do not use this on watering food plants. Only, treated water is suitable for food plants.
- Sand filter method: Create a four-soil-layer makeshift system and pour the water on the soil and let the water seep into the soil. The upper layer of soil is known to filter the heavy particles from the water and let the water percolate deep down. Make sure the first layer of soil is humus-rich top soil which should be two-feet deep. This should be followed by fine building sand, then course sand and the pea-shingle as the final layer. Pea-shingle ensures smooth drainage of water after passing through four layers.
- You can also install a sceptic tank at home. Once waste water is passed through this tank, the sand filter method can be put to use.